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Review

Enhancing Industrial Processes Through Augmented Reality: A Scoping Review

1
Carrera de Ingeniería en Tecnologías de la Información, Facultad de Ingeniería, Industria y Producción, Universidad Indoamérica, Ambato 180103, Ecuador
2
Facultad de Ciencias de la Ingeniería y Aplicadas, Universidad Técnica de Cotopaxi (UTC), Campus La Matriz, Ave. Simón Rodríguez, Latacunga 050102, Ecuador
3
Facultad de Ingeniería en Sistemas, Electrónica e Industrial, Universidad Técnica de Ambato, Av. los Chásquis, Ambato 180104, Ecuador
*
Author to whom correspondence should be addressed.
Future Internet 2025, 17(8), 358; https://doi.org/10.3390/fi17080358
Submission received: 21 May 2025 / Revised: 16 July 2025 / Accepted: 21 July 2025 / Published: 7 August 2025
(This article belongs to the Special Issue Machine Learning and Internet of Things in Industry 4.0)

Abstract

Augmented reality (AR) in industry improves training and technical assistance by overlaying digital information on real environments, facilitating the visualisation and understanding of complex processes. It also enables more effective remote collaboration, optimising problem solving and decision making in real time. This paper proposes a scoping review, using PRISMA guidelines, on the optimisation of industrial processes through the application of AR. The objectives of this study included characterising successful implementations of AR in various industrial processes, comparing different hardware, graphics engines, associated costs, and determining the percentage of optimisation achieved through AR. The databases included were Scopus, SpringerLink, IEEExplore, and MDPI. Eligibility criteria were defined as English-language articles published between 2019 and 2024 that provide significant contributions to AR applications in engineering. The Cochrane method was used to assess bias. The rigorous selection process resulted in the inclusion of 38 articles. Key findings indicate that AR reduces errors and execution times, improves efficiency and productivity, and optimises training and maintenance processes, leading to cost savings and quality improvement. Unity 3D is the most widely used graphics engine for AR applications. The main applications of AR are in maintenance, assembly, training and inspection, with maintenance being the most researched area. Challenges include the learning curve, high initial costs, and hardware limitations.

1. Introduction

The optimisation of industrial processes in today’s increasingly digitalised and globalised business world demands that companies and industries implement innovative strategies to maintain their competitiveness among manufacturers, nationally and internationally, to ensure their permanence in the global market. In this context, business competitiveness is enhanced not only through traditional cost reduction, but also by adopting an organisational approach that fosters innovation and ensures long-term competitiveness to devise new ways to improve customer satisfaction [1,2,3]. This is why continuous improvement has become a crucial objective for companies seeking to improve their efficiency, productivity and competitiveness in the market. This need arises in a context of constant technological evolution and global competition, where companies must adapt to maximise their operational performance and meet market demands; therefore, the optimisation of industrial processes is vital for its ability to improve the use of resources, reduce costs, minimise production times and increase the quality of products or services offered.
Today, the concept of Industry 4.0 represents a new paradigm for organising the manufacturing process, characterised by increasing levels of digitisation and automation capable of driving the digital transformation of industries towards so-called smart factories [4]. Indeed, implementing smart production is of paramount importance to meet the demands of rapidly growing consumers in the global market to achieve high productivity and provide high-quality products at reduced cost and time. In this context, the application of emerging technologies such as augmented reality (AR) as part of Industry 4.0 emerges as a promising technology that offers potential benefits in terms of process improvement and decision making, and has emerged as a promising tool to drive these continuous improvement efforts in optimising industrial processes [5]. Modern AR technology applies virtual information to the real world through computer technologies: the real environment and virtual objects are superimposed on the same image or space in real time.
Similarly, AR has been found to be particularly beneficial for maintenance, training, assembly and inspection and quality control activities [6]. When it comes to the latter, the value and benefits of AR technologies become more evident as the complexity of the elements and assemblies to be inspected increases and AR offers a variety of applications that can revolutionise the way industrial processes are managed and improved.
However, despite the growing interest in AR technology in industrial processes, there is a lack of comprehensive understanding of how this technology can be effectively employed to optimise specific processes in different industrial sectors [7,8]. The purpose of this systematic review is to provide a clear and updated perspective on the successful application of AR in industrial processes. The review identified that studies focusing on the optimisation of industrial processes through the use of AR remain limited.
Therefore, this analysis examines different articles using the PRISMA methodology to better understand the impact and potential of AR in the optimisation of industrial processes. This is achieved through an analytical reading of publications to identify the specific industrial processes where AR has been successfully implemented. Finally, the review determines the degree of optimisation achieved through a quantitative analysis.
A systematic review of the optimisation of industrial processes through the application of AR is based on several essential reasons. Firstly, industry is undergoing a rapid transformation driven by technological advances, and AR is positioned as a promising tool to improve efficiency and productivity in industrial processes [9,10]. However, despite the growing interest in this technology, there is still a lack of complete understanding of how it can be effectively applied to optimise specific industrial processes. Therefore, a systematic review provides a comprehensive assessment of the existing research in this field. Furthermore, given the potential economic and competitive impact of implementing this technology in industry, it is crucial to have a solid and reliable evidence base to support strategic decisions and facilitate the effective adoption of this technology; thus, this project has significant theoretical, methodological and practical value.
Theoretically, it will contribute to the advancement of knowledge by synthesising and critically analysing the existing literature on the application of AR in industry. Methodologically, the use of the PRISMA methodology will ensure a systematic and rigorous review of the existing literature on the application of AR in industry [11], setting a high benchmark for future research in this field, and in practice, the results will provide clear and applicable guidelines for the implementation of AR in industrial processes, helping companies to improve their operational efficiency within their industrial processes.

2. Methodology

The methodology proposed for the systematic literature review is based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. This research strictly follows the PRISMA guidelines, which aim to help authors of systematic reviews to generate a bias-free document of high scientific quality. In its latest version, published in 2020, PRISMA incorporates significant methodological advances in the classification, selection and summarisation of studies, ensuring a more rigorous and transparent review process [11]. In the 2020 statement, it reflects the methodological advances in the classification, selection and summarisation of the different studies.
To achieve this, relevant studies addressing the implementation of AR in the industrial domain were collected. Subsequently, a detailed quantitative analysis was carried out, focusing on the collection and evaluation of numerical data obtained from these studies. This analysis determined the percentage of optimisation achieved in industrial processes thanks to the implementation of AR. By examining key performance indicators, such as operational efficiency, error reduction and time savings, a comprehensive view of the benefits and limitations of this technology in the industrial sector was provided. This methodology not only facilitated an in-depth understanding of current impacts, but also identified potential areas for future research and practical applications.

2.1. Research Questions

Four research questions were posed with the purpose of understanding the importance of implementing AR technology in different industrial processes. Through these questions, we aim to provide a comprehensive and informed understanding of the potential and limitations of AR in the industrial sector, thus supporting informed decisions on its adoption and optimisation in various applications. See Table 1 for a detailed summary of these questions and the rationale behind them.

2.2. Document Search

According to [12], it is recommended that, to achieve a maximum count, searches in systematic reviews should include a combination of databases and publishers. To ensure adequate search performance (i.e., count, precision and number needed to read), we assume that literature searches for a systematic review should be conducted through at least a combination of four databases. The combination of four databases improves both the sensitivity and precision of the search process, ensuring that relevant studies are not missed and that screening efforts are optimised. Therefore, the following sources of information were chosen: Scopus, an extensive citation and abstract database covering a wide range of global and regional scientific journals, conferences and books, with a strict selection process to ensure data quality and relevance; SpringerLink, a renowned scientific platform offering high-quality content to academic researchers, scientific institutions and companies, providing access to a vast collection of books, journal articles and conference papers; MDPI (Multidisciplinary Digital Publishing Institute), a leading open access publishing institute, known for its article processing fee-based business model, which guarantees the rapid publication of peer-reviewed research and ensures unrestricted global accessibility and dissemination of scientific results; and IEEE Xplore, a relevant source of information that provides access to the technical and scientific literature published by the Institute of Electrical and Electronics Engineers (IEEE), including journal articles, conference proceedings, technical standards and other important documents, and which is an essential reference for researchers and practitioners in the fields of engineering, computer science and related technologies.
The choice of these information sources ensures a comprehensive and high quality coverage of the relevant literature, allowing for a rigorous and well-founded systematic review of the implementation of AR in industrial processes [13,14,15]. First, a search for articles in databases from 2019 to 2024 was conducted. This time interval was chosen because the implementation of AR in industrial processes has advanced exponentially in recent years, so it was considered that selecting articles from 2019 to 2024 was an appropriate period to analyse the applications, advantages and disadvantages of AR in industry [16].
This temporal approach allows capturing the most recent and relevant developments in the field. The search for documents in the various databases was carried out by entering the following combination of specific terms: (‘augmented reality’) AND (‘industry’ OR ‘industrial process’ OR ‘manufacturing’ OR ‘production’ OR ‘Industrial’) AND (‘optimization’ OR ‘ Enhancement’ OR ‘ Improvement’ OR ‘Maximization’). These keywords are directly related to the research questions, taking into account that the focus of the systematic review corresponds to the applications of AR in industrial processes. This article search and selection process is essential to ensure that the systematic review includes relevant and high-quality studies that provide a comprehensive understanding of the implications and benefits of AR in industrial processes.

2.3. Paper Selection

For the selection of articles, we used the PRISMA methodology flowchart, which allows us to represent the information through the different phases of a systematic review. This includes the number of records identified, the articles included and excluded, as well as the reasons for exclusions. This diagram was divided into three phases: identification, selection and inclusion. In the identification phase, 437 articles were found in the four databases and publishers; in the first step of this phase, 23 duplicate articles were found of which 414 articles were left for the selection phase. In this phase, as a first step, 306 articles were eliminated according to the reading of titles and abstracts; then, as a second step of the selection phase, the 108 articles were analysed to eliminate 25 according to the eligibility criteria indicated in Table 2.
In addition, as the third step of the selection phase, the remaining 83 articles were screened to eliminate 37 articles according to their relevance and perspective. Subsequently, 46 full articles were assessed for eligibility. Of these, three articles were excluded because they did not meet the appropriate study type for the purposes of the review. Then, using a ‘Cochrane risk of bias’ analysis, which refers to the possibility that the results of a study in a systematic review are distorted due to certain factors, we assessed the potential biases in the included studies. This rigorous selection process ensures the quality and reliability of the studies included in the systematic review. The seven bias domains were adapted to the review to five domains by the investigators [17]. These domains were:
  • D1. Inclusion criteria bias: Inaccuracy of selection criteria will lead to bias [18]: According to the research objective, this article clearly delimits the topic of study and the type of literature review approach, thus establishing the keywords to be searched for. Criteria, such as period and search language, are established to control any potential bias. In this domain, it was decided to include articles that despite not being within the established time period are of high relevance to the research.
  • D2. Data completeness bias: This refers to the completeness and accuracy of the data collected during the assessment of industrial processes and whether methods were applied to ensure the objectivity and validity of the results.
  • D3. Methodological quality bias: To assess the methodological quality of the studies included in the review, considering aspects such as study design, sample size, blinding and other elements that may influence the validity of the results, specifically in the context of AR in industrial processes.
  • D4. Evidence synthesis: Synthesising the results of the studies included in the review in a transparent and objective manner, considering the risk of bias in the interpretation of the results. This involves careful assessment of consistency and heterogeneity among studies, as well as consideration of possible bias in the interpretation of results. It allows the identification of all the components necessary to judge the risk of bias in reporting to improve the credibility of evidence syntheses.
  • D5. Researcher experience bias: Allows the identification of whether he or she or the authors consciously or unconsciously influence the results of the study, either in the design of the study or the interpretation of the data, which may affect the validity of the results.
Using the Risk of Bias web application, designed to visualise risk of bias assessments made as part of a systematic review, a “Traffic Light Plot” graph of the domain-level judgments was produced for each individual article (see Figure 1), which provides a clear visual representation of the risk of bias. In addition, this tool allows the generation of weighted bar charts showing the distribution of risk-of-bias judgments within each domain, as shown in Figure 2, which facilitates a more detailed and accurate understanding of how risk of bias has been assessed for each aspect of the studies reviewed. These visualisations help reviewers and readers to effectively interpret and communicate the results of the risk of bias assessment, thus facilitating informed research decision-making.
At this stage of elimination, due to risk of bias, five articles were eliminated due to their high level of risk, since their results could have been distorted. However, two of them presented some minor concerns as they were outside the CE3, although it was still decided to include them in the research due to their relevance to the topic under study. After a rigorous selection of the articles, 38 were selected for the research at the inclusion phase, as shown in Figure 3, thus representing a robust and adequate set of studies for the analysis and interpretation of the results.

3. Results

Literature Review

Appendix A presents a compilation of various applications of AR in different industrial processes. Each entry includes the title of the article, a description of the industrial process in question, how AR was implemented, as well as the benefits and limitations observed. This information provides a comprehensive overview of the advantages and challenges associated with the use of AR for industrial process optimisation.
AR is applied in a wide variety of industrial processes to improve the efficiency, accuracy and safety of operations. In the field of maintenance, it facilitates the visualisation of procedures and interactive guides that help technicians perform complex tasks with greater precision. For example, in the maintenance of industrial robots and injection moulds, it provides visual instructions that guide the disassembly and assembly of components, improving accuracy and reducing operating time. In the assembly area, AR is used to superimpose visual instructions directly on the operator’s work environment. This includes text, videos and 3D animations that guide workers through the various stages of assembly, improving the accuracy and efficiency of the process. The implementation of AR in the manufacturing and inspection of parts allows for easy comparison of the CAD design with the actual parts and adjustment of the transparency of the 3D representations to avoid confusion.
In logistics and warehouse management, AR is applied to optimise order picking. Systems such as RASPICK use head-mounted devices that display item lists and guide pickers to the correct locations in the warehouse. It also facilitates the identification of storage locations and verification of required parts, improving accuracy and reducing search time. It plays a crucial role in worker training and education. In engine assembly and critical component repair, AR allows students to interact with virtual components in a physical environment, improving understanding and execution of complex tasks. Furthermore, in firefighting training, it provides a comprehensive and realistic training experience, combining the real and virtual worlds to improve operator readiness.
In the quality control process, AR is used to guide inspectors during the visual inspection of welds and other components by overlaying digital information directly on the physical parts. This allows inspectors to quickly compare welds to ideal standards and detect potential defects more efficiently. Finally, in the maintenance of infrastructure such as roads and bus fleets, it improves safety and operational efficiency. It provides real-time visualisations, interactive instruction and human–robot collaboration, reducing risk exposure and improving accuracy and speed of task execution.
Appendix B presents a compilation of AR hardware along with their approximate costs in U.S. dollars and the graphics engine used. This information provides a comparative view of the options available on the market, facilitating the evaluation of AR technologies according to their technical and economic characteristics.
The most widely used hardware for augmented reality applications in industrial processes includes smartphones and tablets, mainly due to their wide availability and affordable price range. HoloLens integrated with ISO14644-14 [19] also stands out as an advanced and specialised option, especially in industrial and professional environments, despite its higher cost. Other hardware such as Vuzix M400 and Epson MOVERIO BT-300 are also popular in specific niches due to their specialised features.
Analysis of the column diagram in the Figure 4 data reveals that HMDs (head-mounted displays) are the most widely used hardware in AR applications in the identified processes, with a total of 21 units. This is due to their ability to deliver immersive and hands-free experiences, making them ideal for a wide range of AR applications. HHDs (hand-held devices) also have a high usage rate, highlighting their popularity and versatility. Hardware such as cameras, monitors, laptops and projectors have a more specific and limited use, but are still important in certain AR contexts. In terms of graphics engines, Unity 3D is the most widely used due to its versatility and ability to support multiple SDKs, such as Vuforia, ARCore and the Mixed-Reality Toolkit (MRTK). This allows developers to create robust and functional applications for a variety of hardware. Other graphics engines and SDKs are also used, albeit to a lesser extent, for specific applications that require particular capabilities.
Appendix C presents an analysis of the impact of AR implementation in industrial processes. It compares the state before and after the adoption of AR, highlighting the percentage of optimisation achieved. This information provides a clear view of the quantitative benefits that AR can bring to efficiency and productivity in industrial environments.
The results show the significant benefits of applying AR in various industrial processes. The implementation of AR has shown a remarkable reduction in task execution time. For example, a reduction in design time by 45.22% and assembly by 25% was observed. Item collection time decreased by 9% for 10-item lists and 12.55% for 20-item lists. For inspection and documentation, inspection time was reduced by as much as 50 percent and fault documentation time by 66 percent. In addition, training and maintenance also showed significant reductions, with training time decreasing by 75 percent and maintenance time decreasing by 46 percent.
Productivity and efficiency also improved significantly with AR. Trainer productivity increased by 10 percent by reducing interruptions during work. Efficiency in both simple and complex tasks increased, with task completion time reduced by 30.31% through the use of HMD hardware. Additionally, the efficiency of disc brake system maintenance increased by 32.53%. Work quality also benefited, reducing the duration of the quality control process by 24.63% for expert operators and 49.08% for non-expert operators. Error reduction is another significant benefit of AR implementation. A 32.35% decrease in errors during spindle assembly and an 81.08% reduction in errors during assembly with AR warnings were observed. In addition, spot-weld accuracy increased by 52%, improving the accuracy of the work performed. Product quality also improved with AR, with product porosity reduced by 14.94% over previous studies, indicating an improvement in final product quality. In terms of costs, maintenance personnel costs per vehicle were reduced by 0.32%, representing a small but significant reduction in operating costs. Optimisation in inspection and repair processes also benefited from AR. The inspection time of highway structures was reduced by 78% and the repair of compressors with an AR MARMA system showed a reduction in repair time by 30%. Thus, it is demonstrated that applying AR in industrial processes provides remarkable benefits, including reduced task execution time, improved productivity and efficiency, reduced errors, improved product quality, and cost savings. These benefits are reflected in an overall optimisation of operational performance and increased efficiency in performing critical tasks in the industrial environment.

4. Discussion

Research Questions

The 38 articles selected above contain sufficient information to make a scientific judgment regarding the optimisation of industrial processes through the application of AR. The questions posed in Section 2 are answered below.
RQ1: Implementing AR in industrial processes offers a wide range of benefits that contribute to the optimisation and efficiency of operations. These benefits include error and time reduction [20,21], as AR enables error identification and avoidance, significantly reducing the error rate in tasks such as assembly [22] and inspection. In addition, task execution times are significantly reduced, as seen in the reduction in design and assembly time, and in the completion of maintenance tasks. AR also contributes to increased efficiency and productivity. This technology helps operators understand design procedures by overlaying virtual information and instructions on the real environment, facilitating the completion of complex tasks. The system allows both hands of the picker to remain free and reduces cognitive load, thus improving work efficiency and productivity. In terms of training, AR allows training to be conducted in a dedicated environment, minimising disruption to daily operations and improving overall efficiency.
In addition, it enables accurate and guided visualisation of procedures, reducing human error and accelerating the learning process. Maintenance optimisation is another key benefit [23,24]. The adaptive mode of AR enables users to recognise faults faster and with fewer movements, improving efficiency and reducing downtime. AR provides contextual and meaningful information automatically, enabling faster and more efficient maintenance of equipment. Improved work and product quality is evident with the use of AR, as accuracy in tasks such as welding and quality control is increased, reducing variability and improving quality standards. AR also reduces the need for additional communications between workers, streamlining the process of video annotation and other documentation procedures. In terms of cost reduction, early detection of errors during assembly through AR prevents major problems, significantly reducing repair and rework costs.
AR offers opportunities for continuous performance improvement, which can lead to significant savings in long-term operating costs. AR also facilitates improved communication and data management with online databases, allowing real-time access, editing and sharing. Similarly, AR provides a 3D visual representation of components and processes, which improves understanding and accuracy in the execution of tasks. Finally, AR increases safety by generating visual signals that warn workers of hazards in their environment, improving safety and reducing the risk of accidents. In addition, it provides a safe and controlled training environment, where users can practise emergency situations without real risks.
RQ2: The most widely used graphics engine for developing AR systems is Unity 3D [20,25,26]. Unity 3D is a widely used graphics engine for developing AR applications in video games, simulations and interactive 2D and 3D experiences. Developed by Unity Technologies, this engine allows developers to create visually stunning and highly interactive content efficiently. One of its main advantages is its ease of use, thanks to its intuitive interface and extensive library of resources and tools that facilitate the creation of graphics and the programming of behaviors. Unity 3D supports multiple platforms, allowing developers to launch their applications on operating systems such as Windows, macOS, iOS, Android, and video game consoles, among others.
The Unity 3D graphics engine is a complete development platform that provides the tools and environment necessary to create, design and run interactive and visual applications. A graphics engine includes capabilities for handling graphics, physics, audio, animations, artificial intelligence, and other essential components for application development. On the other hand, an SDK (software development kit) is a set of tools and libraries that allow developers to integrate specific functionalities into their applications. SDKs are not complete development platforms, but add-ons that are added to a graphics engine or other development environment to provide additional capabilities.
RQ3: AR is emerging as a valuable technology in a variety of industrial processes. Its ability to provide visual information and interactive guidance is revolutionising the way tasks are performed in various industrial processes. In Figure 5 an analysis is presented based on the research of the number of industrial processes where AR is applied, supported by the existing literature.
After interpreting the data provided, the industrial processes in which it is highly recommended to implement AR are as follows: maintenance, assembly, training/coaching and inspection. These processes have been supported by a larger number of articles, suggesting that the implementation of AR in these areas has been widely researched and considered beneficial. Other processes can also benefit from AR, but further evaluation based on specific needs and use cases is recommended.
AR is most widely used in the maintenance process due to a combination of unique advantages that this technology offers to improve efficiency, accuracy and safety in various maintenance tasks [27,28,29,30]. AR provides 3D animated instructions directly on the object or work area, making procedures easier to understand and reducing the possibility of errors. Technicians can receive remote assistance from expert engineers via HMD devices, transmitting live video of the work environment and receiving annotations and AR content superimposed on their field of view, which is especially useful in workshops where the physical presence of the expert is not necessary. In rail vehicle maintenance, AR is used to develop training content that visualises procedures in a 3D space, improving operator understanding and competence.
RQ4: Implementing AR in industrial processes comes with a number of challenges and limitations that must be considered. One of the main obstacles is the learning curve associated with the technology. Operators and designers may need time and training to become familiar with the tools and techniques required to use the system effectively [31,32]. In addition, the portable hardware used in AR requires significant computational power, which can be a technical challenge. Another important limitation is the initial cost of implementation is high, requiring significant investments in specialised hardware and software development tailored to the specific needs of each process. In addition, the narrow field of view of hardware such as HoloLens can limit the amount of information visible simultaneously, making it difficult to fully perceive fault icons in some situations.
The initial installation and configuration of infrastructure such as wireless sensor networks (WSNs) for real-time monitoring can be costly [33,34]. The creation of interactive 3D models and the implementation of AR technologies require a significant investment in time and money, which can be a barrier for some companies. The effectiveness of AR also depends on the quality and compatibility of the hardware used, which can result in additional costs for companies wishing to implement this technology. The AR system requires ongoing maintenance and upgrades to ensure optimal performance, which can demand additional resources and time. In addition, there may be resistance to change from workers and stakeholders accustomed to traditional methods, which may hinder the adoption of new technologies. Insufficient lighting and high dust can slow down and complicate initialisation and monitoring in the process. Implementing AR and motion capture systems is also costly, including hardware, software, and personnel training.
Lighting conditions can affect display stability, which can be problematic in industrial environments. In addition, some workers, especially those with little familiarity with the technology, may tend to ignore screen-based AR, suggesting that while AR is powerful, it requires time and training for users to become accustomed to its use [31,35]. While AR can improve the user experience once mastered, it may require additional time and training for workers to become familiar with the technology and learn to use it effectively, which can delay adoption and initial benefits. Reliance on advanced technology infrastructure, including HMD hardware and stable, high-speed network connections, can be a challenge in technology-constrained industrial environments.
Implementing AR systems can be costly and requires workers to adapt to new work methods, which could lead to resistance or an initial learning curve. The need for calibration and ongoing maintenance of projection systems to ensure that visual cues are accurate and correctly aligned with panels requires additional resources and time. In addition, potential ergonomic discomfort and visibility issues with HMD hardware, especially in low light conditions, may hinder prolonged use and negatively affect the user experience.

5. Conclusions

A systematic review was carried out applying the PRISMA methodology to ensure rigor and transparency in the selection of studies, comprehensively evaluating the effectiveness of AR in the optimisation of industrial processes. The findings reveal that the implementation of AR has generated significant benefits in several industrial areas. Among the main benefits are substantial reductions in task execution times, improvements in operational efficiency and productivity, as well as a notable decrease in errors during process execution, contributing to a substantial improvement in the quality of the final product and a reduction in long-term operating costs.
The industrial processes recommended for the implementation of AR include maintenance, assembly, training, and inspection, areas that have proven to benefit widely according to the researched literature. In terms of technology used, the most prevalent hardware is HoloLens HMDs, followed by HHDs smartphones and tablets. Unity 3D has emerged as the leading graphics engine for AR application development, thanks to its versatility and compatibility with multiple SDKs such as Vuforia and ARCore. Despite the benefits described above, AR implementation faces significant challenges such as the learning curve, which requires extensive training for operators, users and designers. In addition, the high upfront costs of AR acquisition and infrastructure, including advanced hardware and supporting networks, represent a considerable financial barrier for many organisations.

Author Contributions

Writing—review and editing, A.M., J.E.N., A.M.V. and M.V.G.; conceptualisation, J.E.N. and A.M.V.; methodology, J.E.N.; software, A.M.V.; validation, J.E.N. and M.V.G.; formal analysis, J.E.N.; investigation, J.E.N. and A.M.V.; resources, A.M.V.; data curation, J.E.N. and P.A.; writing—original draft preparation, A.M.V.; visualisation, A.M.V.; supervision, M.V.G.; project administration, J.E.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Data are contained within the article.

Acknowledgments

The authors would like to express their gratitude to the research network INTELIA, supported by REDU, for their valuable assistance throughout the course of this work. Additionally, we would like to thank the Indoamerica Technological University for its support in the research processes.

Conflicts of Interest

The authors declare no conflicts of interest.

Appendix A. Application of AR in Industrial Processes

Table A1. Application of AR in industrial processes.
Table A1. Application of AR in industrial processes.
TitleProcessAR DescriptionBenefitsLimitations
A Multi-User Collaborative AR System for Industrial Applications [25]DesignMucsys is a system that provides AR services for various industrial processes through three collaborative components: Mucstudio, which generates scenes; Mucview, which offers AR experiences through camera tracking for collision detection, object editing, data loading, annotation editing and virtual object rendering; and Muccserver, which manages databases and collaborative services. In CNC cutting design, Mucsys allows transforming the CAD model of the cutting head to the “obj” format for visualisation and determines the relative position between the cutting head and the marker. The sensor data are linked to the cutting head model, and the designer prints and places the marker in the corresponding location using Mucstudio. Finally, to verify the design of the model, Mucview represents the virtual CAD model on the real machineThe AR system can identify and avoid errors, reduce time and costs, and reduce the number of physical prototypes through AR technology. This technology efficiently helps operators understand design procedures by superimposing virtual information and instructions on the
real environment.
The main difficulty in implementing the system lies in the learning curve in which operators and designers may need time and training to become familiar with the tools and techniques necessary to use the
system effectively.
A Smart Factory in a Smart City: Virtual and Augmented Realityin a Smart Assembly Line [20]Maintenance and
assembly
AR makes it possible to provide 3D animated instructions that help workers perform assembly and maintenance tasks by projecting information directly onto the workplace using a projector installed above the task. This technique allows instructions to be displayed directly on the object or work area allowing operators to perform the process effectively.Significant reduction in the
error rate. Reduction in task
completion times.
Portable devices require too
much computational power.
An Augmented Reality Assisted Order-Picking System using IoT [36]Order preparationThe RASPICK system has two components: a head-mounted AR device and a web-based warehouse management system. The picker sets up the device, which connects to Wi-Fi and downloads a list of items to be picked. The device displays a list of items to pick along with the required quantity of each. The picker uses the information provided by the device to find the aisle corresponding to the item, identified by an assigned letter displayed on the device’s screen. Once the picker locates the correct aisle, it touches a touch sensor on the side of the device to receive the container number where the item is located. The device guides the picker to the correct aisle and container, displaying the required quantity of each item. The picker scans the QR code of the picked item, and the system confirms the pickup. This process is repeated until the pick list is complete.The system also reduces the picker’s overall cognitive load, allowing the picker to be more efficient in their work.The system cannot map the most efficient picking sequence so that the picker spends the least amount of time to travel on his or her picking trips.
An Augmented Reality System for Operator Training in the Footwear Sector [33]TrainingThe system uses Microsoft HoloLens smart glasses, allowing users to interact with both virtual and real-world elements. The software architecture comprises three layers: interface, management and data. The interface layer allows learners and users to access training content through an intuitive interface, using voice commands or gestures. The management layer allows administrators and trainers to organise and manage training activities, user groups and training materials, ensuring an efficient and effective training process that minimises interference with daily production activities.Training can be conducted in a dedicated environment, minimising disruption to daily production operations and improving overall efficiency.The high initial cost of implementing AR systems requires significant investments in specialised hardware and software development tailored to the specific needs of each process.
An Augmented Reality System to Support Fault Visualisation in Industrial Robotic Tasks [37]Fault man-agement and diagnosticsAR is applied in the process of diagnosing and managing faults in industrial robots. Using the Microsoft HoloLens device, an adaptive AR system was developed that displays 3D virtual metaphors in real time, close to the location of the robot fault. This dynamic visualisation allows technicians to quickly identify problems, as fault icons are positioned so that they are always visible and not hidden by the manipulator.The adaptive AR mode allows users to recognise faults faster and with fewer movements, improving efficiency and reducing robot downtime.The narrow field of view of the HoloLens device may limit the amount of information simultaneously visible, which may make it difficult to fully perceive fault icons in some situations.
An Intelligent Product Service System for Adaptive Maintenance of Engineered-to-Order Manufactur-ing Equipment Assisted by Augmented Reality [34]Inspection and maintenanceIn injection mould maintenance and inspection, AR is used to provide interactive instructions during the maintenance process. This includes visual guides for component assembly and disassembly, as well as inspection tests facilitated by implemented precedence algorithms. Technicians can access these AR instructions through devices equipped with unique QR codes, which allow the visualisation of mould status through a colour-coding system (green, yellow and red), indicating the condition of components quickly and clearly.AR enables accurate and guided visualisation of procedures, which can reduce human error and increase the efficiency of the maintenance process.The initial implementation of AR systems can be costly, especially the installation and configuration of infrastructure such as wireless sensor networks (WSNs) for real-time monitoring.
ARiana: Augmented Reality Based In Situ Annotation of Assembly Videos [38]MaintenanceARiana, a portable augmented reality-based in situ video annotation tool that guides field experts to create annotations efficiently while performing assembly or maintenance tasks. Ariana has three key features, including context awareness enabled by hand-object interaction, multimodal interaction for on-the-fly annotation, and real-time audiovisual guidance enabled by edge download.It reduces the need for additional communications between field workers and annotators, thus improving the efficiency of the video annotation process.Creating interactive 3D models and implementing AR technologies can be costly and require a significant investment in time and money.
Assessing user performance in augmented reality assembly guidance for industry 4.0 operators [39]Mounting-assemblyIn the assembly process, AR is effectively applied through a guidance tool that provides users with a detailed, real-time virtual visualisation of assembly procedures. This enables workers to perform tasks with greater accuracy and efficiency, regardless of their level of prior experience. AR facilitates an intuitive understanding of component position and orientation, reduces ambiguity and improves coordination between physical actions and visual instructions.AR has the potential to improve assembly performance by reducing errors and the time required for assembly tasks, ensuring a very low mental workload.The effectiveness of AR may depend significantly on the quality and compatibility of the hardware devices used, which may result in additional costs for companies or individual users wishing to implement this technology.
Assessment of Augmented Reality in Manual Wiring Production Process with Use of Mobile AR Glasses [40]Mounting-assemblyThe AR system developed for the cable assembly and production process in control cabinets has proven to be an effective assistive device. This system, equipped with AR glasses, works online by identifying elements in the environment and providing meaningful support to the operator on the assembly line. By automatically recognising units and providing appropriate data, the system facilitates the wiring of control cabinets, improving the efficiency and accuracy of the process.The AR system reduces downtime in case of failure. This is achieved by providing contextual and meaningful information automatically at hand, enabling faster and more efficient maintenance of control cabinets.The implementation of augmented reality systems involves a significant upfront cost in terms of hardware and software development.
Augmented Reality for Industrial Quality Inspection: An Experiment Assessing Task Performance and Human Factors [41]Inspection and quality controlThe application of AR in this context focuses on optimising industrial quality inspection using HMD (head-mounted display) HoloLens 2. Using 3D models and 2D images, AR makes it possible to detect and highlight possible defects in physical products by means of visual signals projected directly onto the inspected object. The AR system not only facilitates accurate product tracking in real time, automatically adjusting to movements and turns, but also improves efficiency by clearly grouping and visualising problem areas. With support for multimodal interaction, this innovative approach not only increases accuracy in defect detection, but also streamlines the inspection process, thus improving final product quality and operational efficiency in industrial environments.Using an AR HMD for industrial quality control can significantly reduce task completion time, as well as the number of task errorsImplementing AR systems involves a significant upfront cost in terms of hardware and software development. This can be a barrier for companies that are not willing to make a high initial investment.
Augmented Reality System and Maintenance of Oil Pumps [21]MaintenanceAR is effectively employed in pump maintenance through interactive visualisation of procedures. In the study, a physical model of an oil transfer demonstration unit including Grundfos vertical electric vertical centrifugal pumps was used. AR facilitates the creation of algorithms for disassembly and assembly of pumps, thus optimising maintenance procedures, which streamlines maintenance processes by providing accurate and guided visualisations, but also contributes to the standardisation and continuous improvement of processes.Reduction in the time required to perform maintenance. This is achieved through guided visualisation of the necessary actions, which optimises the process and minimises errors.While AR can improve the user experience once mastered, it may require additional time and training for workers to become familiar with the technology and learn how to use it effectively.
Augmented Reality-Assisted Deep Reinforcement Learning-Based Model towards Industrial Training and Maintenance for NanodropSpectrophotometer [42]Maintenance and trainingThe proposed system uses a model based on deep reinforcement learning assisted by AR. This involves using a machine learning model to help guide workers during maintenance and training tasks. AR is integrated with this model to provide clear and easily understandable instructions for maintenance operators using their devices.The process starts with scanning an image or model of the target object. Features are then extracted and compared to determine its position and orientation in the environment. This is combined with the operator’s action to generate a 3D visualisation on the device’s display. The reinforcement learning algorithm is used to improve the localisation and tracking of objects in the system.Improves process efficiency and reduces costs for training and industrial maintenance. The system offers opportunities for continuous performance improvement that can lead to significant improvements in system performance over time.The system will require ongoing maintenance and upgrades to ensure optimal performance, which may require additional resources and time.
Augmented Reality-Based Method forRoad Maintenance Operators inHuman–Robot Collaborative Interventions [43]MaintenanceThe application of AR augmented reality in the road maintenance process significantly improves safety and operational efficiency. The proposed methodology integrates a set of AR tools that provide real-time visualisations, interactive instruction, and human–robot collaboration (HRC). In a dynamic and hazardous environment, such as road maintenance, operators receive up-to-date information about safe areas and events in their immediate and extended environment. Detailed instructions, including 3D models, images and text, guide operators through each step of the process, enabling accurate and fast execution of tasks. In addition, collaboration with robots, controlled through AR interfaces, facilitates the completion of complex tasks, such as installing safety barriers and sealing cracks, reducing risk exposure and improving work efficiency. This approach not only improves productivity and accuracy, but also minimises the time operators spend in hazardous environments, thus contributing to safer road maintenance operations.Improved process efficiency. AR provides visual instructions directly superimposed on the physical environment, which facilitates and speeds up the process of executing tasks such as installing safety barriers or sealing cracks in roads, thus reducing errors.The high initial cost of implementing AR systems requires significant investments in specialised hardware and software development tailored to the specific needs of each application.
Data Mining and Augmented Reality: An Application to the Fashion Industry [44]Quality controlAR offers differential support to both experts and trainees in the fast-paced quality control process in the fashion industry. First of all, it is used to display the updated sample size for the selected control order, strategically redefining the sampling rules. In addition, it allows the areas to be controlled to be displayed sequentially on the screen, organised according to defect detection. The controllers have direct access to the description of the control set by simply clicking on the corresponding icon on the interface. Moreover, on the physical site, workers can use AR glasses or mobile devices to overlay construction drawings and instructions, facilitating assembly and precise component placement.By providing accurate real-time data and visualisations, AR reduces construction errors and helps maintain alignment with design specifications.There may be resistance from workers and stakeholders who are accustomed to traditional methods and may be reluctant to adopt new technologies.
Design of Augmented Reality Training Content for Railway Vehicle Maintenance Focusing on the Axle-Mounted Disc Brake System [26]MaintenanceAR is applied in rail vehicle maintenance by developing training content that visualises maintenance procedures in a three-dimensional (3D) space. Using mobile devices such as tablets or smartphones, maintenance operators can access detailed, interactive maintenance manuals that project virtual images onto the real environment. These AR manuals include warning signs for risky procedures and allow operators to control the position, scale and rotation of 3D models using touch gestures. This provides an immersive, hands-on training experience that improves understanding and proficiency in the maintenance of critical components such as axle-mounted disc brake systems.AR allows operators to visualise and practice complex maintenance procedures in a controlled and safe environment, reducing human error and enabling faster and more effective training.Creating interactive 3D models and implementing AR technologies can be costly and require a significant investment in time and money.
Development of Augmented RealityApplication for Onsite Inspection of Expressway Structures Using Microsoft HoloLens [45]InspectionAR is applied in the inspection process of highway structures through the use of the Arinspector application, developed for the first-generation Microsoft HoloLens device. During inspection activities, the AR system allows inspectors to perform inspection tasks hands-free by overlaying relevant information such as highway history, technical drawings, previous inspection reports, and specification and standards manuals over the actual scene while the inspector visualises the highway structure. This facilitates detailed and accurate inspections, optimising the time and resources used in the process.Improved communication and data management with online databases as by using the application, highway inspectors can send data to the online database in real time, where everyone can access, edit and share with other relevant people.While the time and resource savings on daily inspections may justify the investment in the long run, the initial cost can be a significant barrier to immediate adoption of this technology, especially for organisations with limited budgets.
Development of Augmented Reality System for Productivity Enhancement in Offshore Plant Construction [46]Inspection and manufacturingThe in-process AR system improves manufacturing and inspection by allowing users to adjust the transparency of 3D representations to easily compare CAD design to actual parts, visualise only relevant disciplines to avoid confusion, adjust the field of view to inspect hidden parts in complex environments, and facilitate access and comparison of drawings and CAD data by selecting parts on the screen, thus improving accuracy and efficiency in installation and inspection.Improved productivity and efficiency: AR allows marine plant construction workers to view crucial information, such as CAD drawings and installation instructions, directly in their field of viewTraining and learning curve: Learning to use AR effectively can take time and effort. This may require additional training for workers, especially those less familiar with advanced technologies.
Development of Augmented Reality Technology Imple-mentation in a Ship-building ProjectRealisation Process [31]Mounting-assembly and repairThe implementation of AR augmented reality in the marine outfitting process offers multiple significant benefits. First, it automates the digital recording of the start and end of work activities through smart devices and QR codes, enabling accurate time and productivity management by recording who performs each task and for how long. In addition, 3D virtual objects projected onto the real environment make it easy for supervisors and managers to visually monitor the progress of assembly activities, generating real-time daily reports to compare progress against planned standard hours, thus optimising planning and resource allocation. AR also plays a crucial role in the early detection of assembly errors by identifying discrepancies before they become costly repairs, such as missing cuts between blocks, potentially significantly reducing costs and procedure times.Reduced costs and time by enabling early detection of errors during assembly through AR prevents major problems at later stages, significantly reducing repair and rework costs, as well as related downtime.Insufficient illumination and high presence of dust slow down and complicate the initialisation and follow-up in the process, and there may be resistance to change in the process.
Dynamic Mixed-Reality Assembly Guidance UsingOptical Recogni-tion Methods [22]Mounting-assemblyThe AR application developed for this process aims to guide users during component assembly using the capabilities of the HoloLens 2 and the Vuforia engine. The AR application provides visual instructions overlaid directly in the user’s field of view, thus facilitating an intuitive and efficient assembly experience. In addition, it uses the HoloLens 2’s hand tracking to validate the user’s actions, ensuring that components are correctly selected and positioned in real time. This is achieved by accurately identifying and tracking objects recognised by the system, enabling greater accuracy and control during the assembly process.Allows manual tracking to validate user actions, ensuring that components are selected and positioned correctly in real time, reducing errors.Implementing AR technology and motion capture systems can be costly, including hardware, software and staff training.
Effect of Augmented Reality Support on Quality Inspection of Welded Structures [35]InspectionApplied in the industrial weld quality control process, AR is used to guide inspectors during the visual inspection of welds. This is achieved by superimposing digital information directly on the physical parts, allowing inspectors to quickly compare welds to ideal standards and detect potential defects more efficiently. In addition to enabling visual guidance, AR also aids in requirements interpretation and part evaluation by facilitating the requirements interpretation process by providing clear and direct indications of the characteristics that welds must meet.It allows for reduced inspection time, especially among less experienced inspectors, and less mental workload by allowing a quick comparison between the inspected parts and the ideal model.Lighting conditions may affect the stability of the display in some cases.
Effectiveness on Training Method Using Virtual Reality and AugmentedReality Applications in Automobile Engine Assembly [47]TrainingAR is effectively used to enhance training in motor assembly. Markerless AR was used to allow students to interact with virtual components in a physical environment, using smart glasses. This facilitated visualisation and manipulation of engine parts, improving understanding and execution of complex tasks. On the other hand, AR with markers provided additional visual guidance during assembly, improving accuracy and efficiency compared to traditional video-based methods. Both approaches provided a more immersive and effective educational experience than conventional methods.AR increases motivation and learning performance compared to traditional video-based methodsThe initial cost and resources required to develop and deploy AR content. Creating interactive 3D models and deploying AR technologies can be costly and require significant investment in time and money.
Evaluating Digital Work Instructions with Augmented Reality Versus Paper-based Docu-ments for Manual, Object-specific Re-pair tasks in a Case Study with Experienced Workers [32]MaintenanceAR is applied in the repair of turbine blades in the metallurgical industry. To do this in the turbine blade repair process, AR provides digital work instructions that are more intuitive and accessible compared to traditional paper-based methods. Cognitive assistance systems (CAS) enhance cognitive abilities by providing digital work instructions. These digital instructions can include 3D models of parts, interactive diagrams and real-time data, all of which help workers better understand tasks and reduce the possibility of errors. AR enables detailed and clear visualisation of turbine components, making it easier to identify and repair problem areas.The AR-based assistance system displays all necessary information by default. This ensures that workers do not skip important steps, such as checking measurements, thus improving job accuracy.Resistance to change: Some workers, especially those with little familiarity with the technology, tend to ignore screen-based AR. This suggests that, while AR is powerful, it takes time and training for users to become accustomed to its use.
Holorailway: an Augmented RealitySystem to Support Assembly Opera-tions in the Railway Industry [48]Maintenance and assemblyIn the process of insulating panel assembly in the industrial rail sector, AR is innovatively and effectively applied through the Holorailway system based on the HoloLens 2 visualisation device. This system uses advanced computer vision technologies to automatically align virtual content with actual railcar components so that workers receive accurate, real-time visual instructions on panel placement and assembly, simplifying the process and significantly improving panel assembly efficiency.The AR system guides workers with accurate, real-time visual instructions, which improves assembly accuracy and reduces the number of errors, and eliminates the need for extensive prior knowledge on the part of operators, facilitating training and reducing the learning curve.The implementation of augmented reality systems such as HoloLens 2 involves a significant upfront cost in terms of hardware and software development. This can be a barrier for companies that are not willing to make a high initial investment.
Improving Effi-ciency of Industrial Maintenance with Context-awareAdaptive Authoring in Augmented Reality [23]MaintenanceThrough the use of AR technology, technicians can access real-time contextualised and visualised information about the specific equipment and components they are repairing or maintaining. This information includes step-by-step guides, animations overlaid on physical devices and relevant equipment data, which facilitates understanding and executing tasks more efficiently. In addition, AR enables better adaptive data management, dynamically adjusting to the specific needs of the end user, contributing to greater accuracy and speed in the execution of maintenance activities.AR improves maintenance efficiency by providing contextualised and visual information in real time, making tasks easier to understand and reducing the time required to complete them.The implementation of augmented reality systems involves a significant upfront cost in terms of hardware and software development.
Integrated Aug-mented and Virtual Reality Technologies for Realistic Fire Drill Training [49]TrainingAR is used in fire training to provide a comprehensive and realistic training experience that combines the real and virtual worlds. Implemented AR uses the VIVE Pro HMD device, which is originally dedicated to VR, but takes advantage of its augmented reality capabilities through its built-in stereo camera. The srworks SDK is used to take advantage of the stereo camera’s capabilities, which include depth perception and approximate object recognition. Artificial intelligence (AI) models are used to recognise detailed information about objects, such as volume and mass, and are used to generate realistic virtual fire effects on which operators can be trained, providing them with a more complete and versatile training experience.Augmented reality provides a safe and controlled training environment where users can practice emergency situations without real risks.The implementation of augmented reality systems involves a significant upfront cost in terms of hardware and software development. This can be a barrier for companies that are not willing to make a high initial investment.
MANTRA: an Effective System Based on Augmented Reality and Infrared Thermography for Industrial Maintenance [50]MaintenanceMANTRA is an innovative solution that combines AR with infrared thermography (IRT) for specific applications in industrial maintenance. MANTRA automates the superimposition of virtual information and temperature data on 3D objects in real time through the joint use of an RGB-D sensor and an IRT camera. This approach ensures high accuracy and robustness in maintenance operations by detecting and estimating the pose of 3D objects with advanced methods such as YOLOV4 for object detection and LINEMOD for pose estimation.MANTRA facilitates faster and more accurate maintenance operations and makes it easier to view crucial information without requiring technicians to take their eyes off the equipment or device they are repairing, which can reduce errors and improve safety.Implementing augmented reality systems such as MANTRA can require significant upfront investment in hardware and specialised software development.
MARMA: A Mobile Augmented Reality Maintenance Assistant for Fast-Track Repair Procedures in the Context of Industry 4.0 [24]MaintenanceMARMA is an AR system that can locate a component in the manufacturing plant and display the corresponding failure mode maintenance instructions in a portable and vivid manner on the operators’ mobile device. A camera acts as the sensory input of the proposed AR system, recording the activity inside the industrial plant. First, the asset of interest is detected in the image plane, while subsequently, a robust tracking algorithm is responsible for tracking the position and scale of the detected asset for subsequent frames of the recording. Based on the calculated position and scale values, the 3D CAD of the specific asset is projected onto the image plane in a user-friendly manner. When the operator approaches the machine, the proposed system provides instructions on the first steps of the maintenance procedure. Then, the user easily controls the system through appropriate buttons that proceed to the previous or subsequent maintenance steps of the asset.Improving the process by replacing paper instructions with digital instructions, taking advantage of AR functions to limit retrieval times.The implementation of MARMA requires specific hardware, such as high-quality cameras and devices capable of running AR applications, which leads to increased implementation costs.
Multimodal Mixed-Reality Impact on a Hand-Guiding Task with a Holographic Cobot [51]MaintenanceAR in manual interaction processes, especially in maintenance and repair tasks, has shown promise in combining virtual and real information, significantly improving efficiency and accuracy. In the context of pick-and-place tasks, the implementation of AR-based systems allows users to manipulate holographic objects with remarkable positioning accuracy while maintaining a margin of error below 3 mm. The integration of tactile feedback through haptic actuators in the air enhances the sense of control and physical perception of the hologram, providing a more natural and familiar experience. This makes it easier for users to immediately confirm their actions, reducing the time demand and improving the execution of complex tasks without the need for extensive learning.AR enables intuitive interaction with holographic objects, reducing the need for extensive learning and enabling more efficient execution of complex tasks.AR systems and haptic actuators may require frequent maintenance and upgrades to ensure optimal performance.
Pervasive Aug-mented Reality to Support LogisticsOperators in Industrial Scenarios:A Shopfloor User Study on Kit Assembly [52]LogisticsAR assists logistics operators during order-picking tasks in industrial plants. A human-centered design (HCD) methodology was used with industrial partners to identify operators’ difficulties and challenges and define requirements. Two methods, HMD and HHD (hand-held device), were then developed, which allow AR content to be configured and visualised in the industrial environment. In short, virtual content can be visualised, allowing operators to know how to perform picking operations, i.e., to have step-by-step instructions, including text, images and 3D models, on how to assemble a given kit.AR offers a more immersive experience, keeping AR information directly in the user’s field of view, which can improve concentration and reduce time spent searching for information.HMD devices tend to be more expensive compared to HHD devices, which can be a barrier to adoption, especially in small and mid-sized businesses
Presenting Job Instructions Using an Augmented Reality Device, a Printed Manual, and a Video Display for Assembly and Disassembly Tasks: What Are the Differences? [53]Mounting-assemblyAR to present task instructions. This device comprises transparent holographic lenses. Users can see both virtual instruction and computer components. Dynamics 365 Guides application was adopted in HoloLens 2 to present the job instructions. The text of each step for both assembly and disassembly tasks was incorporated into the Dynamics 365 application. Virtual circles and squares are added using the AR toolkit to highlight screw locations and cable connections, respectively, to provide supplemental information. When a cable needed to be plugged or unplugged, a virtual hand appeared to highlight the operation. Virtual hands also appeared when pushing or pulling a component was required. The virtual hands disappeared after the participant followed this instruction. The participant could click on a virtual arrow in the upper right corner of the instruction to go to the next step when he or she had completed a step with his or her index finger.By providing a 3D visual representation of components and assembly/disassembly processes, AR can help users better understand the tasks they are performing, which can lead to moreaccurate execution.While AR can improve the user experience once mastered, it may require additional time and training for workers to become familiar with the technology and learn how to use it effectively.
Process Monitoring of Economic and Environmental Performance of a Material Extrusion Printer using anAugmented Reality-based Digital Twin [54]MonitoringAR is used to develop digital twins for process monitoring of a material extrusion printer in the additive manufacturing industry. AR allows virtual elements, such as 3D models and performance data, to be integrated into the user’s physical environment in real time, superimposing them over the real-world view captured by an AR device, or an HHD, such as a cell phone or tablet like Samsung Galaxy S21. AR enables remote monitoring of the printing process from any location with adequate connectivity. Users can monitor print progress, check parameters and make adjustments in real time without being physically present on the manufacturing floor.It allows operators and technicians to visualise digital models of components and printing processes directly on the actual 3D-printer or on the workbench. This facilitates a clearer understanding of how the digital models behave compared to the actual physical process.Users may need time and training to become familiar with AR technology and use it effectively, which can delay adoption and initial benefits.
Process of Materials Picking Using Augmented Reality [55]Order preparationAR is used to improve the order-picking process by reducing information search time and improving accuracy. Only relevant data are displayed in the HMD, making it easier to identify storage locations and verify required parts. Employees use devices equipped with AR technology, such as smart glasses or headsets, which allow them to view digital information overlaid on the physical environment in real time. This information can include details on material storage locations, quantities required and any other instructions relevant to the order-picking process, enabling the identification of material locations in the warehouse.It allows shortening the completion time of collection orders by reducing the search and selection time of materials, thus making the process more efficient.Deploying AR technologies, including HMD devices, can be costly, which could be a barrier for small organisations.
Real-Time RemoteMaintenance Support Based on Augmented Reality (AR) [56]MaintenanceAR in the maintenance process allows shopfloor technicians to receive real-time remote assistance from expert engineers without the need for their physical presence on site. Using devices such as head-mounted displays via HMD, technicians can transmit a live video feed of the work environment to the expert engineer. The latter, in turn, can guide the technician in troubleshooting through annotations and the overlay of AR content directly in the technician’s field of view. This real-time interaction facilitates an accurate understanding of malfunctions and enables the creation of specific AR content as problems arise, eliminating the need to prepare predefined AR scenarios.Ability to reduce mean time to repair (MTTR). Expert engineers can provide immediate and accurate assistance to shopfloor technicians, minimising machine downtime and improving operational efficiency.Dependence on an advanced technological infrastructure, including HMD devices and stable, high-speed network connections. This can be a challenge in technologically constrained industrial environments.
Smart Augmented Reality Instruc-tional System for Mechanical Assembly TowardsWorker-Centered Intelligent Manufacturing [27]Mounting-assemblyAR in the assembly process is used to superimpose visual instructions directly into the operator’s work environment. These instructions can include text, videos, 3D animations and other visual aids that guide the worker through the various stages of assembly. AR helps improve operator accuracy and efficiency by providing clear and detailed real-time directions. The integrated system uses a region-based convolutional neural network (Faster R-CNN), trained on a synthetic tooling dataset generated from CAD models, to detect real physical tooling.The system can decrease completion time and the number of errors compared to traditional paper-based instructional methods.Implementing AR systems can be costly and requires workers to adapt to new work methods, which could generate resistance or an initial learning curve.
Use of Projector-based Augmented Reality to Improve Manual Spot-welding Precision and Accuracy for Automotive Manufacturing [28]WeldingAR is applied in the welding process using a projector-based projection system that highlights spot-weld locations on vehicle panels. This system helps manual welding operators improve the precision and accuracy of spot-weld placement through the use of visual cues. These cues are projected directly onto the panel surfaces, providing visual guidance that facilitates quick and accurate identification of the correct spot-welds, thereby reducing errors and improving the quality of the final product.The use of AR in the welding process improves the precision and accuracy of the welds, which significantly reduces the variability in the location of the welding points, which is crucial to maintain high quality standards in production.Need for ongoing calibration and maintenance of the projection system to ensure that the visual cues are accurate and correctly aligned with the panels. This may require additional resources and time.
Using Augmented Reality to Reduce Workload inOffshore Environments [29]TrainingAR overlays virtual information over the pilots’ actual field of view through an HMD. During simulated missions, pilots used the HMD to receive additional symbology and critical data, such as engine control indicators, displayed directly in their line of sight. This allowed them to perform complex tasks, such as hovering and landing and takeoff maneuvers, with greater awareness of their surroundings and aircraft status, improving their ability to handle unforeseen situations and reducing the risk of errors.Increased pilot situational awareness. Overlaying vital information in the pilot’s field of view enables faster and more accurate decision making, which is crucial in high-workload operations and adverse environmental conditions.Potential ergonomic discomfort and visibility issues with HMD devices especially in low light conditions, which may hinder prolonged use and negatively affect user experience
Using Eye-Tracking to Measure WorkerSituation Aware-ness in Augmented Reality [30]TrainingAR is applied to the process of improving the situational awareness of workers in the construction industry. The use of AR focuses specifically on the creation of visual warning systems that alert workers to immediate hazards in their work environment, such as the proximity of moving objects (trucks, forklifts, etc.). These AR warning systems are designed to improve workers’ ability to perceive and react to these hazards, thereby improving safety on the construction site.AR is used to generate visual signals that warn workers of hazards in their environment. These warnings are superimposed on the workers’ field of vision, helping them to quickly identify and react to hazards.AR eye-tracking devices can be expensive and require regular maintenance. Acquiring high-quality AR devices and accurate eye-tracking systems can be a significant investment for construction companies.
WARM: Wearable AR and Tablet-Based Assistant Systems for BusMaintenance [57]MaintenanceThe application of AR in bus fleet maintenance has been developed using Microsoft HoloLens headsets. This AR solution employs different tracking methods, such as spatial mapping and object detection, to analyse the environment and locate the user in relation to the environment and the bus. Once the bus is identified and located, virtual objects can be added to assist in maintenance. Tests conducted under real-world conditions at the DBUS garage in San Sebastian showed that, although the tablet-based solution was more efficient in terms of data management and processing, AR provided significant added value. The AR allows workers to perform maintenance tasks hands-free and access additional multimedia information, such as videos and photos, which enriches the information system.The application on the tablet connects directly to the maintenance management system, enabling fast and efficient assignment of work orders and data transmission without the need for additional intervention by maintenance managers.Deploying AR technologies, including HMD devices and sensors, can be costly, which could be a barrier for small organisations.

Appendix B. Hardware and Software

Table A2. Hardware and software.
Table A2. Hardware and software.
TitleHardwareApproximate Cost (USD)Graphic Engine
A Multi-User Collaborative AR System for Industrial Applications [25]Smartphones or tabletsSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and through the CAD Exchanger SDK.
A Smart Factory in a Smart City: Virtual and Augmented Reality in a Smart Assembly Line [20]AR In Situ uses projectorsUSD 800 to 1200Unity 3D (2021.4.05.f1)
An Augmented Reality-Assisted Order-Picking System using IoT [36]RASPICK Raspberry Pi Zero W board: Used as the brain of the device.Not specifiedNot specified
An Augmented Reality System for Operator Training in the Footwear Sector [33]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18Not specified
An Augmented Reality System to Support Fault Visualisation in Industrial Robotic Tasks [37]HoloLensHoloLens 1: Around USD 3000. HoloLens 2 with ISO 14644-14: About USD 5407.18.Unity 3D del SDK Vuforia and MRTK (Mixed-Reality Tool Kit)
An Intelligent Product Service System for Adaptive Maintenance of Engineered-to-Order Manufacturing Equipment Assisted by Augmented Reality [34]Smartphones or tabletsSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and Vuforia SDK.
ARiana: Augmented Reality-Based In Situ Annotation of Assembly Videos [38]Vuzix M400About USD 1500 to USD 1800SaliencyMDC algorithm and KCF (Kernelised Correlation Filters) tracing algorithm
Assessing User Performance in Augmented Reality Assembly Guidance for Industry 4.0 Operators [39]Apple iPad Pro 2020Approximately USD 1050–1650Unity 3D
Assessment of Augmented Reality in Manual Wiring Production Process with Use of Mobile AR Glasses [40]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18.Unity 3D
Augmented Reality for Industrial Quality Inspection: An Experiment Assessing Task Performance and Human Factors [41]HoloLensHoloLens 1: Around USD 3000. HoloLens 2 with ISO 14644-14: About USD 5407.18.Unity3D together with the Mixed-Reality Toolkit 2 (MRTK 2) SDK and Vuforia.
Augmented Reality System and Maintenance of Oil Pumps [21]Smartphones or tabletsSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and SDK Vuforia
Augmented Reality-Assisted Deep Reinforcement Learning-Based Model towards Industrial Training and Maintenance for Nanodrop Spectrophotometer [42]HP Pavilion Huawei Nova Y70 Notebook One HP 320HP Pavilion Laptop: USD 600 to USD 1800 Huawei Nova Y70: USD 200 to USD 600 HP 320 camera: USD 80 to USD 300Unity 3D
Augmented Reality-based Method for Road Maintenance Operators in Human–Robot Collaborative Interventions [43]HoloLens and tabletHoloLens 1: Around USD 3000. HoloLens 2 with ISO 14644-14: Around USD 5407.18 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and SDK Mixed-Reality Toolkit (MRTK)
Data Mining and Augmented Reality: An Application to the Fashion Industry [44]Commercial tablet with dual cameraTablets: Mid-range: USD 300–700 High-end: USD 700–1200Web application developed with Xamarin and linked to a LAMP server (Linux, Apache, MySQL and PHP).
Design of Augmented Reality Training Content for Railway Vehicle Maintenance Focusing on the Axle-Mounted Disc Brake System [26]Smartphones or tablets with Android systemSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500. Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and Blender software
Development of Augmented Reality Application for Onsite Inspection of Expressway Structures Using Microsoft HoloLens [45]HoloLensHoloLens 1: Around USD 3000. HoloLens 2 with ISO 14644-14: About USD 5407.18Unity 3D
Development of Augmented Reality System for Productivity Enhancement in Offshore Plant Construction [46]Mobile PhonesSmartphones: Mid-range: USD 400–700 USD High-end: USD 700–1500Project Tango Development Kit (PTDK) integrates with graphics engines such as Unity and Unreal Engine
Development of Augmented Reality Technology Implementation in a Shipbuilding Project Realisation Process [31]Tablet or smartphoneSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity3D and the ARCore SDK
Dynamic Mixed-Reality Assembly Guidance Using Optical Recognition Methods [22]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: Around USD 5407.18 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity Engine and the Vuforia Engine SDK
Effect of Augmented Reality Support on Quality Inspection of Welded Structures [35]Samsung Galaxy Table 8Around USD 250Unity 3D and Vuforia Engine SDK
Effectiveness on Training Method Using Virtual Reality and Augmented Reality Applications in Automobile Engine Assembly [47]EPSON MOVERIO BT-300EPSON Moverio BT-2000: USD 2196.15Unity 3D
Evaluating Digital Work Instructions with Augmented Reality Versus Paper-based Documents for Manual, Object-specific Repair Tasks in a Case Study with Experienced Workers [32]Microsoft Azure Kinect 3D Cameras Cognex DataMan DM 8600 Scanner, 27-inch touchscreen monitor and 43-inch monitorCameras: About USD 399 Scanner: Around USD 1000 27-inch monitor: Around USD 500 to USD 100 43-inch monitor: About USD 1000 to USD 2000Not specified
Holorailway: an Augmented Reality System to Support Assembly Operations in the Railway Industry [48]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18Unity3D, Mixed-Reality SDK Toolkit and Vuforia
Improving Efficiency of Industrial Maintenance with Context-aware Adaptive Authoring in Augmented Reality [23]Smartphones or tabletsSmartphones: Mid-range: USD 400–700 High-end: USD 700–1500 Tablets: Mid-range: USD 300–700 High-end: USD 700–1200Unity 3D and Vuforia SDK
Integrated Augmented and Virtual Reality Technologies for Realistic Fire Drill Training [49]VIVE Pro HMDAbout USD 1199–USD 1400Unity 3D and SRWorks SDK
MANTRA: an Effective System Based on Augmented Reality and Infrared Thermography for Industrial Maintenance [50]Microsoft Surface Book 2, Intel RealSense d415 RGB-D camera and Optris PI640 thermal imaging cameraMicrosoft Surface Book 2: About USD 400 to 600 Intel RealSense d415 RGB-D camera: About USD 450 Optris thermal imager: PI640 USD 7834.00Unity 3D
MARMA: A Mobile Augmented Reality Maintenance Assistant for Fast-Track Repair Procedures in the Context of Industry 4.0 [24]Smartphones that can load the applicationSmartphones: Mid-range: 400–700 USD High-end: 700–1500 USDUnity and Vuforia SDK
Multimodal Mixed-Reality Impact on a Hand-Guiding Task with a Holographic Cobot [51]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18Unity 3D
Pervasive Augmented Reality to Support Logistics Operators in Industrial Scenarios: a Shopfloor User Study on Kit Assembly [52]HoloLens for the HMD method; Asus Zenfone AR or Samsung Galaxy A52 for the HHD method.HoloLens 1: Around USD 3000. HoloLens 2 with ISO 14644-14: Around USD 5407.18 Asus Zenfone AR: USD 300 to 600 Samsung Galaxy A52: USD 300 to 500Unity and Arcore SDK
Presenting Job Instructions Using an Augmented Reality Device, a Printed Manual, and a Video Display for Assembly and Disassembly Tasks: What Are the Differences? [53]HoloLensHoloLens 1: Around 3000 USD. HoloLens 2 with ISO 14644-14: About 5407.18 USD.Dynamics 365 Guides
Process Monitoring of Economic and Environmental Performance of a Material Extrusion Printer Using an Augmented Reality-based Digital Twin [54]Samsung Galaxy S21Around USD 480Unity 3D
Process of Materials Picking Using Augmented Reality [55]Epson MOVERIO BT-300 and Vuzix MT300EPSON Moverio BT-2000: USD 2196.15 Vuzix MT300: Around USD 1500 to USD 1800Unity 3D
Real-Time Remote Maintenance Support Based on Augmented Reality (AR) [56]HoloLens and desktop PCsHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18 Desktop PC: Around USD 600Unity 3D, Vuforia SDK and MRTK (Mixed Reality Tool Kit).
Smart Augmented Reality Instructional System for Mechanical Assembly Towards Worker-Centered Intelligent Manufacturing [27]Logitech C920 Pro webcams and a monitorCameras: About USD 100 Monitor: About USD 600 to USD 1800Unity3D
Use of Projector-based Augmented Reality to Improve Manual Spot-welding Precision and Accuracy for Automotive Manufacturing [28]Projectors (NEC NP-PA500UG) and CamerasProjectors: About USD 2000 Cameras: About USD 100SAR software does not specify exact.
Using Augmented Reality to Reduce Workload in Offshore Environments [29]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18Unity3D
Using Eye-Tracking to Measure Worker Situation Awareness in Augmented Reality [30]HoloLens and iPhone SEHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18 iPhone SE: Around USD 600Unity with Mixed-Reality Toolkit 2 (MRTK2)
WARM: Wearable AR and Tablet-Based Assistant Systems for Bus Maintenance [57]HoloLensHoloLens 1: Around USD 3000 HoloLens 2 with ISO 14644-14: About USD 5407.18Unity 3D, Mixed-Reality Toolkit SDK and Vuforia.

Appendix C. Impact of AR Implementation in Industrial Processes

Table A3. Impact of AR implementation in industrial processes.
Table A3. Impact of AR implementation in industrial processes.
TitleBefore AR ImplementationAfter AR ImplementationPercentage of Optimisation (%)
A Multi-User Collaborative AR System for Industrial Applications [25]The time taken to perform the design task was 23 min.The time taken to perform the activity using the system was 12.6 min.It is observed that the design task was completed 45.22% faster.
A Smart Factory in a Smart City: Virtual and Augmented Reality in a Smart Assembly Line [20]The time to execute the assembly task using paper instructions was 3:24 minThe time to execute the assembly task using 3D guide was 2:34 minThe time to execute the task is reduced by 25 %.
An Augmented Reality-Assisted Order-Picking System Using IoT [36]The collection time for 10 items was 145 s and for 20 items, it was 280 sThe collection time for picking up 10 items was 131 s and for 20 items, it was 240 sA decrease in the time to collect the items is observed by 9% for lists of 10 items and 12.55% for lists of 20 items.
An Augmented Reality System for Operator Training in the Footwear Sector [33]Time spent by trainers with interruptions in their work in the traditional way (% of total training hours) 20/100%Time spent by trainers with interruptions in their work with AR (% of total hours of training) 10/100%.Productivity increase of 10% is seen.
An Augmented Reality System to Support Fault Visualisation in Industrial Robotic Tasks [37]The average time of the system to recognise the type of failure in a non-adaptive way in seconds 97.85The average time of the system to recognise the type of failure in an adaptive way in seconds 71.82A 26% decrease in the time to recognise the fault is observed.
An Intelligent Product Service System for Adaptive Maintenance of Engineered-to-Order Manufacturing Equipment Assisted by Augmented Reality [34]Inspection time in days = 2 and fault documentation time = 1.5 hInspection time in days = 1 and fault documentation time = 0.5 hReduction in mould inspection time by up to 50% and fault documentation time by approximately 66%.
ARiana: Augmented Reality Based In Situ Annotation of Assembly Videos [38]Time to annotate the assembly process with Ajalon (state-of-the-art video annotation tool) 17.86 min.Time to annotate the assembly process with ARiana (AR-based video annotation tool) 5.2 min.Implementing ARiana reduces the time by approximately 70%.
Assessing User Performance in Augmented Reality Assembly Guidance for Industry 4.0 Operators [39]Average time to complete assembly activity with technical documents 839 sAverage time to perform the assembly activity with AR 583 sA 30.51% reduction in the assembly activity is observed.
Assessment of Augmented Reality in Manual Wiring Production Process with Use of Mobile AR Glasses [40]Average time in minutes of assembly time without AR glasses by Tester 1: 17:40 and by Tester 2: 19:03Average time in minutes of the assembly duration with AR glasses by Tester 1: 11:06 and by Tester 2: 7:00By using AR glasses in the assembly process, a decrease of 37% is observed for Tester 1 and 36% for Tester 2.
Augmented Reality for Industrial Quality Inspection: An Experiment Assessing Task Performance and Human Factors [41]Task completion time and number of errors of a simple task with a display time: 630 sTask completion time and number of errors of a task with AR time: 439 s30.31% time reduction by using AR with an HMD device
Augmented Reality System and Maintenance of Oil Pumps [21]Average time performed during oil pump maintenance with manual instructions only = 672 s.Average time executed during oil pump maintenance with system recommen-dations = 424.5.Using the recommendations of the AR system, a time reduction of 36.83% could be seen.
Augmented Reality-Assisted Deep Reinforcement Learning-Based Model towards Industrial Training and Maintenance for Nanodrop Spectrophotometer [42]The accuracy of the Chan et al. model and other 3D systems with geometry recognition using GAN is = 87.2%.Accuracy of the RL-PipTrack system: AR-assisted deep RL-based model has an average Reward = 1000 + standard deviation = 0%.RL-PipTrack improves performance by approximately 14.68% compared to the model of Chan et al.
Augmented Reality-based Method for Road Maintenance Operators in Human–Robot Collaborative Interventions [43]Time to execute the task by expert users without AR—2.5 min.Time to execute the task by expert users with AR—3.5 minUsing AR shows a clear increase in efficiency when performing the task as it reduces the time by about 28%.
Data Mining and Augmented Reality: An Application to the Fashion Industry [44]Standardised duration of the quality control procedure Expert OK = 10.19 Non-expert OK = 9.84Standardised duration of QC procedure with AR technology Expert OK = 7.68 Non-expert OK = 5.01It is observed that the normalised duration of the quality control process using AR of expert operators is 24.63% faster and 49.08% faster in non-expert operators.
Design of Augmented Reality Training Content for Railway Vehicle Maintenance Focusing on the Axle-Mounted Disc Brake System [26]Group A obtains an efficiency score of the executed task of the axle-mounted disc brake system through manual brochure type 47.2Group A obtains an efficiency score of the light maintenance task of the axle-mounted disc brake system through AR 63.5A higher efficiency of 32.53% of the task performed by AR guide is observed.
Development of Augmented Reality Application for Onsite Inspection of Expressway Structures Using Microsoft HoloLens [45]The actual inspection cycle from an on-site inspection to data entry in the office takes approximately 4.5 h.Using the digital AR approach developed for an in situ inspection of highway structures can be performed in an inspection time of 1 hUsing an AR approach can decrease inspection time by approximately 78%.
Development of Augmented Reality System for Productivity Enhancement in Offshore Plant Construction [46]Average working time (min.) for interference check of the system > 40; Estimated workload > 180Average working time (min) for interference check at the plant < 15; Estimated workload < 60In the inspection process, the checking and interference time is reduced by 62.5% and the workload time by 33.33%.
Development of Augmented Reality Technology Implementation in a Shipbuilding Project Realisation Process [31]The number of labour hours required for repair activities in the equipment process prior to AR is 12,973.06 h.The number of labour hours required for repair activities in the equipment process with AR is 9600 h.The application of AR technology in the repair process reduces the process time by 26%.
Dynamic Mixed-Reality Assembly Guidance Using Optical Recognition Methods [22]Number of components placed in the assembly task by inexperienced users 71Number of components placed in the assembly task by experienced users 80It is observed that the number of components placed by experienced users is 12.67% higher than that of
Effect of Augmented Reality Support on Quality Inspection of Welded Structures [35]Mean task completion time of G1 = 1238.3 s and G2 achieved a mean time of 1528 s with paper support.Mean task completion time of G1 = 927.8 s and G2 achieved a mean time of 1051.5 s with the AR approach.G1 task completion time is reduced by 25.07% and G2 by 31.18%.
Effectiveness on Training Method Using Virtual Reality and Augmented Reality Applications in Automobile Engine Assembly [47]The percentage improvement after performing the task with VR training is calculated to be 23/40.The percentage improvement after performing the task with AR training without markers is 37/40.An improvement is observed when performing the task when trained with AR without markers 60% higher than that of VR.
Evaluating Digital Work Instructions with Augmented Reality Versus Paper-based Documents for Manual, Object-specific Repair Tasks in a Case Study with Experienced Workers [32]The time to repair with paper guide is 466.1 sThe repair time using AR CAS guide is 367.3 sThe time is reduced by 21.19% using the AR CAS guide.
Holorailway: an Augmented Reality System to Support Assembly Operations in the Railway Industry [48]The overall average time in assembly by traditional method is 108.37 s and the number of errors is 17The overall average time in assembly by AR method is 56.5 s and the number of errors is 2By using AR in the assembly, the time is reduced by 52.13% and the errors decreased by 88%.
Improving Efficiency of Industrial Maintenance with Context-aware Adaptive Authoring in Augmented Reality [23]The time to perform maintenance tasks with manual paper-based procedure is approximately 13 minThe time to perform maintenance tasks with the use of AR is 7 minA reduction in time to perform the maintenance activity of about 46% is observed.
Integrated Augmented and Virtual Reality Technologies for Realistic Fire Drill Training [49]According to [58], the time to complete the fire training was 6 min with VR.The training lasted 5 min, during which time the participants were asked to simulate AR/VR firefighting training using the system.This reduced the training time by 16.66% compared to the VR method.
MANTRA: An Effective System Based on Augmented Reality and Infrared Thermography for Industrial Maintenance [50]The time to perform the diagnostic task in minutes with detailed guidance is 6.74 and the number of errors is 3.60Time to perform the diagnostic task in minutes with AR is 6.00 and the number of errors is 1.33There is a decrease in time of 10.98% and a decrease in errors of 62.96%.
MARMA: A Mobile Augmented Reality Maintenance Assistant for Fast-Track Repair Procedures in the Context of Industry 4.0 [24]Compressor repair is performed with paper-based procedure.Compressor repair is performed with the MARMA procedure, an AR system.Experts mentioned that MARMA can reduce the total compressor repair time by 30% compared to the paper-based procedure.
Multimodal Mixed-Reality Impact on a Hand-Guiding Task with a Holographic Cobot [51]The time spent during cobot execution without (V) haptic feedback is 26.614 sThe time taken during cobot execution with (V + H) with haptic feedback is 24.027 sCobot execution time with (V+ H) is reduced by 9.72 with respect to (V).
Pervasive Augmented Reality to Support Logistics Operators in Industrial Scenarios: a Shopfloor User Study on Kit Assembly [52]The average collection time per component, instructed by role, considering sequential order is 36 s and non-sequential order is 28 sThe average collection time per component, instructed by HMD sequentially is 11 s and non-sequentially is 13 s and by an HHD sequentially is 25 s and non-sequentially is 17 s.Sequentially by HMD and HHD, the task is executed 70% and 31% faster, respectively, while non-sequentially it is executed 54% and 39% faster, respectively.
Presenting Job Instructions Using an Augmented Reality Device, a Printed Manual, and a Video Display for Assembly and Disassembly Tasks: What Are the Differences? [53]The number of errors when performing a task by printed manual is 1.33.The number of errors when performing a task by AR is 0.33.Errors are reduced by 75.19% using AR.
Process Monitoring of Economic and Environmental Performance of a Material Extrusion Printer Using an Augmented Reality-based Digital Twin [54]The porosities of PLA by Hebeeb et al. and Liao et al. are calculated to be 22.5% and 10.1%, respectively.The average porosity of this study is calculated to be 7.56%Product porosity is reduced by 14.94% compared to Hebeeb and 2.54% compared to Liai.
Process of Materials Picking Using Augmented Reality [55]Time to select the part 4.04 sTime to pick up the part with the EPSON Moverio HMD 4.01 sThe HMD reduces the picking time by 1.47%.
Real-Time Remote Maintenance Support Based on Augmented Reality (AR) [56]Approximate time to execute the maintenance task of the current method = 140 sApproximate time to execute the maintenance task of the current method = 62 sIt is inferred that the time of the maintenance task can be reduced by approximately 55%.
Smart Augmented Reality Instructional System for Mechanical Assembly Towards Worker-Centered Intelligent Manufacturing [27]Time for spindle assembly task with paper manual instructions = 755 s and 34 errors.Time for the spindle assembly task with AR instruction = 504 s and 23 errors.Time decrease of 33.24% and 32.35% decrease in errors is observed for the spindle assembly task with AR instruction.
Use of Projector-based Augmented Reality to Improve Manual Spot-welding Precision and Accuracy for Automotive Manufacturing [28]Accuracy for the six spot-welding positions welded without AR is 4.08 mm.Accuracy for the six spot-welding positions welded with AR is 1.94 mmIncrease of approximately 52% in operator accuracy when spot-welding.
Using Augmented Reality to Reduce Workload in Offshore Environments [29]Average distance travelled in (m) from EDYV platform to turbine 4 without HMD 3855Average distance traveled in (m) from EDYV platform to turbine 4 without HMD 3551AR reduces the distance traveled by 8.92%.
Using Eye-Tracking to Measure Worker Situation Awareness in Augmented Reality [30]The number of failures in an assembly task without receiving AR warnings is 74The number of failures in an assembly task with HMD and receiving AR warnings is 14The number of failures in the assembly task is reduced by 81.08%.
WARM: Wearable AR and Tablet-Based Assistant Systems for Bus Maintenance [57]The maintenance personnel costs per vehicle EUR/(vehicle × 10,000 km) is EUR 24.78The maintenance personnel costs per vehicle EUR/(vehicle × 10,000 km) is EUR 24.7Costs are minimised by 0.32%.

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Figure 1. Bias analysis. Green for low risk, yellow for some concerns, and red for high risk.
Figure 1. Bias analysis. Green for low risk, yellow for some concerns, and red for high risk.
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Figure 2. Cochrane Bias bar chart.
Figure 2. Cochrane Bias bar chart.
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Figure 3. PRISMA flow diagram.
Figure 3. PRISMA flow diagram.
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Figure 4. Hardware used in the processes.
Figure 4. Hardware used in the processes.
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Figure 5. Processes in which AR is applied.
Figure 5. Processes in which AR is applied.
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Table 1. Main questions and motivations.
Table 1. Main questions and motivations.
NumberQuestionMotivation
RQ1What are the main benefits of applying AR in the optimisation of industrial processes?Identify the advantages of applying AR in industrial processes.
RQ2What is the most used graphics engine?Identify market trends and benefit from a large support community to make informed decisions.
RQ3In which industrial processes is it recommended to implement AR?Ensure a strategic and beneficial adoption of AR in industrial processes.
RQ4What challenges and limitations do industries face when implementing AR?Identify the drawbacks that arise when implementing AR.
Table 2. Criteria and descriptions.
Table 2. Criteria and descriptions.
AbbreviationCriteriaDescription
C1Study DesignArticles related to applications of AR in industrial processes.
C2LanguageOnly articles written in English were selected.
C3Time RangeArticles published between 2019 and 2024 were selected.
C4Significant ContributionArticles that provide information on the applications of AR in engineering through implementation and obtaining tangible results.
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MDPI and ACS Style

Miranda, A.; Vallejo, A.M.; Ayala, P.; Garcia, M.V.; Naranjo, J.E. Enhancing Industrial Processes Through Augmented Reality: A Scoping Review. Future Internet 2025, 17, 358. https://doi.org/10.3390/fi17080358

AMA Style

Miranda A, Vallejo AM, Ayala P, Garcia MV, Naranjo JE. Enhancing Industrial Processes Through Augmented Reality: A Scoping Review. Future Internet. 2025; 17(8):358. https://doi.org/10.3390/fi17080358

Chicago/Turabian Style

Miranda, Alba, Aracely M. Vallejo, Paulina Ayala, Marcelo V. Garcia, and Jose E. Naranjo. 2025. "Enhancing Industrial Processes Through Augmented Reality: A Scoping Review" Future Internet 17, no. 8: 358. https://doi.org/10.3390/fi17080358

APA Style

Miranda, A., Vallejo, A. M., Ayala, P., Garcia, M. V., & Naranjo, J. E. (2025). Enhancing Industrial Processes Through Augmented Reality: A Scoping Review. Future Internet, 17(8), 358. https://doi.org/10.3390/fi17080358

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