Enhancing Wire Arc Additive Manufacturing for Maritime Applications: Overcoming Operational Challenges in Marine and Offshore Environments

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses a highly topical and underexplored research area by evaluating the applicability and robustness of Wire Arc Additive Manufacturing (WAAM) systems onboard ships and offshore platforms. The work demonstrates substantial depth in the review of current technologies and introduces promising concepts for the real-time control and stabilization of WAAM systems in marine environments. However, the manuscript in its current form suffers from critical issues in structure, clarity, and experimental depth that should be addressed before publication.

 

1. While the introduction provides an extensive overview of the WAAM process and its relevance in the marine industry, the core objectives of the study are not clearly delineated. In particular, the section spanning lines 149–162 presents a fragmented enumeration of aims and tasks that are only loosely interconnected. A more structured and concise formulation of the research objectives is strongly recommended. This could be achieved by reformulating the key research tasks into short, focused bullet points, explicitly linked to the content structure of the article (e.g., control systems, software tools, material behavior). Moreover, the manuscript is excessively long (over 50 pages), with frequent redundancies between the introduction, methodology, and discussion. For instance, the impact of shipboard vibrations and oscillations is repeatedly addressed in the Introduction (lines 62–79), Results (263–321), and Discussion (826–834). These repetitions should be eliminated to improve clarity and focus.

 

2. A major limitation of the manuscript is the relatively weak experimental foundation of the proposed contributions. While the authors mention that an adaptive automated WAAM system was tested both in laboratory and onboard (lines 263–283), the article does not present quantitative experimental data to support the performance of the proposed system. For example, no metrics are provided to demonstrate the extent to which vibrations were compensated or defects were reduced. The manuscript would benefit significantly from the inclusion of controlled comparisons between WAAM processes conducted with and without vibration compensation, or before and after the implementation of the feedback control system. These could include: bead geometry deviation, porosity density, dimensional accuracy, or surface roughness under real shipboard conditions. Without such data, the claimed effectiveness of the proposed system remains speculative.

 

3. The inclusion of detailed tables (Tables 1–3) summarizing technical and software tools for WAAM monitoring, diagnostics, and control is appreciated and adds value. However, these tables are overly extensive (more than 10 pages) and contribute to a loss of narrative coherence. It is suggested to relocate the extended versions of these tables to a supplementary document and retain summarized forms in the main manuscript, referencing the full content as appropriate. For example, Table 1 could be reduced to the most relevant diagnostic techniques used in real-time WAAM monitoring in marine environments, while less directly applicable methods (e.g., corrosion testing under laboratory salt spray conditions) can be moved to the appendix.

 

4. In several sections, critical concepts are introduced without sufficient technical rigor. For instance, the manuscript refers to the use of "machine learning" (lines 204–206, 605–607) and "digital twin platforms" (lines 880–882) without specifying the algorithmic frameworks, data pipelines, or validation metrics involved. These terms should not be used generically, but rather contextualized with precise information (e.g., supervised vs unsupervised learning, data dimensionality, latency, architecture of the digital twin). Furthermore, although deep learning is mentioned in relation to droplet detection and weld pool morphology (lines 292–298), the models used, the size of the training dataset, and the evaluation metrics are not reported. If this component is truly part of the authors’ original contribution, it should be clearly isolated in the methodology and supported by quantitative results.

 

5. The Discussion section (lines 808–870) reiterates many points already covered in the introduction and literature review. While it does stress the need for vibration compensation, thermal control, and adaptive process modeling, it does not critically reflect on the limitations of the authors’ proposed system, nor does it benchmark their approach against existing state-of-the-art implementations. The novelty of the manuscript would be significantly reinforced by a clearer emphasis on what is new in this work compared to prior studies. For instance, is the integration of a 6-DOF platform with feedback from a 9-axis accelerometer in real shipboard environments novel? Is the fusion of real-time imaging with arc voltage control via a robotic arm unique? These aspects should be highlighted and compared to literature findings in the Discussion.

 

6. The section on the metallurgical behavior of different alloys (lines 634–807) is comprehensive but lacks specific links to WAAM process constraints. The analysis of Ti-6Al-4V, Inconel 718, and 316L steel includes useful data on microstructural transformations but is not always connected to WAAM-specific parameters such as deposition rate, interlayer temperature, or shielding gas interactions. More importantly, most of the discussion lacks experimental validation (e.g., no metallographic images or mechanical testing results from the authors’ work are presented). A synthetic comparative table summarizing the key properties of alloys (weldability, microstructural stability, corrosion resistance, vibration sensitivity) in the WAAM process for marine use would significantly improve clarity.

 

7. The manuscript would benefit from careful linguistic and stylistic revision. Several expressions appear to be literal translations from another language, resulting in non-idiomatic or awkward formulations. For example:

• "functional capabilities" → consider "functional performance" or "operational capabilities"
• "components formed under thermal cycles" → should be "components subjected to repeated thermal cycling"
• "the study reveals the positive influence of magnetic fields on grain structure" → consider "the study demonstrates that applying a longitudinal magnetic field improves grain refinement"

A professional language editing service or a thorough copy-edit by a native technical editor is strongly recommended before submission.

 

8. The abstract is currently overly detailed and lacks focus on the key achievements and findings of the work. It should be rewritten to emphasize:

• the specific technological problem addressed (vibrational instability of WAAM in marine contexts);
• the proposed solution (adaptive control, gyrostabilized platform, monitoring system);
• the core results (preferably quantitative, if available);
• the relevance for marine engineering applications.

Similarly, the conclusion (lines 884–911) could be made more impactful by summarizing the concrete contributions and future directions, rather than repeating descriptive content.

Author Response

Response to Reviewer №1

Dear Reviewer,

On behalf of the authoring team, I would like to express our sincere gratitude for your thorough and professional evaluation of our manuscript. Your detailed comments and suggestions served as the foundation for a careful and comprehensive revision of the original text. We have reduced the overall length of the article, eliminated redundant content, and significantly improved its structural clarity. Additionally, the abstract, discussion, and conclusions have been completely rewritten, and supplementary data and a comparative table were added, in line with your recommendations. Below, please find our point-by-point response to your main comments:

1. Research Objectives and Structure
   The research goals and objectives have been reformulated in a more concise and structured manner (lines 157–165) and logically aligned with the key sections of the manuscript (e.g., control systems, software tools, material behavior). Repetitions identified between the Introduction, Results, and Discussion sections have been eliminated. The total text length has been reduced and its structure significantly improved.
2. Experimental Basis and Validation
   The adaptive automated Wire Arc Additive Manufacturing (WAAM) system has been thoroughly tested in both laboratory and real shipboard environments (Figure 1).

[Figure 1. Real testing of the WAAM system on a ship]

While the current automatic feedback control system has demonstrated promising performance, it is still undergoing optimization to improve stability and precision. We are actively refining its algorithms and control parameters, and a full description of the improved methodology will be presented in a forthcoming publication. Our prior research on simulating shipboard conditions has resulted in several peer-reviewed studies:

Comparative analysis of printing performance under land-based vs. shipboard conditions:
https://doi.org/10.1016/j.cjmeam.2023.100067 

Machine learning-based prediction of print quality:
https://doi.org/10.1007/s12666-025-03670-3

Advancement of shipboard printing via magnetic control technology:
https://doi.org/10.1016/j.mtcomm.2024.108035,
https://doi.org/10.1007/s11665-025-11183-9

We are currently preparing a new article focused on quantitative experimental data and performance comparisons, which will substantiate the effectiveness of the proposed automated system. In accordance with your feedback, the present manuscript does not include preliminary claims regarding system performance.

Tables
As recommended, extended versions of Tables 1–3 have been moved to the Appendix. Condensed and generalized versions have been retained in the main text with appropriate cross-references.

Technical Terminology and Rigor
Sections referencing digital twin systems and machine learning have been revised to clarify the specific approaches used (e.g., supervised learning, feedback loop architecture, digital model parameters). References to deep learning applications have also been made more precise.

Discussion Section
The discussion section has been substantially revised. Comparisons with recent research have been added, and the novelty of our approach has been more clearly articulated — in particular, the integration of a six-degree-of-freedom gyrostabilized platform with a 9-axis accelerometer for WAAM stabilization in shipboard environments.

Metallurgical Properties
In addition to the extended text, we have included a comparative table of WAAM-compatible alloys, highlighting their key properties in the context of marine engineering (e.g., weldability, vibration resistance, microstructural stability).

Language and Style
Stylistic revisions have been made throughout the manuscript to improve clarity and precision. Technical terminology has been refined and awkward phrasing corrected. The manuscript was additionally edited by a native English-speaking technical editor.

Abstract and Conclusions
Both the abstract and conclusion sections have been rewritten with a focus on the stated technological problem, the proposed solution, the key findings, and their relevance for marine industry applications

We once again thank you for your valuable feedback, which has significantly improved the scientific rigor and overall quality of our work.

 

Respectfully,
On behalf of the authors,

Pavlenko Petro
Corresponding Author 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

In light of the examination of the manuscript — focused on the application of Wire Arc Additive Manufacturing (WAAM) in maritime scenarios — it is evident that the document lacks the essential attributes required to be considered a high-impact scientific contribution. When assessed against methodological criteria typical of a scientific review, significant shortcomings are detected in both structure and analytical depth. The main weaknesses are summarized below:

• The manuscript does not specify the bibliographic search strategy (consulted databases, keywords, inclusion/exclusion criteria), which prevents the evaluation of the review’s exhaustiveness and reproducibility.

• It is not indicated whether quality filters were applied (e.g., by impact factor, level of evidence, or publication date), nor is there a comparative assessment of the cited sources.

• Although more than 100 references are cited, many are presented in an accumulative manner without critical integration. Comparative frameworks between technologies are not built, nor are key empirical results contrasted.

• Typical visual resources found in well-structured reviews — such as comparative technology tables, trend diagrams, or variable relationship charts — are not included.

• The text is mostly limited to compiling, describing, and evaluating existing technologies, methods, and materials for the WAAM process under maritime conditions, without strictly following a systematic scientific review protocol.

• Although the authors explicitly state that they developed their own automated system, the text does not provide quantitative data or sufficient experimental evidence (e.g., specific frequencies, measured amplitudes, number of replicated experiments, statistical analysis, etc.). This significantly undermines the scientific credibility of the study.

Author Response

Response to Reviewer №2

Dear Reviewer,

On behalf of the authors, I would like to express our sincere gratitude for your careful reading of the manuscript, your positive assessment of its content, and your constructive comments. We are especially thankful for your recognition of the scientific soundness and practical relevance of our study. Please find below our detailed responses and a description of the revisions made.

1. “In reviewing the manuscript dedicated to the application of Wire Arc Additive Manufacturing (WAAM) in marine scenarios, it becomes clear that the document lacks the essential attributes required to be considered a significant scientific contribution. Methodologically, the manuscript falls short of standards typical for a review article. Several key weaknesses are summarized below…”

Response:

We sincerely thank the reviewer for the detailed and constructive feedback. Your comments have significantly contributed to the refinement of our manuscript, and we highly value the time and expertise you have invested in its evaluation. Below, we respond point-by-point to each of your observations.

2. The manuscript does not indicate a bibliographic search strategy (databases used, keywords, inclusion/exclusion criteria), which prevents evaluation of completeness and reproducibility.

Response:

We appreciate this important observation. In response, we have now clearly indicated the sources of scientific data and bibliographic materials used in the manuscript. Specifically, we relied on scientific databases including Scopus, Web of Science. A clarification has been added in the revised manuscript (Section X), specifying that we limited our source selection to publications from the last 5 years (2000–2025), with a focus on peer-reviewed articles with technological, engineering, or experimental relevance to WAAM in maritime settings.

3. It is not stated whether quality filters were applied (e.g., impact factor, level of evidence, date), and no comparative assessment of cited sources is presented.

Response:

Thank you for raising this point. When selecting sources We have now clarified in the revised manuscript that publications were selected based on their relevance, citation frequency, and inclusion in Q1–Q2 quartile journals when available. However, we respectfully clarify that the manuscript was not intended as a systematic bibliographic review. Rather, it integrates methodological insights and applied findings from the authors’ experimental work with contextual literature. Nevertheless, we have included qualitative commentary on selected foundational sources to highlight their methodological contributions or industrial relevance where appropriate (e.g., in the Discussion section).

4. Despite citing over 100 references, many are presented cumulatively without critical integration. Comparative frameworks between technologies are not established, and key empirical results are not cross-analyzed.

Response:

We acknowledge this shortcoming and have restructured the Discussion section to emphasize comparative aspects. We now differentiate the technical capabilities and constraints of specific WAAM-related tools and materials more clearly. In particular, we added a comparative table (Table 4) summarizing the metallurgical behavior, weldability, thermal sensitivity, and corrosion performance of key alloys (e.g., Ti-6Al-4V, Inconel 718, 316L, S235) specifically in the context of WAAM under marine conditions. This provides readers with a clearer comparative understanding aligned with your recommendation.

5. Typical visual resources found in structured reviews—such as comparative technology tables, trend diagrams, or intervariable relationship diagrams—are not included.

Response:

Thank you for this valuable suggestion. As noted above, we have now added a comparative summary table focused on metallic alloys relevant to WAAM in maritime environments. This table synthesizes the complex material behavior under WAAM-specific conditions and enables a visual overview of practical implications for shipbuilding and offshore platforms.

6. The text is largely descriptive and does not adhere to a systematic scientific review protocol.

Response:

We fully understand your concern. However, we respectfully clarify that the manuscript was not conceived as a traditional systematic review. Drawing from our experimental experience with WAAM in dynamically changing conditions aboard marine vessels, our intent was to present an applied methodological study that synthesizes practical knowledge, system-level observations, and engineering insights into the optimization of WAAM tools under maritime constraints. We have revised the abstract and introduction to clearly reflect this applied scope, which combines selected literature with our own technical findings and field challenges.

7. Although the authors explicitly state that they developed their own automated system, the text does not provide quantitative data or sufficient experimental evidence (e.g., specific frequencies, measured amplitudes, number of replicated experiments, statistical analysis, etc.). This significantly undermines the scientific credibility of the study.

Response: (taken from the response to reviewer No. 1)

The adaptive automated Wire Arc Additive Manufacturing (WAAM) system has been thoroughly tested in both laboratory and shipboard environments (Figure 1). While the current automatic feedback control system has demonstrated promising performance, it is still undergoing optimization to enhance its stability and precision. We are actively refining its algorithms and control parameters, and the improved methodology will be detailed in a forthcoming publication. Additionally, our prior research on simulating shipboard conditions has yielded several peer-reviewed publications:

Comparative analysis of printing performance under land-based vs. shipboard conditions:
https://doi.org/10.1016/j.cjmeam.2023.100067 

Machine learning-based prediction of print quality:
https://doi.org/10.1007/s12666-025-03670-3

Advancement of shipboard printing via magnetic control technology:
https://doi.org/10.1016/j.mtcomm.2024.108035,
https://doi.org/10.1007/s11665-025-11183-9

Figure1  Real testing of the WAAM system on a ship

We are currently preparing a new article focused on quantitative experimental data and performance comparisons, which will substantiate the effectiveness of the proposed automated system. In accordance with your feedback, the present manuscript does not include preliminary claims regarding system performance.

We once again thank you for your valuable feedback, which has significantly improved the scientific rigor and overall quality of our work.

Respectfully,
On behalf of the authors,

Pavlenko Petro
Corresponding Author

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The key question of the authors concerns enhancing wire arc additive manufacturing for maritime applications. Their work is an example of an extensive review article. The subject of the work is essential for service work performed in marine and offshore environments. However, this work does not comprehensively solve any specific problem. In this work, which is exemplary in terms of content, there is no indication of the motivation why ship crews should perform service works during the cruise of sea vessels and not in a repair shipyard. Even if it is only a military application, the authors could mention it. With that in mind, their effort to undertake such a work would have been more understandable.
The authors attempted to present new additive manufacturing methods, and it would be difficult to add anything to this matter.
The conclusions submitted by the authors are correct. However, they unnecessarily mention scientific aspects when, indeed, the dominant character of this work is utilitarian and concerns applied research.
The only critical remarks concern the quality of the layout of three tables and the pointless double insertion of brackets “()” on page 39.

There is also no reference source in line 104.

 

Author Response

Response to Reviewer №3

Dear Reviewer,

On behalf of the authors, I would like to express our sincere gratitude for your careful reading of the manuscript, your positive assessment of its content, and your constructive comments. We are especially thankful for your recognition of the scientific soundness and practical relevance of our study. Please find below our detailed responses and a description of the revisions made.

1. Motivation for on-board maintenance vs. dockyard repair is not clearly stated. Even if it concerns military use, this should be explicitly mentioned.
   Response:

Thank you for this important comment. We fully agree that clarifying the motivation is critical for understanding the practical context of WAAM application on maritime platforms. In the revised version of the manuscript, the following clarification has been added to the section 3.1 WAAM Technology in Maritime Environments:

“The application of WAAM technology onboard vessels is particularly relevant in situations where urgent operational requirements necessitate at-sea repair or restoration work—such as during extended autonomous voyages, in remote areas, or when access to shipyard infrastructure is limited. This capability may prove critical for military, Arctic, or expeditionary missions where vessel downtime is either impossible or economically unfeasible.”

This addition improves the clarity of the rationale and emphasizes the relevance of the proposed approach not only from an engineering standpoint but also from logistical and strategic perspectives.

2. While the authors present novel additive manufacturing methods that are difficult to further improve upon, the conclusions overly emphasize scientific aspects, whereas the work is predominantly applied in nature.
   Response:

We appreciate your acknowledgment of the accuracy of our conclusions and the comprehensiveness of the analysis. We fully agree that the overall focus of the paper is applied and engineering-oriented. Accordingly, the “Conclusions” section has been revised to place greater emphasis on the practical implications and technological contributions of the research. The discussion of scientific elements (e.g., microstructural modeling) has been shortened and reframed to better reflect their application-oriented role. This revision aligns with your valid observation of the utilitarian character of the manuscript.

3. Critical remarks pertain to table formatting and a redundant set of parentheses on page 39. Additionally, a reference is missing in line 104.
   Response:

Thank you for your attention to editorial details. In response to your comments:

The duplicate parentheses have been removed. The missing reference has been inserted in line 104 as citation [12]. Tables 1–3 have been reformatted to enhance readability and ensure compliance with the journal’s formatting guidelines.

We sincerely appreciate your thoughtful evaluation of the core content and your specific comments, which have helped us to improve the manuscript’s scientific rigor, clarity, and editorial quality. We hope that the revisions made adequately reflect your recommendations and significantly enhance the manuscript’s value for the target academic and engineering audience.

Sincerely,
On behalf of all co-authors,
Corresponding Author

Pavlenko Petro

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised manuscript demonstrates a clear and commendable effort by the authors to address the major concerns raised in the initial review. The following key improvements have been made:

 

1. Although the experimental setup is now better described, the manuscript still lacks quantitative metrics demonstrating the effectiveness of the proposed system (e.g., bead geometry deviation, porosity levels, defect rates before/after stabilization). A comparative table or numerical summary of these effects—if available—would strongly reinforce the claims made.
2. The section describing the RMT model (lines 276–282) would benefit from additional methodological detail. Specifically, the authors should report the training dataset size, input features, model architecture, and performance metrics beyond RMSE/MAE. These clarifications are essential for reproducibility.
3. While the novelty of the proposed system is acknowledged, the manuscript could be strengthened by explicitly benchmarking its performance against other WAAM stabilization or monitoring approaches, whether commercial or experimental.

Author Response

For research article

Response to Reviewer 1 Comments
1. Summary
Dear Reviewer, We fully agree with your comments. They are professional and help us improve the paper.
2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Yes/Can be improved/Must be improved/Not applicable
Are all the cited references relevant to the research?	Yes/Can be improved/Must be improved/Not applicable
Is the research design appropriate?	Yes/Can be improved/Must be improved/Not applicable
Are the methods adequately described?	Yes/Can be improved/Must be improved/Not applicable
Are the results clearly presented?	Yes/Can be improved/Must be improved/Not applicable
Are the conclusions supported by the results?	Yes/Can be improved/Must be improved/Not applicable
3. Point-by-point response to Comments and Suggestions for Authors
Comments 1: While the experimental setup is now better described, the manuscript still lacks quantitative metrics demonstrating system effectiveness (e.g., weld geometry deviation, porosity levels, defect rates before/after stabilization). A comparative table or numerical summary of these effects, if available, would significantly strengthen the claims.
Response 1: We fully agree that quantitative metrics are critically important to substantiate the reported improvements. Accordingly, we have added new materials to the article summarizing the results of a recent experimental study on the deposition of ER50-6 steel under vibration conditions, both without stabilization and with the use of a longitudinal magnetic field (see from Line 330…). Data are presented on the reduction of geometric deviations, porosity levels, and defect rates, as well as improvements in mechanical properties. These results confirm the effectiveness of the proposed stabilization approach under conditions simulating real marine dynamics.
Comments  2: The section describing the RMT model (lines 276–282) would benefit from additional methodological detail. Specifically, the authors should report the training dataset size, input features, model architecture, and performance metrics beyond RMSE/MAE. These clarifications are essential for reproducibility.
Response 2: We fully agree with the reviewer that quantitative metrics are critical to substantiate the reported improvements. Accordingly, we have added new content summarizing results from a recent experimental study involving ER50-6 steel deposition under vibrational conditions, with and without stabilization via longitudinal magnetic fields ( see Line 330…). The data include reductions in weld geometry deviation, porosity, and defect occurrence, as well as measurable improvements in tensile and yield strength. These results support the effectiveness of the stabilization strategy under realistic marine-like dynamics.
Comments 3: While the novelty of the proposed system is acknowledged, the manuscript could be strengthened by explicitly benchmarking its performance against other WAAM stabilization or monitoring approaches, whether commercial or experimental.
Response 3: We thank the esteemed reviewer for this useful and constructive comment. In response, we have expanded the "Discussion" section (starting from Line 835) by highlighting the advantages of existing commercial solutions and the WAAM system discussed in the paper.
4. Additional clarifications
[Here, the sections revised for the second time were highlighted in green]

On behalf of all the authors,

Corresponding author,

Pavlenko Petro

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

After the latest round of revisions, the manuscript demonstrates a level of methodological soundness, clarity of exposition, and value to the community that warrants its acceptance. The authors have satisfactorily addressed all previously noted critical observations and have strengthened the work.

Author Response

For research article

Response to Reviewer 2 Comments
1. Summary
Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Yes/Can be improved/Must be improved/Not applicable
Are all the cited references relevant to the research?	Yes/Can be improved/Must be improved/Not applicable
Is the research design appropriate?	Yes/Can be improved/Must be improved/Not applicable
Are the methods adequately described?	Yes/Can be improved/Must be improved/Not applicable
Are the results clearly presented?	Yes/Can be improved/Must be improved/Not applicable
Are the conclusions supported by the results?	Yes/Can be improved/Must be improved/Not applicable
3. Point-by-point response to Comments and Suggestions for Authors
Comments 1:After the latest round of revisions, the manuscript demonstrates a level of methodological soundness, clarity of exposition, and value to the community that warrants its acceptance. The authors have satisfactorily addressed all previously noted critical observations and have strengthened the work.
Response 1:[Dear reviewer! We have made additional corrections to the text of the article. Details of the experimental studies and their results are provided. Line 330 and beyond. Added specific data to the RMT model and forecasting method. Line 284 and beyond. The discussion highlights the differences and features of the WAAM system discussed in the article in Line 835 line and beyond. On behalf of the team of authors, I would like to express my sincere gratitude to you for your valuable comments and recommendations. Thank you for pointing this out. I/We agree with this comment.
4. Additional clarifications
[Here, the sections revised for the second time were highlighted in green]

On behalf of all the authors,

Corresponding author,

Pavlenko Petro

 

Author Response File: Author Response.docx