Additive Manufacturing of Copper—A Survey on Current Needs and Challenges

Abstract

Additive manufacturing (AM) of copper is subject to dynamic development regarding available processes and the quality of produced parts. While challenging, AM processes for copper provide parts with a quality comparable to other metallic material groups like steels. The reasons for the lower prevalence of additive manufacturing of copper components in industrial applications are currently not sufficiently researched, especially in light of the significant progress made in the maturity of this technology. A survey is used to investigate the assessments of protagonists in the field of copper AM. The needs of current and potential users of copper AM are analyzed and outlined. This study reveals that the most relevant technical limitation for users is the reduced surface quality of parts, while overall processes need to become less costly and more reliable to find broader use. Answers given hint to a higher degree of automation, the possibility of multi-material processing, and the upscaling of machine and part sizes as relevant future trends in the copper AM sector.

1. Introduction

1.1. Additive Manufacturing of Copper Materials

Copper is used as a material in a wide range of technical applications due to its high electrical and thermal conductivity [1,2]. Manufacturing with additive processes provides significant potentials for copper and its applications, but is simultaneously challenging [2,3]. Additive manufacturing (AM) is not the only feasible way to produce copper parts, which are typically produced with processes like forging, machining, extrusion, casting and powder metallurgy. However, these processes lack flexibility regarding lot size and production time because of necessary steps before production, e.g., the provision or manufacturing of tooling equipment [4]. Processing complex and intricate structures poses an additional limitation of conventional manufacturing processes, which, even if possible, drives up the cost of production massively. The combination and grading of materials through additive manufacturing poses an opportunity for the creation of parts where mechanical and functional properties need to be altered within the part volume [4,5].

The properties of pure copper can be enhanced by alloying with other elements, particularly with regard to mechanical strength and the possibility of use under demanding service conditions [4]. These for example include high-temperature applications, applications in corrosive environments and the usage under high cyclic loading. Modern components that need to meet functional and mechanical requirements are often characterized by complex designs, which are only possible through comprehensive material processing and complex joining processes. The combination of the potential of AM processes and the properties of copper materials offers the opportunity to further increase the functionality and quality of copper components [2,6]. Complex designs with internal structures are often only feasibly manufactured with additive processes. These are design opportunities that have the potential to significantly contribute to technological development in several sectors, for example, the energy sector [7]. Mass customization and a lower amount of material waste when manufacturing complex structures are benefits [8,9,10]. Additionally, some of the technical and economic challenges in the production of complex functional components can be mitigated or completely eliminated by additive manufacturing processes. Lightweight parts which make use of topology optimization and monolithic designs for aerospace applications are one example [11]. Utilizing the extraordinary thermal conductivity of copper materials and AM, high performing heat exchangers, rocket engine combustion chambers and parts with thermocouple sensor integration are possible to manufacture [12,13]. In material-locking connections, the combination of copper and aluminum allows for the development of lighter heat exchangers, utilizing copper only where necessary [13]. Novel product design methods become increasingly important to consider and utilize these potentials [14].

Besides design opportunities, there is a metallurgical component to the potentials of additive manufacturing [11,15,16]. For copper alloys, there are opportunities to control the size and shape of metallic grains within the copper matrix, as well as to influence the dissolution and precipitation of alloying elements through process adjustments.

For processes similar to laser powder bed fusion (LPBF), changes in the electrical conductivity of additively manufactured copper specimens can be observed, exceeding the international annealed copper standard (IACS) up to 2% [17]. However, the condition for a specimen with an electrical resistance identical to or lower than conventionally manufactured copper is a low number of defects. Pores, impurities and dislocations in the atomic lattice structure result in a lower electrical conductivity. Due to the challenges of manufacturing copper via LPBF, some findings also show a severely reduced conductivity after laser powder bed fusion, with a porosity of 15% resulting in a 68.9% conductivity of copper compared to the IACS [18]. Megahed et al. present results for the additive manufacturing of copper with electron beam melting, reaching relative densities of 99.99%. Their study finds an electrical conductivity of 66% IACS, which further proves the influence of factors besides the relative density, such as grain boundary angles and the chemical composition [19].

A wide range of processes is available for the additive manufacturing of copper components [2,3]. The selection of processes feasible for the manufacturing of copper parts ranges from, but is not limited to, processes with laser or electron beams, binder jetting (BJ) for the production of preforms and consequent sintering as an indirect processing route, as well as metal fused deposition modeling (MFDM) [2,4,20].

1.2. Properties of Additively Manufactured Copper Components and Material Specimens

Differences between copper samples and components can be observed when comparing conventionally and additively manufactured ones. Current research shows that these differences are becoming increasingly less pronounced. Figure 1 summarizes the results for selected mechanical, functional and surface properties, and the results are presented in a normalized form. The sample condition R290 as defined by the DIN EN 13599 standard for Copper Electrolytic Tough Pitch (Cu-ETP) is used to provide values for comparison [21]. Properties from additive processes are compared to a tensile strength of 290 MPa, an electrical conductivity of 57 MS/m and a thermal conductivity of 394 W/mK. The C11000 supplier standard from KME SE is used to provide a value for the surface roughness. The lowest roughness for a sheet thickness of 0.1 mm is Ra = 0.13 µm. The comparison is aimed to provide the best currently achievable values of common copper AM processes to provide insight for the assessment of process capabilities. LPBF as a commonly used processing method can provide a tensile strength of 290 MPa and a thermal conductivity of 415 W/mK. The surface roughness is vastly higher, with an Ra value of up to 20 µm [20]. Binder jetting results in significantly lower performing parts, with a reported tensile strength of 177 MPa and thermal conductivity of 328 W/mK [22]. For the electrical conductivity of copper parts manufactured by LPBF and BJ, similar values of 57 and 52 MS/m, respectively, can be observed [23].

It has been shown that, compared to a conventional delivery standard for semi-finished copper products, properties of significantly different quality can be achieved using additive manufacturing processes. While there are significant deviations in mechanical properties and information about surface roughness for some processes such as binder jetting is significantly limited or not available at all, there exist great similarities in functional properties between conventional and additive manufacturing. As requirements are subject to changes regarding the application in parts, these differences are highly relevant. The application of AM in prototyping may allow differences in part and material properties [24].

Overall, the technologies of copper AM are caught between sufficient technological maturity for use in certain applications, while research projects are generally still focused on fundamental objectives [4]. These include achieving a high relative density and matching the functional and mechanical properties of conventionally manufactured copper components. Based on existing research, this study will present the results of a survey aimed at shedding light on the exact reasons that are slowing down the further adoption of copper additive manufacturing. Possible shortcomings and limitations of the study are discussed. The derived findings can be used to evaluate the focus of current research and aims to provide a new impetus for future research projects as well as to facilitate the application of additive manufacturing in the copper industry. In summary, the following research question in going to be answered: what is currently hindering the further adoption of the seemingly sufficiently matured technology of AM for copper parts?

2. Materials and Methods

Based on the state of research, a questionnaire was developed and distributed via Google Forms. Relevant industry professionals were invited to participate in the survey, which includes answers given between 22 October 2024 and 8 January 2025. Contact was made via electronic mail and LinkedIn. The contacts originate from research about institutions related to the copper industry. These include companies from the fields of semi-finished copper product manufacturing and component manufacturing as well as research and development in the copper sector. The investigation of possible participants was based on a two-part approach: the examination of relevant companies and of individuals working in the copper sector directly. Industry networks and interest groups like the Kupferverband e.V., an association of companies of the copper industry based in Germany, served as a starting point. Employees in relevant positions of companies engaged in the Kupferverband were contacted via LinkedIn. The Institute of Product Development and Machine Elements further promoted the survey through its network of contacts on LinkedIn. Overall, nearly 300 people were contacted directly with an invitation to this survey.

In order to encourage participants to share their opinions and insights, the survey was conducted anonymously. All participants were informed that their answers would be used for research and publication in a scientific paper.

The content of the questionnaire and the answer options are based on the current state of research about the additive manufacturing of copper. The questions primarily address technical challenges, but regulatory problems and the level of information on available additive manufacturing options are queried as well. While the predefined answers are based on the most likely responses, optional free text responses were permitted for most of the questions.

In order to reduce the scope of interpretation, some answer options are provided with explanatory additions. These should create clearer possibilities for differentiation and explain the meaning of the answer options. These are shown in the ‘Answer Options’ column in Table 1, Table 2 and Table 3. To encourage potential participants not familiar with the topic of additive manufacturing, the term 3D printing was used in this survey, even though it is not the scientific term commonly used in research. For this paper, only the term additive manufacturing is used. The questions were divided into three sections: demographic information, and general and specific questions.

The demographic section as presented in Table 1 is designed to describe the participants and to classify their answers regarding relevance and viewpoint. The first question concerns the country of origin which helps to assess local characteristics and to determine whether a representative group of participants could be addressed. A geographical focus of interests related to the topic of this study can be identified in this way. Being aware about the specific sectors and industries of origin plays an important role in the evaluation of answers and certain requirements formulated by the participants. The answers to this 2nd question are also suitable for validating whether all participants come from a very similar industry environment and therefore results may disproportionally reflect a certain point of view. The participant’s professional position is important against the background of the strong differences in the views of users and interested parties in the technology field that is the subject of this study. Employees of companies in commercial sectors may show different priorities when assessing technological maturity and problems than managers or individuals from an academic environment. The professional backgrounds of the participants are therefore taken into account by question 3.

Table 1. Overview of the questions and answer options given in the online survey in the demographics section of this study.

#	Question	Answer Options	Multiple Answers Possible?
1	Which country are you from?	List of 195 countries and regions	No
2	Which sectors or industries are you working in?	Plant and mechanical engineering Manufacturing Maritime applications Mobility Building and construction Electrical engineering and energy Research Optional free text response	Yes
3	What is your current position?	Student (in training) Technician (laboratory, production) Engineer (planning, supervision) Manager (administrating research or production) Optional free text response	No

Table 1. Overview of the questions and answer options given in the online survey in the demographics section of this study.

#	Question	Answer Options	Multiple Answers Possible?
1	Which country are you from?	List of 195 countries and regions	No
2	Which sectors or industries are you working in?	Plant and mechanical engineering Manufacturing Maritime applications Mobility Building and construction Electrical engineering and energy Research Optional free text response	Yes
3	What is your current position?	Student (in training) Technician (laboratory, production) Engineer (planning, supervision) Manager (administrating research or production) Optional free text response	No

Table 2 shows the questions for the general part of the questionnaire which are designed to be answered by as many participants as possible. In terms of content, questions 4 and 5 aim to evaluate the experiences of the study participants with additive manufacturing. Question 6 serves to clarify whether participants have previous experience with AM of copper components. Questions 7, 8 and 9 relate to AM-specific technical challenges, but can essentially be answered by anyone, regardless of experience with AM. The possible answers allude to the most common difficulties and opportunities of additive manufacturing processes. Participants can also choose from a selection of advantages of additive manufacturing that were considered particularly relevant.

Table 2. Overview of the questions and answer options given in the online survey in the general section of this study.

#	Question	Answer Options	Multiple Answers Possible?
4	How long have you worked with 3D printing processes?	No experience Less than 2 years experience 2 to 5 years of experience More than 5 years experience More than 10 years experience	No
5	Which AM technologies are you familiar with (know about, worked with)?	With no AM technology Processes for polymer materials (e.g., FFF, SLS, SLA) Processes for metallic materials (e.g., LPBF, DED, EBM) Optional free text response	Yes
6	What are your experiences with additively manufactured copper parts?	I don’t have experience with AM copper parts I know about specific parts and their manufacturers I tested additively manufactured copper parts for my industry I apply additively manufactured copper parts for my industry Optional free text response	No
7	Based on AM-specific challenges: What do you perceive as the biggest barriers to the widespread adoption of AM for copper parts?	Higher costs Technical limitations (achievable part properties) Flaws in production (deviations from the production standard) Lack of awareness (possibilities of copper AM unknown) Regulatory issues (e.g., certifications for the automotive or aerospace sector) Optional free text response	Yes
8	What improvements would you prioritize to promote the use of AM for copper components in your industry?	Cost reduction Process reliability Achieving material properties identical to conventionally processed copper Optional free text response	Yes
9	Which of the potentials offered by additive manufacturing of copper components are most relevant for your industry?	Production without specific tools Production with short lead times Manufacturing of complex shapes, undercuts, hollow structures Manufacturing of individual parts or prototypes Monolithic design, combining of components Integration of components like sensors during manufacturing Lower overall resource consumption and environmental footprint Optional free text response	Yes

Table 2. Overview of the questions and answer options given in the online survey in the general section of this study.

#	Question	Answer Options	Multiple Answers Possible?
4	How long have you worked with 3D printing processes?	No experience Less than 2 years experience 2 to 5 years of experience More than 5 years experience More than 10 years experience	No
5	Which AM technologies are you familiar with (know about, worked with)?	With no AM technology Processes for polymer materials (e.g., FFF, SLS, SLA) Processes for metallic materials (e.g., LPBF, DED, EBM) Optional free text response	Yes
6	What are your experiences with additively manufactured copper parts?	I don’t have experience with AM copper parts I know about specific parts and their manufacturers I tested additively manufactured copper parts for my industry I apply additively manufactured copper parts for my industry Optional free text response	No
7	Based on AM-specific challenges: What do you perceive as the biggest barriers to the widespread adoption of AM for copper parts?	Higher costs Technical limitations (achievable part properties) Flaws in production (deviations from the production standard) Lack of awareness (possibilities of copper AM unknown) Regulatory issues (e.g., certifications for the automotive or aerospace sector) Optional free text response	Yes
8	What improvements would you prioritize to promote the use of AM for copper components in your industry?	Cost reduction Process reliability Achieving material properties identical to conventionally processed copper Optional free text response	Yes
9	Which of the potentials offered by additive manufacturing of copper components are most relevant for your industry?	Production without specific tools Production with short lead times Manufacturing of complex shapes, undercuts, hollow structures Manufacturing of individual parts or prototypes Monolithic design, combining of components Integration of components like sensors during manufacturing Lower overall resource consumption and environmental footprint Optional free text response	Yes

The last section of the survey form consists of five specific questions listed in Table 3 and is optional. These questions can only be answered in a qualified manner if the survey participant in question has expert insights into the needs of the copper processing industry. Ideally, the respondent already had an idea about copper additive manufacturing before taking part in the survey, so that an informed answer to the questions is possible. If this is not the case, however, the answer options themselves provide sufficient impetus to respond. Overall, the aim of the questions in the specific section, particularly with regard to the general section, is to further sharpen the content of the answers. The different domains of technical properties and possible defects are covered by these questions. The knowledge the specific section offers researchers in the field of copper AM lies in the possibility of being able to derive a precise focus of research and development needs. It is also possible to assess when the manufacturing process has reached a sufficient level of maturity by asking participants about less relevant properties and specifying which deviations from conventionally manufactured copper are permissible. The last questions are aimed at a final evaluation of applicability of copper AM and also provides the participants with an opportunity to answer the overall intent of the survey directly to share their personal assessment.

Table 3. Overview of the questions and answer options given in the specific and optional part of this study.

#	Question	Answer Options	Multiple Answers Possible?
10	What do you perceive as the main technical barriers to the adoption of AM for copper in your industry?	Reduced mechanical properties Reduced thermal properties Reduced electrical properties Limited surface quality Reduced shape accuracy Limited part size Optional free text response	Yes
11	To utilize potentials offered by additive manufacturing, which negative aspects of AM are acceptable for the application of copper parts in your industry?	Reduced electrical conductivity Reduced thermal conductivity Reduced surface quality Reduced mechanical properties Optional free text response	Yes
12	To what degree are diminished material properties acceptable in your industry?	≤1% ≥1% ≥5% ≥10%	No
13	Considering all positive aspects (e.g., production on demand, design freedom, toolless manufacturing) and negative aspects (e.g., size limitations, diminished material properties), what is your personal assessment about the quality of AM copper parts?	I do not have sufficient experience for an assessment The overall quality is not sufficient for my industry The overall quality is sufficient for my industry The overall quality is sufficient, and copper AM is applied in my industry Optional free text response	No
14	Which of the following AM trends do you believe could promote increased adoption of AM for copper parts in your industry?	Higher degree of automation of AM systems Multi-material printing Upscaling of machines and part sizes Optional free text response	Yes

Table 3. Overview of the questions and answer options given in the specific and optional part of this study.

#	Question	Answer Options	Multiple Answers Possible?
10	What do you perceive as the main technical barriers to the adoption of AM for copper in your industry?	Reduced mechanical properties Reduced thermal properties Reduced electrical properties Limited surface quality Reduced shape accuracy Limited part size Optional free text response	Yes
11	To utilize potentials offered by additive manufacturing, which negative aspects of AM are acceptable for the application of copper parts in your industry?	Reduced electrical conductivity Reduced thermal conductivity Reduced surface quality Reduced mechanical properties Optional free text response	Yes
12	To what degree are diminished material properties acceptable in your industry?	≤1% ≥1% ≥5% ≥10%	No
13	Considering all positive aspects (e.g., production on demand, design freedom, toolless manufacturing) and negative aspects (e.g., size limitations, diminished material properties), what is your personal assessment about the quality of AM copper parts?	I do not have sufficient experience for an assessment The overall quality is not sufficient for my industry The overall quality is sufficient for my industry The overall quality is sufficient, and copper AM is applied in my industry Optional free text response	No
14	Which of the following AM trends do you believe could promote increased adoption of AM for copper parts in your industry?	Higher degree of automation of AM systems Multi-material printing Upscaling of machines and part sizes Optional free text response	Yes

3. Results

In total, 36 replies reached the authors of this study. This number of survey participants is within the expected and feasible range for the investigation of complex research questions in highly specialized subject areas [25,26]. Over 250 individuals worldwide were contacted directly.

3.1. Demographic Section

Figure 2 highlights the country of origin of participants. With 24 responses from Germany, there is a clear focus on the origin of the study participants. Three responses were received from the UK, and one response each was submitted from Austria, Brazil, Canada, China, France, India, Poland, Switzerland and the United States of America. This means that exactly two thirds of the participants came from Germany. Nevertheless, the remaining third of responses offers a significant international perspective. The country of origin of study participants overlaps with countries from which research results in the field of additive manufacturing of copper originate. Besides considerable research from Germany [19,27,28,29,30,31,32,33], researchers based in, but not limited to, France [17,34], China [35,36,37], North America [38,39,40], Poland [23], the United Kingdom [18] and Australia [41] are contributing significantly to the development of copper AM.

Figure 3 shows that participants frequently took advantage of the possibility for describing their field of activity more precisely by giving multiple answers. The 36 study participants in total gave 52 answers regarding their sector of work. The multiple answers show that many participants often deal with cross-sectional topics and cannot be clearly assigned to one single sector. There is a clear focus on research and general manufacturing technologies. Mechanical and plant engineering as well as energy technology are further expected regions of interest. The sporadic mention of other sectors such as construction, aerospace and mobility underlines the importance of copper for a wide range of industries, even though representatives of these fields took part in the study much less frequently. The overall focus on research was expected in view of the novelty of the topic and the existing challenges, which do not allow the reliable use of AM for copper components.

There also is an emphasis on the position of study participants; as shown in Figure 4, a majority of them are engineers. According to the definition of the answers, these 19 participants take on planning and monitoring activities in the operational area. Only six participants are managers and therefore have an administrative role. An additional four participants work at a commercial level in production or component testing, and the two remaining are enrolled in training of some kind. Despite the participants’ predominant activities in the field of research, only five participants explicitly stated an academic position with two being professors and three indicating to be research assistants or PhD students.

The results of the demographic section can be summarized as follows: the typical study participant comes from Germany, is an engineer and works in the field of research. This research often takes place in the context of specific industries.

3.2. General and Specific Section: Additive Manufacturing of Copper Components

As Figure 5 clearly indicates, most of the study participants are familiar with additive manufacturing technologies. Seventeen participants stated that they had more than five years of experience in this field with an additional five participants even reporting more than 10 years. According to their own statements, 12 participants have between two and five years of experience, which can be considered a significant amount of time in the comparatively young business environment of additive manufacturing. Only seven participants report either less than two years of experience with AM or none at all. Overall, it can therefore be stated that this is a group of participants who have a sufficient amount of experience in AM. This is also underlined by the answers given regarding experience with process groups in the AM field. Only two participants reported that they had no experience with AM processes, while one participant explicitly mentioned that they had experience with additive manufacturing in the field of ceramic materials. All other participants indicated that they had experience with the common AM processes for polymer materials and metal. The distribution of answers for experience in the additive manufacturing of copper components is significantly more uniform compared to the two previous questions. Ten participants have no experience with additively manufactured copper components, while eleven are at least familiar with AM components made of copper and their corresponding manufacturers. Fifteen participants use copper components, have at least tested them for their industry or are actively doing research on them. Overall, the typical study participant has a cross-sectional knowledge of various AM processes and material groups, with at least two or more years of experience. Typical polymer and metal processes are known to most participants. The experience with copper parts is more mixed, as the reported experiences range from no experience to testing and already applying AM copper parts in their own field of work.

Next, the answers related to questions from the general and specific section, specifically to questions 7, 8 and 10, are examined. The answers given, regarding the obstacles to the further adoption of AM in the copper sector in relation to AM-specific challenges, already paint a clear picture. Only two participants took the opportunity to provide further information. This and the common selection of the predefined answer options shows that the assumptions these answer options provide match the perception of the participants. In line with the current state of research, several different obstacles, such as costs, technical limitations or production errors based on the challenging processing are identified. One participant also emphasized the high reflectivity of copper as an important barrier. In this regard, researchers assert that adjusted strategies for processing, like preheating and slower laser scanning speeds, are not sufficient to completely offset the low absorption rate for infrared lasers [42]. Another participant also emphasized higher costs as a problem, but mentioned that certain applications are only possible with AM processes. This statement further supports the consideration of the aforementioned potentials of copper AM compared to costs [40,43].

The selected answers as presented in Figure 6 clearly show that regulatory issues do occur, but prove to be much less of an obstacle for the participants in this study than the technical limitations of copper AM. High cost, production errors and insufficient knowledge of this comparatively young manufacturing technology were mentioned less often, but all with roughly the same prevalence.

The most commonly selected technical deficiency of the AM process for copper was surface quality. Participants furthermore mentioned through free text the higher costs as a consequence of technical limitations, as well as the low technological maturity and challenges in the scalability. Unfortunately, it is not clarified whether the participant in question referred to the scalability of part or lot sizes. Process stability is a general AM issue, but was addressed specifically for copper in earlier research [44]. Nevertheless, it is still frequently mentioned in the conducted survey. Another participant alluded to the lower productivity and higher cost connected to producing and handling powder. As more research is conducted, aimed at exploiting the potentials of copper AM and mitigating its challenges, the situation is expected to change in favor of copper AM [45].

Despite the mentioned problems regarding technical performance, the participants prioritize process reliability and costs when asked about the biggest potential improvements that could further adoption. In third place and with significantly fewer mentions was the matching or exceeding of part properties compared to conventionally manufactured copper components listed. An increase in productivity or awareness of AM technologies in the copper sector is considered negligible. These results match with the overall AM issues of cost and reliability. Copper is then mostly used for its outstanding functional properties, which is reinforced by the fact that mechanical properties are not seen as a particular barrier for the application of copper AM. Thermal and electrical properties are mentioned only slightly more often, which was not anticipated, since these are key properties that distinguish copper from other materials. The limited surface quality was mentioned by far the most. Although these limitations in surface quality can be overcome by means of post-processing, the necessary additional efforts add to the already higher costs.

The next set of questions from the specific part of the survey presented by Figure 7 is aimed at the technical compromises that users of copper AM are prepared to make and the exact potentials they want to use in return. Among the relevant potentials that users want to benefit from, there is a clear focus on complex structures and undercuts, as well as on the ability to manufacture one off components and prototypes more easily. In contrast there is significantly less interest in the integration of components or any potential improvement with regard to environmental impact. One participant emphasized the targeted control of the microstructure of parts and mechanical properties as an AM potential for their industry. This rare mention of the metallurgical aspects is in harsh contrast to the previously conducted research about these aspects, especially regarding copper alloys [46,47,48]. Question 9 asked the participants to state their perception of the most relevant potentials of copper AM. The answers given match the market situation for AM in general. Unique selling points like individualization and new design possibilities are most commonly demanded.

The answers to question 11 as to which negative characteristics can be accepted by the survey participants show a graded result as well. A notable portion of five participants did not answer, while most of the answers identified mechanical properties as a domain in which reduced part properties are acceptable. With 7 and 10 responses, respectively, thermal and electrical properties were mentioned less frequently. Several free text answers were given to this question. One participant emphasized the elimination of expensive tools and molds through AM processes, which can justify a reduced component quality. One respondent mentioned porosity as an answer to acceptable reduced properties. Although this answer differs from the answer options given, these are related to relative density and therefore porosity. By pointing out that subsequent machining of surfaces is always necessary, another participant further supports the default answers given with regard to acceptable deviations in surface quality. According to the answers to question 12 on the permissible degree of deviations in properties, it can be deduced that in most cases deviations of between one and ten percent are permissible. These answers are consistent with the overall assessment of the use of copper as presented in the introduction of this work. Notably, seven participants did not answer this question.

The evaluation of the answers regarding the assessment of the participants on the applicability of copper AM reveals a divided opinion of the participants. As shown in Figure 8, most of the participants do not feel capable to make an assessment, with a total of 18 people who did not give a precise answer. A small proportion of six people rated the quality of AM-manufactured components as sufficient for their own applications. However, twice as many respondents rated the quality as insufficient. One participant explicitly emphasized that the quality is sufficient and that AM is used for their field of work. Another participant did not give a clear answer, as they work in research and as of their current progress a clear statement about the usability was not possible. For another participant, the perfect application regarding the potential of component complexity, required properties and batch sizes to justify the higher costs of production using AM is still missing. The findings of the study support the statement by Nemani et al. regarding the limited application of copper AM in comparison to the additive manufacturing of other metallic materials [4]. Most of the participants of the study have at least to some degree experience with additive manufacturing, with only 6% stating that they have no experience at all. Still, 42% state that it is not possible for them to make an assessment about the applicability of copper. To some degree diminished material or part properties are acceptable to users.

Several free text answers were also given to the question of future trends. Greater process stability and reduced costs were mentioned, although these are less trends in the spirit of the question than areas for improvement. In addition to the possibility of processing different materials in one process, one participant emphasized new production technologies with regard to different laser wavelength in the green and blue spectrum. Once again, the topic of adjusting special material properties using additive manufacturing was mentioned in another response. As the most frequent answer, a greater degree of automation was mentioned, with increased size of machines and components and the simultaneous processing of several materials falling not far behind.

The largest identifiable homogeneous group of participants consists of people from Germany who have an academic background in their employment. Therefore, the interaction of belonging to this group and the answers given are also considered. The answers from this group are not in direct contrast to the overall answers, but there are slight differences in the focus of some answers to questions. This group of participants has a higher proportion of people who already have experience with copper AM. Surface quality is seen as a less relevant technical obstacle, while reduced electrical and thermal properties are considered to be more important. A different focus is also evident in the view of which improvements should be prioritized. The need to produce copper with comparable material properties to conventionally produced copper and to be able to carry out the production processes with a high level of reliability are seen as ahead of cost reduction. The group in question sees the processing of several materials in one production process as more relevant for contributing to the further spread of copper AM than a higher degree of automation, which is a focus of the overall responses.

A comprehensive list of all answers collected in the study can be found in Appendix A in

Table A1. Summary of all collected answers.

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Brazil

Plant and mechanical engineering, Manufacturing

Manager (administrating research or production)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA)

I don’t have experience with AM copper parts.

Higher costs, Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability

Production without specific tools, Production with short lead times, Manufacturing of individual parts or prototypes

Although cost might not be a technical barrier I see it as the main reason, together with the maturity of the technology (not stable yet) and reduced scalability

Reduced electrical conductivity, Reduced thermal conductivity, Reduced surface quality, Reduced mechanical properties, The advantages to be able to produce a part without expensive tools or molds are important and will allow a reduced quality to some extent

≥10%

I do not have sufficient experience for an assessment.

Better machine process stability, and cost reduction

UK

Manufacturing

Technician (laboratory, production)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Higher costs, Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Cost reduction, Process reliability

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality, Reduced shape accuracy

Reduced electrical conductivity

≥5%

The overall quality is not sufficient for my industry.

China

Manufacturing

Manager (administrating research or production)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Technical limitations (achievable part properties)

Process reliability

Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality

Reduced mechanical properties

≥1%

The overall quality is not sufficient for my industry.

Upscaling of machines and part sizes

France

Manufacturing, Research

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Technical limitations (achievable part properties), Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of individual parts or prototypes

Limited surface quality, Reduced shape accuracy

Reduced electrical conductivity, Reduced mechanical properties

≥5%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems

UK

Electrical engineering and energy

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA)

I don’t have experience with AM copper parts.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Cost reduction

Production with short lead times, Manufacturing of individual parts or prototypes

Reduced electrical properties

Reduced thermal conductivity, Reduced mechanical properties

≥1%

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems, Multi-material printing

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Canada

Research

Professor

More than 10 years experience

Processes for metallic materials (e.g., LPBF, DED, EBM), Ceramics

I apply additively manufactured copper parts for my industry.

It depends on the application. For some it is the only solution and for others it is very costly

Cost reduction, Process reliability

Production without specific tools, Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Monolithic design, combining of components, Integration of components like sensors during manufacturing

Limited surface quality, Oxidization

Porosity

≤1%

The overall quality is sufficient for my industry.

Higher degree of automation of AM systems, Upscaling of machines and part sizes

Switzerland

Research

Manager (administrating research or production)

More than 10 years experience

Processes for metallic materials (e.g., LPBF, DED, EBM)

I do research on additively manufactured copper parts

Higher costs, Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Process reliability

Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components

Limited surface quality, Reduced shape accuracy, Limited part size

Reduced surface quality

≥5%

N/A - we are doing research

Multi-material printing, new AM processes (e.g., green/blue laser AM)

India

Research

Manager (administrating research or production)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Technical limitations (achievable part properties)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Integration of components like sensors during manufacturing

Reduced mechanical properties, Limited surface quality

Reduced surface quality, Reduced mechanical properties

≥5%

The overall quality is sufficient, and copper AM is applied in my industry.

Multi-material printing, Upscaling of machines and part sizes

UK

Plant and mechanical engineering, Manufacturing

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Higher costs, Technical limitations (achievable part properties), Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components, Integration of components like sensors during manufacturing

Reduced thermal properties, Limited surface quality

Reduced electrical conductivity, Reduced mechanical properties

≥1%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Poland

Manufacturing, Research

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Higher costs, Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Production without specific tools, Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components

Reduced thermal properties, Limited surface quality, Limited part size

Reduced electrical conductivity

≥5%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems, Multi-material printing, Upscaling of machines and part sizes

Germany

Electrical engineering and energy, Research

Engineer (planning, supervision)

Less than 2 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Higher costs, Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Cost reduction, Process reliability

Production with short lead times, Manufacturing of individual parts or prototypes, Monolithic design, combining of components, Lower overall resource consumption and environmental footprint

Reduced electrical properties, Limited surface quality, Reduced shape accuracy

Reduced mechanical properties

≥5%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems, Multi-material printing

Germany

Manufacturing, Research, aero

Engineer (planning, supervision)

More than 10 years experience

Processes for metallic materials (e.g., LPBF, DED, EBM)

I apply additively manufactured copper parts for my industry.

Lack of awareness (possibilities of copper AM unknown)

Cost reduction, production rate

Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Reduced shape accuracy, Limited part size

The overall quality is sufficient for my industry.

Multi-material printing, Upscaling of machines and part sizes

USA

Plant and mechanical engineering, Manufacturing

Technician (laboratory, production)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Higher costs, Technical limitations (achievable part properties)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality, Reduced shape accuracy, Limited part size

Reduced electrical conductivity

≥5%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems, Upscaling of machines and part sizes

Germany

Plant and mechanical engineering

Managing Director

No experience

With no AM technology

I don’t have experience with AM copper parts.

Higher costs, Technical limitations (achievable part properties)

Cost reduction, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures

Reduced mechanical properties, Limited part size

Reduced electrical conductivity, Reduced thermal conductivity

≥ 5%

I do not have sufficient experience for an assessment.

Multi-material printing, Upscaling of machines and part sizes

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Germany

Research

Research Assistant

Less than 2 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Process reliability

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality, Reduced shape accuracy

Reduced mechanical properties

The overall quality is not sufficient for my industry.

Germany

Plant and mechanical engineering, Research

Research Assistant

Less than 2 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I additively manufactured copper parts for research.

Technical limitations (achievable part properties), Lack of awareness (possibilities of copper AM unknown)

Process reliability

Manufacturing of complex shapes, undercuts, hollow structures, Monolithic design, combining of components

Higher degree of automation of AM systems, Multi-material printing

Germany

Manufacturing, Research

PhD Student

Less than 2 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Higher costs, Technical limitations (achievable part properties), Reflectivity of copper for laser based technologies

Cost reduction, Process reliability

Manufacturing of complex shapes, undercuts, hollow structures

Reduced mechanical properties, Reduced electrical properties, Limited surface quality, Reduced shape accuracy, High costs for powder production and handling, as well as low throughput

I do not have sufficient experience for an assessment.

Achieving and adjusting special material properties through additive manufacturing

Germany

Research

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Flaws in production (deviations from the production standard), Regulatory issues (e.g., certifications for the automotive or aerospace sector)

Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Lower overall resource consumption and environmental footprint

Reduced thermal properties, Limited part size

Reduced surface quality, Reduced mechanical properties

≥1%

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Germany

Manufacturing, Mobility, Electrical engeneering and energy

Engineer (planning, supervision)

2 to 5 years of experience

With no AM technology

I don’t have experience with AM copper parts.

Higher costs, Technical limitations (achievable part properties), Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Achieving material properties identical to conventionally processed copper

Production without specific tools, Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Reduced mechanical properties, Reduced thermal properties, Reduced electrical properties, Limited part size

Reduced surface quality

≥1%

I do not have sufficient experience for an assessment.

Multi-material printing, Upscaling of machines and part sizes

Germany

Building and construction

Technician (laboratory, production)

Less than 2 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Higher costs, Lack of awareness (possibilities of copper AM unknown)

Cost reduction

Manufacturing of complex shapes, undercuts, hollow structures

≥5%

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems

Germany

Plant and mechanical engineering

Engineer (planning, supervision)

More than 10 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Lack of awareness (possibilities of copper AM unknown)

More awareness and distribution of information about AM potentials and options

Production without specific tools, Manufacturing of complex shapes, undercuts, hollow structures

Reduced electrical properties

Reduced surface quality

≥5%

I do not have sufficient experience for an assessment.

Germany

Plant and mechanical engineering

Engineer (planning, supervision)

2 to 5 years of experience

Processes for metallic materials (e.g., LPBF, DED, EBM)

I apply additively manufactured copper parts for my industry.

Higher costs, Technical limitations (achievable part properties)

Cost reduction, Process reliability

Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality, Reduced shape accuracy

Reduced thermal conductivity, Reduced mechanical properties

≥5%

The overall quality is sufficient for my industry.

Germany

Research

Engineer (planning, supervision)

More than 10 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Higher costs

Cost reduction, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components

Reduced thermal properties, Reduced electrical properties, Always looking for the perfect application

Reduced surface quality, Reduced mechanical properties

≤1%

There is no perfect application in terms of complexity, required properties, batch size, etc. to justify the higher costs

Higher degree of automation of AM systems, Multi-material printing

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Germany

Manufacturing, Electrical engeneering and energy, Research

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I apply additively manufactured copper parts for my industry.

Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Process reliability, Achieving material properties identical to conventionally processed copper

Production with short lead times, Manufacturing of individual parts or prototypes

Reduced mechanical properties, Reduced electrical properties

Reduced electrical conductivity, Reduced thermal conductivity

≥1%

The overall quality is sufficient for my industry.

Multi-material printing, Upscaling of machines and part sizes

Germany

Manufacturing

Manager (administrating research or production)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Higher costs, Technical limitations (achievable part properties), Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability

Manufacturing of complex shapes, undercuts, hollow structures

Reduced thermal properties, Limited surface quality

Reduced mechanical properties

≥5%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems

Germany

Research

Student (in training)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Higher costs, Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components

Reduced thermal properties, Reduced electrical properties

Reduced surface quality, Reduced mechanical properties

I do not have sufficient experience for an assessment.

Multi-material printing, Upscaling of machines and part sizes

Germany

Research

Professor

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I apply additively manufactured copper parts for my industry.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Lower overall resource consumption and environmental footprint

Reduced electrical properties, Limited part size

Reduced thermal conductivity, Reduced surface quality

≥1%

The overall quality is sufficient for my industry.

Multi-material printing

Germany

Manufacturing

Student (in training)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Regulatory issues (e.g., certifications for the automotive or aerospace sector), Time restrictions (general problem of AM)

Cost reduction, Process reliability

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Limited surface quality

Reduced mechanical properties

≥5%

N/A

Higher degree of automation of AM systems

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Austria

Metallindustrie

Technician (laboratory, production)

No experience

Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Technical limitations (achievable part properties)

Achieving material properties identical to conventionally processed copper

Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes

Reduced thermal properties, Reduced electrical properties, Limited part size

Reduced electrical conductivity, Reduced thermal conductivity

≤1%

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems

Germany

Research

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Lower overall resource consumption and environmental footprint

Reduced mechanical properties, Reduced thermal properties, Reduced electrical properties, Reduced shape accuracy, Limited part size

Reduced surface quality

≥1%

I do not have sufficient experience for an assessment.

Upscaling of machines and part sizes

Germany

Plant and mechanical engineering, Electrical engeneering and energy

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Production without specific tools, Manufacturing of complex shapes, undercuts, hollow structures, Lower overall resource consumption and environmental footprint

Reduced mechanical properties, Reduced thermal properties, Reduced electrical properties

Reduced mechanical properties

≥1%

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems, Upscaling of machines and part sizes

Germany

Plant and mechanical engineering

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I know about specific parts and their manufacturers.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard),

In our manufacturing industry, copper is rarely or not used at all, only brass components for maritime use

Manufacturing of individual parts or prototypes

Reduced mechanical properties, Limited surface quality, Reduced shape accuracy, Limited part size

Reduced surface quality, Subsequent machining is usually always necessary

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems, Multi-material printing, Upscaling of machines and part sizes

Germany

Plant and mechanical engineering, Research

Engineer (planning, supervision)

More than 5 years experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Higher costs, Technical limitations (achievable part properties), Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Cost reduction, Process reliability, Achieving material properties identical to conventionally processed copper

Production without specific tools, Production with short lead times, Manufacturing of individual parts or prototypes, Lower overall resource consumption and environmental footprint

Reduced thermal properties, Limited surface quality, Reduced shape accuracy

Reduced mechanical properties

≥1%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems

Q 1

Q 2

Q 3

Q 4

Q 5

Q 6

Q 7

Q 8

Q 9

Q 10

Q 11

Q 12

Q 13

Q 14

Germany

Research

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Technical limitations (achievable part properties), Flaws in production (deviations from the production standard)

Process reliability, Achieving material properties identical to conventionally processed copper

Production with short lead times, Manufacturing of individual parts or prototypes

Reduced thermal properties, Limited surface quality, Reduced shape accuracy

Reduced electrical conductivity, Reduced mechanical properties

≥1%

The overall quality is not sufficient for my industry.

Higher degree of automation of AM systems

Germany

Electrical engeneering and energy

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I tested additively manufactured copper parts for my industry.

Higher costs, Technical limitations (achievable part properties)

Cost reduction, Achieving material properties identical to conventionally processed copper

Production without specific tools, Manufacturing of individual parts or prototypes

Reduced electrical properties, Limited surface quality, Limited part size

Reduced surface quality, Reduced mechanical properties

≥1%

Cannot yet be conclusively assessed

Higher degree of automation of AM systems, Upscaling of machines and part sizes

Germany

Plant and mechanical engineering

Engineer (planning, supervision)

2 to 5 years of experience

Processes for polymer materials (e.g., FFF, SLS, SLA), Processes for metallic materials (e.g., LPBF, DED, EBM)

I don’t have experience with AM copper parts.

Flaws in production (deviations from the production standard), Lack of awareness (possibilities of copper AM unknown)

Exploiting the unique process advantages of AM compared to conventional manufacturing processes

Production without specific tools, Production with short lead times, Manufacturing of complex shapes, undercuts, hollow structures, Manufacturing of individual parts or prototypes, Monolithic design, combining of components, Lower overall resource consumption and environmental footprint, Targeted control of the developed microstructure and mechanical properties

Limited surface quality, Reduced shape accuracy

I do not have sufficient experience for an assessment.

Higher degree of automation of AM systems, Multi-material printing

. As some of the participants answers were collected using a German version of the questionnaire, all answers given in German have been translated to English for accessibility.

4. Discussion

There are a number of factors that could bias the results of the study presented or reduce its representativeness. At 36, the number of study participants is not very high, but is comparable and of a similar order of magnitude to studies focusing on similarly niche scientific questions [25,26]. The overall size of the pool of potential participants in question must also be taken into account. The copper industry is simply a smaller sector than for example the steel industry or sectors such as the automotive one. Thus, a smaller number of participants is not surprising, compared to other studies of this kind. Most of the responses also came from Germany. This is most likely due to the high research activities regarding copper AM in Germany, as well as the developed copper industry and the network of those carrying out the survey being based in Germany. The portion of participants who can be associated with the network of the Institute for Product Development and Machine Elements and who took part in the study is unlikely to be significant due to the correspondence with a large number of external contacts. The focus of the responses from Germany poses the potential to bias the derived statements according to local geographical industry circumstances. However, the aspects examined are predominantly of a technical nature and thus only slightly influenced by local political or economic factors. While it is unlikely that technical experts from other countries would display completely different priorities, the small sample size from participants outside of Germany has to be recognized.

By conducting a chi-square test, it is possible to statistically prove the insignificance of the influence of the country of origin on the answers given [49]. This is done exemplarily for the answers regarding the biggest perceived barriers for copper AM and the improvements prioritized by the participants for questions seven and eight. They are connected to the highly relevant questions in this study about needs and challenges of copper AM. The numbers of answers given are compared to the expected values. Regulatory issues are omitted, as the chi-square test should only be applied on values higher than five, as well as all free text answers, which cannot be analyzed using the chi-square test. The null hypothesis for this chi-square test is that there is no connection between participants originating from Germany and their answers. The alternative hypothesis is that there is a connection.

With a chi-square value of 0.735 as presented in Figure 9, the analysis clearly shows that there is no statistical evidence for a connection between answers given for question seven and the participants originating from Germany or a non-German country. In addition, the critical value (p-value) for a significance level of 0.05 and four degrees of freedom is 9.488. In the present case, the p-value is 0.95. The alternative hypothesis can therefore be safely rejected.

The same analysis is correct for question eight and the answers given, respectively and shown in Figure 10. The chi-square value is approximately 0.494. The p-value for a significance level of 0.05 and two degrees of freedom is 5.991. In the present case, the p-value is 0.78. Here, too, the alternative hypothesis can be safely rejected. There is no statistically verifiable correlation between origin from Germany or a non-German country and the answers given.

One additional way of assessing the usability and accuracy of the study results is to compare them with the current state and impetus of research. The results are plausible compared to the impression given by research about the current state of the copper AM technology, as the participants either make statements which are in line with research findings or are supplementing them with new perspectives that are not completely contradicting the findings of existing research.

5. Conclusions

This scientific publication presents the approach and results of a survey on the barriers to the adoption of the additive manufacturing of copper. The following key findings can be derived from the participants’ responses to the questionnaire:

• The average study participant has over two years of experience with additive manufacturing for metals and polymers, is an engineer in research and comes from Germany or Europe.
• Reduced mechanical, thermal and electrical properties can be acceptable for users. Most answers indicate an acceptable degree of diminished properties of between ≥1% and ≥5% but ≤10%.
• The number of participants who deem the applicability of copper AM for their industry as unfeasible due to lacking overall quality is twice as large as participants who consider part quality to be sufficient; 42% of participants are not able to make an assessment of the applicability of copper AM, again hinting at a low market penetration of this technology.
• Important trends identified in this study are a higher degree of automation as well as multi-material printing and the upscaling of machine sizes.
• Challenges: technical limitations are mentioned the most by the participants of the study, while higher costs, production flaws and a lack of technology awareness are also mentioned. Of the technical limitations, the surface quality is most frequently mentioned.
• Needs: AM processes need to become more reliable and less costly, while producing parts with a quality similar to conventionally manufactured parts.