3D Printing as a Disruptive Technology for the Circular Economy of Plastic Components of End-of-Life Vehicles: A Systematic Review
Round 1
Reviewer 1 Report
By considering that the manuscript entitled: “3D printing as a disruptive technology for the circular economy of plastic components of end-of-life vehicles: a systematic review” is a review, the bibliography related to the 3D printing and its potentiality in the prospective of circular economy is very poor. The innovative character that authors should bring to the scientific literature with their work is not evident.
Major revisions are required before the publication.
A further investigation of the most recent literature related to the future perspective in the research field of 3D printing as a “disruptive technology for the circular economy” is suggested. Please, study in deep this aspect in order to improve the quality of the work.
The manuscript is not a scientific article, for such a reason, in my opinion, the titles of sections “Materials and method” and “Results” could be removed by re-organizing the related sections.
Why the authors have chosen to report the research method in the manuscript? I think that the section Materials and Method could make you lose the focus of the topic. I suggest to re-organize the manuscript by focusing the attention on the literature related to theme rather than explain how the study was carried out.
Please, check the captions of Figures and Tables. In some case they are missing.
It could be more motivating to report original figures, elaborated by the authors.
Please, check and read the manuscript carefully, for example lines 221-222 must be deleted.
Improve the quality of the images (for example fig. 4). Please, check the requirements in the authors guideline.
Author Response
By considering that the manuscript entitled: “3D printing as a disruptive technology for the circular economy of plastic components of end-of-life vehicles: a systematic review” is a review, the bibliography related to the 3D printing and its potentiality in the prospective of circular economy is very poor. The innovative character that authors should bring to the scientific literature with their work is not evident.
Major revisions are required before the publication.
Answer: The authors really appreciate the time spent considering the present manuscript and tried to answer to all questions of the reviewer accordingly. They are listened below each point in the present document. In addition, the alterations made in the original manuscript are highlighted in yellow.
- A further investigation of the most recent literature related to the future perspective in the research field of 3D printing as a “disruptive technology for the circular economy” is suggested. Please, study in deep this aspect in order to improve the quality of the work.
Answer: The authors acknowledge the comment from the reviewer. An effort has been made to improve the sub-section related to the 3D printing. In addition, the discussion section was also improved, and it also discusses the aforementioned topic.
- The manuscript is not a scientific article, for such a reason, in my opinion, the titles of sections “Materials and method” and “Results” could be removed by re-organizing the related sections.
Answer: The authors agree with the reviewer and have organized the manuscript according to the PRISMA guidelines for systematic reviews.
- Why the authors have chosen to report the research method in the manuscript? I think that the section Materials and Method could make you lose the focus of the topic. I suggest to re-organize the manuscript by focusing the attention on the literature related to theme rather than explain how the study was carried out.
Answer: As mentioned in the previous question, the authors decided to organize the manuscript following the guidelines of PRISMA for systematic reviews. Indeed, such organization method was also suggested by another reviewer. The authors hope that this decided had significantly improved the understanding of the document and therefore, it would be more appealing to the readers.
- Please, check the captions of Figures and Tables. In some case they are missing.
Answer: The authors revised all the captions and revised them accordingly. The alterations to the original text are highlighted in yellow.
- It could be more motivating to report original figures, elaborated by the authors.
Answer: The authors acknowledge the comment from the reviewer. They made an effort and altered most of the figures in the manuscript and tried to incorporate as many original figures as possible.
- Please, check and read the manuscript carefully, for example lines 221-222 must be deleted.
Answer: The authors deleted the mentioned lines and corrected the manuscript accordingly.
- Improve the quality of the images (for example fig. 4). Please, check the requirements in the authors guideline.
Answer: The authors agree with the reviewer and improved the quality of all figures.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This is a systematic review, and does not cover the topic and discuss the results comprehensively. The overview of this topic and identification of gaps is not comprehensive. The PRISMA guidelines should be followed.
1. The abstract needs to be rewritten. It is less specific about the systematic review. It is general and/or includes background etc.
2. The circular economy is not well introduced. Improve this sub-section.
3. Same comments for sub-sections 1.2 and 1.3.
4. The introduction section does not introduce the review? What to study, interpret, and/or address in this systematic review? The whole section needs to be rewritten.
5. The methodology needs to be improved. The PRISMA guidelines should be followed.
6. The information sources should be well covered.
7. The selection process should be well described.
8. The results are not discussed appropriately.
9. What are the conclusions of this systematic review? Improve this section.
Other comments: The graphs are not much clear. Improve the figures quality.
Author Response
This is a systematic review, and does not cover the topic and discuss the results comprehensively. The overview of this topic and identification of gaps is not comprehensive. The PRISMA guidelines should be followed.
Answer: The authors really appreciate the time spent considering the present manuscript and tried to answer to all questions of the reviewer accordingly. In addition, they altered the manuscript in order to correctly follow the PRISMA guidelines for systematic reviews. In addition, the alterations made in the original manuscript are highlighted in yellow.
- The abstract needs to be rewritten. It is less specific about the systematic review. It is general and/or includes background etc.
Answer: The authors agree with the reviewer. The abstract section was rewritten and now describes the methodology used and the most relevant results from the study. In addition, the PRISMA guidelines for abstracts checklist was followed.
- The circular economy is not well introduced. Improve this sub-section.
Answer: The authors acknowledge the comment from the reviewer. The introduction section was rearranged in order to be more attractive to the reader. The concept of circular economy is explored in the new section “2. circular economy in the automotive industry. Herein, not only the concept of circular economy is explored but also it was contextualized in automotive industry. In addition, examples of how some automotive companies are adapting to circular economy were also added to the text.
- Same comments for sub-sections 1.2 and 1.3.
Answer: As aforementioned, the introduction section was completely altered, including their subsections. The authors hope that the information that was added contributed for the enrichment of the text.
- The introduction section does not introduce the review? What to study, interpret, and/or address in this systematic review? The whole section needs to be rewritten.
Answer: The authors understood the comment from the reviewer and completely changed the introduction section. By the end of this section, a new paragraph approaching these questions was added.
- The methodology needs to be improved. The PRISMA guidelines should be followed.
Answer: The authors agree with the comment from the reviewer and altered the submitted manuscript in order to correctly follow the PRISMA guidelines for systematic reviews.
- The information sources should be well covered.
Answer: The present study uses as principal source of information, the published papers associated to Scopus database. Then, the process of selection and analyses of the papers was reformulated in order to clarify them. In addition, the authors include a new limitations section (section 6.) where they identify the limitations of the present study and propose new strategies to improve their data collection process.
- The selection process should be well described.
Answer: The methodology section was improved in order to clarify the data collections and selection process, following the PRISMA guidelines and its checklist.
- The results are not discussed appropriately.
Answer: The discussion of the results has been reformulated in order to be more explicit. Herein, the discussion of the results of the analysis of the texts is included in the new section “3D printing as a path to improve the circular economy of ELV polymers”.
- What are the conclusions of this systematic review? Improve this section.
Answer: The authors agree with the reviewer and rewritten the conclusions section in order to include the most relevant results from the information analysed from the systematic review and auxiliar bibliography consulted. Furthermore, a new section concerning the recommendations for future works was also added.
Other comments: The graphs are not much clear. Improve the figures quality.
Answer: The authors modified the figures in order to improve their quality.
Author Response File: Author Response.docx
Reviewer 3 Report
1. This study seems interesting. The experiments are well presented, and the results have value for practitioners. However, discussion is very limited. The chapter Results and discussion is mainly about results. There is barely any discussion involved.
2. Figures 1 —Now is year 2022. Please update it.
3. Strengthen the abstract section. It is very lengthy in preset form. Remove unnecessary information and add key conclusions of the work in the last two lines.
4. Discuss the motive behind the work. The clear application of the work should be discussed in the introduction section. From the introduction section application of the work is not clear.
5. There are numerous spelling and grammatical errors. Please revise the manuscript thoroughly. Sentences are also not complete.
6. The novelty of the work should also be discussed in a separate paragraph.
7. Try to make a bridge between current and previously published work and specify the gap area and objective of the work. Add the specific gap observed from the literature at the end of the introduction section.
8. Experimental section needs a clear and concise discussion.
9. Work is presented well but the technical discussion is very poor.
Please finish it. Some leading works regarding “3D printing or plastic components” should be discussed in the introduction.
1.Kuo, C.-C.; Chen, J.-Y.; Chang, Y.-H. Optimization of Process Parameters for Fabricating Polylactic Acid Filaments Using Design of Experiments Approach. Polymers 2021, 13, 1222.
2.Madhu, N.R., Erfani, H., Jadoun, S. et al. Fused deposition modelling approach using 3D printing and recycled industrial materials for a sustainable environment: a review. Int J Adv Manuf Technol 122, 2125–2138 (2022)
3.Wolfs, R.J.M., Suiker, A.S.J. Structural failure during extrusion-based 3D printing processes. Int J Adv Manuf Technol 104, 565–584 (2019).
4.Muñoz, I., Alonso-Madrid, J., Menéndez-Muñiz, M. et al. Life cycle assessment of integrated additive–subtractive concrete 3D printing. Int J Adv Manuf Technol 112, 2149–2159 (2021).
10.Authors should more clearly emphasize the contribution of this work in relation to the existing solutions in the literature.
11.What is the main difficulty when applying proposed method? Authors should clearly state the limitations of the proposed method in practical applications.
12.Please show some directions for the future study.
13.The abstract is also not sufficiently informative, concise and clear. No any quantitative results. Please amend it.
14.Conclusions must be comprehensive and not written like a report. Please amend it.
15.Please add the applicability of present work in the conclusion section.
16.Does your paper have industrial applications? If yes, who are the likely users?
17.What is your main contribution to the field?
18.Finally, I would suggest the author to address the questions above in the revision. I am pleased to review the revised manuscript.
Author Response
The authors really appreciate the time spent considering the present manuscript and tried to answer to all questions of the reviewer accordingly. They are listened below each point in the present document. In addition, the alterations made in the original manuscript are highlighted in yellow.
- This study seems The experiments are well presented, and the results have value for practitioners. However, discussion is very limited. The chapter Results and discussion is mainly about results. There is barely any discussion involved.
Answer: The authors agree with the reviewer. For that reason, the results and discussion section was separated. The results are presented in the new section “3. Results”, while the discussion is presented in section “4. 3D printing as a path to improve the circular economy of ELV polymers”. These sections, which follow the PRISMA guidelines for systematic reviews, were reformulated and more deeply discussed. All the alterations were highlighted in yellow.
- Figures 1 —Now is year 2022. Please update it.
Answer: The authors acknowledge the comment from the reviewer. However, the Eurostat database does not provide any information from 2020 till the present day. That information was included in the text in section “2. Circular economy in the automotive industry” and was highlighted in yellow. To complement the information, a sentence with an estimation for the recycling of ELV for the year 2030 was included in the text and is also highlighted in yellow.
- Strengthen the abstract section. It is very lengthy in preset form. Remove unnecessary information and add key conclusions of the work in the last two lines.
Answer: The Abstract section was rewritten according to the PRIMA guidelines for abstracts checklist. The authors added information concerning the methodology used and main conclusions of the study.
- Discuss the motive behind the work. The clear application of the work should be discussed in the introduction section. From the introduction section application of the work is not clear.
Answer: The authors acknowledge the comment from the reviewer. The introduction section was improved in order to summarize the main goals of the work, the motivation behind it and the most relevant questions to which it was intended to give answer to.
- There are numerous spelling and grammatical errors. Please revise the manuscript thoroughly. Sentences are also not complete.
Answer: The authors reviewed the entire manuscript and corrected it accordingly.
- The novelty of the work should also be discussed in a separate paragraph.
Answer: The abstract and introduction sections were both rewritten. By the end of these sections, the authors tried to clarify the novelty and the practical use of the present manuscript. In addition, by following the PRISMA guidelines for systematic reviewers, the organization of the manuscript was improved.
- Try to make a bridge between current and previously published work and specify the gap area and objective of the work. Add the specific gap observed from the literature at the end of the introduction section.
Answer: The authors acknowledge the comment from the reviewer. The main gap that the present manuscript aims at covering is to provide a practical systematic review, that is easy to consult and understand, that shows the opportunities that 3D printing can offer to the automotive industry. In addition, it covers data concerning recycling and reuse of ELV materials. If the authors could name a gap between other published work, it would be the crossing of all this information, actualized with data from 2021. These facts are clarified throughout the manuscript.
- Experimental section needs a clear and concise discussion.
Answer: The authors agree with the reviewer and improved the discussion section (section 4), which now is separated from the results section.
- Work is presented well but the technical discussion is very poor.
Please finish it. Some leading works regarding “3D printing or plastic components” should be discussed in the introduction.
Answer: The authors acknowledge the comment from the reviewer and considered the papers that were suggested. The theme of 3D printing and +plastic components has now its own section, which is section 4 of the manuscript. In addition, part of the information was explored and discussed in the introduction section.
1.Kuo, C.-C.; Chen, J.-Y.; Chang, Y.-H. Optimization of Process Parameters for Fabricating Polylactic Acid Filaments Using Design of Experiments Approach. Polymers 2021, 13, 1222.
2.Madhu, N.R., Erfani, H., Jadoun, S. et al. Fused deposition modelling approach using 3D printing and recycled industrial materials for a sustainable environment: a review. Int J Adv Manuf Technol 122, 2125–2138 (2022)
3.Wolfs, R.J.M., Suiker, A.S.J. Structural failure during extrusion-based 3D printing processes. Int J Adv Manuf Technol 104, 565–584 (2019).
4.Muñoz, I., Alonso-Madrid, J., Menéndez-Muñiz, M. et al. Life cycle assessment of integrated additive–subtractive concrete 3D printing. Int J Adv Manuf Technol 112, 2149–2159 (2021).
10.Authors should more clearly emphasize the contribution of this work in relation to the existing solutions in the literature.
Answer: The authors acknowledge the comment from the reviewer. The entire manuscript was reformulated in order to highlight the possible opportunities that 3D Printing may provide for the automotive industry in a more practical way and not only from the literature point of view. In addition, it follow the PRISMA guidelines for systematic reviews, which focuses on a more clear and concise presentation of the results.
11.What is the main difficulty when applying proposed method? Authors should clearly state the limitations of the proposed method in practical applications.
Answer: The authors added a new section (section 6.) where information concerning the limitations of the present work were provided. This section was added according to the PRISMA guidelines for systematic reviews.
12.Please show some directions for the future study
Answer: The authors added a new section (section 6.) where information concerning the recommendations for future studies were provided. This section was added according to the PRISMA guidelines for systematic reviews.
13.The abstract is also not sufficiently informative, concise and clear. No any quantitative results. Please amend it.
Answer: The authors agree with the reviewer. As mentioned in the answer to question 3 of the reviewer, the Abstract was rewritten and now describes the methodology used and the most relevant results. The authors hope that these alterations helped to improve the clarity of the abstract.
14.Conclusions must be comprehensive and not written like a report. Please amend it.
Answer: The conclusions section was rewritten. The authors include the most relevant results from the papers analyzed in the systematic review and further bibliography and summarized the main conclusions from this analysis. Furthermore, the section conclusions also follows the PRISMA guidelines recommendations and requirements.
15.Please add the applicability of present work in the conclusion section.
Answer: The authors acknowledge the comment from the reviewer. They altered the conclusions section where now the opportunity paths are identified in order to clarify the applicability of the manuscript.
16.Does your paper have industrial applications? If yes, who are the likely users?
Answer: In the methodology section, it was added a detailed description concerning the data extraction in which the identification of the topics are made. These topics, which are discussed in the manuscript, may help stakeholders from the automotive industry to interpret data and learn about the new trends in AM applied to vehicle manufacturing. This statement was included in the manuscript.
17.What is your main contribution to the field?
Answer: The present manuscript aims at exploring the opportunity that 3D printing may offer for the circular economy of ELV to be accelerated by providing a literature revision concerning 3D printing, circular economy, and recycling. Furthermore, it provides a guiding path for stakeholders in the automotive industry concerning to the challenges and strategies to integrate AM into the circular economy of ELV. This statement was clarified in the manuscript in the abstract, introduction and conclusion sections.
18.Finally, I would suggest the author to address the questions above in the revision. I am pleased to review the revised manuscript.
Answer: The authors acknowledge all the comments from the reviewer and hope that they made the necessary alterations to meet the reviewer expectations.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Thanks to the authors for agreeing with the review suggestions. The manuscript was improved, I agree for the publication of the paper.
Reviewer 2 Report
The comments/suggestions are well addressed.
Reviewer 3 Report
The manuscript now can be accepted in the journal for publication as this review paper seems interesting.
