Development of 3D Printing Raw Materials from Plastic Waste. A Case Study on Recycled Polyethylene Terephthalate

Round 1

Reviewer 1 Report

The authors responded to most of my comments. However, the decimal point in Table 5 and 6 are still not consistent. There are still formatting errors and the authors still do not include other printing parts apart from the tensile bar to show the reader. It would be great if the authors able to illustrate that in the main text. 

Author Response

Thank you for pointing this out. The reviewer is correct, and we have changed the decimal points in all tables. As suggested by the reviewer, we have included the parameters of the parts as well as the setting and parameters using during the preparation in table 3. We are trying to illustrate other parts apart from the tensile bar but unfortunately, we are running out of time as the most important part was the tensile. The English language and structure of the paper was edited by academic school for paraphrasing (professor.co.uk).

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript reported a study on 3D printing (FDM) of PET and recycled PET with a discussion on processing and mechanical testing. It is an interesting topic. It can be accepted after a major revision.

1. The first sentence in abstract is wrong, it should be “Abstract: Fused Deposition Modelling (FDM) is the most common 3D printing technology”.
2. The English language should be improved
3. More details of the extrusion process such as extrusion temperature and speed should be provided.
4. More details of the FDM process such as nozzle temperature and speed should be provided,
5. More discussion and explanation should be provided to state why the mechanical property of recycled PET is close to virgin one.
6. Further characterization such as FTIR should be provided to confirm the composition of recycled PET, as well as the samples after extrusion.
7. It will be interesting to compare the mechanical properties between virgin PET and recycled PET which is being extruded and grounded for one, two, or three times.

Author Response

1. The first sentence in abstract is wrong, it should be “Abstract: Fused Deposition Modelling (FDM) is the most common 3D printing technology”.

Answer: As suggested by the reviewer, we have changed the first sentence in abstract.

1. The English language should be improved

Answer: English language and structure were studied by one of the academic schools of paraphrasing and English language (professor.co.uk)

1. More details of the extrusion process such as extrusion temperature and speed should be provided.

Answer: Table 3 was added to provide the filament fan speed and diameter of material during the 3 tests.

1. More details of the FDM process such as nozzle temperature and speed should be provided,

Answer: Table 2, 3 and figure one is showing the filament fan speed and a sample of extrusion machine was provided.

1. More discussion and explanation should be provided to state why the mechanical property of recycled PET is close to virgin one.

Answer: As suggested by the reviewer, we are trying to provide and explain why the mechanical properties of recycled materials shows that the latest is close to the virgin one .

1. Further characterization such as FTIR should be provided to confirm the composition of recycled PET, as well as the samples after extrusion.

Answer: In further investigation we will provide FTIR in the next phase of the test procedures we try to focus on confirming the composition and samples.

1. It will be interesting to compare the mechanical properties between virgin PET and recycled PET which is being extruded and grounded for one, two, or three times.

Answer: Thank you for this suggestion. Although we agree that this is an important consideration but It would have been interesting to explore this aspect. However, in our study, this would not be possible because of the luck of materials and availability of 3d printing laboratory due to the pandemic.

The manuscript has been resubmitted to your journal. We look forward to your positive response.

Thanking you

Yours sincerely,

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors addressed most of my questions and it is recommended to publish in Applied Sciences.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This paper is about developing new materials for FDM 3D printer from recycled PET plastic. This is very interesting and also good for the environment. The concept and overall experiment are adequate. However, there are minor improvements that can make this paper better. Please see the details below

1. I do not think figure 1 is necessary as it does not provide helpful information to the readers. I suggested removing it from the manuscript.
2. In table 3, can authors split the column between Filament fan speed (%) and extruder(rpm)?
3. In table 4, Mpa should be written as “MPa” and please be consistent with the unit and decimal points.
4. The word in figure 6 is very small; please make them larger.
5. The number on the figure is repeatable and not in order; please recheck throughout the manuscript.
6. There are many formatting errors; please recheck.
7. Instead of showing the filament picture, are there pictures or photos of the 3D printed part printed from the recycled PET rather than the tensile bar? This will give more info on the surface, finishing to the readers. 

Author Response

review 1-6: edited.

review 7: As the individual filament properties could not be studied they were not included in that study. 

Reviewer 2 Report

Thank you for your paper. This is an interesting topic area but I found it very hard to follow your paper in terms of the abstract, paper structure, and the English. In this form, your work is not being communicated to a sufficiently high level.  It makes it very difficult for me to assess the scientific merits at this time. It needs to be presented in a much clearer and logical way. 

Author Response

 Extensive editing of English language and style

Reviewer 3 Report

The authors have presented a new recyclable method of 3D printing and give an important result concerning the optimal geometry structure at which the strength is very large. The results are clearly illustrated and the experimental technics is well explained and showed. I strongly recommend the publication of this work in the Journal of Applied Sciences in its present form. 

Author Response

English language and style are revised