Optimization of Selective Laser Sintering Three-Dimensional Printing of Thermoplastic Polyurethane Elastomer: A Statistical Approach

Round 1

Reviewer 1 Report

The work presents a statistical approach to optimize the selective laser sintering printing parameters of thermoplastic ployrethane elastomers. Although it is a standard work, I have the following concern about the article which need to be addressed prior to recommendation:

1. The introduction to AM is already give in section 1, why for abstract has got the introduction sentences?

2. I suggest to improve the abstract a bit to add some good results from the study and not just texts to attract readers. 

3. The decimal places are upto 5 digits? What is the significance?

4. Why were the authors so much interested in conducting a statistical approach of study although there are recent technologies in the same genre? 

5. What is novel in this work? Using RSM for design and optimization is what the authors want to show? Or the material? method?

6. The literature review is to be made concise, as the work looks more like a literature review than an experimental work. 

7. if there are so many literature available regarding the optimization of parameters while AM of polymer, what was the motivation behind the experiments performed by the authors? The research gap is not clear in teh manuscript and must be placed just after the literature review and it must be clear and concise. 

8. The last paragraph of the literature survey stating the objectives is quite confusing. The numbering must be done in different way so as to avoid confusion amongst the readers. 

9. Line 270, wrong way of representation of units. 

10. There is a large variation of powder size, how do the authors ensure repeatability of the experiments? Are there any error analysis done to this regard?

11. Fig 3: the representation of sub-numbers in the images is abrupt and unevenly sized. 

12. I think the description intending the type of instruments used in the study are unnecessarily described. hardness, microscope, minitab, etc. For a knowledgeable audience, these are familiar equipment and software. 

13. the authors are advised to mention just the make model and technical specifications of equipment used rather than describing the entire system. 

14. Table 5 and 6: units missing.

15. Incorrect representation of units for density.

16. What is the significance of using a CCD design for optimization (line 381)

17. Line 409-415: How are the parameters measured? What do the authors mean by simple equation?

18. The authors have compressed the surface plots images, owing to which they look abrupt and misleading (fig 6-10). 

19. I found there are numerous unnecessary capitalization of texts throughout the manuscript. I advise the authors to have a thorough reading before submitting any manuscript. 

20. What do fig 11 signify? These look just blurry images without any proper clarification to the present context of study. Although the authors have mentioned a vague description of the optical images, there is no clear distinguishable difference between the images presented here. Similarly for fig 12.

21. How were the layer thickness measured? The authors have represented the thickness upto 3 digits. Do the authors claim that the thickness comes up to nano-level?

22. Figure 13, the cross-section of the sample is not distinguishable from the SEM image. the powder morphology is shown, how about the chemical content characterization? 

23. The conclusion is lengthy. I suggest to improve the conclusions by presenting it in a concise manner with bullets or numbering so as to enhance the quality of the paper. Why and what for is the result should not be placed in the conclusion, rather a concluding remark on each of the result obtained must be presented in this section. 

24. The citations look obsolete. The authors are advised to add some recent publications from the last 5 years in the reference section. 

Author Response

Please see the attachment.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

In this study, the authors describe the influence of process parameters on the properties of SLS formed TPU materials. The method used can be applied to other materials in SLS process. However, the following issues should be addressed before it can be accepted for publication.

1.     The section of literature review should focus on the SLS forming of TPU materials.

2.     In the section of 3.1, the detailed introduction to Shore hardness (A) durometer, Minitab, Optical Microscope (OM), and Scanning Electron Microscope (SEM) are unnecessary as these are common devices that the researchers and readers are familiar with.

3.     The conclusion section of the manuscript needs to be streamlined.

4.     Is the mechanical properties of TPU samples printed using the optimized processes better or worse compared to similar research results in the literature? Please provide a brief comparative analysis in the manuscript.

Moderate editing of English language required

Author Response

Please see the attachment.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

In this manuscript, the authors studied the impact of two 3D printing parameters, laser power ratio and layer thickness, to a series of 3D printing product properties. The authors firstly conducted a thorough literature review and extracted these two key parameters and properties to be measured and then designed and manufactured a series of samples using different combinations of parameters. The hardness, elastic modulus, and density of each sample is measured. Statistical analysis was also conducted to investigate the significance of the factors. The overall manuscript is good, but there are some questions that need the authors to answer / address.

 

1, Line 75, the full name of TPU is needed.

2, Line 80, line 250, will the shape, size of the design impact the conclusion? Also, can the conclusion made from studying this particular sample be generalized to all designs?

3, Figure 2, what is the red mark in the figure? The dimensional labels need to be adjusted since some are overlapped with lines

4, The authors use TPU as materials for prototype in this paper, what materials can be used for real-life application for this particular design? will it have similar responses if using other materials?

5, line 290, in page 14, line 400, it says the design was done by inputting the factor values of 12 samples with times two replications of similar design. Here says 24 distinct combination of parameters and 3 replication for each. Are they conflict?

6, line 302, is this a new section, seems independent from the above. If so this section may need to be separated from above, it is a little sudden that the paper suddenly starts to introduce the equipment.

7, why is Fig. 4a needed? It seems that 4b have more details and contains all information in 4a.

Author Response

Please see the attachment.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have incorporated the necessary changes as per the suggestion, and the paper looks better now.