Development of a Novel Resistance Heating System for Microforming Using Surface-Modified Dies and Evaluation of Its Heating Property
Round 1
Reviewer 1 Report
Dear Authors,
Topics and innovation fully meet the journal's requirements. The title and keywords correspond to the content.
The article presents in my opinion a very interesting and innovative concept of using the cover layer on tools for plastic micro-processing as a "generator" of heat in the process of resistance heating.
I think that it is suitable for publication in the magazine Metals, however, requires a slight refinement.
1. In the introduction, there is no reference to other methods of heating used in microforming, such as laser and electromagnetic heating methods.
2. Line 23-43 - incorrect form of references to literature
3. Line 62 to 90 with Figure 3 and Figure 4. Lack of information that the results of previous research are presented here - "Development of a novel resistance heating system for microforming by Ryota et.al, Proc. Eng. 207 (2017) 1016-1021.
4. Figure 5 - according to the title (b) I would suggest to draw a heating system like in Figure 1.
Line 120-133. Containing Fig. 6 and Fig. 7. Considerations would be greatly improved by adding the figure containing yield curves for Ti for different temperatures (this is just a suggestion that does not need to be implemented).
5. Line 153 -154 and further Figure 9. Sequence: from Figure 8: Ti, Cu, SS should be consistently applied, or changed.; 2nd: I have not found an attempt to explain or reference the result for Ti on Figure 9. Why temp. Increase ratio for Ti / 1um is smaller than SS / 1 um.
6. Line 189-193 with Fig. 14. There are no research results justifying the thesis about the growth of "Forging depth".
Conclusions
7. The first part of Conclusion 1 has no reference in the text. The results of the FEM simulations provided do not apply to the materials used.
8. Conclusion 3 is not documented. (photos of samples, measurements or unloading curve in Fig. 13)
9. It is also controversial. The traditional punch had a temperature of 400 C and a coated one 600 C. This resulted in a decrease in the yield stress of material under deformation and further consequences.
Author Response
Answer to reviewer #1’s comments:
Thanks for your comments. We have revised our paper following your questions and comments and corrected English in the paper by a native scientist. Please find answers to your questions below.
1. In the introduction, there is no reference to other methods of heating used in microforming, such as laser and electromagnetic heating methods.
Ans: We added comments on other heating methods, such as laser heating and ultrasonic heating with some reference papers in the introduction.
2. Line 23-43 - incorrect form of references to literature
Ans: We modified the form of references.
3. Line 62 to 90 with Figure 3 and Figure 4. Lack of information that the results of previous research are presented here - "Development of a novel resistance heating system for microforming by Ryota et.al, Proc. Eng. 207 (2017) 1016-1021.
Ans: We added discussions on our previous research with the reference of "Development of a novel resistance heating system for microforming by Ryota et.al, Proc. Eng. 207 (2017) 1016-1021. And changed Fig.4 for explaining our new coating approach.
4. Figure 5 - according to the title (b) I would suggest to draw a heating system like in Figure 1. Line 120-133. Containing Fig. 6 and Fig. 7. Considerations would be greatly improved by adding the figure containing yield curves for Ti for different temperatures (this is just a suggestion that does not need to be implemented).
Ans: Yes, we added image of heating system in the Figure.
Regarding a figure containing yield curves for Ti for different temperatures, we just added some comments on the temperature dependence of the flow stress for Ti by referring previous paper.
5. Line 153 -154 and further Figure 9. Sequence: from Figure 8: Ti, Cu, SS should be consistently applied, or changed.; 2nd: I have not found an attempt to explain or reference the result for Ti on Figure 9. Why temp. Increase ratio for Ti / 1um is smaller than SS / 1 um.
Ans: The effect of rate of temperature increase for materials with low resistivity, such as Cu is greater that high resistant materials, such as Ti and Stainless steel. However, the resistivities for Ti and Stainless steel are not so different. Other influential factors such as heat conductivity, surface roughness, natural oxide film on the surface, may also influence the rate of temperature increase. The reason that “increase ratio for Ti /1um is smaller than SS /1 um” is still under investigation.
6. Line 189-193 with Fig. 14. There are no research results justifying the thesis about the growth of "Forging depth".
Ans: we added a figure of the measured forging depths for different conditions to justifying the results in Fig. 14.
7. The first part of Conclusion 1 has no reference in the text. The results of the FEM simulations provided do not apply to the materials used.
Ans: We added discussions in Chapter 2 and comments in conclusion 1 for matching each other.
8. Conclusion 3 is not documented. (photos of samples, measurements or unloading curve in Fig. 13)
Ans: Measurement results of the forging depth shown in Fig. 14 (newly added) can fit the document.
9. It is also controversial. The traditional punch had a temperature of 400 C and a coated one 600 C. This resulted in a decrease in the yield stress of material under deformation and further consequences.
Ans: This is one effect in which higher temperatures can be achieved using coated dies with the same current density and as a result, the material deforms in lower flow stress.
Reviewer 2 Report
Work is interesting and mith cause significant interest of the technicians and researchers. It is quite original and well illustrated. At the same time, for such a requested field Authors give very poor referencing (DOI: 10.1016/S0921-5093(02)00643-3; DOI: 10.1299/jsmepes.2018.23.A223; and many others).
What is especially important is to estimate the fundamental size limit for electric heating system developed in this study.
Authors should be consistend and provide correct error estimation for all studies under consideration. Figs. 6,8,9 needs to be completed by error bars. Fig.13 must show the points. Fig. 8 must show a,b,c parts and part a must give numerical data for linear fit with corresponding error analysis.
Is there any chance to confirm experimentally the obtained thickness of the coatings - SEM or TEM data would be most usefull. Without them the scientific soundness can not be given a high rate.
Author Response
Answer to reviewer #2’s comments.
Thanks for your comments. We have revised our paper following your questions and comments and corrected English in the paper by a native scientist. We also change some figures for easier understanding our paper. Please find answers to your questions below and revised paper.
1. Work is interesting and mith cause significant interest of the technicians and researchers. It is quite original and well illustrated. At the same time, for such a requested field Authors give very poor referencing (DOI: 10.1016/S0921-5093(02)00643-3; DOI: 10.1299/jsmepes.2018.23.A223; and many others).
Ans: We added some references related to heating assisted forming and add comments on these previous works.
2. What is especially important is to estimate the fundamental size limit for electric heating system developed in this study.
Ans: It is a very good question and advice to our research. We have limitation on coating system. In general, the thickness for ceramic materials coated on a micro die is less than with 2 or 3 um, and as a results, the heat source is limited. We think that size of the product should be important to the estimation.
3. Authors should be consistend and provide correct error estimation for all studies under consideration. Figs. 6,8,9 needs to be completed by error bars. Fig.13 must show the points. Fig. 8 must show a,b,c parts and part a must give numerical data for linear fit with corresponding error analysis.
Ans: We agree with reviewer’ consideration. However, the purpose is to develop the heating system and qualitatively evaluate its effects. So we have not do the error analysis yet. We are going to evaluate quantitatively the effects in our future works.
4. Is there any chance to confirm experimentally the obtained thickness of the coatings - SEM or TEM data would be most usefull. Without them the scientific soundness can not be given a high rate.
Ans: thanks for a very good question and advice to our research. We will do it in our future works.
Round 2
Reviewer 2 Report
Authors made some improvements and ignore some of my comments. Work can be accepted in the present state although it migt be much better if revision would be appropriate. At long last, this is authors who must be interested to make their work most strong and took into account all reviewers suggestions.
