Research on the Micro-Extrusion Process of Copper T2 with Different Ultrasonic Vibration Modes
, Yulan Lei 1, Haiou Zhang 2, Zhaochen Zhang 1, Yuchu Sheng 1 and Guangchao Han 1,3,4,*Round 1
Reviewer 1 Report
This manuscript describe newly ultrasonic micro-extrusion process and results. The deformation characteristics of the tool vibration and the workpieace vibration were compared in the results and deformation mechanism was discussed in the discussion. The data has been acquired in detail. However, in understanding the processing phenomenon, I will determine that the manuscript needs to be major revised.
Throughout the description, the captions in the figure should be explained for each fine sentence.
Line 94; Grain size L was not displayed in Figure 3. Please change caption of Figure 3.
Line 99; Figure 4 (a) should be displayed as cross sectional view. The hole through which the
extruded product passes should be displayed.
Line 101; Please unify “the mold” in the sentence and “the die” in caption of Figure 4.
Line 128, 129; Figure 5 and Figure 6;
The stress-strain curve was difficult to understand extrusion process in this manuscript.
In usual, force-stroke curve was used in extrusion process.
Please change the figure from the stress-strain curve to the force-stroke curve.
Of course, please also change Figure 9.
These data were need for more figure. For example, regarding as Figure 5, compare the maximum reduction results in a bar chart with two vibration mode. And compare the maximum reduction results and ultrasonic power output with line graph such as Figure 8 (a), (b).
Line 154; Figure 10;
Please add a number of samples in sentence and add an error bar in the Figure 10.
Line 159; “the grain size of broken crystals ~~ that of static extrusion.” was not understand only seeing Figure 11. Please show an example or arrows in the figure.
Line 168; Ultrasonic softening effect
Please discuss the relation and difference between maximum reduction of stress and extrusion length. Relation between experimental results and the Eqs. (2) ～ (4) should be discussed.
Line 264; The authors name were different from published paper.
Author Response
Point-to-point responses to the comments
Metals-623716
Title: Research on the Micro-extrusion Process of Copper T2 with Different Ultrasonic Vibration Modes
Authors: Linhong Xu , Yulan Lei , Haiou Zhang , Zhaochen Zhang , Yuchu Sheng , Guangchao Han
Responses and changes:
Thank you for giving us the opportunity to revise our manuscript and for the thoughtful and valuable comments on this manuscript. We have revised this paper and all the changes are highlighted in the Marked Revision. The point-to-point responses to the comments are listed as following.
Reviewer 1:
Comments and Suggestions for Authors
This manuscript describe newly ultrasonic micro-extrusion process and results. The deformation characteristics of the tool vibration and the workpiece vibration were compared in the results and deformation mechanism was discussed in the discussion. The data has been acquired in detail. However, in understanding the processing phenomenon, I will determine that the manuscript needs to be major revised.
Throughout the description, the captions in the figure should be explained for each fine sentence.
Point 1: Line 94; Grain size L was not displayed in Figure 3. Please change caption of Figure 3.
Response 1: In the revised manuscript (p.4 lines 107 and lines 116), we have changed the sentence and the caption of Figure 3 to focus on the different grain size.
obtain different initial grain sizes L (L represents the grain size), such as L=21, 147 and 230μm,
Figure 3. Microscopic microstructure of heat treated specimen with different grain size.
Point 2: Line 99; Figure 4 (a) should be displayed as cross sectional view. The hole through which the extruded product passes should be displayed.
Response 2: We have corrected the Figure 4(a) in the revised manuscript p.4 to display the cross sectional view of the extruded mold.
Point 3: Line 101; Please unify “the mold” in the sentence and “the die” in caption of Figure 4.
Response 3: We have unified “the mold” to replace “the die” (caption of Figure 4) in the revised manuscript. (p.4 lines 118-119)
Figure 4. The scheme diagram (a) and pictures (b) of micro forming die mold and tool.
Point 4: Line 128, 129; Figure 5 and Figure 6;
The stress-strain curve was difficult to understand extrusion process in this manuscript.
In usual, force-stroke curve was used in extrusion process.
Please change the figure from the stress-strain curve to the force-stroke curve.
Of course, please also change Figure 9.
These data were need for more figure. For example, regarding as Figure 5, compare the maximum reduction results in a bar chart with two vibration mode. And compare the maximum reduction results and ultrasonic power output with line graph such as Figure 8 (a), (b).
Response 4: In the micro-extrusion experiments of this paper, the extruded diameter of mold (shown in Figure 4(a)) is gradually dwindled from 0.5mm to 0.4mm. And the simple force-stroke curve will be affected by the different area of cross section. So the stress-strain curves are used in this paper to reflect the micro-extrusion process and the micro-forming characteristic accurately by eliminating the effects of different cross-sectional area.
In order to compare the maximum reduction of true stress of different vibration mode more clearly, we have renewed the Figure 6 with bar chart in the revised manuscript (p.6 lines 150~151).
Point 5: Line 154; Figure 10;
Please add a number of samples in sentence and add an error bar in the Figure 10.
Response 5: We have increased some description of Figure 10 in the revised manuscript p.8 lines 175-176, and add an error bar in the p.10, Figure 10(d) and (e).
Meanwhile, the micro-extrusion lengths appears with an obvious shape of V in Figure10 (d) and (e), wherein the extrusion length of 95% workpiece vibration reduces from 2.48mm to 2.31mm and then increases to 2.73mm when the initial copper specimen grain size increases from 21μm to 147μm and 230μm. The size effect phenomena of different grain sizes are appeared to affect the micro-extrusion ability of T2 copper.
Figure 10. Micro-extrusion lengths with different initial grain size.
Point 6: Line 159; “the grain size of broken crystals ~~ that of static extrusion.” was not understand only seeing Figure 11. Please show an example or arrows in the figure.
Response 6: In order to show the grain size of broken crystals with 95% tool vibration and 95% workpiece vibration clearly, we have added some red circles in the revised manuscript p.11 in Figure 11 and sentence in lines 185 to show the smaller broken crystals comparing with that of static extrusion.
shown in the areas with red circles in Figure 11 (a) ~ (I)
Figure 11. Microscopic microstructure of micro-extruded specimen with different vibration modes.
Point 7: Line 168; Ultrasonic softening effect
Please discuss the relation and difference between maximum reduction of stress and extrusion length. Relation between experimental results and the Eqs. (2) ～ (4) should be discussed.
Response 7: We have increased the discussion about the relation between maximum reduction of stress and extrusion length, and the relation between experimental results and the Eqs. (2)～(4) in the revised manuscript (p.13 lines 233-240).
The stronger ultrasonic softening effect can explain the phenomenon of the lower micro-extrusion stress and larger micro-extrusion length of workpiece vibration mode comparing with tool vibration mode. On the other hand, with the increasing of ultrasonic power output, the tool or workpiece vibration amplitude will be increased at the same time under different ultrasonic vibration modes, which also means higher ultrasonic energy. So the higher ultrasonic softening effect can be generated with high ultrasonic power output, which can also explain the phenomena of maximum reduction of stress and longest extrusion length with 95% ultrasonic power output in Figure 6~Figure 8.
Point 8: Line 264; The authors name were different from published paper.
Response 8: There are some typos for the author’s name, and we have corrected the authors name in the revised manuscript (p.15 lines 302)
[3] Jun, H., Tetsuhide, S., Tomoaki, Y., Tomomi, S., Ming, Y.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The subject-matter of this study is interesting. Nevertheless, before it can be published, changes to the following aspects ought to be introduced.
The charts presented while discussing the power demand of the extrusion process (point 3.1) were made with the coordinates true stress – true strain. How were those parameters determined? Both are not homogenous, their distribution depends on, among others, the shape of the tool and friction forces on the contact surface. The dependencies used for calculating those parameters ought to be presented. In the Reviewer’s opinion it would prove more beneficial to present the coordinates extrusion force – stamp dislocation. In the point 3.3 of the study the average grain size in the workpiece after the extrusion process should be determined. Moreover, a comment on the visible refinement of the structure as a result of plastic strain is necessary. Numerous errors can be observed in the study. The text ought to be verified by a native speaker.Author Response
Point-to-point responses to the comments
Metals-623716
Title: Research on the Micro-extrusion Process of Copper T2 with Different Ultrasonic Vibration Modes
Authors: Linhong Xu , Yulan Lei , Haiou Zhang , Zhaochen Zhang , Yuchu Sheng , Guangchao Han
Responses and changes:
Thank you for giving us the opportunity to revise our manuscript and for the thoughtful and valuable comments on this manuscript. We have revised this paper and all the changes are highlighted in the Marked Revision. The point-to-point responses to the comments are listed as following.
Reviewer 2:
Comments and Suggestions for Authors
The subject-matter of this study is interesting. Nevertheless, before it can be published, changes to the following aspects ought to be introduced.
Point 1: The charts presented while discussing the power demand of the extrusion process (point 3.1) were made with the coordinates true stress-true strain. How were those parameters determined? Both are not homogenous, their distribution depends on, among others, the shape of the tool and friction forces on the contact surface. The dependencies used for calculating those parameters ought to be presented. In the Reviewer’s opinion it would prove more beneficial to present the coordinates extrusion force-stamp dislocation.
Response 1: In this paper, the experimental parameters about ultrasonic micro-extrusion process have been introduced in in the revised manuscript p.4 lines 121-124. The ultrasonic power outputs of ultrasonic generator are set from 0, 35%, 65% to 95%, which indicate different vibration amplitudes of mold or tool. And the true stress-true strain curves are transformed from the force-stroke curves. In the micro-extrusion experiments of this paper, the extruded diameter of mold (shown in Figure 4(a)) is gradually dwindled from 0.5mm to 0.4mm. And the simple force-stroke curve will be affected by the different area of cross section. So the stress-strain curves are used in this paper to reflect the micro-extrusion process and the micro-forming characteristic accurately by eliminating the effects of different cross-sectional area.
Point 2: In the point 3.3 of the study the average grain size in the workpiece after the extrusion process should be determined. Moreover, a comment on the visible refinement of the structure as a result of plastic strain is necessary.
Response 2: In this paper, it is interesting to find the grain refining phenomena and there are many broken fine-grains appeared near grain boundaries under tool vibration or workpiece vibration mode, while the grain size of broken crystals is smaller than that of static extrusion for all three initial grain sizes. But the broken crystals phenomena are not uniform distributed in all the cross section and should be obvious in the ultrasonic extrusion processes with the higher ultrasonic power output, such as 95% power output. So the average grain size is hard to be calculated. And we will pay more attention to study the average grain size after ultrasonic extrusion process in the future research.
The cause of grain refining and the generation of broken crystal should be attributed to the ultrasonic plastic strain. The assisted ultrasonic energy absorbed by the workpiece through tool vibration or workpiece vibration can improve the micro-formability of T2 copper and enhance the plastic strain of micro-extrusion, so the grain refining phenomena and the broken crystals are generated.
Point 3: Numerous errors can be observed in the study. The text ought to be verified by a native speaker.
Response 3: We have revised the manuscript carefully and corrected the errors, which have been highlighted in the manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper is interesting and discusses in some form the process of residual stress relief without the authors describing this phenomena in this way. The authors have applied the vibration stress relief method within the process of micro-extrusion. The results prove that the longer we are going to vibrate our tool the lower the stresses will be inside the workpiece. This proves that the vibration stress relief method works also on micro-extrusion. Overall the modal analysis is missing in the paper. The missing information for the potential reader is the resonance frequency of the tested material and the frequency of the vibration tool and the tested workpiece. The best case would be the information about the modes of tool and workpiece. This information would allow the reader to understand how close the tool has to get to the resonance frequency of the workpiece. There are some editing mistakes like figures with numbers without spaces in text, or mistakes like descriptions being separated from figures in the text (fig. 13). The English is overall good enough, but the reviewer encourages the authors to simplify some of the longer sentences. I recommend major revision of the paper. I hope that the changes proposed in these paragraphs will improve the quality of this paper and will enlarge the potential readers list.
Author Response
Point-to-point responses to the comments
Metals-623716
Title: Research on the Micro-extrusion Process of Copper T2 with Different Ultrasonic Vibration Modes
Authors: Linhong Xu , Yulan Lei , Haiou Zhang , Zhaochen Zhang , Yuchu Sheng , Guangchao Han
Responses and changes:
Thank you for giving us the opportunity to revise our manuscript and for the thoughtful and valuable comments on this manuscript. We have revised this paper and all the changes are highlighted in the Marked Revision. The point-to-point responses to the comments are listed as following.
Reviewer 3:
Comments and Suggestions for Authors
Point 1: The paper is interesting and discusses in some form the process of residual stress relief without the authors describing this phenomena in this way. The authors have applied the vibration stress relief method within the process of micro-extrusion. The results prove that the longer we are going to vibrate our tool the lower the stresses will be inside the workpiece. This proves that the vibration stress relief method works also on micro-extrusion. Overall the modal analysis is missing in the paper. The missing information for the potential reader is the resonance frequency of the tested material and the frequency of the vibration tool and the tested workpiece. The best case would be the information about the modes of tool and workpiece. This information would allow the reader to understand how close the tool has to get to the resonance frequency of the workpiece.
Response 1: We have increased the ultrasonic vibration modal of tool vibration and workpiece vibration by Ansys software and description in the revised manuscript (p.3 lines 111~115 and p.4 Figure 4 (c) and (d))
Figure 4. The structure of micro forming mold/ tool and the simulated ultrasonic vibration modals .
And the simulated ultrasonic vibration modes of mold or tool supported by the ultrasonic vibration system were shown in Figure 4(c) and (d) . It is clear that resonant frequency of the ultrasonic vibration system is fluctuated from 19091Hz to 19345Hz with different loading of tool and mold, which is among the working range of ultrasonic generation and without any adjustment of ultrasonic system.
Point 2: There are some editing mistakes like figures with numbers without spaces in text, or mistakes like descriptions being separated from figures in the text (fig. 13). The English is overall good enough, but the reviewer encourages the authors to simplify some of the longer sentences. I recommend major revision of the paper. I hope that the changes proposed in these paragraphs will improve the quality of this paper and will enlarge the potential readers list.
Response 2: We have revised the manuscript carefully and corrected the errors, which have been highlighted in the manuscript.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for your fine revise of manuscript.
Please recheck the detail of results as following.
Line 170: ~~ from 1467.98 MPa to 1500.71 MPa and then reduced to
1367.77 MPa ~~ grain size increase from 21 µm to 147 µm
and 230 µm.
→From the figure 9 (g), grain size 21 µm maximum true
stress probably taken an 1367.77 Mpa. But, 1467.98 MPa
was written in the line 170. Are there small mistakes ?
When line 170 has small mistakes, please correct the text.
And please add a text regarding as the L=147 µm take a
maximum true stress in static extrusion and take a minimum
extrusion length in figure 10 at 95% vibration.
I think it will be easier for readers to understand the phenomenon
of size effect.
Author Response
Reviewer 1:
Comments and Suggestions for Authors
Thank you for your fine revise of manuscript.
Please recheck the detail of results as following.
Line 170: ~~ from 1467.98 MPa to 1500.71 MPa and then reduced to
1367.77 MPa ~~ grain size increase from 21 µm to 147 µm
and 230 µm.
→From the figure 9 (g), grain size 21 µm maximum true
stress probably taken an 1367.77 Mpa. But, 1467.98 MPa
was written in the line 170. Are there small mistakes ?
When line 170 has small mistakes, please correct the text.
And please add a text regarding as the L=147 µm take a
maximum true stress in static extrusion and take a minimum
extrusion length in figure 10 at 95% vibration.
I think it will be easier for readers to understand the phenomenon
of size effect.
Response 1: There are some mistakes in Line 170 for describing the figure 9 (g).
In the revised manuscript (p.8 lines 169 ~ lines 116), we have corrected the sentence and added some conclusion about the phenomenon of L=147 µm in Lines 178~ Lines 181.
For example, the maximum true stress of static extrusion increases from 1367.77MPa to 1500.71MPa and then reduced to 1467.98MPa when the initial copper specimen grain size increases from 21μm to 147μm and 230μm (as shown in Figure 9 (g)).
So the copper specimen with grain size L=147µm can take a maximum true stress and take a minimum extrusion length under all extrusion conditions including tool vibration, workpiece vibration and static extrusion. The significant size effect phenomenona of different grain sizes are appeared to affect the micro-extrusion ability of T2 copper
Author Response File: Author Response.pdf
Reviewer 2 Report
I accept the authors' answers.
Author Response
Thanks very much for your kind work and consideration on publication of our paper. On behalf of my co-authors, we would like to express our great appreciation for your thoughtful and valuable comments on this manuscript.
Reviewer 3 Report
The paper has been improved. I recommend to accept the paper in the present form.
Author Response
Thanks very much for your kind work and consideration on publication of our paper. On behalf of my co-authors, we would like to express our great appreciation for your thoughtful and valuable comments on this manuscript.
Round 3
Reviewer 1 Report
The manuscript has been revised successfully.
