Investigation of the Influence of Cutting Parameters on Conical Pick Cutting Performance and Rock Damage
Round 1
Reviewer 1 Report
The conical pick is an important rock breaking tool, the cutting parameters have great effect on conical pick cutting performance. The conical pick cutting rock numerical simulation model and rock damage quantitative analysis software are established to research the influence cutting parameters on cutting force and rock damage. Meanwhile, the research content has certain theoretical and engineering significance. There are several problems need to be corrected.
1. English expression is not accurate enough, therefore, I suggest you to modify your manuscript to improve your manuscript, and polish your manuscript language with a native English speaker.
2. It is suggested to add some references in the Introduction section to help readers to understand the research background and the research status.
3. Page8, the cutting angles have a great effect on rock damage, and the rock damage cloud with different cutting angles are shown in Figure 10. It can't be seen that the impact of the cutting angle on rock damage, the damage thickness is basically the same, and the notch size is changed, so the paper should give a more specific explanation.
4. Due to the structure and size of the pick, when the cutting depth increases to a certain extent, limited by the size of the pick, the contact area between the pick and the rock will not increase, and then the rock breaking volume of the pick will not increase significantly. Figure 13 does not support this estimate. Please check and modify the expressions.
I would suggest authors to go through the articles given here:
DOI: 10.1007/s11665-015-1546-6
DOI 10.1007/s00603-014-0680-z
Author Response
- English expression is not accurate enough, therefore, I suggest you to modify your manuscript to improve your manuscript, and polish your manuscript language with a native English speaker.
Response: We tried our best to improve the manuscript and made some changes to the manuscript. These changes will not influence the content and framework of the paper. And here we did not list the changes but marked in red in the revised paper. We appreciate for Editors/Reviewers' warm work earnestly and hope that the correction will meet with approval.
- It is suggested to add some references in the Introduction section to help readers to understand the research background and the research status.
Response: We sincerely appreciate the valuable comments. We have checked the literature carefully and added more references on and into the Introduction part in the revised manuscript.
- Page8, the cutting angles have a great effect on rock damage, and the rock damage cloud with different cutting angles are shown in Figure 10. It can't be seen that the impact of the cutting angle on rock damage, the damage thickness is basically the same, and the notch size is changed, so the paper should give a more specific explanation.
Response: We think this is an excellent suggestion. We have revised that, and added a figure to explain the phenomenon, page 9-10.
- Due to the structure and size of the pick, when the cutting depth increases to a certain extent, limited by the size of the pick, the contact area between the pick and the rock will not increase, and then the rock breaking volume of the pick will not increase significantly. Figure 13 does not support this estimate. Please check and modify the expressions.
Response: Thanks for your great comment. It is a mistake about the expressions, and we have modified the mistake. And thanks for your suggestion.
I would suggest authors to go through the articles given here:
DOI: 10.1007/s11665-015-1546-6
DOI 10.1007/s00603-014-0680-z
We tried our best to improve the manuscript and made some changes marked in red in revised paper which will not influence the content and framework of the paper.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The research has important engineering practical application value, but this type of research was carried out a long time ago in the second half of the 20th century. The authors used here only newer possibilities for showing the results (colour charts, visualizations of rock damage). However, even then, the influence of speed and depth of cutting, and the distance between two picks on the cutting force’s value were investigated. The research topic is interesting, but there are many issues to correct. My comments are:
1. I suggest supplementing the introduction with the research results of such researchers as Piotr Cheluszka (Silesian University, Poland), Krzysztof Krauze, Krzysztof Kotwica, Łukasz Bołoz, Kamil Mucha (AGH University of Science and Technology in Kraków, Poland), Józef Jonak and Jakub Gajewski (Lublin University of Technology, Poland).
2. It cannot be said that there is only one force (Fc) acting on the pick. Three forces (Ps, Pd, Pb) act on the pick, which are components of the force Fc. I recommend you read the following publication: https://doi.org/10.3390/en15196886.
3. Show in the Figure where is the angle ψ, please.
4. One time a large letter F is a force, another time a factor (line 145), and another time a function (line 150).
5. Equations 9 and 10. Lack of explanation of what Ge and Gp are.
6. Line 162: What does "shear model" mean?
7. Line 169: What kind of material parameters?
8. Line 175: Show in the additional figure the pick, please. Is it possible to change the pick on the test bench? Currently, the most commonly used picks are with a tip angle of 90o (https://doi.org/10.2478/ntpe-2020-0019)
9. Figure 5 is too small.
10. Lines 199-200: On what basis were these parameters assumed? Have they been statistically determined?
Here, the cutting angle is 50o, and before that (line 175) it is 55o. Why?
11. Line 203: How the errors were calculated?
12. Line 244: In line 200, you said the cutting speed was 2 m/s and a depth of 9 mm. If they were changed, why and how were they determined?
13. Line 296: Why such values of cutting depth were assumed?
14. Chapter 4 is just like a report. There is no discussion at all, and most importantly, no reference to the results obtained with the research of other scientists. It needs to be complemented.
15. According to the reference, more than half of the publications are from domestic authors.
Based on the comments above, in my opinion, the authors must correct the manuscript, therefore I suggest that it should be reconsidered after major revision.
Also, I found some minor errors:
Line 36: [5] should be after "et al."
Line 43: After "materials" should be a point, not a semicolon.
Line 73: The point in the title should be removed.
Line 248: Figure 9, not Figure 1.
Author Response
- I suggest supplementing the introduction with the research results of such researchers as Piotr Cheluszka (Silesian University, Poland), Krzysztof Krauze, Krzysztof Kotwica, Łukasz Bołoz, Kamil Mucha (AGH University of Science and Technology in Kraków, Poland), Józef Jonak and Jakub Gajewski (Lublin University of Technology, Poland).
Response: Thank you very much for your valuable comments. The papers of outstanding researchers have been added. We have added more references into the Introduction in the revised manuscript, which helps to improve the quality.
- It cannot be said that there is only one force (Fc) acting on the pick. Three forces (Ps, Pd, Pb) act on the pick, which are components of the force Fc. I recommend you read the following publication: https://doi.org/10.3390/en15196886.
Response: Thanks for your suggestion. The cutting force of the conical pick has been discussed in the manuscript, however, the components of the cutting force (Fc) did not discuss in the manuscript. In the paper, we mainly studied the cutting force of a conical pick and rock damage, but did not study the component force of conical pick.
- Show in the Figure where is the angle ψ, please.
Response: The angle ψ is the friction angle between the conical pick and the rock, which is not a certain parameter in the conical pick cutting rock model. Therefore, the friction angle between the conical pick and rock is not be added into the Figure 1. The friction angle is determined by the cutting parameters of conical pick and rock property parameters which is obtained by the experiment.
- One time a large letter F is a force, another time a factor (line 145), and another time a function (line 150).
Response: Thank you very much suggestion about the letter of the variable. As your suggestion, we have changed the Frate as Srate in the line162-163. The Fe and Fcap are changed as Ee and Ecap, which makes the variable letter clearly.
- Equations 9 and 10. Lack of explanation of what Geand Gpare.
Response: Thanks for your comment about the explanation of Ge and Gp. The Ge-elastic shear modulus, Gp-plastic shear modulus.
- Line 162: What does "shear model" mean?
Response: Thanks for your great comment. It is a large mistake, it is not the “shear model”, it should be “shear modulus”. And we have changed in the manuscript in the line 184.
- Line 169: What kind of material parameters?
Response: We think it is a great comment. The material parameters B and M, B-residual stress intensity parameter, M-residual stress intensity index. And the explanation of the letter “B” and “M” have been added into the manuscript.
- Line 175: Show in the additional figure the pick, please. Is it possible to change the pick on the test bench? Currently, the most commonly used picks are with a tip angle of 90o(https://doi.org/10.2478/ntpe-2020-0019)
Response: We have read your comment and your recommended paper. We have checked some data and found that the tip angle of conical pick is greater than 80°. And the selection of tip angle is based on the rock hardness, conical pick cutting condition and the rock breaking equipment. And the tip angle of conical pick is less than 90° as show in the following figure.
- Figure 5 is too small.
Response: We have enlarged the Figure 5 to make it clear to watch. Thanks for your suggestion.
- Lines 199-200: On what basis were these parameters assumed? Have they been statistically determined?
Here, the cutting angle is 50°, and before that (line 175) it is 55°. Why?
Response: The parameters is selected to modified and verified the numerical simulation model in line 199-200. And the parameter of the conical pick is intermediate value of the variable range for the numerical simulation research. Therefore, the parameters are selected to verified the numerical simulation model.
The cutting angle 50° and 55° are included in the research range. And the controlling variables method is selected to research the influence of different cutting parameters on cutting performance of the conical pick. Therefore, we did not intentionally ensure that the cutting angle was a fixed value during researching other cutting parameters influence on cutting performance.
- Line 203: How the errors were calculated?
Response: Thanks for your comment about the error. The explanation of calculation errors has been added into the manuscript. We have added the definition about the error. Defined the error between the experimental and numerical simulation result is the ratio of the difference between the experimental results and numerical simulation results to the experimental results.
- Line 244: In line 200, you said the cutting speed was 2 m/s and a depth of 9 mm. If they were changed, why and how were they determined?
Response: In the line 200, the cutting parameters is selected to verified and modified the numerical simulation model. And the cutting parameters of conical pick in the line 244 is applied to research the cutting angle effect on the cutting performance of conical pick. Owing to the different research purpose, the cutting parameters of conical pick are different in the two places of the manuscript.
- Line 296: Why such values of cutting depth were assumed?
Response: The cutting depth of the conical pick is considered the structural parameters of conical pick. And the research of the cutting depth aims to research the influence law of cutting depth on cutting performance of conical pick.
- Chapter 4 is just like a report. There is no discussion at all, and most importantly, no reference to the results obtained with the research of other scientists. It needs to be complemented.
Response: We think your comment is greater. And we have added some references to complete the manuscript.
- According to the reference, more than half of the publications are from domestic authors.
Based on the comments above, in my opinion, the authors must correct the manuscript, therefore I suggest that it should be reconsidered after major revision.
Also, I found some minor errors:
Line 36: [5] should be after "et al."
Line 43: After "materials" should be a point, not a semicolon.
Line 73: The point in the title should be removed.
Line 248: Figure 9, not Figure 1.
Response: Thanks for your comments. We have modified the mistakes in the manuscript to improve the quality.
Author Response File: Author Response.pdf
Reviewer 3 Report
Notes in the attachment.
Comments for author File: Comments.pdf
Author Response
- The authors use the terms: "average peak cutting force". Please explain what this force is. Draw the distribution of forces.
Response: In the process of rock breaking with conical pick, while the cutting force reaching the peak cutting force the rock will crack. Therefore, the peak force occurring indicated that there will be forming some rock fragments. So, the average peak cutting force of the conical pick is meaningful to describe the force of conical pick.
- As the authors have determined: "friction angle between the rock and conical pick". Please describe.
Response: The angle ψ is the friction angle between the conical pick and the rock, which is not a certain parameter in the conical pick cutting rock model. Therefore, the friction angle between the conical pick and rock is not be added into the Figure 1. The friction angle is determined by the cutting parameters of conical pick and rock property parameters which is obtained by the experiment.
- Please provide information about the force and displacement sensor. How were the signals recorded? With what frequency?
Response: Thanks for your suggestion about the sensors of experimental test bench. And we have added the content “The force sensor transmits the signal to the signal acquisition instrument through the force signal transmitter, and then the data is recorded by the signal acquisition computer. The displacement sensor signal transmits to the signal acquisition instrument and the displacement data is recorded by the signal acquisition computer. The signal acquisition frequency is set as 1000Hz.” into the manuscript.
- Lack of description of cutting parameters. The authors provided only one cutting data. Have their values been changed?
Response: Thanks for your comment. We have added the description of the cutting parameters into the manuscript to help readers to understanding the manuscript. We use the method of control variables to study the influence of different variables on cutting performance. So when we study a variable, we will change the value of this variable.
- How the cutting tool was used. Please describe.
Response: The cutting tool is applied to cutting rock. The rock cutting process of the pick can be roughly divided into four steps: the first step is that the pick contacts and compresses the rock; The second step is to produce a dense core in the rock; The third step is to enlarge the dense core and form cracks; The fourth step is crack propagation to form rock debris.
- Incorrect numbering of figures, pages 8 and 10.
Response: That is a mistake. And we have corrected the picture number.
- Please explain the differences in figures 12 and 15. Different sampling frequency?
Response: The difference between the two figures is that the researching variable is different. In the Figure 12 is indicated the cutting force curves with different cutting depths, but the Figure is the cutting force curves of different cutting speeds.
- What was "Cutting distance"? In Figure 1: 1m, in Figure 12: 0.1m?
Response: Thank you very much about the comment. Thanks to point the mistake in the manuscript. The cutting distance should be 0.1 m, and we have modified the mistake in Figure 1(Figure 9).
- Please write how is the force Fc determined? Mean value at the selected point, mean value of the entire signal, or some other statistical measure?
Response: Thank you for your comment. The force Fc is determined by the cutting parameters. According to the theoretical model of Gokan and Roxborough, the cutting force is determined by the rock property parameters, cutting parameters and conical pick structural parameters. However, the rock is a heterogeneous quasi brittle material. The force curve of conical pick is fluctuating. We selected the mean peak cutting force to describe the force of the conical pick is more significant.
- Has the wear of the cutting tool been measured? Maybe there is an influence of wear on the test results?
Response: The wear of the cutting tool will have great influence on conical pick cutting performance. And we will further study the influence of wear on cutting performance of the cutting tool.
- Where does the increase in the force signal come from at the beginning of the cut?
Picture nr 18.
Response: In the process of conical pick cutting rock, when the conical pick contacts the rock, the cutting force of conical pick will increase sharply. Therefore, the increase in the force the cutting beginning. While the rock beginning to break, the cutting force curve fluctuates within a certain range.
- How the error of the obtained results was determined. Between experimental results and simulation results? Please write a method.
Response: We have added the definition of the error between experimental results and simulation results into the manuscript. Defined the error between the experimental and numerical simulation result is the ratio of the difference between the experimental results and numerical simulation results to the experimental results.
We tried our best to improve the manuscript and made some changes marked in red in revised paper which will not influence the content and framework of the paper. We appreciate for your work. Thanks for your comments and suggestions.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thanks to the authors for their answers. Please note the numbering of the figures. The number 11 is twice.
Author Response
Thanks for your comment about the manuscript. We have tried our best to modify the manuscript. And the comment about the Figure 11 has been revised.
Thank you for your comment and suggestion again.
Reviewer 3 Report
I would like to thank the authors for the corrections made in the article. The authors took my comments into account. I propose to publish an article.
Author Response
Dear reviewer
Thanks for your suggestion and comment. We have modified the manuscript. Thanks for your affirmation of the manuscript.
