Finite Element Simulation of Orthogonal Cutting of H13-Hardened Steel to Evaluate the Influence of Coatings on Cutting Temperature

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors investigate the impact of tool coatings on heat generation during the cutting of hardened H13 steel. Using finite element simulations, they compare maximum temperatures among different coatings (TiC, TiN, Al2O3, TiAlN) and find that TiN generates the lowest temperature at the tool's cutting edge, while Al2O3 generates the highest. They advocate for TiAlN coating due to its superior thermal isolation properties. Furthermore, their study indicates that coating thickness affects the temperature gradient, recommending a thickness below 5 μm. Finally, they validate their findings through actual cutting experiments. However, it is crucial to make minor changes and respond to inquiries before contemplating publication.

1- There's no reference to Figure 1 within the document's text.

2- Figure 2 presents two sub-figures labeled a and b. Could you clarify the content or meaning of these sub-figures a and b?

3- In Table 2, could you specify the meaning or content of the first column?

4- How do the maximum temperatures at the tool's cutting edge vary among the different coatings (TiC, TiN, Al2O3, TiAlN), and what are their exact values?

5- What is the temperature difference between the tool's cutting edge and the coating-substrate interface for each coating material? What are the exact values for these differences?

6- For the TiAlN coating, how does the temperature gradient change concerning the increase in coating thickness? What gradient values are reached for thicknesses of 3 μm, 5 μm, 7 μm, and 10 μm?

7- At what temperature does the gradient become problematic for the TiAlN coating in terms of coating failure?

8- What is the recommended range of coating thickness values to maintain thermal stresses below a critical level during cutting?

9- At the end of your abstract, you mentioned validating numerical results through real experiments. Would it be possible to include images from these experiments using the FLIR A315 camera?

10- Your publication doesn't specify the specific machining type used. Did you work on milling or turning operations?

 

Comments on the Quality of English Language

The English language in your text displays a commendable level of quality. Your sentences are skillfully constructed, successfully conveying the intended message.

Author Response

Response to Reviewer 1 Comments

The authors investigate the impact of tool coatings on heat generation during the cutting of hardened H13 steel. Using finite element simulations, they compare maximum temperatures among different coatings (TiC, TiN, Al₂O₃, TiAlN) and find that TiN generates the lowest temperature at the tool's cutting edge, while Al₂O₃ generates the highest. They advocate for TiAlN coating due to its superior thermal isolation properties. Furthermore, their study indicates that coating thickness affects the temperature gradient, recommending a thickness below 5 μm. Finally, they validate their findings through actual cutting experiments. However, it is crucial to make minor changes and respond to inquiries before contemplating publication.

Q1: There's no reference to Figure 1 within the document's text.

Reply: Thanks for your valuable and constructive suggestion first. We have added the reference to Figure 1 in the document’s text, as your suggestion. The modification part was presented in the first to third lines in the second paragraph.

As shown in Fig. 1, the heat transferred into coated cutting tools comes from three heat sources, including heat from the primary deformation zone, heat generated in the secondary deformation zone and heat produced in the tertiary deformation zone.

Q2: Figure 2 presents two sub-figures labeled a and b. Could you clarify the content or meaning of these sub-figures a and b?

Reply: Thanks for your valuable and constructive suggestion first. We have clarified the content or meaning of these sub-figures a and b in the revised manuscript. The sub-figure (a) shown a schematic diagram of orthogonal cutting test. The sub-figure (b) presented a cutting temperature distribution obtained by the finite element method.

Q3: In Table 2, could you specify the meaning or content of the first column?

Reply: Thanks for your valuable and constructive suggestion first. The density of material has an effect on the deformation of the material and the phenomenon of tool-chip separation during the simulation process for metal cutting, which in turn affects the cutting temperature. Therefore, it is necessary to list the density of material in the Table 2.

Q4: How do the maximum temperatures at the tool's cutting edge vary among the different coatings (TiC, TiN, Al₂O₃, TiAlN), and what are their exact values?

Reply: Thanks for your valuable and constructive suggestion first. The variation of the maximum cutting temperature of the rake face for different coated tools has been shown in Fig.5. The Al₂O₃ coated tool has the highest maximum temperature (1171°C) on rake face. The highest maximum temperature of Al₂O₃ coated tool was followed by the maximum temperature (1169°C) of TiC coated tool and the maximum temperature (1145°C) of TiAlN coated tool. The lowest maximum temperature on rake face was 1129°C for TiN coated tool.

Q5: What is the temperature difference between the tool's cutting edge and the coating-substrate interface for each coating material? What are the exact values for these differences?

Reply: Thanks for your valuable and constructive suggestion first. According to your suggestion, we presented the temperature difference for each coating material in the third paragraph of the third part. Details are as follows.

For TiAlN coated tool, the temperature at the interface between coating and substrate was 126°C lower than that of the rake face. For Al₂O₃ coated tool, the temperature gradient was 122°C. The temperature gradients were 116°C and 108°C for TiC and TiN coatings, respectively. TiAlN and Al₂O₃ coatings exhibited better thermal barrier properties than the other two coating materials, which could be attributed to their lower thermal conductivity.

Q6: For the TiAlN coating, how does the temperature gradient change concerning the increase in coating thickness? What gradient values are reached for thicknesses of 3 μm, 5 μm, 7 μm, and 10 μm?

Reply: Thanks for your valuable and constructive suggestion first. The temperature gradient increased with the increase in coating thickness. For coating thicknesses of 3 μm and 5 μm, the temperature decreases were 119℃ and 184℃, respectively. When the tool coating thickness reached 7 μm and 10 μm, the temperature decrease was almost 300°C. Details in the revised manuscript are as follows.

The temperature gradient between the temperature on rake face and that on coating-substrate interface increased with the increase of coating thickness. When the tool coating thickness reached 7 μm and 10 μm, the temperature decrease was almost 300°C. For coating thicknesses of 3 μm and 5 μm, the temperature decreases were 119℃ and 184℃, respectively.

Q7: At what temperature does the gradient become problematic for the TiAlN coating in terms of coating failure?

Reply: Thanks for your valuable and constructive suggestion first. We are carrying out research about this question. We intend to reveal the failure mechanism of the TiAlN coated cutting tool by investigating the relationship among the internal temperature gradient of the coated tool, the internal thermal stress of the coated tool and the tool failure pattern. We will show these results in our next paper.

Q8: What is the recommended range of coating thickness values to maintain thermal stresses below a critical level during cutting?

Reply: Thanks for your valuable and constructive suggestion first. To maintain thermal stresses below a critical level during cutting, the recommended range of coating thickness values should be kept less than 5 μm. We described the question in the last paragraph of the third part of the revised manuscript.

Q9: At the end of your abstract, you mentioned validating numerical results through real experiments. Would it be possible to include images from these experiments using the FLIR A315 camera?

Reply: Thanks for your valuable and constructive suggestion first. Yes. The images obtained from these experiments by using the FLIR A315 camera are applied to validate the numerical results.

Q10: Your publication doesn't specify the specific machining type used. Did you work on milling or turning operations?

Reply: Thanks for your valuable and constructive suggestion first. In the revised manuscript, we have clearly stated that the type of machining is orthogonal turning operation. We have explained this question at the end of the first paragraph of the second part in the revised manuscript.

Q11: The English language in your text displays a commendable level of quality. Your sentences are skillfully constructed, successfully conveying the intended message.

Reply: Thanks for your appreciation of the quality of English language of our manuscript very much.

Thanks for your valuable comments and suggestions again.

Reviewer 2 Report

Comments and Suggestions for Authors

The submitted paper presents numerical research results with the main goal of studying the influence of coating material on a cutting temperature. The paper is well prepared, but some small bads was found:

 

1. line 88 and Table 2: check units, usually I use GPa not a Gpa.

 

2. line 159 please describe a producer of a software

 

3. table 2. lines 184, 226 227, and many else: In my opinion, you should use a unit J/kg K, not a J/kg^oC

Author Response

Response to Reviewer 2 Comments

The submitted paper presents numerical research results with the main goal of studying the influence of coating material on a cutting temperature. The paper is well prepared, but some small bads was found:

Q1: Line 88 and Table 2: check units, usually I use GPa not a Gpa.

Reply: Thanks for your valuable and constructive suggestion first. We have modified the units of these two places and have marked them red in the revised manuscript.

Q2: Line 159 please describe a producer of a software

Reply: Thanks for your valuable and constructive suggestion first. The producer of the software is Third Wave Systems. We have marked this producer in red font in the revised manuscript.

Q3: Table 2. lines 184, 226 227, and many else: In my opinion, you should use a unit J/kg K, not a J/kg℃

Reply: Thanks for your valuable and constructive suggestion first. We have modified the original unit to the unit “J/kg·K”

Thanks for your valuable comments and suggestions again.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors

I have some questions and comments about the article.

My questions:

1.      Figure 1 needs to be improved in better quality

2.      Regarding Table 1, are there other methods of producing these coatings, e.g. PLD?

3.      Figure 2 needs to be improved in better quality

4.      You need to correct Englisch, e.g. line 197 subsrate

5.      Figure 4 needs to be presented in a more visual form

6.      Thermal conductivities do not correlate with Figure 5. Why?

7.      What are the physical units in equation 1?

8.      Conclusions are more a description of the results than a scientific summary of the results obtained

Unfortunately, the article is more of a report on the results obtained than a scientific article that brings something new.

The presentation of the results leaves much to be desired

 

References do not contain references to recent literature.

Comments on the Quality of English Language

You need to correct Englisch, e.g. line 197 subsrate

Author Response

Dear reviewer, the detailed replies are listed in the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors,

I read with great interest your paper entitled "Finite Element Simulation of Orthogonal Cutting of H13 Hardened Steel to Evaluate the Effect of Coating on Cutting Temperature", but would like to correct the following.

(m) mandatory

(o) optional

[1] (m) C1: p. 4, l. 149-151: "In this work, TiC, TiN, Al2O3, and TiAlN four coated cutting tools are investigated with finite element method when H13". I feel that the expression "four layers" above the sentence is misleading to readers. I think changing it to "four kinds of coating materials" would be better.

[2] (m) In my opinion, it is rare to have a style in which the preface of a paper is divided into sections. I would like you to consider this point.

[3] (m) p. 8 l. 231- l. 233: "Eleven points were examined along the direction perpendicular to the rake plane from the point with the highest temperature". While this is mentioned, in the next sentence it says, "The temperatures of these 12 points were extracted and analyzed using the AdvantEdge software." What is discussed is which number of data is correct? Please confirm.

[4] (m) Other remarks: Other comments were made directly in the manuscript. We would appreciate it if you could refer to them when revising the manuscript.

Best regard,

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Response to Reviewer 4 Comments

I read with great interest your paper entitled "Finite Element Simulation of Orthogonal Cutting of H13 Hardened Steel to Evaluate the Effect of Coating on Cutting Temperature", but would like to correct the following.

(m) mandatory

(o) optional

Q1: (m) C1: p. 4, l. 149-151: "In this work, TiC, TiN, Al₂O₃, and TiAlN four coated cutting tools are investigated with finite element method when H13". I feel that the expression "four layers" above the sentence is misleading to readers. I think changing it to "four kinds of coating materials" would be better.

Reply: Thanks for your valuable and constructive suggestion first. According to your suggestion, this sentence has been revised. Details are as follows.

In this work, TiC, TiN, Al₂O₃ and TiAlN four kinds of coating materials are investigated by finite element method when machining H13 hardened steels.

Q2: (m) In my opinion, it is rare to have a style in which the preface of a paper is divided into sections. I would like you to consider this point.

Reply: Thanks for your valuable and constructive suggestion first. According to your suggestion, the subsection of the preface has been cancelled.

Q3: (m) p. 8 l. 231- l. 233: "Eleven points were examined along the direction perpendicular to the rake plane from the point with the highest temperature". While this is mentioned, in the next sentence it says, "The temperatures of these 12 points were extracted and analyzed using the AdvantEdge software." What is discussed is which number of data is correct? Please confirm.

Reply: Thanks for your valuable and constructive suggestion first. The 12 points mentioned in the sentence of “The temperatures of these 12 points were extracted and analyzed using the AdvantEdge software.” include the eleven points and the point at which the maximum temperature appears on rake face.

Q4: (m) Other remarks: Other comments were made directly in the manuscript. We would appreciate it if you could refer to them when revising the manuscript.

Reply: Thanks for your valuable and constructive suggestion first. According to your suggestion, we have checked the whole manuscript and improved the English writing. The whole changes have been marked with red font in the revised manuscript.

Thanks for your valuable comments and suggestions again.

Reviewer 5 Report

Comments and Suggestions for Authors

The work regards the study of the influence of coatings on cutting temperature. In particular, a numerical model (FEM  model) was developed to investigate several coating materials with different thickness. The validation with an IR camera has been proposed. 

 

General comment:

The paper is interesting since it proposes a numerical approach to understand the behaviour/effect of coatings on cutting temperatures. The model validation with the Infrared Thermography technique (IRT) is interesting and has been appreciated. However, above all regarding the validation with IRT, a lot of information has been missed and it is difficult to understand the goodness of validation and then the proposed model. 

So, to improve the paper and make it suitable for application the following information needs to be provided:

- IR camera: it is not clear what kind of IR camera has been used for the tests. It seems a cooled camera, but the model in the paper (A315) refers to an uncooled microbolometric detector. 

- It is necessary to indicate: the adopted lens and then the obtained geometrical resolution in terms of mm/pixel that is very important to obtain good accuracy with IR camera.

- Did you estimate the emissivity ? The emissivity is very important and a not accurate emissivity value, above all for very low values, can involve high errors in temperature measurements. Moreover, emissivity changes as a function of temperature. Did you consider this variation ? 

- What are the other imposed values of the object parameters ? (Distance, Reflected temperature, % relative humidity, etc.)

- Add visible images/pictures with Infrared images. 

Please, add some references about IRT used to measure or estimate temperatures,  for example:

- 10.1080/10589759.2015.1121266;

- 10.3390/ma9030122;

 

Comments on the Quality of English Language

Some sentences need to be revised and some terms can be changed to make the paper more comprehensible. 

Author Response

Dear reviewer, the detailed replies are listed in the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I accept a manuscript in present form.

Author Response

Response to Reviewer 2 Comments

I accept a manuscript in present form.

Reply: Thanks for your appreciation of our manuscript very much.

Thanks for your valuable comments and suggestions again.

Author Response File: Author Response.doc

Reviewer 3 Report

Comments and Suggestions for Authors

The article is ready for publication.  

Author Response

Response to Reviewer 3 Comments

The article is ready for publication.

Reply: Thanks for your appreciation of our manuscript very much.

Thanks for your valuable comments and suggestions again.

Author Response File: Author Response.doc

Reviewer 4 Report

Comments and Suggestions for Authors

Good!

Author Response

Response to Reviewer 4 Comments

Good!

Reply: Thanks for your appreciation of our manuscript very much.

Thanks for your valuable comments and suggestions again.

Author Response File: Author Response.doc

Reviewer 5 Report

Comments and Suggestions for Authors

The authors addressed my raised points. Please, change the value of the thermal sensitivity. It is 50mK (20 mK is a common value of cooled IR cameras. 

Please, replace the term "thermal imager" with "IR camera".  

Author Response

Response to Reviewer 5 Comments

The authors addressed my raised points.

Q1: Please, change the value of the thermal sensitivity. It is 50mK (20 mK is a common value of cooled IR cameras.

Reply: Thanks for your valuable and constructive suggestion first. We have modified the value of the thermal sensitivity and have marked them blue in the revised manuscript.

Q2: Please, replace the term "thermal imager" with "IR camera".

Reply: Thanks for your valuable and constructive suggestion first. According to your suggestion, we have checked the whole manuscript and replaced the term “thermal imager” with “IR camera”. The whole changes have been marked with blue font in our revised manuscript.

Thanks for your valuable comments and suggestions again.

Author Response File: Author Response.doc