Machining of Inserts with PCD Cutting-Edge Technology and Determination of Optimum Machining Conditions Based on Roundness Deviation and Chip-Cross Section of AW 5083 AL-Alloy Verified with Grey Relation Analysis
Round 1
Reviewer 1 Report
While the background of this study and the survey of related papers are described in detail in the introduction, there are many questions about the experimental contents of this study. In particular, the reasons for selecting the parameters measured in the cutting experiments are not clear, there is no consideration of the surface roughness of the machined surface and tool wear, which are important in cutting, and there is insufficient comparative study of the three types of cutting edges finished by grinding, laser processing, and electrical discharge machining. The paper was judged to be unacceptable. Please refer to the following comments.
Page 3, line 104; “polycrystalline cubic diamond (PCD)”, The term cubic is incorrect, please delete it.
Page 3, line 118; “Another experiment was aimed at optimizing the input factors for machining aluminum bars by turning and achieving the required quality parameter such as roundness deviations and minimizing the formation of flare on the surface at the main cutting edge, as well as the required performance parameter (chip cross section) to eliminate the damage of the machined surface by the remaining chip shape.”; This is where the biggest problem with this paper lies. It is necessary to clearly state the reason why the less common parameters such as roundness deviations and chip cross sections were used instead of cutting forces, surface roughness of the finished surface, and tool wear rate, which are considered as indices of machinability in many papers.
Page 4, line 151; “The wear of the machined surface, the chips and the cutting edge depends on…”, Wear of the machined surface is clearly wrong. Correct for wear on the cutting edge.
Page 4, line152; “…the cutting speed (or rotation frequency)”, I think rotation frequency is actually rotation speed.
Page 4, line158; “corner radius Rε(°)”, The correct unit of the corner radius is mm.
Page 4, Table 1; The correct unit for feed rate is mm/rev.
Page 4, line167; DMG MORI ecoTurn 450 is not a machining center, but a turning center.
Page 5, Figure 2; Please correct the aspect ratio of the figure to 1:1.
Page 5, Table 3; Add “Al bal.” to the last line of the table.
Page 5, Table 4; Correct the unit of stress to MPa. The density of the aluminum alloy is obviously wrong (too small). Please check it.
Page 6, line 193; According to the manufacturer's website, Cimcool Cimstar 40B is a semi-synthetic type oil. Please correct it.
Page 6, Figure 3; Please correct the aspect ratio of the figure to 1:1. Please add a scale bar so that you can see the size of the object. Figure3. (a); It is unclear which part of the insert you want to show. Please improve the picture.
Page 6, line 205; “…as the dialectic.”, The correct term is "dielectric fluid". Please correct it.
Page 7, line 214; “…diamond into graphite…”, I think this point needs to be verified by Raman spectroscopy.
Page 7, line 218; On page 6, line 204, it is described as 4 erosion processes, but in this part there are only 3 erosion processes described. Please check.
Page 7, line 226; “The grinding medium was water sprayed…”, In line 221, it is explained that a grinding wheel was used, and the explanation is inconsistent. Please check.
Page 7, line 231; For laser processing, please add processing parameters such as laser wavelength, power, pulse width, focusing spot size and scanning speed.
Page 8, line 246; Please add the model number of 3D light microscope from Alicona.
Page 8, line 252; In this section, the shape of the cutting edge (surface roughness and edge roundness of the cutting edge) finished by grinding, laser processing, and electrical discharge machining is compared, but as mentioned in the reference paper, I think it is necessary to compare the tool wear rate and tool life.
Page 9, from line 257 to line 267; There is a discrepancy between the description in the text and the figure. Figure 9 does not show the comparison of Rn. Figure 10 does not show the comparison of Ra and Rz. There is serious confusion in the explanation of how Ra and Rz are measured. Figure 11 does not show the processing time. Please check it.
Page 9, line 265; “…the parameter evaluation results…”, In this explanation, the reason for choosing LASER is unclear due to insufficient evidence. Please explain the parameter evaluation specifically and clearly.
Page 9, line 271; I think these three lines have nothing to do with the content of the paper.
Page 10, line 278; I think multiple measurements and averaging are necessary because the chip thickness generally varies greatly from place to place, even for continuous chips. Please explain the chip evaluation method used in this study in detail. Also, I think it is inappropriate to use calipers to measure chip thickness because they are too thin, and a micrometer is necessary. Please confirm this.
Page 11, line 306; ,24÷8, Please explain the meaning of 8. Also, this calculation requires two different experiments, which is not consistent with the explanation in the text (24 experiments). Please check.
Page 11, from line 309 to 317; The content of this part is a duplicate of the previous sentence.
Page 12, Figure 12, Please add a scale bar.
Page 12, “The chip cross section is an important parameter…”; As mentioned before, please explain the importance of the chip cross section in detail. In turning, the chip width is approximately equal to the depth of cut, and the chip thickness is affected by the tool feed and shear angle. In order to evaluate the cutting condition, two-dimensional cutting experiments should be conducted to calculate the shear angle. I don't think the chip cross section evaluation is significant.
Page 13, line 391, In order to evaluate the process quality, it is necessary to measure the roughness of the machined surface.
Page 16, line 479; “…achieve the maximum material removal and turning power while minimizing the damage to the cutting edge,”; There is no explanation of the material removal rate or tool wear measurement data in this study. Therefore, this text is not convincing at all.
Page 17, line 491; “as follows 0.079 m/min for cutting speed,”, Since this is the difference in GRG factor, isn't the unit (m/min) wrong?
Page 17, line 498; “On this basis we can say that the feed rate significantly affects the turning performance…”, Almost all cutting textbooks explain that the tool feed affects the theoretical surface roughness of machined surface in turning. It appears to be a statement of what is well known about turning process.
Page 17, line 500; “and increasing the radius of the cutting edge by increasing.”, This part has nothing to do with the text. Please delete it.
Page 17, line 506; “…significantly affected by an increase in feed rate…”, This is natural because of the geometric relationship in cutting. However, it is necessary to consider the cause of the effect of cutting speed. Also, it is geometrically impossible for the cross-section to change little with respect to the depth of cut.
Page 18, line 517; “…with greater depth of cut…”, In finish turning, it is common practice to reduce the depth of cut in order to reduce cutting resistance and the effect of elastic deformation. The meaning of optimization is different for finishing and roughing operations. In this paper, I feel that the assumption of optimization is not fully explained.
Page 19, line 542; “As the cutting speed increases. the surface quality deteriorates and…”, This part is not convincing at all because the data of surface roughness of the machines surface is not shown.
Page 19, line 545; “The surface quality is represented by the deviation of roundness.” I believe that deviation of roundness is a parameter that describes the accuracy of the shape, but cannot describe the quality of the finished surface. This explanation is clearly wrong.
Page 19, line 557; “…worsens the surface quality due to the adhesion of the cracked elements of the material to the machined surface.”, It is not convincing because there is no evidence such as measurement data.
Page 20, line 559; “…with the size Rn also on the formation of the increment.”, This explanation is not convincing because there is no experimental data to compare with tools finished by EDM and grinding.
Page 20, line 595; This sentence duplicates the content of the abstract and is not appropriate for Discussion.
Page 21, line 616; “The presented solution can be applied by technologists in the production of newly designed products.” The results of this research are very limited and will not be useful for parameter selection in general machining sites. Evaluation of the surface roughness of the finished surface, the accuracy of the machining dimensions, and tool wear rate would be much more useful than chip cross-section.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript entitled "Machining of inserts with PCD material cutting edge and determination of optimum machining conditional of Al alloy by using Gray Relation Analysis" presents an experimental study on the effect of various process conditions on roundness deviation and chip cross section of an aluminum alloy during turning. This work is of moderate interest and should be considerably improved before being considered for publication.
At first, the title of the manuscript should be considerably changed in order to reflect the subject of the paper which is relevant to the roundness deviation and chip cross section. The name of the machining process (turning) should be mentioned as well as the aluminum alloy used. Moreover "Gray" should be spelt as "Grey" in the entire manuscript.
In the Introduction section, line 95 the first line of the paragraph should be indented. At line 99 the authors should omit the period "." before the phrase "EDM or LASER". This error is done multiple times within the manuscript and should be corrected. When the authors of a paper are mentioned, the reference should be placed after their names, e.g. Jia and Li et al. [21]. Moreover, the authors should check again the journal recommendations for the correct style of mentioning the names of authors. In the paragraph beginning at line 102, several changes should be conducted. The sentence "Measurement of the total ... main cutting edge" should be corrected as it is incomprehensible. This paragraph should be shortened in order to be more concise and mentioning the same subjects more than once should be avoided. The phrase "minimizing the formation of flare on the surface" should be rephrased as it is not appropriate. The part beginning from "In 1982, Deng ...
electro spark machining" seems irrelevant as in the previous part of the paragraph, the contents of the paper were summarized. In the last
paragraph of theIintroduction the authors state that there is no other work conducted regarding the influence of input cutting factors in
turning with GRA; however this statement is incorrect as there are relevant works even with roundness as objective. Thus, they should
rephrase this paragraph and stress their novelty in a different way.
In section 2, line 158 the corner radius Rε is stated to have degrees (o) as unit instead of mm which is the correct. The quality of Figures 2 and 3 should be improved. Subsection 3.1 may be interesting but the results obtained by turning the aluminum alloy with inserts created by other sharpening methods than laser should be also presented and compared in order for this subsection to be more meaningful. Moreover, in section 3.2 the authors should justify in detail their choice to include the chip cross section as response variable of the experiment. As it is generally an uncommon variable in the relevant literature, it is required that the authors convince about the importance of this variable.
In subsection 3.3, the authors present the formula used to normalize data for the case "the higher the better" but, in line 391, they mention that they used the case "smaller is better". Thus, they should correct this formula to the one they used. The authors should justify the target value for chip cross section and how it can be useful in practice.
The paragraph beginning in line 475 should be carefully rephrased as various parts are incomprehensible e.g. in line 479 material removal and turning power are mentioned but they are not measured in the experiment or in line 487 the phrase "with minimal formation of a stable elevation" etc. In line 498, the sentence "On this basis ... cutting edge by increasing" should be either properly justified or removed. In line 509, the authors should explain in more details the meaning of the phrase "an increase whether stable or unstable". In lines 527-8 the phrase "which have a significant ... a decrease in GRG" should be corrected in order to be comprehensible. In the caption of Figure 16 "sectin" should be changed to "section" and in the caption of Figure 17, "roudness" should be corrected to "roundness". In line 542 and other parts of the manuscript the authors relate the roundness error which is relevant to the dimensional accuracy, with surface quality. However, surface roughness is more appropriate to be used to evaluate surface quality. Thus, they should properly correct this statement in the manuscript. In line 564, what is the meaning of the "increment"?
Finally, in the conclusion section, the first paragraph is generally irrelevant with the analysis conducted in the paper, thus it should be
omitted and more relevant statements should be included.
In conclusion, the authors should try more to convince about the importance of their work, by justifying the choice of response variables and by properly connecting the analysis conducted in subsection 3.1 with the rest of the paper. Moreover, various errors and ambiguous phrases should be also properly corrected in the manuscript before it can be considered for publication.
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I have checked the revisions to the paper in response to the initial comments. I think the corrections are sufficient. There is only one place where you need to provide the unit for the melting range of Al alloy in Table 3 (is it °C?).
Author Response
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Author Response File: Author Response.docx
Reviewer 2 Report
The authors have almost totally neglected to perform most of the proposed modifications to their manuscript except for some minor corrections and some rephrasing in the conclusions section. Their work cannot be published unless they perform all the required modifications, most of them which are repeated again:
1) In the paragraph beginning in line 101 "In this paper, the influence..." the authors should shorthen most of the sentences in order to be more concise and move the part beginning with "Deng ... electro spark machining [31]" to another paragraph or a more suitable subsection e.g. subsection 3.2.
2) In the same paragraph, the sentence "Measurement of total ... main cutting edge" should be corrected as it is incomprehensible.
3) In the last paragraph of the Introduction section, the authors should rephrase the paragraph and stress their novelty in a different way as the statement that there is no other paper regarding GRA method in turning is incorrect.
4) Moreover, the authors should add some more papers in the Introduction section regarding works on roundness error in turning involving GRA method.
5) In section 3.2 and other parts of the manuscript the authors must convince with appropriate justifications from the relevant literature or industrial practice about the importance of including the chip cross section as response parameter. This parameter is uncommon in similar investigations and the authors have not convinced about its necessity compared to the use of other quantities such as cutting forces, power or tool wear.
6) The authors should also mention which is the desired value for chip cross section regarding the optimization process with GRA.
7) Regarding the equation 3, the authors should correct it with the formula corresponding to "smaller is better" and the relevant term in line 338, as they want to minimize their variables instead of maximizing them. Moreover, in line 372 they should use again the phrase "smaller is better" which was correct.
8) The authors should provide detailed description of the measurement of chip cross section in any case, including a relevant schematic. At which positions was the chip cross section calculated? How many measurements were conducted for each case and how variable was the geometry of the chip? Moreover, the chip images for every experiment should be provided in order to observe the variation of its size in each experiment.
9) In the paragraph beginning with "The underlined values ... the cutting edge" several parts should be corrected. For example in line 420 the authors mention "the maximum material removal and turning power while minimizing the damage to the cutting edge". However none of these three responses (material removal rate, turning power, cutting tool wear) are measured and presented in the manuscript, so this phrase and other similar should be removed.
10) In the same paragraph, the phrase "with minimal formation of a stable elevation" should be explained.
11) In the same paragraph, at the last sentence "On this basis ... the cutting edge" the authors state that the chip shape affects the damage on the surface of the product. However, without providing images of the damage or without properly correlating the chip shape with damage this phrase should be removed.
12) In line 448, in the sentence "It was shown that the effect ... Figure 16 and Figure 17." the authors state that the change of chip cross section and roundness deviation can indirectly show the formation of a built up edge which is not appropriately justified or proven by providing images of the cutting tool edge and the BUE formation. If they cannot provide the images, this phrase should be removed.
13) The authors should remove any statement regarding surface quality as they have not measured surface roughness but roundness error which is relevant to dimensional accuracy. For example, some phrases that should be removed are in line 485, "As the cutting speed increases, the surface quality deteriorates ... while as the feed rate increases the surface quality deteriorates ..." or in line 488 "The surface quality is represented by the deviation of roundness".
14) In the entire revised manuscript the authors have chosen to mention "Built-up edge" on various occasions without presenting any measurements or photos indicating the size of built-up edge during the experiments. Thus, they should either remove all the phrases regarding built-up edge or provide measurements in order to justify their statements.
In conclusion, if the authors do not perform all the recommended modifications to their manuscript it cannot be recommended for publication.
Author Response
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Author Response File: Author Response.docx
Round 3
Reviewer 2 Report
The authors have performed several modifications to their manuscript. However, there are still some minor issues with the manuscript which are required to be dealt with before it can be recommended for publication.
1) The paragraph with the additional references placed at the end of the Introduction section (lines 124-144) should be placed after line 101, before the sentence "The paper presents the results ... two phases".
2) The responses which were provided by the authors regarding the importance of chip cross section as a parameter in the previous review (Point 5) should be also included in the manuscript (in subsection 3.2).
3) Regarding formula 3 the authors stated that they use "higher is better" method, something mentioned in lines 354 and 388. However both of their goals are related to minimization: minimum roundness deviation and minimum chip cross section. Then, how can the use of "higher is better" be explained? Moreover, if they actually used maximization instead of minimization of the two process parameters, they should correct their results accordingly.
4) Regarding the process of measuring the chip cross section, the authors should include their responses to the previous review (Point 8) also in the manuscript.
5) In page 15, the authors state that they included images relevant to the measurement of chip-cross section in Figure 12 but in Figure 12 they present diagrams that were already in the manuscript. Thus, they should properly include the required images in a new Figure.
6) The quality of several figures should be enhanced e.g. Figure 9, Figure 15a,b.
Author Response
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Author Response File: Author Response.docx
Round 4
Reviewer 2 Report
The authors have performed the necessary corrections, thus the manuscript is recommended for publication.
