Machinability Assessment and Multi-Objective Optimization of Graphene Nanoplatelets-Reinforced Aluminum Matrix Composite in Dry CNC Turning
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have conducted some interesting research work, and the following are some suggestions for manuscript revision:
- The description of the research objectives and content in the introduction is relatively brief, lacking sufficient details to clearly showcase the specific direction and expected outcomes of the study. It is recommended that the author provide a more detailed explanation.
- The experimental design includes only 9 experimental runs, which is too few. This may lead to insufficient evaluation of the interaction effects and nonlinear influences of the cutting parameters, thereby affecting the predictive capability and optimization results of the model. It is suggested that the author increase the number of experiments, possibly by adopting a Box-Behnken Design (BBD) or a full factorial design, to enhance the comprehensiveness and reliability of the results.
- During the data analysis, there is a lack of discussion on the residual terms of the model. It is recommended that the author include a test of the residuals to more thoroughly assess the model's applicability and accuracy.
- Although the author has validated the effectiveness of the optimization algorithm through new validation experiments, there is no direct comparison with historical experimental data. It is suggested that the author add a comparison between the prediction results of the optimization algorithm and historical experimental data to further validate the effectiveness and reliability of the algorithm.
Author Response
We are grateful for the opportunity to resubmit our manuscript and provide a detailed account of the changes made based on the invaluable feedback from the reviewers. We sincerely appreciate the reviewers' insightful comments and constructive revisions, which we strongly believe that they have significantly improved the quality of our work. In this resubmission, we have carefully addressed each reviewer’s comments, as detailed below. To facilitate the review process, we have highlighted all modifications/amendments in blue within the manuscript, therefore making it easier for the reviewers and editor to identify the changes made.
Reviewer #1
The authors have conducted some interesting research work, and the following are some suggestions for manuscript revision:
Response: The authors appreciate the positive feedback provided.
Comment 1:
The description of the research objectives and content in the introduction is relatively brief, lacking sufficient details to clearly showcase the specific direction and expected outcomes of the study. It is recommended that the author provide a more detailed explanation.
Response:
The authors thank the reviewer for the comment. The last paragraph of “Introduction” section has been rewritten to more accurately introduce the research objectives of the paper; i.e., that is to say machinability study of the composite Al-Gr0.5% and optimization using the NSGA-II algorithm. The new content is as follows:
“This work examines the effect of cutting conditions; cutting speed, feedrate and depth of cut on machinability attributes related to surface roughness and main cutting force when turning graphene nanoplatelets (GNPs) reinforced aluminum with 0.5 wt.% graphene. The former criterion represents machining quality whereas the latter focuses on power consumption that directly affects manufacturing cost. Both criteria are examined for their simultaneous minimization. A custom response surface design of experiments derived from an L9 Taguchi orthogonal array design is established with low number of experiments to reduce experimental cost whilst successfully studying the independent parameter effects owing to curvature presence as a robust property of response surface methodology. Machinability aspects for both pure aluminum and composite material are discussed with reference to observations related to surface quality of machined specimens and chip morphology. From the perspective of optimization efforts, the well-known non-dominated sorting genetic algorithm (NSGA-II) is applied to efficiently examine beneficial non-dominated solutions. The study takes advantage of NSGA-II special algorithmic operators to generate a uniformly distributed Pareto front of solutions”.
Comment 2:
The experimental design includes only 9 experimental runs, which is too few. This may lead to insufficient evaluation of the interaction effects and nonlinear influences of the cutting parameters, thereby affecting the predictive capability and optimization results of the model. It is suggested that the author increase the number of experiments, possibly by adopting a Box-Behnken Design (BBD) or a full factorial design, to enhance the comprehensiveness and reliability of the results.
Response:
The authors thank the reviewer for this valuable and insightful suggestion. Unfortunately owing to unavailable resources for this time period, additional machining experiments cannot be conducted. However, to mention the important aspects concerning the insufficient evaluation and reduced regression model capabilities when few experimental trials are performed, a note has been amended to the revised manuscript. The note is in the first paragraph in “Materials and Methods” section, highlighted in blue and is as follows:
“It should be noted that during the establishment of experimental designs, issues such as preliminary testing and initial screening while maintaining minimal resources and cost should be considered. Should a design of experiments involve a low number of trials, insufficient predictability and model reliability may be experienced.”
Comment 3:
During the data analysis, there is a lack of discussion on the residual terms of the model. It is recommended that the author include a test of the residuals to more thoroughly assess the model's applicability and accuracy.
Response:
The authors thank the reviewer for the comment. Residuals for both statistical results examined for surface roughness Ra and main cutting force Fz were assessed by applying the “Anderson-Darling” hypothesis test, as mentioned in the manuscript. It is found that both sets for residuals follow the normal distribution indicated by the corresponding p-values that reveal insignificant contribution to the statistical test.
Comment 4:
Although the author has validated the effectiveness of the optimization algorithm through new validation experiments, there is no direct comparison with historical experimental data. It is suggested that the author add a comparison between the prediction results of the optimization algorithm and historical experimental data to further validate the effectiveness and reliability of the algorithm.
Response:
The authors thank the reviewer for the comment. By supposing that the reviewer considers the experimental results as the “historical experimental data” the authors find it hard to compare the different values obtained either by the algorithm or the verification machining experiment since both sets are “close to optimal values” as opposed to those obtained by the experiments.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript “Machinability Assessment and Multi-Objective Optimization of Graphene Nanoplatelets-Reinforced Aluminum Matrix Composite in Dry CNC Turning” presents a model to optimize the machining process for Al and Al+Gr0.5%. The reviewer does not recommend the manuscript acceptance for publishing in Metals as it is because there is missing more discussion about the results obtained, as well as more evidences to support the data interpretation, such as material characterization. The reviewer recommends that the authors add more Al machining results to be compared with Al+Gr0.5%. Besides that, a list of points to be considered for further submission is presented below:
Page 3 Table 1: The reviewer recommends 0.50 instead of 0.500 for α.
Page 3 Line 119-122: “high-purity aluminum was selected (Al 96.83%) in the form of orthogonal billet, mixed with 500 m2 /g graphene nanoplatelets-GNPs. As a matrix material, the high-purity aluminum in the form of rectangular cross-section billet was mixed with GNPs to produce the working composite material through casting.” The reviewer recommends more details regarding the material processing, temperatures, cooling rate, etc...
Page 3 Line 120: Please provide the graphene supplier.
Page 3 Line 123: The reviewer recommends typing simply” pure Al” instead of “high-purity matrix aluminum”. Please review the whole manuscript.
Page 3 Line 123: “spectrographic characterization of high-purity matrix aluminum.” The reviewer recommends more details, e.g., standard followed, equipment used, etc…
Page 3 Table 2: The reviewer recommends title “Spectrographic characterization of high-purity matrix aluminum. wt.%.” and deleting all “(%)” from the table. What is the element “T 400604”?
Page 4: The reviewer recommends adding SEM images and hardness of Al and Al+Gr0.5% to evaluate the effectiveness of Al characteristics/properties changing by adding graphene.
Page 4 Line 141: “A TNMG160404-MF2 TP200 CVD-coated carbide cutting insert was used for conducting the CNC turning experiments.” Is it Sandvik’s? Please specify the manufacturer.
Page 5 Figure 4: The reviewer recommends deleting this image.
Page 6 Table 3: The reviewer recommends using “Al” instead of “Ref.AL” and “Al-Gr0.5% instead of “AL-Gr0.5%”. Please review the whole document.
Page 9: The reviewer recommends SEM images of the chips to be interpreted if adding graphene to Al altered the cutting mechanisms.
Page 10 Figure 10: The reviewer recommends plotting Fz maps for Al machining too.
Page 11 Figure 11: The reviewer recommends plotting Ra maps for Al machining too.
Page 18 Line 492: typo “grapheme”
Author Response
We are grateful for the opportunity to resubmit our manuscript and provide a detailed account of the changes made based on the invaluable feedback from the reviewers. We sincerely appreciate the reviewers' insightful comments and constructive revisions, which we strongly believe that they have significantly improved the quality of our work. In this resubmission, we have carefully addressed each reviewer’s comments, as detailed below. To facilitate the review process, we have highlighted all modifications/amendments in blue within the manuscript, therefore making it easier for the reviewers and editor to identify the changes made.
The manuscript “Machinability Assessment and Multi-Objective Optimization of Graphene Nanoplatelets-Reinforced Aluminum Matrix Composite in Dry CNC Turning” presents a model to optimize the machining process for Al and Al+Gr0.5%. The reviewer does not recommend the manuscript acceptance for publishing in Metals as it is, because there is missing more discussion about the results obtained, as well as more evidences to support the data interpretation, such as material characterization.
Comment 1:
The reviewer recommends that the authors add more Al machining results to be compared with Al+Gr0.5%. Besides that, a list of points to be considered for further submission is presented below:
Response:
Amendments and modifications have been conducted with reference to the comments below.
Comment 2:
Page 3 Table 1: The reviewer recommends 0.50 instead of 0.500 for α.
Response:
The recommended modification referring to “depth of cut” parameter in Table 1 has been corrected.
Comment 3:
Page 3 Line 119-122: “high-purity aluminum was selected (Al 96.83%) in the form of orthogonal billet, mixed with 500 m2 /g graphene nanoplatelets-GNPs. As a matrix material, the high-purity aluminum in the form of rectangular cross-section billet was mixed with GNPs to produce the working composite material through casting.” The reviewer recommends more details regarding the material processing, temperatures, cooling rate, etc...
Response:
Details and illustrations have been amended concerning the process of fabricating the experimental specimens-composites. The content is presented in sub-section 2.2 Workpiece Material Fabrication.
Comment 4:
Page 3 Line 120: Please provide the graphene supplier.
Response:
The vendor of Graphene nanoplatelets (Alfa Aesar) has been mentioned in sub-section 2.2 Workpiece Material Fabrication in the revised manuscript. The vendor of high-purity aluminum (Viohalco S.A.) is also mentioned.
Comment 5:
Page 3 Line 123: The reviewer recommends typing simply ”pure Al” instead of “high-purity matrix aluminum”. Please review the whole manuscript.
Response:
We keep the expression high-purity aluminum since this is the specification of the vendor.
Comment 6:
Page 3 Line 123: “spectrographic characterization of high-purity matrix aluminum.” The reviewer recommends more details, e.g., standard followed, equipment used, etc…
Response:
Chemical contents table was provided by Viohalco S.A. Greece along with the material (high-purity aluminum 96.83%). As far as the standard is concernced, is ISO 3522:2007. “Aluminium and aluminium alloys - Castings - Chemical composition and “mechanical properties.
Comment 7:
Page 3 Table 2: The reviewer recommends title “Spectrographic characterization of high-purity matrix aluminum. wt.%.” and deleting all “(%)” from the table. What is the element “T 400604”?
Response:
Corrections were made accordingly as per the reviewer’s suggestion. “T 400604 element” was deleted since this entity is faulty (typing inconsistency) and thus it was removed. The authors thank the reviewer for this important notification.
Comment 8:
Page 4: The reviewer recommends adding SEM images and hardness of Al and Al+Gr0.5% to evaluate the effectiveness of Al characteristics/properties changing by adding graphene.
Response:
Unfortunately there is no SEM equipment in our laboratory facilities. All microscopy images illustrated in our manuscript were obtained using a typical metallographic microscope (WILD M50).
Comment 9:
Page 4 Line 141: “A TNMG160404-MF2 TP200 CVD-coated carbide cutting insert was used for conducting the CNC turning experiments.” Is it Sandvik’s? Please specify the manufacturer.
Response:
A Seco® TNMG160404-MF2 TP200 CVD-coated carbide cutting insert by was used for conducting the CNC turning experiments. This amendment regarding the cutting insert manufacturer, has been amended to the revised manuscript.
Comment 10:
Page 5 Figure 4: The reviewer recommends deleting this image.
Response:
This figure has been removed as per the reviewer’s suggestion. Consequently all figures have been revised and renumbered accordingly.
Comment 11:
Page 6 Table 3: The reviewer recommends using “Al” instead of “Ref.AL” and “Al-Gr0.5% instead of “AL-Gr0.5%”. Please review the whole document.
Response:
The corrections referring to modifications “Al” instead of “Ref.AL” and “Al-Gr0.5% instead of “AL-Gr0.5%” have been made as per the reviewer’s suggestions. The whole manuscript has been reviewed and corrected.
Comment 12:
Page 9: The reviewer recommends SEM images of the chips to be interpreted if adding graphene to Al altered the cutting mechanisms.
Response:
Unfortunately there is no SEM equipment in our laboratory facilities. All microscopy images illustrated in our manuscript were obtained using a typical metallographic microscope (WILD M50). See also comment #8.
Comment 13:
Page 10 Figure 10: The reviewer recommends plotting Fz maps for Al machining too.
Response:
Contour plots referring to machining parameter interactions for main cutting force Fz in the case of pure Al., have been amended to the revised manuscript.
Comment 14:
Page 11 Figure 11: The reviewer recommends plotting Ra maps for Al machining too.
Response:
Contour plots referring to machining parameter interactions for surface roughness Ra in the case of pure Al., have been amended to the revised manuscript.
Comment 15:
Page 18 Line 492: typo “grapheme”
Response:
The typographical error “grapheme” instead of “graphene“ has been corrected.
Reviewer 3 Report
Comments and Suggestions for Authors- This paper shows some similarities with the authors' previously published paper on Machinability Under Dry CNC Hard Turning Conditions from 2024.
There are some paragraphs in this paper that are very similar to the previously published paper. These parts are mainly about the methodology, theoretical aspects, not strictly results and discussions, but these similarities should be significantly reduced. I ask the authors to write the paper from a blank page, and not to re-edit the existing text. Please reduce the similarities to the earlier paper. - Lines 34-37 - Please describe exactly what these mechanical properties are.
- Lines 125-127 - Please provide specific models of this equipment.
- Line 135 - please explain "surface imperfections" and "cylindricity accuracy". How do you measure both of these.
- Line 159 - please add roughness measurements accuracy obtained from that device.
- Table 3 - please explain the selection of that paraemters.
- Fig. 15-17 - please add your own plots not generated from software because its difficult to read (plots are not clear).
Author Response
We are grateful for the opportunity to resubmit our manuscript and provide a detailed account of the changes made based on the invaluable feedback from the reviewers. We sincerely appreciate the reviewers' insightful comments and constructive revisions, which we strongly believe that they have significantly improved the quality of our work. In this resubmission, we have carefully addressed each reviewer’s comments, as detailed below. To facilitate the review process, we have highlighted all modifications/amendments in blue within the manuscript, therefore making it easier for the reviewers and editor to identify the changes made.
Comment 1:
This paper shows some similarities with the authors' previously published paper on Machinability Under Dry CNC Hard Turning Conditions from 2024. There are some paragraphs in this paper that are very similar to the previously published paper. These parts are mainly about the methodology, theoretical aspects, not strictly results and discussions, but these similarities should be significantly reduced. I ask the authors to write the paper from a blank page, and not to re-edit the existing text. Please reduce the similarities to the earlier paper.
Response:
The authors understand the reviewer’s valuable comment. We agree with the reviewer that a notable similarity exists with one of our published manuscripts mainly in a content related to general aspects and basic theories (i.e. functional attributes of the NSGA-II algorithm). The paper was checked and rewritten to most of the parts exhibiting high similarity percentage.
Comment 2:
Lines 34-37 - Please describe exactly what these mechanical properties are.
Response:
A brief mention to some notable alloys and their properties has been amended to the revised manuscript in “Introduction” section. The paragraph amended, is as follows:
“Exact mechanical properties of lightweight materials may be mentioned depending on the material under question. Aluminum and its alloys exhibit excellent strength, ductility, rigidity and corrosion resistance. Aluminum is a good heat and electricity conductor. Magnesium and its alloys is also a lightweight material with beneficial properties like aluminum and titanium. Magnesium exhibits strength, good ductility, low density, corrosion resistance and high resilience. Titanium and its alloys exhibit low thermal conductivity, good strength-to-weight ratio, etc”.
Comment 3:
Lines 125-127 - Please provide specific models of this equipment.
Response:
The model types of equipment used have been amended to the revised manuscript.
Comment 4:
Line 135 - please explain "surface imperfections" and "cylindricity accuracy". How do you measure both of these?
Response:
A paragraph has been amended to the revised manuscript describing the typical examination of casted experimental components. The paragraph is in sub-section “2.2.Workpiece Material Fabrication”.
“Cylindrical rods were visually examined in terms of notable surface imperfections whereas typical accuracy of cylindricity was tested using a dial indicator mounted to the CNC machine tool’s carrier to allow back and forth movements while slightly rotating the clamped specimens to check accuracy throughout the parts’ entire length of 300 mm.”
Comment 5:
Line 159 - please add roughness measurements accuracy obtained from that device.
Response:
The authors have amended the key specifications of Taylor Hobson Surtronic 3+ roughness tester used in the experiments. Based on the user manual the specifications include: “± 5 % accuracy; 2 %repeatability and automatic calibration with traceable standards”.
Comment 6:
Table 3 - please explain the selection of those parameters.
Response:
The selection of process parameters was based on the tool manufacturer’s recommendations as well as trial-and-error / preliminary machining experiments.
Comment 7:
Fig. 15-17 - please add your own plots not generated from software because it’s difficult to read (plots are not clear).
Response:
Figures and corresponding captions referring to the roughness measurements of validation experiments (figs. 15, 16 and 17 in the revised manuscript) have been revised such that clear depictions for roughness profiles are provided.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript can be accepted.
Author Response
The authors want to thank the reviewer for the manuscript acceptance.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors improved the manuscript quality by accepting the reviewer's recommendations and suggestions. Some considerations are listed below before the reviewer recommends the acceptance of this manuscript for publishing in Metals:
1) The reviewer recommends presenting the materials by their symbols instead of their names, e.g., Mg instead of Magnesium or Al instead of Al. Please review the whole manuscript.
2) Line 56: The reviewer recommends distributing the references for the subjects that they present instead of grouping them, e.g., SiC [7,8], TiC [9], MgO [10-12].... instead of "[7-15]" as it is presented.
3) Line 154: The reviewer recommends providing the manufacturer/model of the scale used. Please follow this advice to all the equipment listed in the manuscript.
4) Line 258: The reviewer recommends deleting the units between parenthesis in “…Fz (N) and surface roughness Ra (μm)…” because they are sown in Table 3.
5) Line 306 Figure 7: The reviewer recommends specifying the material machined (Al or Al-Gr0.5%.
6) Line 391: The reviewer recommends “wt%” instead of “w.t.%”. Please review the whole manuscript.
7) Line 403: The reviewer recommends “… cutting speed, i.e., 120 m/min.” instead of “… cutting speed; i.e. 120 m/min.” i.e. and e.g. always between commas. Please review the whole manuscript.
8) The reviewer recommends using the same style all text long, e.g., “Al-Gr0.5%” or “Al-Gr.0.5%” Fz and Ra italic or Fz and Ra normal, etc… Please review the whole manuscript.
Author Response
Responses to Reviewer #2
We are grateful once again for the opportunity to resubmit our manuscript. To facilitate the review process at this state, we have highlighted the new modifications/amendments in green within the manuscript, therefore making it easier for the reviewer and editor to track and identify the changes made.
Comments and responses are as follows:
“The authors improved the manuscript quality by accepting the reviewer's recommendations and suggestions. Some considerations are listed below before the reviewer recommends the acceptance of this manuscript for publishing in Metals:”
Comment 1
The reviewer recommends presenting the materials by their symbols instead of their names, e.g., Mg instead of Magnesium or Al instead of Al. Please review the whole manuscript.
Response
The authors revised the issue of materials presentation as per the reviewer’s suggestion.
Comment 2
Line 56: The reviewer recommends distributing the references for the subjects that they present instead of grouping them, e.g., SiC [7,8], TiC [9], MgO [10-12].... instead of "[7-15]" as it is presented.
Response
The authors totally agree with the reviewer’s comment. The references were suitably distributed according the scientific subject they refer to. This section has been revised and highlighted in green.
Comment 3
Line 154: The reviewer recommends providing the manufacturer/model of the scale used. Please follow this advice to all the equipment listed in the manuscript.
Response
The type of electronic scale implemented for our experimental work was the PCB 1000-1 weighting Scale. The advice concerning the reference in equipment models was followed as per the reviewer’s suggestion.
Comment 4
Line 258: The reviewer recommends deleting the units between parenthesis in “…Fz (N) and surface roughness Ra (μm)…” because they are shown in Table 3.
Response
The authors deleted the units corresponding to Fz and Ra as suggested.
Comment 5
Line 306 Figure 7: The reviewer recommends specifying the material machined (Al or Al-Gr0.5%).
Response
The authors specified the “material machined”, illustrated in Fig.7
Comment 6
Line 391: The reviewer recommends “wt%” instead of “w.t.%”. Please review the whole manuscript.
Response
The authors revised the points in the manuscript where “w.t.%” appears. The authors used “wt%” as suggested.
Comment 7
Line 403: The reviewer recommends “… cutting speed, i.e., 120 m/min.” instead of “… cutting speed; i.e. 120 m/min.” i.e. and e.g. always between commas. Please review the whole manuscript.
Response
The authors revised the points in the manuscript where “…; i.e.” is appeared.
Comment 8
The reviewer recommends using the same style all text long, e.g., “Al-Gr0.5%” or “Al-Gr.0.5%” Fz and Ra italic or Fz and Ra normal, etc… Please review the whole manuscript.
Response
The authors checked the manuscript and maintained the expression “Al-Gr0.5%” throughout the whole manuscript. In addition, all parameters referring to independent and dependent variables, were italicized to keep the same format throughout the manuscript.
