Effect of Twist Drill Geometry and Drilling Parameters on Hole Quality in Single-Shot Drilling of CFRP/Al7075-T6 Composite Stack

Round 1

Reviewer 1 Report

Dear Author,

The article presents the results of the drilling process for CFRP/AL7075-T6.

In my opinion, it should be analyzing the accuracy of tools that were used before machining and after to see the influence of real shape on the materials and also the wear process. 

The drawing 7 have to be improved to better show the difference between the.

Moreover I recommend to include more in depth analysis in conclusion to compare results with the data from the article already publish.

 

Kind regards,

Reviewer

Author Response

Point 1: In my opinion, it should be analyzing the accuracy of tools that were used before machining and after to see the influence of real shape on the materials and also the wear process.

Response 1: Thank you for the opinion. However, in this article, we focused on the effect of the customized twist drill geometry on the thrust force during drilling and the hole quality which is determined from hole diameter error and hole surface roughness. The study of tool wear was not in the scope of the current work. Therefore in this study, only five holes were drilled for each drill bit under study. Under such conditions for carbide tool material, tool wear is insignificant and can be negligible.

Point 2: Drawing 7 have to be improved to better show the difference between the.

Response 2: Figure 7 has been improved accordingly as shown below (attachement)

Point 3: Moreover I recommend to include more in depth analysis in conclusion to compare results with the data from the article already publish.

Response 3: The authors appreciate the suggestion. However, we found that most published articles on the study of CFRP drilling do not identical setting in terms of machining parameters or the combination of parameters are not identical, thus making valid comparison not justifiable. The twist drill used in this study has unique design and customised based on end user recommendation in one aerospace manufacturing company. As such, the drills bit used in this study were not identical to any typical drill bit found on a commercially available catalogue, which most previous works have used.

Author Response File: Author Response.docx

Reviewer 2 Report

I can not paste my report.

Comments for author File: Comments.doc

Author Response

Point 1: The investigation indicates that that the maximum thrust force for both CFRP and Al7075-T6 are highly dependent on the feed rate. Also, the optimum tool parameters are found. The optimum parameters are benchmarked against existing industry practice of the capability to produce higher hole quality and efficiency. I recommend the paper for publication since the results obtained can be applied in engineering practice.

Response 1: Author acknowledged the comments and would like to thank the reviewer for the recommendation.

Author Response File: Author Response.docx