The effect of drill point angles on drillability in CFRP/Al-7075 stacking drilling

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Aydin E., NALBANT M.

JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, vol.35, no.2, pp.917-931, 2020 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 35 Issue: 2
  • Publication Date: 2020
  • Doi Number: 10.17341/gazimmfd.548419
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Art Source, Compendex, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.917-931


In this study, the drillability of CFRP/Al-7075 stacked structure which is formed by carbon fiber reinforced polymer composite (CFRP) material, which is used intensively in the field of military and civil aviation, and Al-7075 alloy has been investigated by drilling with uncoated carbide drills with different point angles. In the drilling processes thrust force (F-z), moment (M-z), hole average surface roughness (R-a), chip structure and delamination (Fa) occurring in CFRP material were investigated. Experimental studies were performed under dry cutting conditions with 50 m/min cutting speed and 0.05 mm/rev constant feed rate by using three different drill (120 degrees-130 degrees-140 degrees) point angles uncoated carbide drills have different. 120 degrees and 130 degrees point angle drills are showed close F-z and F-d values in the CFRP material, while the lowest F-z, M-z, R-a and lowest F-d value are obtained respectively in 130 degrees-120 degrees-140 degrees point angle drills. In the 140 degrees point angle drill, a large amount of burring and built-up edge (BUE) was formed on the main cutting edge and Al chips were plastered in the drill helix flutes. After experimental studies, the effects of drill point angles on thrust force and average surface roughness were determined by ANOVA at 95% confidence interval and multiple comparison tests were applied. As a result, it has been seen that uncoated carbide drill has 130 degrees point angle gives better results in terms of moment, thrust force, average surface roughness and delamination, under specified cutting parameters and drilling conditions in CFRP/Al-7075 stacking drilling.