Drill geometry and operating effects when cutting small diameter holes in CFRP

IS Shyha, David Aspinwall, Sein Soo, SA Bradley

Research output: Contribution to journalArticle

173 Citations (Scopus)


The paper details experimental results when drilling small holes (1.5 mm diameter cemented carbide drills with varying end point and helix geometry) in thin quasi-isotropic, unbacked carbon fibre reinforced plastic (CFRP) laminate (typical cutting time similar to 0.4 s/hole). The study utilised an L12 Taguchi fractional factorial orthogonal array with analysis of variance (ANOVA) employed to evaluate the effect of drill geometry and drilling conditions on tool life and hole quality. Main effects plots and percentage contribution ratios (PCR) are detailed in respect of response variables and process control factors. More conventionally, tool wear and cutting force data are plotted/tabulated, together with micrographs of hole entry/exit condition and internal hole damage. Drill geometry and feed rate in general had the most effect on measured outputs. Thrust force was typically below 100 N at test cessation; however, drill wear progression effectively doubled the magnitude of force from test outset. Entry and exit delamination factors (F-d) of similar to 1.3 were achieved while the maximum number of drilled holes for a tool life criterion VB(B)max of
Original languageEnglish
Pages (from-to)1008-1014
Number of pages7
JournalInternational Journal of Machine Tools and Manufacture
Issue number12-13
Publication statusPublished - 1 Oct 2009


  • Small holes
  • CFRP
  • Drilling
  • Composites


Dive into the research topics of 'Drill geometry and operating effects when cutting small diameter holes in CFRP'. Together they form a unique fingerprint.

Cite this