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

Shyha, Islam, Aspinwall, David, Soo, Sein Leung and Bradley, Sam (2009) Drill geometry and operating effects when cutting small diameter holes in CFRP. International Journal of Machine Tools and Manufacture, 49 (12-13). pp. 12-13. ISSN 0890-6955

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Abstract

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 ∼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 (Fd) of ∼1.3 were achieved while the maximum number of drilled holes for a tool life criterion VBBmax of ≤100 μm was 2900 holes using a stepped, uncoated drill with a feed rate of 0.2 mm/rev.

Item Type:	Article
Uncontrolled Keywords:	small holes, composites
Subjects:	H700 Production and Manufacturing Engineering
Department:	Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User:	Islam Shyha
Date Deposited:	21 Jan 2013 09:40
Last Modified:	13 Oct 2019 00:30
URI:	http://nrl.northumbria.ac.uk/id/eprint/11021

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