Effect of laminate configuration and feed rate on cutting performance when drilling holes in carbon fibre reinforced plastic composites

Shyha, Islam; Soo, Sein Leung; Aspinwall, David; Bradley, Sam

Abstract

Composites use in the aerospace industry is expanding, in particular carbon fibre reinforced plastics (CFRP) for structural components. Machinability can however be problematic especially when drilling, due to CFRP's inherent anisotropy/in-homogeneity, limited plastic deformation and abrasive characteristics. Following a brief review on composites development and associated machining, the paper outlines experimental results when twist drilling 1.5 mm diameter holes in 3 mm thick CFRP laminate using tungsten carbide (WC) stepped drills. The control variables considered were prepreg type (3 types) and form (unidirectional (UD) and woven), together with drill feed rate (0.2 and 0.4 mm/rev). A full factorial experimental design was used involving 12 tests. Response variables included the number of drilled holes (wear criterion VBBmax ≤ 100 μm), thrust force and torque, together with entry and exit delamination (conventional and adjusted delamination factor values calculated) and hole diameter. Best results were obtained with woven MTM44-1/HTS oven cured material (3750 holes) while the effect of prepreg form on tool life was evident only when operating at the higher level of feed rate. Thrust forces were typically under 125 N with torque values generally below 65 Nmm over the range of operating parameters employed. Finally, the delamination factor (Fd) measured at hole entry and exit ranged between ∼1.2–1.8 and 1.0–2.1 respectively.

• Journal Article Type: Article
• Acceptance Date: Feb 11, 2010
• Online Publication Date: Feb 18, 2010
• Publication Date: 2010-06
• Deposit Date: Dec 14, 2020
• Journal: Journal of Materials Processing Technology
• Print ISSN: 0924-0136
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 210
• Issue: 8
• Pages: 1023-1034
• DOI: https://doi.org/10.1016/j.jmatprotec.2010.02.011
• Keywords: CFRP, Prepreg form, Delamination, Composites, Drilling
• Public URL: http://researchrepository.napier.ac.uk/Output/2686934
• Related Public URLs: http://nrl.northumbria.ac.uk/id/eprint/11018/