Measurement and evaluation of hole attributes for drilling CFRP composites using an indigenously developed cryogenic machining facility. (15th March 2020)

• Record Type: Journal Article
• Authors: Khanna, Navneet; Pusavec, Franci; Agrawal, Chetan; Krolczyk, Grzegorz M.
• Is Part Of: Measurement. Volume 154(2020)
• Publication Date: 2020-03-15
• Subjects: Cryogenic drilling -- CFRP composites -- Dimensional accuracy -- Inverse delamination factor -- Thrust force; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2020.107504
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: Cryogenic drilling of CFRP composites gives better results as compared to dry drilling. Cryogenic drilling improves the surface finish of holes by 14–38%. Four facet drill bit gives better hole quality at higher feed under cryogenic drilling. Cryogenic drilling improves the entry inverse delamination factor by 5–68%. Abstract: This study compares drilling performances of carbon fibre reinforced plastic (CFRP) composites under dry and cryogenic environments. Industry-relevant outcomes namely thrust force, hole quality (cylindricity- CYL, circularity- CIR, and average surface roughness- Ra ) and inverse delamination factor, are analysed to adopt a green machining technique. Measurement of industry-relevant hole quality parameters have not been explored and explained for cryogenic machining of CFRP composites. To measure CYL and CIR deviations, points are selected on the chosen plane(s) with a spherical probe of the coordinate measuring machine. A pitch of 1 µm is taken between two neighboring points for measurement. Ra values are measured using surface roughness tester, and inverse delamination factors are measured using a vision measurement machine. Ra values of holes are considerably decreased by 14–38%, and entry inverse delamination factor increased by 5–68% under cryogenic drilling when compared with dry drilling. These results advocate the suitability of cryogenic drilling for the industry.