Kim, Yong-hwan, Ph.D. (1989) Behaviour of polymeric materials in machining. PhD thesis, University of Warwick.

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Abstract

The machining characteristics of a glassy thermoplastic (Polyvinyl Chloride) and a semi-crystalline thermoplastic (High Density Polyethylene) have been studied. Chip formation mechanisms, cutting forces and surface integrity were found to be dependent, on the cutting conditions and tool geometry. Results were explained by considering the different nature of the microstructure. Segmented and discontinuous chips were produced with PVC, and continuous and segmented chips were produced with HDPE. It was observed that surface damage was closely related to the nature of chip formation in these plastics. Chip formation, surface damage and tool wear mechanisms when machining Glass-Fibre-Reinforced-Plastic (GFRP) were also studied. Cutting tools used were High-Speed-Steel (HSS), cemented carbide (P type and K type) and coated carbide (titanium carbide - and triple-coated). Discontinuous chips were always produced when machining GFRP. Sliding contact is present at the tool/chip and tool/work interface. The principal aspects of surface damage include fibre breakage, resin cracking, resin decomposition and fibre/resin interface debonding. Cutting temperature is not high, but excessive heat generates when the flank wear land develops. Coated carbide tools showed the best performance and HSS tools the poorest. The main wear mechanisms are abrasive wear with HSS tools, attrition wear with cemented carbides, and discrete plastic deformation followed by attrition wear with coated carbides.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	T Technology > TJ Mechanical engineering and machinery
Library of Congress Subject Headings (LCSH):	Machining, Polyvinyl chloride -- Machinability, Polyethylene -- Machinability, Glass-reinforced plastics -- Machinability
Date:	May 1989
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Pashby, Ian
Sponsors:	Korea (South). Kwahak Kisulbu
Extent:	206, [95] leaves
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/4161

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