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Title: Evaluation of cutter path strategies and orientations when high speed milling hardened AISI H13 work tool steel
Author: Toh, Chun Kiong.
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2005
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The use of High Speed Milling (HSM) for the production of moulds and dies is becoming more widespread. Critical aspects of the technology include cutting tools, machinability data, cutter path generation and technology. Much published information exists on cutting tools and related data (cutting speeds, feed rates, depths of cut, etc.), however, relatively little information has been published on the evaluation of cutter paths for this application. Most of the research work is mainly focused on cutter path generation techniques. Works with regard to cutter path evaluation on tool wear and tool life, surface integrity and relevant workpiece machinability characteristics are scant. Therefore, a detailed knowledge on the evaluation of cutter path strategies and orientations when high speed rough and finish milling is essential in order to improve productivity and surface quality respectively. The present work deals with some aspects related to the evaluation on the machinabiltiy of hardened AISI H13 hot work tool steel of 52 Rockwell Hardness C scale when high speed rough and finish milling using designated cutter path strategies and orientations. A literature review has been carried out to identify the various geometrical forms that are commonly utilised and common cutter path strategies presently employed in the mould and die industries. A review on the cutter path strategies and techniques is identified and classified according to the rough or finish milling stage. The selection and evaluation techniques notably feed rate, cutting tools and cutter path strategies and orientations are presented. Machinability criteria in terms of tool life and tool wear, cutting forces, tool wear and vibration signatures, cutting temperature and chip formation are reviewed. Last but not the least, surface integrity analysis on machined hardened steels are detailed and reviewed. The experimental work was divided into three phases. The first phase dealt with the investigation by employing high axial depths of cut (10 mm < Ai <20 mm) on three main cutter path strategies when rough milling hardened steels. In the second phase, the spotlight of the research was on finish milling an inclined workpiece surface using different cutter path orientations through machinability assessments in order to identify the optimum cutter path orientation. In the final phase, the effect of various cutter path orientations on workpiece surface integrity when finish milling hardened steels was investigated. The experimental results for Phase 1 revealed that in general where higher material removal rates, shorter machining time, longer tool life and higher volume of metal removed were of concern, raster cutter path strategy was the most favourable at all axial depths of cut employed. In Phase 2 when finish milling at an inclined workpiece angle of 75 0, tool life was highest when employing a downward cutter path orientation. On the other hand, upward cutter path orientation would be preferred where low workpiece surface roughness was concerned. In the final phase, surface integrity analysis revealed that upward cutter path orientation in particular the single direction raster vertical upward orientation was the most preferred in achieving optimum component life.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available