Improved Manufacturing Processes for Machining of Hard Metal Alloys in an SME

Abstract

This thesis examines the implementation of an improved manufacturing information system for production engineering that was carried out over a period of 30 months within a Knowledge Transfer Partnership (KTP). The Department of Mechanical Engineering at the University of Bath collaborated with the Helander Precision Engineering Company in Tewkesbury. The operations, manufacturing processes and information systems used by Helander are described together with a review of the hard metals used for the precise machining of industrial components manufactured from stainless steel, cobalt-based superalloys and nickel-based superalloys. The thesis contains a review of machining of hard alloys, statistical process control of machining and measurement systems analysis and an experimental study of the Inconel 718 superalloy is included which demonstrates how microstructure and mechanical hardness are affected by the machining process. Methods of process control & process verification for manufacture including the use of gauge R&R are described to verify the accuracy of measurement tools. These methods are applied in two case studies which examine the manufacture of a simple part and a complex part. Helander’s manufacturing processes are reviewed and practical methodologies are implemented for avoiding out of specification machined components. Improved accuracy in machining is achieved by the use of the Ballbar test to check accurate machine tool positioning. A future direction for Helander is additive layer manufacturing for net shape components and trials were undertaken by sub-contractors for Helander. The KTP programme has made significant improvements in process control and understanding of hard to machine materials by integrating industrial and academic expertise in the field of precision engineering.

Date of Award	27 Jun 2017
Original language	English
Awarding Institution	University of Bath
Supervisor	Stephen Newman (Supervisor) & Martin Ansell (Supervisor)