Process capability management for selective laser melting

O'Regan, Paul 2019. Process capability management for selective laser melting. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This research was undertaken to improve the understanding of the selective laser melting (SLM) manufacturing process. It engineers an approach that can provide quantitative evidence of SLM process integrity. This was needed to underpin the acceptance of SLM components. The research established an assessment technique that can be applied to manage the process capability of SLM machines. This will enable more effective process set-up and control. This in turn will enable improvements in process capability and provides a basis for a more informed product design for manufacture. This research investigated the application of the established Renishaw productive process pyramid (PPP) to the SLM manufacturing process. The resulting SLM-PPP can be applied to enable a better understanding of the quality control and management of the SLM process. Ishikawa fishbone diagrams have been provided for each of the four layers of the SLM-PPP. These diagrams provide researchers and original equipment manufacturers a foundation that can be used to understand the variables that affect builds. This framework can be further developed in the future. An arrangement of 12 artefacts on an SLM build plate was specifically engineered for this project to enable direct comparisons and assessments of each build. A co-ordinate measuring machine (CMM) was used to measure the artefacts. The suitability of the CMM was evaluated to ensure it could provide repeatable and reproducible data. The gauge evaluation was investigated and the specified measurement process was validated and assured. The gauge evaluation process was engineered, developed and tested. The CMM was shown to provide the accuracy and precision required in the context of the measurement of the test piece features, this had not been previously proven. An accumulative quality ranking matrix was developed, providing a novel method for combining the various feature measurements into a visually appealing format, which is easier to understand and evaluate. This method was engineered and tested, and then adopted to inform the remaining research undertaken. The artefacts can be combined with the quality matrix approach to assure process quality. SLM specific parts can be produced in set locations and evaluated after each build. Data from these parts can feed back into the process setting stage to improve precision and/or accuracy. The individual artefact can be used to understand that the process used to make the artefact has been enacted correctly.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	Selective Laser Melting; Process Control; Productive Process Pyramid; Ishikawa fishbone diagram; Process Foundation; Gauge Repeatability and Reproducibility.
Funders:	EPSRC
Date of First Compliant Deposit:	28 February 2020
Last Modified:	04 Aug 2022 01:57
URI:	https://orca.cardiff.ac.uk/id/eprint/129992

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