Machining Distortion Minimisation
Overview
Inherent and machining induced stresses can cause distortion in final aerostructures, with potentially costly consequences amounting to millions of US dollars. This innovative work has resulted in a process that minimises stress and distortion through the careful selection of material and machining strategies. To verify the conclusions, element deletion, finite element analysis, and additional machining were employed.
Commercialisation opportunities
Provision of professional services
Problem addressed
Distortion of aerostructures results in parts being reworked or scrapped. This is an unacceptable loss, both financially and environmentally.
Innovation
- By investigating complex machining strategies such as helical milling and tool path optimisation, it is possible to dramatically decrease the induced stress in a component, leading to a subsequent reduction in distortion.
- By analysing deep residual stress via sectioning and careful measurement of post-machined distortion, it is possible to identify the optimal material and heat treatment for a given component.
- The process monitoring system included thermal and visual cameras, as well as vibration, strain, and displacement gauges, all synchronised to the milling operations via an acoustic pick-up. The data was logged on a computer and analysed in real time.
Key impact
- Improved process for the production of aerostructures.
- Deterministic down-selection of suppliers based on analysis of intrinsic residual stress and its effect on the distortion of the final part.
- A suite of in-process monitoring technology is available to any machining operation to identify the optimal machining parameters.
Application
- Improvement of processes in multi-axis machining centres.
- Improvement of component reliability through the selection of optimal materials and machining strategies.
The Hong Kong Polytechnic University (PolyU)
With over 80 years of proud tradition and ranking among the world’s top 100 institutions, The Hong Kong Polytechnic University (PolyU) aspires to be a leading university with world-class research and education.
PolyU is a home for educating thinkers, discoverers, innovators and communicators in delivering positive impact. We are committed to nurturing tomorrow’s leaders today, through a holistic education that provides graduates unrivaled placements to thrive in communities, industries and businesses.
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