In June 2011 Surrey Satellite asked The Engineering Quest to develop a machining process for a titanium assembly within a space-based optical telescope.

The assembly comprised nine complex high-precision titanium components that needed to line up and assemble within a 5-micron tolerance. The aim was to provide the dimensional stability and precision that would support this level of accuracy when the assembly was subjected to high g-forces and large temperature variations.

Due to the high cost of titanium we were asked to manufacture the parts without any allowance for yield, and we used aluminium and steel components to test our programmes and machining strategy.

Design for Manufacture

We began by working with the customer to review the design and ensure manufacturability and cost effectiveness. We also added reference features to help with the alignment of the components.

To determine residual stress at each stage of the process, test pieces were made and measured, using Mitutoyo roundness measurement instruments. Based on careful analysis of the results, our engineering team adjusted the manufacturing process, and the customer was sent weekly progress reports.

Fine-tuning the design process with a successful outcome

The design was changed several times to improve the stability of the assembly. The final parts were subjected to four heat treatment process and five machining phases. Dimensional information was gathered at each stage and a report was produced for each item. This information was supplied to the customer with the final assembly.

All the components were washed using our Ultrasonic Wash Station and the cleanliness of each item was checked using Millipore Patch Testing. The final assembly was carried out on a flow bench to ensure minimal contamination.

Shortly after we successfully delivered the first assembly we received an order for a further three.