Design and evaluation of Lightweight milling fixture

Important results from the project

The aim of the project is to significantly decrease the weight of milling fixtures for milled machine components (usually weighing 600 to 1600 kgs), enabling higher efficiency and reduced machine wear. The challenge with reduced mass for the fixtures is that the risk of resonant oscillations induced from the milling tool increases. The project has verified a calculation methodology to optimize the fixture against this type of eigenmode oscillations and implemented the methodology on a newly developed fixture that has been manufactured and tested with excellent results.

Expected long term effects

Lightweight fixtures enable reduced machine wear and faster milling program. The effect of the actual calculation methodology is significant because the fixtures are not suitable for prototype construction in terms of their size. The function of the fixtures should be ensured before production, so as not to risk costly modifications or disposal if they would have eigenmodes that correspond to the oscillations induced from the machining. The methodology can be crucial to take new business, reduce own risk and enable the development of fixtures according to specifications.

Approach and implementation

The calculation methodology was developed by RISE on a smaller milling fixture, developed in a previous project. The calculation model could thus be correlated. With the methodology a new larger fixture was optimized before manufacturing. The production was done mainly by Composite service, but partly by TMS and Saab. Frequency measurements were performed by Saab. The project has built up important expertise in the development, optimization and construction of milling fixtures in composite materials, and processing of thick pre-fabricated laminates has also been of value.