Background
In the aerospace sector, parts such as engine mounts or multi-link cabin doors often feature multiple holes oriented in different directions. These are not just structural supports-they are also critical alignment components. Each hole must precisely align with its mating component, regardless of its angle or orientation. The geometric complexity is especially high in double-curved surfaces, where no simple datum exists.
Challenge
Multi-axial holes on a non-flat surface demand strict control of coaxiality and coplanarity. Traditional machining methods struggle when:
The reference planes for different holes cannot be established through conventional clamping.
Manual alignment introduces cumulative errors.
Multiple setups increase the risk of displacement and tolerance stack-up.
To solve this, the part must be machined in a single setup where all axes and datums are coordinated in real time. The required coaxiality tolerance is often below 0.01 mm, which exceeds the stability range of most 3-axis setups.
Solution
We adopted a fully integrated 5-axis CNC workflow:
Advanced Fixture Design:
Custom jigs were developed to support complex curved surfaces. These jigs maintain consistent reference positioning even for asymmetric geometries.
On-Machine Probing:
A high-precision touch probe system was used to re-establish datums on the curved surface after clamping. The rotational probe collected real-time positional feedback to adjust all subsequent tool paths.
Simultaneous Multi-Axis Machining:
All hole features, including those at compound angles, were machined in a single setup using synchronized rotary and linear axes. This avoided repeated repositioning and ensured that all bore centers remained coaxial to design specs.
Result
Coaxiality achieved: <0.008 mm deviation between opposite-direction holes
Processing time reduced: 38% faster due to one-time setup
Scrap rate lowered: From 6.2% to 0.9% after process refinement
This workflow demonstrates our capability to solve complex machining challenges where form and function converge-especially in parts where geometry isn't flat, square, or simple.
