For a European customer’s robot part frame project, Xu Feng combined stress relief, 5-axis finish machining, selective grinding and full CMM inspection to address complex geometry and demanding drawing requirements. The project covered prototyping and a small production batch of 14 sets.
Project Background
A European company commissioned Xu Feng to manufacture metal frames for robot part products. The scope included prototypes and a low-volume batch of 14 sets. The frames featured machining surfaces in multiple orientations, internal cavities and numerous holes, with an extensive set of dimensions specified on the 2D drawings.
Key requirements included parallelism and perpendicularity of 0.02 mm on specified planes, a surface roughness of Ra 0.8 μm in selected areas, and a black anodized finish. Meeting the brief required coordinated planning across machining, inspection and protective packaging.
Manufacturing Challenges
Complex geometry with tight geometric tolerances
The frames required machining from multiple directions while maintaining the specified relationships between critical planes. The 0.02 mm parallelism and perpendicularity requirements made datum control and machining setup strategy central to the process.
Distortion control and local surface finish requirements
Stress release during material removal was a distortion risk that the process needed to address. Selected areas also required Ra 0.8 μm, calling for a dedicated finishing operation in addition to the main machining work.
Extensive dimensional verification and protection in transit
The detailed 2D drawings required comprehensive dimensional checks before shipment. Once machining and surface treatment were complete, the parts also needed packaging designed to reduce the risk of collision damage during transport.
Xu Feng’s Solutions
1. Separate roughing and finishing, supported by stress relief
Xu Feng left a machining allowance of 0.5 mm after roughing for the subsequent finishing operations. The project process included stress-relief heat treatment at 185–195 °C for 6–8 hours. Completed parts were also held at 20 °C for at least 96 hours for stabilization.
These conditions were specific to this project; their suitability for another component depends on its material, condition and drawing requirements.
2. Use 5-axis finish machining to control critical plane relationships
To address the 0.02 mm parallelism and perpendicularity requirements, Xu Feng used precision 5-axis machining to finish the relevant critical faces in a single setup. This reduced datum-transfer errors associated with repeated setups and worked alongside stress relief as part of the geometric accuracy control strategy.
3. Apply selective grinding and a black anodized finish
Grinding was used in the areas specified at Ra 0.8 μm to address the local surface finish requirements. The parts received black anodizing, with a specified oxide layer thickness of at least 10 μm, preferably 12 μm or greater. The coating thickness requirement was included alongside the appearance requirements in the project’s surface treatment specification.
4. Combine full CMM inspection with custom protective packaging
Xu Feng used full coordinate measuring machine (CMM) inspection to check the dimensional and relevant geometric requirements of the parts before shipment. Custom die-cut packaging inserts were also prepared to locate and separate the components, reducing the risk of impact damage in transit.
This project illustrates how Xu Feng coordinates machining allowance, stress relief, precision finishing, inspection and packaging for complex metal components. It also demonstrates the process planning required to support prototype and low-volume manufacturing with demanding drawing requirements.
Planning a complex frame or a component with tight geometric tolerances? Share your 2D drawings, 3D models, material specifications and quantities with Xu Feng to discuss manufacturability and inspection needs. Discuss your custom machining project →
