5-Axis CNC Solutions for Medical Articulated Arm Components

Project Background

With the continuous advancement of medical technology, articulated arms are widely used in rehabilitation training, surgical assistance, and imaging positioning equipment. As core functional components, they not only need to achieve precise positioning and smooth motion but also maintain reliable structural stability over long-term use.

These high-precision components are often small, complex, and feature multi-surface, freeform geometries. Achieving tight tolerances and high-quality surface finishes in such a limited space. Not all manufacturers can consistently deliver such components within short lead times.

For a new articulated arm project, a European medical equipment company chose WayKen as a partner. With extensive experience in 5-axis machining and complex part process optimization, WayKen meets the project requirements for quality, efficiency, and delivery schedule.

Part Structure Analysis & Machining Solutions

The articulated arm parts’ small size, thin walls, and complex features demanded precise machining. The following solutions were applied:

1. Small Size & Thin-Wall Freeform Structures

The smallest parts of the articulated arm project measured just 30 × 31.5 × 20 mm, with wall thickness as thin as 0.79–1.14 mm. Such small and thin parts are highly prone to deformation from cutting and clamping forces, and irregular freeform shapes make stable fixturing even more challenging.

Machining Solution

WayKen designed flexible fixtures to support critical thin-wall areas and used temporary infill material in areas where edges could not be damaged, reducing deformation risk. The material underwent two stress-relief processes before machining to stabilize internal stress.

Stepwise Machining Strategy

• Rough machining retained 0.3–0.5 mm allowance to maintain structural rigidity and prevent early deformation.
• Semi-finishing was used to relieve residual stress, stabilizing the part before final machining.
• Finishing adopted small-depth, multiple-pass cutting, with careful control in critical thin-wall regions.

These steps ensured dimensional stability and overall geometric accuracy even in millimeter-thick wall sections.

2. Critical Tolerance Control

Multiple assembly-critical points demanded high precision. Functional holes for interfacing with other components required φ8 mm g6 precision at a depth of 22.2 mm, while associated mating surfaces demanded parallelism and perpendicularity within 0.03 mm. Even minor deviations could cause improper motion after assembly.

Machining Solution

WayKen optimized machining references, selecting stable surfaces directly associated with high-precision holes and avoiding the impractical “virtual reference A.” Holes were first pre-machined on a lathe for initial concentricity, followed by five-axis machining with residual stock and precision reaming to finalize dimensions and axial alignment.

Production occurred in a 24 ± 1 ℃ controlled environment, with thermal compensation minimizing heat-induced errors. Real-time in-machine probing and offline CMM verification ensured all dimensions and tolerances consistently met specifications.

3. Complex Internal Structures & Limited Tool Access

The articulated arm parts featured multiple internal channels, including undercuts, angled holes, and intersecting passages. Narrow channels and overlapping holes rendered conventional tools inaccessible, while undercuts and angles heightened toolpath planning complexity.

Machining Solution

WayKen employed CAM software to simulate internal channels, optimize toolpaths, and define entry sequences. Toolpath animations were presented to the client, illustrating machining order, tool approach angles, and fixturing strategies. Production commenced only after client approval, ensuring process feasibility and building trust.

Long-reach end mills and ball cutters enhanced accessibility. Angled holes were machined using five-axis directional drilling followed by finishing passes, while intersecting holes were deburred with flexible rotary tools and inspected via endoscope. This approach guaranteed internal quality and dimensional accuracy.

Through detailed analysis, precise process simulation, and client verification, WayKen successfully resolved complex internal structure challenges, ensuring high-precision assembly and reliable performance of the articulated arm components.

Delivery & Outcome

The articulated arm components were delivered on schedule and passed installation validation on the first attempt. The assembled system achieved smooth, stable motion and fully met all design specifications.

The client especially recognized WayKen’s ability to deliver high-quality parts within a tight timeframe, as well as our professional expertise in complex precision machining. Following this successful collaboration, the client has confirmed plans for subsequent batch development and a long-term partnership.