Unfilled PEEK Wafer Retention Ring for a Semiconductor Equipment OEM

The requirement

A wafer-handling equipment maker needed a retention ring for a vacuum wafer environment: large, thin and circular, with a surface that would not shed particles onto the wafer. The ring also had to hold its roundness and flatness from batch to batch rather than only on the first article.

The challenge

A large, thin circular part that warps easily when stress releases unevenly, with strict low-particle surface requirements for the wafer environment.

Our approach

A symmetrical, layered cutting strategy with low-force vacuum fixturing. Sharp tungsten-carbide tooling and dry machining. Verification on a CMM at a controlled 20 °C once the part had fully stabilised.

Five steps from drawing to delivery

1. DFM review and material plan — The drawing was reviewed for thickness, flatness and the low-particle requirement before the blank was cut, and unfilled natural PEEK was confirmed against that requirement rather than a glass-filled grade.
2. Fixturing, tooling and programming — Sharp tungsten-carbide tooling and a low-force vacuum fixture, with a symmetrical layered cutting strategy programmed so the ring is never held asymmetrically.
3. Rough and finish machining — Dry machining throughout, with the cut sequence kept symmetrical so residual stress releases evenly instead of warping the ring.
4. In-house inspection — CMM verification at a controlled 20 °C, taken only once the part has fully stabilised rather than straight off the machine.
5. Documentation and delivery — A dimensional report per batch tied to the drawing revision, with material certificates and batch traceability so a later ring can be compared against an earlier one.