316L Stainless Steel Component: O-Ring Groove DFM Review

Client details withheld under NDA unless a client has agreed to be named. Tolerance values are identified as drawing requirements or inspected results, as applicable.

The O-ring groove tolerance

An O-ring seals by being compressed in its groove, so the groove tolerance sets how much the seal is squeezed at assembly. Across several rounds before the first prototype was cut, the review found an O-ring groove tolerance that would over-compress the seal at assembly, and covered groove depth, sealing-face finish, and thread-interface tolerance requirements, around ±0.02–0.03 mm.

The tolerance callouts for the O-ring groove and the joint interface were requested from the client before quoting (see “Needed before quoting” below).

Scope of the review

Engineering concerns raised before quoting

1. Most complex part. Features down to 1.5 mm diameter on complex curved surfaces. Needs micro-tooling and careful setups, and will be the main cost driver.
2. Joint between two parts. Flush alignment matters on a premium product: even 0.05 mm of misalignment is visible and feels rough. Confirm the tolerance and whether a small relief groove is acceptable.
3. A pocket that traps liquid. Recommend a small drain hole (Ø1.5 mm) at the bottom. Worth raising with the designer before production.
4. Mirror finish with PVD. Any machining marks show through the coating. Near-perfect surface prep adds hand-polishing cost.
5. Logo on a curved surface. Needs 3D laser engraving, since a standard 2D laser distorts on curves.

Needed before quoting

← Back to Engineering & CNC DFM Support · What the DFM review covers