Tolerance Feasibility Depends on the Part
There is no responsible universal tolerance for every machined PEEK component. Achievable dimensions depend on material grade, stock condition, overall size, wall thickness, feature depth, material-removal ratio, datum strategy, fixturing, machining temperature and inspection conditions.
Requirements approaching ±0.005 mm are not presented as a site-wide capability. They can be considered only for suitable features after drawing review, process planning and inspection-method confirmation.
Features Reviewed Separately
The quotation should distinguish turned outside diameters, precision bores, milled profiles, flatness, parallelism, hole position, thread geometry and surface roughness. Each feature responds differently to cutting heat, clamping force and residual stress.
Large thin rings, deep pockets and broad flat plates normally present more deformation risk than compact, well-supported components. PEEK 1000, GF30 and CF30 also behave differently because reinforcement changes stiffness, thermal expansion, abrasion and electrical behaviour.
A Controlled Machining Sequence
Dimensionally demanding parts may require stable stock selection, balanced roughing, controlled allowance, release and re-clamping, thermal stabilization, intermediate stress-relief review and light final cuts. Sharp tools, effective chip removal and controlled cutting heat help reduce local expansion and surface damage.
The process sequence is selected for the actual geometry. Annealing is evaluated case by case and is not added as a generic marketing claim.
Surface Roughness
Specify surface roughness as a measurable requirement such as Ra, together with the surface location and functional purpose. A sealing face, bearing surface, cosmetic surface and general machined face may require different processes and inspection methods.
Do not apply the tightest finish to every surface unless it is functionally required. Unnecessary finishing increases machining time and cost and may create additional dimensional risk in thin sections.
Inspection and Reporting
Critical dimensions should be associated with a defined datum system and inspection method. Depending on the feature, inspection may use micrometers, bore gauges, height measurement, optical equipment, roughness measurement or CMM inspection. CMM reporting is available only when it is confirmed in the quotation and included in the inspection scope.
Parts should be allowed to stabilize before final inspection. Measuring a warm component can produce a result that does not represent its stable room-temperature condition.
Information Required for Tolerance Review
- Nominal dimensions and tolerances
- Datum structure and GD&T
- Material grade
- Critical fits and mating components
- Surface roughness locations
- Operating temperature
- Inspection method and report format
- Quantity and repeat-order expectations
Upload the drawing and clearly mark sealing, bearing, alignment and assembly-critical features. The engineering review will identify risks, questions and the inspection scope before a quotation is accepted.