Annealing cycle calculator

Extruded PEEK holds internal stress. Machining releases it unevenly and the part moves overnight. The fix is a soak between roughing and finishing, and the schedule scales with the thickest section.

When the cycle is worth its hours

• Thin wallsUnder about 3 mm, or a wall much thinner than the rest of the part.
• Heavy removalMore than roughly half the block cut away, or deep pockets.
• Tight featuresBores and slots held tighter than ±0.05 mm.
• Hot serviceParts that will run continuously above about 150 °C move again in service if the stress is still in them.
• Long and slenderWhere a small bow ruins straightness.

How to use it

Rough the part leaving finishing stock on the features that matter, run the cycle, then finish. Whatever the roughing released gets cut away in the finishing pass. Doing it after finishing is too late, which is why a part that has already moved is usually scrap. Background is in the guide to annealing PEEK parts.

Typical schedule shape, not a specification. The stock supplier publishes the schedule for the grade you bought and that one wins. Filled grades and compression moulded plate often tolerate a faster ramp than this.