Tempering generally describes the heat treatment of the material over a longer period of time.
The aim here is to maintain certain desirable service properties. In the case of plastics, this is achieved by heat storage in a convection oven with temperature control. Tempering is divided into 3 phases:
- slow, uniform heating
- maintaining a constant temperature over a longer period of time
- very slow and steady cooling down until the room temperature is reached
The duration and temperatures of the individual phases depend on the respective material and the wall thickness of the workpiece. Here, the permissible continuous service temperature must never be exceeded.
Objectives of tempering:
- reduction of internal stresses caused by extrusion or machining.
- increase crystallinity to improve strength and chemical resistance
- increase dimensional stability over a wide temperature range
The semi-finished plastic products we use are tempered by our suppliers after extrusion. In many applications, however, one-time annealing is not sufficient. In particular, complicated finished parts with strong, one-sided machining tend to warp. For certain materials and/or component geometries, it is therefore necessary to insert an annealing process after rough pre-machining and then to manufacture the final geometry in a further machining step. This procedure ensures the best possible dimensional accuracy. We will be happy to advise you on this as early as the quotation phase.
We have two computer-controlled tempering furnaces with the following dimensions:
- 700 x 600 x 500 mm
- 1300 x 1200 x 620 mm