Oven control for dental material pressing and hardening - detects degree of filling of shaping space by speed of movement of piston in pressure cylinder

摘要

The raw material (18) is pressed into the shaping space (14) by a ram (20) driven by the pressure cylinder (22). It is guided by a rod (24) into the interior (36) of the oven which is heated by a spiral element (34). A seal (32) enables a partial vacuum to be produced in the oven. The position of the driving piston (26) in its cylinder (22) is detected by a probe (44) mounted alongside it on a control plate (40) supported by the guiding rod. An analogue measurement pick-up, e.g. a potentiometer, can register the speed of the piston for use as a PI regulator. An opto-encode can be used as the pick-up with a control unit in the form of a micro-controller for piston drive and oven heating.