Process and device for tempering molding tools for processing plastics

A process for tempering an injection molding tool for processing plastics comprising the steps of:

• dividing the tempering process into a start-up phase, and a stationary operating phase, the start-up phase being completed after the tool has been activated and a predetermined nominal tool temperature is reached or exceeded for a first time;
• measuring the tool temperature continuously during an entire cycle at a site equally acted upon thermally for the respective cooling circulation by both the injected melt and the cooling, said site being located within a range of the geometric center between a molded part contour and cooling ducts, and within a range of the center between a cooling water inlet and cooling water outlet while maintaining a sufficiently large space from the molded part contour;
• comparing the actual measured tool temperature to a predetermined nominal temperature value;
• inducing a first cooling medium impulse into the injection process at a time Z.sub.1 in order to effect a predetermined heat dissipation within the time range of the greatest temperature difference between the injected melt and the cooling ducts, the time Z.sub.1 being fixed by a signal of a machine sequence control, said induction of the first cooling medium impulse being dependent on tempering of preceding cycles;
• inducing additional cooling medium impulses into the injection process at a time Z.sub.2 when a predetermined nominal temperature value has been exceeded, wherein time Z.sub.2 is fixed by a signal of the machine sequence control, said signal being triggered at a defined time close in time to the end of the cycle.