Determining point of pressure increase in a molding tool during plastic injection molding measures temperature changes.

: Hellstern, P.; Boog, C.; Fischer, G.; Schmidberger, E.

Abstract
NOVELTY - The time point at which pressure rises is determined with a temperature sensor which detects a short term temperature increase during the general temperature increase. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is made for the process equipment which includes a temperature sensor. Preferred Features: The pressure rise occurs when the melt reaches a wall of the tool close to the temperature sensor which can be close to the sprue and at a ponit remote from the sprue. Both sensors have a rapid response to temperature change. USE - For determining the point at which the injection pressure is changed to follow up pressure in an injection molding cycle. ADVANTAGE - The method eliminates the use of a number of expensive pressure sensors.