Mannesmann Aktiengesellschaft

Demag Ergotech Gmbh

Dietmar Krosse

Helmut Schreiner

Holger Schmidt

Ulrich Reichstein

A pressure measuring device for an injection molding machine having a plasticizing screw operated by a rotary drive and an injection drive includes a load detector having a deformation zone which forms part of a transmission member of the injection drive and is of reduced cross section, and a sensor. The deformation zone elastically deforms in response to a driving force acting on the transmission member, with the sensor measuring a change in shape of the deformation zone.

Pressure measuring device for an injection molding machine

In a machine for injection molding thermoplastic materials in a molding tool by seriatim injection cycles, wherein an injection pressure stage and a subsequent holding pressure stage are employed, and wherein parameters of a change-over point from the injection pressure to the holding pressure have a trend of varying, a method for regulating the trend of the change-over point in each injection cycle, involving (a) establishing upper and lower pressure, and time boundary target parameters for a working window, (b) establishing upper and lower temperature boundary target parameters for a working band, (c) defining the change-over point within said working window, by specifying a pressure, at a given time, (d)measuring the actual pressure at the time of changing from the injection pressure to the holding pressure, and detecting any pressure and time differences from the boundary target parameters of the working window, (e) measuring the actual temperature, and detecting any temperature differences from the boundary target parameters for the working band, (f) shifting the change-over point in proportion to the detected differences, subject to the conditions that the (i) changing of the time is in the same direction as any detected difference, (ii) changing of the pressure is in the opposite direction from any detected difference, and (iii) changing of the temperature in the same direction as the detected difference, and of the pressure is in the opposite direction of the detected difference.

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Wiehe, Germany

Dietmar Krosse