Method and apparatus for adjusting zero point of a pressure sensor of an injection apparatus

摘要

A method and apparatus for adjusting a zero point of a pressure sensor of an injection apparatus, which method and apparatus enable precise zero-point adjustment for the pressure sensor. Pressure of resin is detected by use of the pressure sensor, while a screw is moved, and a detection value corresponding to a detected pressure is obtained. The zero point of the pressure sensor is adjusted on the basis of the detection value. The detection value is obtained when the screw is moved in a state in which a flight speed is rendered lower than a screw speed. In this case, since the frictional resistance which acts on resin in the vicinity of the inner circumferential surface of the heating cylinder upon movement of the screw can be decreased, loads stemming from the frictional resistance are prevented from serving as disturbance against the detection value. As a result, zero-point adjustment for the pressure sensor can be performed precisely.