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A Digital Detection of the Injection Speed by Using the Screw Position Encoder
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Shioiri, Takayoshi / Yamasawa, Kiyohito
This paper describes the detection method of the injection speed and the dynamic characteristic using an encoder for the screw position detection of a screw type injection molding machine. It explains the mechanism of the injection speed detection of the digital methods that those methods are Ēt-method which measures the movement distance of a screw and ĒÔ-method which measures the movement time of a screw, comparing with the analogue method using the analogue differential circuit. And, the injection speed of an injection molding machine is measured with the digital injection speed detection equipment which uses the microprocessor. It is found that the main factors of the detection error of the injection speed are dominated by the accuracy of the position detection. Furthermore, we propose a practical system, which makes the error decrease by introducing the averaging detected values. The detection accuracy by averaging a reasonable number of the detected values is calculated.
Key words: Injection speed / Digital detection / Ēt-method / ĒÔ-method