注塑机的压力传感器应用方案.pptx

Application Notes Pressure Sensor in Plastic Machinary By Michael Sali Plastic injection molding machine Plastic Machinery Plastic Injection molding machines are used to manufacture plastic parts. Injection molding machines typically include a reservoir of molten plastic and a nozzle through which the molten plastic is forced at high pressures into a mold. The plastic is thereafter packed and cooled to form the part. In the manufacture of such parts, it is important to precisely determine the pressure of the injected melt to maintain accuracy of the part because the part must be made at a constant pressure. This is so because otherwise the resulting part may include voids, ripples, poor dimensional accuracy or the like. Plastic Machinery Working Process Cycles CST 3 Pressure sensor mounted on plastic machine In a plastic injection machine, pressure sensors are mounted in the injection molding nozzle, hot runner system or cool runner system and inside the cavity of the mold. it can measure plastic pressure from the injection molding nozzle to cavity plastic pressure somewhere in between plastic injection molding, mold filling, pressure maintaining and cooling process. Those data can be recorded by the monitoring system, to be used for true time control of the molding pressure, combine inspect or exclude product process appear malfunction after molding. CST 4 Pressure sensors on plastic machine there is a need for pressure transducer devices which can accurately measure the pressure of molten plastic within injection molding machines. Additionally, such pressure transducers are faced with the following constraints: 1. the pressure transducer must have low working stresses to avoid metal fatigue cracking under repetitive cyclic loading; 2. the pressure transducer, for economic practicality, must be physically arranged such that it can easily be integrated within injection molding machines shot chamber/nozzle area; and 3. the pressure transducer must not disrupt t