Plastics - 100 % Quality Injection Molding - KISTLER - #4

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4 www.kistler.com The Benefits of Cavity Pressure Measurement Systems Modern injection molding technology is faced with ever more exacting requirements and a rising number of complex injection molding processes. Equipped with high-performance systems based on measuring the pressure in the mold cavity, injection molding machines are able to produce flawless high-quality parts. These systems can automatically monitor, optimize and control injection molding processes, boost productivity and cut costs. During the first decades of industrial injection molding the development of control systems focused on machine parameters alone. However, these processes had a rather limited informative value or benefit for users. From the early 1990s on, it became clear that for many applications, high process constancy and optimum part quality could only be ensured over a long period of time by using measuring systems which focused on the pressure in the mold cavity. Mold cavity pressure measurement and systems using cavity pressure for monitoring and controlling injection molding processes offer a range of technical and economical benefits such as the following: • Reduction of the reject quota • Optimization of the cycle time • Shortening of installation and setup times • Minimization of material requirements • Reduction of personnel costs • Less energy costs • Active mold protection Systems measuring the pressure in the mold cavity are almost fully automatic and easy to operate. Piezoelectric sensors have proved to be suitable for both direct and indirect cavity pressure measurement. Modern system solutions operate with a closed circuit which includes mold cavity pressure recording with the help of piezoelectric sensors, smart electronic equipment and ergonomic software. The processes within the mold are crucial to the quality of the injection molded parts, yet they can never be viewed directly. Attempts at describing process phases in terms of machine parameters such as hydraulic pressure, have not yielded any success. The main reason for this lies in the fact that machine parameters cannot record the effects of sprue solidification or melt compressibility.