Plastics - 100 % Quality Injection Molding - KISTLER - #5

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www.kistler.com 5 More Efficient Processes – Better Quality Mold cavity pressure is the most informative process parameter Only a continuous documentation of the mold cavity pressure profile yields a detailed record of the processes occurring during the injection, compression and holding pressure phases of injection molding. Only this parameter correlates with all other quality-related part properties such as weight, morphology, fidelity of reproduction, flashes, sink marks, voids, shrinkage and warpage. The mold cavity pressure not only optimizes the switch-over from compression to holding pressure, in each cycle, its profile can also be used as a criterion for determining the switch-over point. It allows better maintenance of the tight part weight tolerances and numerous other quality features than any other switch-over strategy, be it based on the hydraulic pressure, screw stroke or time. Quality assurance and documentation with the help of mold cavity pressure control The documentation of the mold cavity pressure not only proves the quality of the finished part but also allows selective monitoring and early detection of process deviations. Useful algorithms such as statistic process control or neuronal networks can deliver very precise information on the effect of the mold cavity pressure and other process or machine parameters on the mold quality. Precise assessment of the molded parts requires systems which analyze their weight and dimensions as well as correlating features such as streaks and other surface defects while also providing automatic control of reject/accept gates. In the near future, most modern injection molding systems are likely to rely on an automatic determination of the optimum process parameters. Mold cavity pressure control systems are reliable and durable Despite the high number of benefits, many injection molders are still skeptical when it comes to mold cavity pressure control. On the one hand, they are averse to the investment costs and on the other hand they anticipate downtimes and follow-up costs. Experience shows, however, that improper handling of the sensors during installation, maintenance or mold changes is the main cause of machine downtimes. The systems themselves have proven their sturdiness, reliability and durability. The large-scale production of high-quality, cost-efficient parts provides a competitive edge and as such it is the decisive criterion for the success of any injection molding business. In its wake, quality assurance will attain major importance for all injection molding processes. With a view to increasingly complex processes and more exacting quality requirements, only machines with high-performance systems which are based on cavity pressure control will be able to deliver flawless highquality molded parts. Prof. Dr.-Ing. Dr.-Ing. E.h. Walter Michaeli Institute of Plastics Processing (IKV) at RWTH Aachen University