| Autor: |
Hopmann, Ch., Schmitz, M., Theunissen, M., Nikoleizig, P. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2017, Vol. 1914 Issue 1, p1-6, 6p, 4 Diagrams, 2 Graphs |
| Abstrakt: |
In the plastics processing industry a growing demand for precision moulded parts can be identified, especially regarding avoidance of warpage as well as achieving high process stability. To meet these requirements, an approach based on local material properties within the injection mould during the moulding process is pursued. The goal of the pvT-optimised process is the optimisation of the shrinkage by establishing a constant specific volume of the melt and part during the injection moulding process. This is pursued by controlling the holding pressure according to the in-mould pressure and part temperature on the basis of specific materials pvT-data. Due to the nature of flow dynamics and material characteristics the pressure within the mould is inhomogeneous. Especially in injection and compression phase, pressure varies from ambient pressure at the flow front to a high injection pressure caused by the pressure loss. In packing phase local specific volume varies due to pressure differences and temperature differences. To establish a local control of the specific volume, in addition to the injection pressure the temperature is added as a controlled variable. To achieve an accurate and dynamic temperature control, tempering concepts including fluid-based tempering, CO2- tempering, resistance heating as well as heating by laser radiation and electromagnetic induction are evaluated regarding usability, reaction time and performance. In addition, local temperature and pressure measurements are needed to accurately adapt the temperature in the mould. Therefore, available measurement techniques for injection moulding were evaluated regarding reaction time and efficiency. A mould concept is developed to meet the requirements needed for an inline, online as well as a self-optimising temperature control, based on a model-based measurement correction, predictive temperature control and a system-wide optimisation function. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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