Einfluss variothermer Werkzeugtemperierung auf die Oberflächengüte von Kunststoffbauteilen
Research output: Thesis › Doctoral Thesis
The visual appearance of plastic parts, in addition to the fulfillment of other technical of mechanical requirements, continuously gains importance due to the increasing applications demanding high-gloss surface finishes in markets segments like automotive and consumer electronics. Advanced manufacturing techniques in injection molding are determined to enable the direct production of high-gloss parts and to eliminate the need of subsequent finishing processes. As an injection molding specialty, Rapid Heat Cycle Molding (RHCM) enables the fulfillment of many of those demands. Most established RHCM technologies lead to either irregularities in temperature distribution, inefficient use of energy for heating and cooling, prolonged cycle times and/or high costs of acquisition. To address these issues, this work focusses on the development of a highly efficient RHCM-system, utilizing Joule-heating of functional mold coatings. The coating system comprises of several layers. The heating layer is forming the cavity surface, so that the polymer melt has direct contact with a hot surface during injection. The cooling of the mold can be implemented using conventional mold temperature controllers. Wattages of only about 1 kW are sufficient to dynamically temper mold areas of about 130 mm × 120 mm. Furthermore, the characterization and evaluation of the effects of RHCM on the surface quality of injection molded plastic parts was studied. To enable investigations on the effects of RHCM on part surface quality, an injection mold including two RHCM technologies was developed and built. Various positive effects of RHCM, especially reduction of sink marks and improvements of mold surface replication were analyzed and confirmed. Moreover, this work covers the complex interconnections of temperatures, filler types and thermal properties as factors influencing part surface quality. It is shown that RHCM enables the manufacturing of adequate surface finishes, although glass-filled polymers were used.
|Translated title of the contribution||Influence of Rapid Heat Cycle Molding on the Surface Quality of Injection Molded Parts|
|Publication status||Published - 2015|