Study On Process And Equipment For RHCM Based On Water Heating

Plastics industry is one of the most important industry categories. People had made lots of explorations and practices on new injection molding technology and process for the demands of ordinary production and living. In such background, the Rapid Heating Cycle Molding (RHCM) came into being. The Rapid Heating Cycle Molding is a dynamic mold temperature control technology which will improve the molding temperature in injection process. The problems, such as weld line, flow mark, and spray mark, can be souled by RHCM. Products’ surface can also get a high gloss surface. Appearance quality and mechanical properties of plastic parts will be improved highly without subsequent re-processing surface treatment processes. RHCM is widely used in foreign country. For the no perfect effect of electric heating and complicated structure, it was hardly to be used ordinary.Based on the inductive and analysis of the variable mold technology and research, a new water-heating RHCM plastic molding process was promoted which using high-pressure hot water and low-temperature chilled water as the heat transfer medium. The main focus was about its process research and equipment development. Subject to the theoretical principles of RHCM injection molding process, integrated with application of electrical control, knowledge of the mechanics of fluid flow and score forming process and other disciplines, developed a hydrothermal dynamic mold temperature control equipment for the injection molding process RHCM. This equipment integrated PLC control and touch screen monitor technology. Control the system with PLC and set system operating parameters or monitor system status in time by HMI. The water heating RHCM devices can provide hot water up to 180℃, following the set parameters. Through contact with the injection molding machine signal, pus with the equipment of the chiller, compressed air machine, automatically dynamic adjustment of the injection mold surface mold temperature can achieve. Specifically, in the mold heating stage, open the hot water loop, putting the 140℃180℃ hot water into the mold heating and cooling system lines. After the heating, automatically switch the chilled water loop, rapidly cooling the mold to low down product temperature for eject. At last, using compressed air to clear cold water, prepare for heating the mold of next injection molding cycle. After a lot of adjustment and modification of the original design, the device can fully meet the design requirements finally, which provides equipment protection for RHCM.Following the successfully developed of the RHCH water heat temperature control equipment, the structure of the traditional mold were modified necessary for characteristics of RHCM technological process. Designed a special mold for dynamic temperature control technology injection molding. It was difference from ordinary mold, using insert structure, and there were insulation panels between insert and moving mould plate or fixed mould plate. Heating cooling lines were directly processed and installed on the inserts of the core and cavity while insulation measures were taken between the mold and the injection molding machine. In this case, ensure that the mold cavity surface can be rapid heated and cooled, saving production time. In the end, under the support of the design CAE computer-assisted injection molding technology, simulated and analyzed the influence of process parameters on product quality in RHCM high mold temperature injection molding process. Orthogonal analysis of experimental design methods was used to get perfect process factors. In experiment, equipment reliability and stability, good heat transfer performance of mold, simulation optimization results were tested and verified. Thus perfect results provided a strong theoretical support and practical guidance for the promotion of RHCM process.