A15 电热式变模温控制技术应用

Introduction

It is well known that the high temperature of mold in plastic injection molding improves every quality aspects except the prolonging the cycle time. Especially it was well observed on the molding of the super engineering plastics and composite polymers. And many attempts were carried out in order to keep the mold as warm as possible. But these attempts were restricted always by the following process which obliges to cool down the mold in order to freeze the filled resin in the mold and take it out of the mold. (1-2)

Wonder injection molding with Momentary Mold Surface Heating Process makes it possible to keep the mold surfaces on which molten resin flow for being filled without restrictions in less than 15 seconds up to over 300C by heating it with electric micro heater and cool it down again under the resin freezing temperature in a few seconds which is not longer than that of conventional injection molding processing. 

It would not only enable to get no defect plastic molded articles but also enhance the thermal resistance and strength of the resins up to 40% of former ones without restrictions of conventional process. In these sense it can substitute in perfect conditions the injection compression molding, low pressure high speed injection molding, thin wall injection molding, the bright surface injection molding and no weld injection molding for no painting applications. (8-9)

Background

Because of ever-lasting unsatisfactory desire for the injection molded plastic articles, recently several attempts were carried on into three categories: machine, heating and insulation.

The strong and big machines with the high injection speed and high pressure and rugged large clamp with small–injection-unit combination and high–performance controlled with hydraulic were tried to overcome the obstacles of filling the less 0.5mm thin PC battery housings and less 1.5mm note book PC housings which was molded at the condition with the injection speed of 1000 g/s and the injection pressure of 276 MPa. And a new design of machine combining injection molding and compression molding was tried to produce fine textured Compact Disc. By J.P. Ibar from Eknet Research melt viscosity reduction of plastics by vibration was experimentally discovered in order to achieve easy filling as a additional machine device idea. (3-4)

By Dupont-Japan and Daewoo Electronic a mold heated with electric heater was developed and adopt to produce Super engineering plastics and no painting TV cabinet production.

By Sekisui Chemical and TOPLA plastic Inc. a mold heating system with radiation and the hot air and adopt to produce the Bright Surface plastic articles. (6)

By Ube Industries Ltd. in Japan a mold heating system using various shapes of gas burner was devised and tried to adopt it for blow molding. (5)

By the Asahi-Kasei Ltd. In Japan a trial insulating the surface of mold the synthetic polymer was devised and tried to adopt it for no weld and no paint applications. (7)

These strong efforts step forward to get some progressing, for instance filling pressure reduction and thin wall molding and surface defect improvements. But these do not achieve the perfect goals at all because the filling and quality are still unsatisfactory and cycle time extension and poor durability etc. Accordingly we could not observe these techniques in actual industry and are still look forward to searching the ideal condition molding process like as this Wonder molding with Momentary Mold Surface Heated Process (E-MOLD Process).

Heat the Surface of the Mold only

By simple experiment it was observed that it takes more than 30 seconds to heat it up to 180C a steel plaque with the size of 30mm thick and 100mm square. Consequently we have to focus on taking the surface of mold in order to heat it up very quickly and cool it down again very quickly. It is possible to heat the surface of mold up to 300C in 15 seconds by E-MOLD Process.