Method for injection molding of plastic products having excellent transcription properties
US6203731A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1998 |
| Grant date | Mar 20, 2001 |
| Priority date | — |
| Expiry date | Oct 16, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2945/76739
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
If the surface of metallic mold should not be highly transcribed to the surface of product in injection molding the plastic products, the transcription defects such as weld, shrinkage, etc. are caused to the surface of product. Further, if the resin should be exposed to the surface of high temperature metallic mold more than necessary during the molding, the filler and the like of glass and so forth are contained into the resin, and in this case, they are left over on the surface of metallic mold, resulting in the transcription defect. These problems can be solved by heating the surface temperature of metallic mold higher than the glass transfer temperature of resin if the resin is non-crystal and higher than the fusion point temperature if the resin crystal, with the temperature raising speed of more than 2.degree. C. every second, maintaining this temperature during the resin charging, and by cooling at the lowering speed of more than 2.degree. C. every second after the completion of charging. This temperature control shall be conducted with the feed back control while detecting the surface temperature of metallic mold by the temperature detection sensor mounted at the position c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.