Mold for injection molding a thermoplastic part free from sink marks using a void inducing member
US5540581A · kind A · utility
4Cited by
10References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 24, 1995 |
| Grant date | Jul 30, 1996 |
| Priority date | — |
| Expiry date | May 24, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/1704
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
When injection-molding a molten thermoplastic resin into a molding having different thicknesses, a void inducing member is set in a cavity corresponding to heavy sections. Then gas pressure is applied passing through a gas passageway to a tip end of the void inducing member, thus forming a void nucleus in the resin adjacent to the tip end of the void inducing member. The void nucleus develops to a void by shrinking force of the resin as the molten resin cools.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.