Process for gas assisted injection molding
US5174932A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1991 |
| Grant date | Dec 29, 1992 |
| Priority date | — |
| Expiry date | Jun 18, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/1732
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for injecting a viscous fluid, such as a thermoplastic, and a non-viscous fluid, such as a gas, into a mold cavity of a mold body includes providing a valve element mounted for reciprocation in a nozzle body flow passage to regulate a flow of viscous fluid through the nozzle body discharge end and into a mold cavity. The valve element includes a barrel having a first end selectively engaging a portion of the nozzle body discharge end to prevent a flow of viscous fluid therepast and a second end. A bore extends longitudinally through the barrel and a pin is positioned in the barrel bore. The pin has a first end located adjacent the barrel first end and a second end. A non-viscous fluid flow passage is defined between the pin and the barrel. A viscous fluid flows through the nozzle body flow passage around the barrel and into a mold cavity. A non-viscous fluid flows through the non-viscous fluid flow passage defined between the barrel and the pin and into the mold cavity. A non-viscous fluid cavity is formed in the viscous fluid which then cools to form an injection molded part. An initial portion of the non-viscous fluid is then allowed to flow out of the non-viscous fluid …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.