Process for injection molding with incremental initial ejection
US5932164A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 31, 1996 |
| Grant date | Aug 3, 1999 |
| Priority date | — |
| Expiry date | Dec 31, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/40
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of molding plastic parts, particularly those with low draft angles, textured surfaces or other mold release challenges, comprising the steps of placing a cavity substantially defining the exterior of the plastic part and a core substantially defining the interior of the plastic part into position defining the plastic part therebetween and injecting heated thermoplastic between the cavity and the core to form the plastic part. The molding machine is then operated to simultaneously withdraw the core and incrementally eject the plastic part from the core by an incremental ejection distance insufficient to disengage the plastic part from the core, wherein the plastic part is supported by the cavity during the incremental ejection from the core. The molding machine is next operated to withdraw the core and the part engaged thereon from the cavity, and fully eject the part from the core. The incremental ejection breaks the adhesion between the part and the core while the part is supported in the cavity, making full ejection of the part easier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.