Method of manufacturing a multilayer molding
US5645786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1996 |
| Grant date | Jul 8, 1997 |
| Priority date | — |
| Expiry date | Jul 9, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/57
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An improved method of manufacturing a multilayer molding having a core and a surface layer by means of a double nozzle structure can eliminate a damaging phenomenon of producing a mixture of a resin material for forming the core remaining in and out of the aperture of the inner nozzle of the double nozzle structure and a resin material for forming the surface layer in the initial stages of molding operation by effectively driving back the remaining resin into the inner nozzle. A double nozzle structure that can suitably be used with such a method includes a shut-off pin arranged in the inner nozzle disposed at the center of the outer nozzle. The resin material for forming the core is driven out simultaneously with the resin material for forming the surface layer coming from the outer nozzle. The operation of resin injection from the inner nozzle is terminated at an arbitrarily selected moment during the operation of injecting the resin material for the surface layer of the outer nozzle. Then, the inside of the inner nozzle is brought into a no-load condition while the shut-off pin is held to its open position. Thereafter, the remaining resin material for the core found in and out o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.