Adaptive process control for injection molding
US4816197A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 12, 1988 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Apr 12, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/7646
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for controlling certain parameters of an injection molding cycle applying PVT optimization wherein the injection pressure and injection velocity of the melt are utilized to calculate an average viscosity for the melt during injection in a qualifying cycle of the machine as well as subsequent production cycles. A ratio of the average viscosity in a given cycle relative to the viscosity in either the qualifying cycle or a preceding cycle is utilized to adjust the holding time and cooling time, thereby achieving PVT optimization. In a second aspect, an injection molding machine is utilized to develop PVT constants for a given material by pressurizing the material in the barrel against the blocked outlet nozzle, measuring the volume during pressurization, and then weighing the pressurized shot after it is purged from the barrel in order to calculate the specific volume of the material. Plotting specific volume against a variety of pressure and temperature values produces a plot of PVT relationships from which the constants can be derived.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.