Injection molding process control
US4146601A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 21, 1974 |
| Grant date | Mar 27, 1979 |
| Priority date | — |
| Expiry date | Oct 21, 1994 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/76
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Both a method and apparatus are disclosed for controlling a cyclically operated injection molding machine such that uniform, high quality molded articles are repeatedly produced from plasticized synthetic resinous material. The method and apparatus include integration of a sensed injection pressure with respect to time from the beginning of an injection stroke until plasticized material in a mold reaches a predetermined pressure. The integration defines a work index which is compared with a preset allowable range. If the work index lies outside the preset range, an adjustment is made to the back pressure acting on the plasticizing screw during the plasticizing portion of the subsequent molding cycle. The apparatus is permitted to make a predetermined number of adjustments in the back pressure after which a suitable indication is made that the molding apparatus is out of control itself. Other viscosity-affecting parameters may be controlled including injection screw rotary speed and injection screw velocity, and barrel temperature of the plasticizing apparatus. A mold cavity pressure sensor indicates that the cavity is full, and thereupon stops the integration and may also reduce th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.