Dynamic Feed Control For Injection Molding

Patent · Tue Sep 17 00:00:00 EDT 1996

OSTI ID:879242

Kazmer, David O ^[1]

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1. San Francisco, CA

The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

• Research Organization: Stanford University (Stanford, CA)
• DOE Contract Number: FG51-94R020440
• Assignee: Stanford University (Stanford, CA)
• Patent Number(s): US 5556582
• Application Number: 08/340177
• OSTI ID: 879242
• Country of Publication: United States
• Language: English