Method and apparatus for the control of injection molding
AssigneesThe Hong Kong University of Science and Technology, Moog Japan Ltd.
InventorsFurong Gao, Chunhua Zhao
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Abstract
This invention relates to a method and apparatus for the control of injection molding and, in particular, for determining a suitable time for transfer from injection velocity control to packing pressure control. The invention uses a derivative of, preferably the nozzle pressure, and inputs this to a fuzzy inference system. The fuzzy inference system uses said rules and knowledge to provide a suitable transfer time as an output. It is preferred that the sample pressure is filtered prior to calculation of the derivative.
Claims12
A method for the control of injection molding and the determination of a transfer point from injection velocity control to packing pressure control comprising:
- sensing a nozzle pressure or cavity pressure in a mold at discreet time intervals;
- calculating a differential of the sensed nozzle or cavity pressure at said discreet time intervals;
- calculating at least one input based on said differential pressure for input into a fuzzy inference system
- applying knowledge from said fuzzy inference system and outputting a value indicating a suitable time to transfer from injection velocity control to packing pressure control;
- and
- wherein said input is calculated by using dP(i+1)/dP(i) where dP(i+1)=P(i+1)−P(i) and P(i) denotes the pressure at the ith sampling time interval.
A method for the control of injection molding and the determination of a transfer point from injection velocity control to packing pressure control comprising:
- sensing a nozzle pressure or cavity pressure in a mold at discrete time intervals;
- obtaining the nozzle pressure or cavity pressure in the mold at discrete time intervals;
- calculating at least one input based on a ratio of relative changes in pressure for input into a fuzzy inference system;
- and
- applying knowledge from said fuzzy inference system and outputting a value indicating a suitable time to transfer from injection velocity control to packing pressure control.
An apparatus for the control of injection molding to provide a transfer time for transfer from injection velocity control to packing pressure control comprising:
- sensing means to sense and sample the pressure in a mold cavity or nozzle pressure at discrete time intervals;
- processing means to calculate the differential of said pressures;
- a fuzzy inference system for utilizing inputs relative to said derivatives of said pressure and for outputting an indication of a transfer time from injection velocity control o packing pressure control;
- and
- wherein said ratio of differential pressures includes input P(i+1)/dP(i) where dP(i+1)=P(i+1)−P(i) and P(i) denotes the pressure at the ith sampling time interval.
Dependencies are inferred from the claim text.