Method for controlling injection molding machines
AssigneeUSM Corporation
InventorsPeter Hold, Angelo J. Notte, Marc A. Rizzi
Life of this patent
Estimating the term…
Abstract
Method for controlling the parameters of injection molding processes in a machine having a barrel with a plasticating chamber and a screw, rotatably and slidably disposed in said chamber, hopper means adjacent one end of said chamber communicating therewith and nozzle means disposed in the other end of said chamber communicating with a mold. Control of the injection molding process is achieved through an event recognition philosophy by sensing screw position, screw injection velocity, melt temperature, comparing the values at certain instances during the work cycle with known or desired values and using these values, changes of values and differences of values to monitor and initiate changes in the process parameters.
Claims8
A method for controlling the parameters of an injection molding process, said molding process including;
- sequence of steps feeding material into a plasticating chamber, applying, by the use of heaters, a predetermined amount of heat to the chamber, rotating a plasticating screw located in the chamber at a predetermined speed to plasticate the material, slidably retracting the screw during plastication, under a predetermined back pressure, to a charged position to collect a quantity of plasticated material ahead of the screw, and injecting the material into a mold by a forward sliding thrust of the screw, the forward sliding thrust of the screw stopping at a predetermined standard position said control method comprising:
- A. detecting the sliding speed of the screw during injection;
- B. detecting the temperature of the plasticated material;
- C. detecting the position of the screw during injection:
- D. comparing the detected screw position with the predetermined standard position when the sliding speed of the screw is reduced substantially to zero;
- E. adjusting the charged position of the screw to compensate for any difference in the detected screw position and the standard position for subsequent injection cycles;
- F. comparing the detected temperature of the plasticated material with a predetermined standard temperature;
- and
- G. adjusting the supply of heat energy to the plasticating chamber to compensate for any difference in the temperature of the plasticated material and the standard temperature for subsequent injection cycles by selectively adjusting rotational screw speed, back pressure, and the heat applied by the chamber heaters according to a priority sequence which maximizes the input of mechanical energy.
Dependencies are inferred from the claim text.