Abstract: A control system for controlling a molding machine used for exothermic curing senses the rate of change of the temperature of the material in the mold. When the rate of change of temperature has first exceeded and then fallen below a predetermined reference level, it is determined that the exothermic curing reaction has been completed, and the mold is opened after a predetermined delay.

Abstract: A method is provided for determining the profile of a molded part as a means of checking the quality of a given molded part and/or as a basis for effecting adjustments in the molding machine controls. In accord with the subject method a plurality of pressure sensings are taken simultaneously at different locations in the molding machine. These sensings are employed in accord with a known mathematical formula for establishing a profile of the part being molded wherefrom it is possible to determine the physical characteristics which the molded part will have. For purposes of establishing the profile of the part, the values of the pressure sensings in pounds per square inch are plotted against the distance from the gate at which the pressure is measured, the latter distance being indicated in suitable units of length. The method for determining the profile of a molded part is also operable for purposes of determining whether any material flow has occurred at a given location in the molding machine.

Abstract: A method is provided which is particularly suited for employment in conjunction with the operation of an injection molding machine for purposes of determining during the cycle of operation of the machine whether the material flow conditions to the mold cavity of the machine which are required for the production of parts having the desired characteristics are present. More specifically, a method is provided wherein a comparison is made between the slope of a portion of the actual profile curve being generated during the flow of the material to the mold cavity of the machine and the slope of a corresponding portion of the theoretical profile curve which should be generated by the material flowing to the mold cavity if parts having the desired characteristics are to be produced. For purposes of determining the slope of a portion of the actual profile curve, a pair of pressure sensings are taken and time measurements corresponding thereto are made.