Evaluating pressure profile of material flowing to mold cavity

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. The values for pressure and time obtained therefrom are then plotted on a graph having cavity pressure as the ordinate and time as the abscissa. Through the use thereof, one is capable of producing a portion of an actual profile curve. The slope of the latter referenced plotted portion of the actual profile curve is determined and then compared to the slope of the corresponding portion of the theoretical profile curve. Based on the latter comparison, any corrective adjustments, if found to be required, can then be made in the molding machine controls. Moreover, such adjustments can be made so as to take effect either during the same cycle of operation of the machine or during a succeeding cycle of operation thereof.

Dependencies are inferred from the claim text.