Wax injection molding apparatus and control system

Abstract

An injection molding apparatus capable of producing disposable wax patterns or the like and which apparatus includes a logic control and a servo-control especially designed to provide a substantially automatic molding process and to continuously monitor and to dynamically control certain variable parameters which are encountered during the molding process, as for example, in the present embodiment of apparatus, the control of the dynamics of fluid (wax) flow and pressure for providing substantially an automatic molding process. The servo-control is a 'closed loop' servo type of control which, in the present embodiment of apparatus, continuously provides signals which relate to the fluid (wax) flow, i.e. velocity and acceleration, and fluid pressure which is then occurring in the molding cycle, and which signals are then compared with preselected input or reference signal levels whereupon a difference therebetween is then used to adjust or drive the fluid flow and pressure control systems of the apparatus toward a dynamic or balanced state which reduces this difference in signals between the input and measured signal levels to zero. The logic control for use with the molding apparatus is of the type that enables a substantially automatic molding cycle to be programmed for said apparatus whereby uniform product output is repeatedly obtained.