APPARATUS FOR EXTRUSION OF PLASTIC NET

An extrusion apparatus, having two die members which are moved relative to one another to extrude a plurality of spaced strands of plastic material in one direction and a plurality of spaced strands in a second direction to form an integral net or net-like structure is operated by generating a first electrical signal having a wave form correlated to a desired motion of the die members, monitoring the actual motion of the die members and generating a second electrical signal having a wave form corresponding thereto, comparing the first and second signals and generating a variable third signal adjusted to compensate for detected differences between the first and second signals, and transmitting the third signal to a torque motor-servo valve combination which controls flow of oil to a hydraulic cylinder piston assembly operatively connected to one or both of the die members for carrying out the desired motion thereof. The motion is carried out with a high order of precision and reproducibility enabling the extrusion of a wide variety of sizes and shapes of plastic net or similar structures.