Abstract: A casting machine die evacuation system has a vacuum source for evacuating the die cavity during casting connected to a chill block vent passage through a vacuum cut-off plug driven by a high pressure hydraulic system into an evacuation position at the start of casting and into a vacuum cut-off position in response to fast shot plunger operation. The tip of the plug is held in contact with the chill block so that cast material flow into the chill block vent passage will flow around the diameter of the plug without acting to unseat the plug from its vacuum cut-off position.

Abstract: A computerized die-casting machine control includes a microcomputer and a programmable controller having presettable inputs to establish a desired machine operating sequence. Temperature sensors at the holding furnace, cover die, ejector die, gate and at the die impact bushing monitor the die casting variables and produce input signals to the shot-control micro-computer. The micro-computer is programmed to take pre-programmed actions to correct out of tolerance conditions in the machine on a continuous on-line basis during machine operation.

Abstract: A die casting machine has a hydraulic shot ram controlled by a servo system that includes pre-settable thumbwheel switches to establish a desired memory of shot speed values and shot position presets in a programmable computer. An analog output responsive to the control program in the programmable computer produces a direct current analog velocity command signal. A servo amplifier includes means for comparing the command analog signal and a feedback signal from transducers sensing velocity of the hydraulic ram and position of valve means to produce an on-off servo valve signal so that a servo valve will modulate flow from a third state Olmsted shot valve so as to compensate for shot speed changes produced by changes in operational conditions including wear and build-up on a cylinder and ram; hydraulic oil heat-up during operation of the machine; and changes in flow characteristics of a molten metal due to temperature variations thereof.

Abstract: A hydraulic press having upper and lower hydraulically operated plates whereby the upper plate is movable with a long stroke cylinder and the lower plate is movable wth a short stroke cylinder. The press has a grooved load bearing rod which is attached to the upper moving plate and passes through the upper fixed plate of the press with a series of slots machined in the rod. A split ring and an especially ground shim are located on a bushing in the upper plate and in one of the ground grooves. A locking plate is attached to the lower part of the upper fixed plate and using a hydraulically operated cylinder has locking plates which move into and out of engagement with the grooved rod to accurately locate the position of the upper moving plate when the machine is stroked. This method of adjusting the horizontal position or parallelism of the plates enable very accurate positioning of the mold or dies which are mounted between the plates of the press.