A light metal injection molding machine includes an injection cylinder, a seal cylinder, a plunger, and a seal mechanism having a first annular body, a second annular body and a third annular body. The first annular body is arranged in an opening of the seal cylinder, and maintains a semisolid state of a molding material in a first gap between its inner periphery surface and the plunger. The second annular body is arranged in the opening between the injection cylinder and the first annular body, and includes an anterior internal groove formed over its whole inner periphery surface and a plurality of anterior transverse holes passing through the inner periphery surface. The third annular body is accommodated into the anterior internal groove transformably in a radial direction of the plunger, and tighten the plunger by pressurization from molding material flowing into the anterior transverse holes.

A punch pin assembly includes a punch rod, a punch pin and a punch pin connection rod connected therebetween. A heat-conducting medium conveying loop is arranged in the punch rod and the punch pin connection rod. The heat-conducting medium conveying loop communicates with the outside of the punch rod separately through a first medium port and a second medium port which are formed in the punch rod.

A feed device for a metal melt in an injection molding device of, for example, a metal-molding machine has a reservoir for the metal melt and a feed duct, in which the metal melt can be fed to a mold cavity. The feed duct includes a cylinder bore, in which a piston is arranged axially displaceably. A collection chamber for the metal melt, from which the metal melt can be introduced into the mold cavity through a continuing line as a consequence of an axial displacement of the piston, is provided in the cylinder bore. The cylinder bore is surrounded by a first heater, which has at least one heating element.

An injection assembly (1) of a die casting machine comprises valve means for controlling the advancement and return of the injection piston (20) and of the multiplier piston (42). The valve means comprise a plurality of valves, including a proportional delivery valve (104), a proportional injection discharge valve (112) and a proportional multiplier valve (118). Electronic control means (300) are provided which are configured and/or programmed to execute an air purge cycle which performs the opening and closing of the valves, alternately, for a predetermined number of times.

An injection assembly (1) of a die-casting machine is provided with electronic control means (300) of the valves, configured and programmed for carrying out a plurality of diagnostic tests on said valves. The test management program provides for the execution of a test for each valve and the comparison of parameters detected during said test with a predefined interval or with a threshold value. Furthermore, means are provided for displaying the results of the diagnostic tests.

Provided is a die casting machine and die casting machine control method that are able to change the operation of a plunger at an appropriate timing. A die casting machine operates a plunger such that the plunger moves forward, detects that molten metal extruded from a sleeve by the forward movement of the plunger has arrived at a cavity, determines a deceleration starting position and a intensification starting position for changing the operation of the plunger, using, as a reference (reference position Ls), the position of the plunger 15 at the time when it is detected that molten metal has arrived at the cavity, and, when the plunger moves to the deceleration starting position and intensification starting position, changes the operation of the plunger to operations corresponding to the respective positions.

An injection device of light metal injection molding machine and an injection control method thereof are provided, in which a melt in a supply unit is supplied into an injection unit through a communication passage, a plunger of the injection unit is retracted to measure the melt, the communication passage is closed, and the plunger is advanced to inject the melt into a mold device through an injection nozzle of the injection unit. After the injection and before the measurement, the plunger is advanced under a pressure at which the melt does not come out from the injection nozzle to make the melt in the injection unit flow back into the supply unit through the opened communication passage.

A piston of a die-casting apparatus comprises: a piston head fabricated of a first material; an elongate, inner carrier coupled to the piston head; a generally annular body seated on the carrier adjacent the piston head; and a wear ring disposed on the piston head, the wear ring being fabricated of a second material. The first material has a higher toughness and a lower hardness than the second material.

An injection assembly, for pressure die casting systems, has an injection cylinder adapted to inject liquid metal into a casting cavity; the injection cylinder is actuated by a hydraulic flow of an oil-pressure controlled circuit; the oil-pressure controlled circuit includes a hydraulic cushion which blocks and releases the flow of the hydraulic fluid in the injection cylinder and provides a counter-pressure of preset value to control the injection speeds and to prevent cavitation in the injection cylinder.

A method for casting metals under pressure by a cold-chamber method includes placing a bolt of the metal to be cast in one of at least two casting chambers and selecting a casting chamber from the at least two casting chambers and feeding and introducing the selected casting chamber into a diecasting machine, the selected casting chamber having one outlet opening. The selecting and feeding of the casting chambers is carried out alternately from the at least two casting chambers. The method further includes heating the bolt by means of induction. Melting of the bolt in the selected casting chamber is carried out after the feeding and introducing of the selected casting chamber into the diecasting machine but before an opening of the outlet opening of the selected casting chamber in order to fill the cavities is completed.