Abstract: A die casting machine and a control method for avoiding damage to devices by performing operation control of a hydraulic operating means and an electric servomotor, that are adapted as drive sources in an injection step, separately and not performing coordinate control. The die casting machine includes a tubular injection sleeve, an injection plunger, an electric servomotor and a hydraulic operating means that are used as a drive source of an injection step, and a control means which controls the electric servomotor and the hydraulic operating means separately, when injecting and filling the cavity of the mold, which has been closed, with the molten metal by the advancing of the injection plunger, during a low-speed injection step and a high-speed injection step which is performed at a higher speed than the low-speed injection step, in the injection step.

Abstract: A die casting machine provided with an electric servomotor and a hydraulic cylinder as drive sources for injection is enhanced in operation stability in an injection step. In the injection step, the rotational speed of an injection electric servomotor (3) is pattern-controlled to follow a preset speed command pattern while the forward speed of a piston (5a) caused by driving of an injection hydraulic cylinder (5) is feedback-controlled with an addition signal of the forward speed of the piston (5a) caused by driving of the injection electric servomotor (3) and the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5). Alternatively, the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5) may be pattern-controlled to follow a preset speed command pattern while the rotational speed of the injection electric servomotor (3) is feedback-controlled with the addition signal.

Abstract: A die casting machine provided with an electric servomotor and a hydraulic cylinder as drive sources for injection is enhanced in operation stability in an injection step. In the injection step, the rotational speed of an injection electric servomotor (3) is pattern-controlled to follow a preset speed command pattern while the forward speed of a piston (5a) caused by driving of an injection hydraulic cylinder (5) is feedback-controlled with an addition signal of the forward speed of the piston (5a) caused by driving of the injection electric servomotor (3) and the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5). Alternatively, the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5) may be pattern-controlled to follow a preset speed command pattern while the rotational speed of the injection electric servomotor (3) is feedback-controlled with the addition signal.

Abstract: This invention discloses a molten metal supply system that can supply molten metal to a downstream process at a constant pressure and molten metal flow rate. The molten metal supply system includes a molten metal supply source, a plurality of injectors, and a plurality of check valves.

Abstract: In a hybrid injection system of a die casting machine, the occurrence of a large electric power loss can be prevented by avoiding a large current at a pressure-holding step and the size of a motor is reduced. In an injection system comprising an injection cylinder (16) housing an injection piston (15) for injecting molten metal to a mold and an electric booster (8) of hydraulic cylinder type, a head chamber (8H) to the electric booster communicates fluidly with a head chamber (16H) of the injection cylinder, causing a booster piston rod (5) to be housed in the electric booster (8) to move linearly and thus pressing under pressure to move the injection piston to perform injection molding.

Abstract: In a die-casting machine having an injection cylinder device (10) for injecting molten material to a casting die and a boost cylinder device (20) for boosting a hydraulic oil supplied to the injection cylinder device (10), back-pressure of the injection cylinder device (10) and back-pressure of the boost cylinder device (20) are synchronously controlled by a flow-rate control valve (17) capable of continuously adjusting flow-rate of the hydraulic oil discharging channel (16). Accordingly, boosting characteristic can be made in accordance with burr critical boost curve, thereby avoiding burr occurrence in die-casting products in advance. Therefore, high-quality die-casting products without burrs can be manufactured even in a high-speed casting method or using low-accuracy dies.

Abstract: In a die-casting machine having an injection cylinder device (10) for injecting molten material to a casting die and a boost cylinder device (20) for boosting a hydraulic oil supplied to the injection cylinder device (10), back-pressure of the injection cylinder device (10) and back-pressure of the boost cylinder device (20) are synchronously controlled by a flow-rate control valve (17) capable of continuously adjusting flow-rate of the hydraulic oil discharging channel (16). Accordingly, boosting characteristic can be made in accordance with burr critical boost curve, thereby avoiding burr occurrence in die-casting products in advance. Therefore, high-quality die-casting products without burrs can be manufactured even in a high-speed casting method or using low-accuracy dies.

Abstract: A shot piston device for molten plastic material with a force-operated piston guided in a cylinder provided with an inlet and an outlet, wherein valve arrangements ensure that the cylinder is filled during the return stroke of the piston and the cylinder content is discharged during the work stroke of the piston. The piston is fixedly connected by a drive bolt to a differential piston arranged upstream or in front of the piston. At least in its rearward extreme position, the differential piston covers and closes the outlet arranged in the corresponding differential cylinder. The circumference of the piston has at least one groove located underneath the inlet and extending from the end face of the piston facing the differential piston. The length of the groove is shorter than the length of the piston. A closing ring is arranged so as to be axially slidable on a cylindrical portion of the drive bolt arranged in front of the end face of the piston facing the differential piston.

Abstract: A vertical die cast apparatus having a novel docking/shot assembly in which the docking and docking cylinder and shot cylinder are constructed in one compound cylinder. A novel construction for supporting the docking/shot assembly is also provided.

Abstract: A method and apparatus for injecting molten material such as molten metal into a die cavity under pressure from a shot cylinder wherein a valve arrangement is provided which prevents undesirable pressure spikes in the die cavity during injection of molten material, and which effects rapid pressure buildup in the die cavity during solidification and curing of the molten material. The valve arrangement is operative to effect a regenerative or counterforce mode in the shot cylinder which limits the force applied during injection of molten material into the die cavity so as to substantially reduce pressure spikes, the regenerative mode being terminated in response to a predetermined pressure within the die cavity indicating that the die cavity is full.

Abstract: An arrangement for controlling an injection process for a die casting machine comprising an injection cylinder connecting to a plunger tip, a hydraulic circuit arrangement which supplies pressurized hydraulic oil to the cylinder at a plurality of rates of flow, and a control unit applying to the hydraulic circuit arrangement a plurality of signals when the plunger tip comes to a plurality of positions so as to change the middle speed of the plunger tip during one injection process, the hydraulic circuit arrangement providing with a plurality of combinations among a valve of the type of a pilot operated check valve which mounts a flow rate setting unit with a mechanical stopper and two position directional valve operated by the signals, and a method for operating the die casting machine comprising the steps of pouring melted metal into the injection cylinder, moving the plunger tip at a low speed to a position at which the level of the melted metal in the cylinder reches up to a portion near an entrance to a c

Abstract: A die-casting apparatus having a runner 31 through which molten metal is injected into a die cavity for die-casting an article, a squeeze passage 17 communicating with the die cavity 30 at a portion other than the portion where the runner 31 is communicated with the die cavity 30, and a squeeze plunger 36 snugly and slidably disposed in the squeeze passage 17 and adapted to commence, before the runner 30 is closed by solidification of metal therein, to forcibly displace the molten metal from the squeeze passage 17 back into the die cavity to effect a squeeze on the molten metal in the die cavity 30. The stroke of the squeeze plunger 36 is greater than one half of the length L of the squeeze passage 17. The cross-sectional area S and the length L of the squeeze passage are given by:S.gtoreq.0.35L.sup.

Abstract: A method and apparatus for controlling an injection process in cold-chamber die-casting machines which work on a three-phase system whereby an automatic initiation of the third phase without delay is possible. Beginning with the plunger of the apparatus in a certain starting position, the time is measured which elapses until a pressure in a working cylinder ahead of the plunger has reached a predetermined value. The time delay of the valve system which releases the pressure medium feed in the third phase is subtracted from the time measured so as to arrive at a time differential. At the end of the time differential, which elapses when the injection process begins with the plunger in its original or starting position, serves as a starting signal to trigger the valve system.

Abstract: An injection piston for a die casting machine comprising, a piston die having a chamber therein open at one end, a die rod having an end slidable in the chamber for changing the volume thereof. A coolant is supplied to the chamber to act as a damper to the movement of the die rod toward the press die when the injection piston is moved under pressure into a mold. The coolant flows in a coolant path comprising a feed path defined in the die rod and a discharge path at least a portion of which is defined between the press die and the die rod and the rest of which is defined in the die rod. A slidably mounted immersion valve is in the end of the die rod adjacent the chamber and movable into a neutral, a first and a second position for selectively permitting the flow of coolant into and out of the chamber, blocking the flow of coolant altogether and permitting the flow of fluid only out of the chamber depending on the increase of pressure exerted on the injection piston as it is forced into a mold.

Abstract: An injection molding machine wherein the ram in the injection cylinder can be moved at several speeds and can be subjected to different fluid pressures by an apparatus having a two-way valve whose inlet is connectable to one or more pumps by way of discrete check valves and whose outlet is connected with a chamber of the injection cylinder by a conduit containing an electrically adjustable pressure relief valve. The valve member of the two-way valve is movable between a first position in which it completely seals the inlet from the outlet and several second positions in which it acts as a flow regulating means to permit the fluid to flow from the inlet to the outlet at a selected rate. The valve member is movable by a solenoid-operated pilot valve which cooperates with a stop extending into the path of movement of the valve member and being movable axially by a reversible motor which is controlled by the programming system of the injection molding machine.

Abstract: In the method, a shot sleeve, for receiving a metered quantity of melt through an inlet or filling opening and connected to the mold cavity, has its volume continuously diminished in such a manner as to maintain a constant communication between the space above the melt in the shot sleeve and the mold cavity for escape of all the gas or air above the melt into the mold cavity before the opening of the shot sleeve into the mold cavity is completely closed by the advancing melt. This is effected, during the shot-pre-filling phase, by an accelerated motion of an injection piston from a rest position, at which the filling inlet to the shot sleeve is open, through the shot sleeve toward the mold cavity opening. As a result of the accelerated motion of the piston, the melt spreads over the melt engaging surface of the injection piston and the formation of a standing wave is prevented.