Abstract: The vent includes a plurality of passages formed by a plurality of stacked plates. The passages are dimensioned to permit the free flow of air but to prohibit the passage of molten metal. During die casting, air is free to exit the die while molten metal is retained.

Abstract: A vacuum valve includes a first and second die block both adapted to be secured to a die of a die pair. A slot is in one of the die blocks in fluid communication with a mold cavity. A valve member is movable between a first position permitting fluid flow through the slot in a second position inhibiting fluid flow through the slot. A power operated actuator includes a reciprocal movable output member. A gear drive mechanism is coupled with the output member and with the valve for changing movement of the actuator into movement of the valve member. A controller controls the reciprocation of the actuating member.

Abstract: A valve for a vacuum die casting machine has a cover die block and an ejector die block. A slotted member and an abutting slotless member abutting the slotted member are movable between an open, fluid-passing position and a closed, fluid-blocking position. A controller directs movement of the valve between the open and closed positions. The valve is moved to its open position as the air within the cavity and associated lines is being evacuated and is moved to its closed position as the shot is injected into the die cavity. The slotted and slotless members may either be rotatable drums or elongated bars. The slotted drum includes a slotted end and an actuation end. Similarly, the slotted elongated bar includes a slotted end and an actuation end. Alignment of the slot of either the rotatable slotted drum or the movable slotted bar with the vacuum passage allows the passage of fluid.

Abstract: The delivery unit includes a transfer member in the form of a linear transfer plunger or slide that acts to transfer controlled amounts of lubricant from a loading chamber to a delivery chamber for delivery by air pressure to the casting apparatus. Various delivery units are included arranged in three groups having similar characteristics including a charge control mechanism and the form of the transfer plunger. Various arrangements of die casting apparatus with a lubricant delivery unit for delivering lubricant into selected locations of a die casting machine are also included.

Abstract: A vacuum-controlling system for controlling the degree of vacuum in the vacuum system of a vacuum die-casting machine operates to: detect the degree of vacuum H at the instant of closure of the vacuum valve to the die mold cavity; compare the detected degree of vacuum H with a preset degree of vacuum Ho; correct a first position of the injection plunger for opening the vacuum valve by moving the first position in the advancing direction of the plunger by a specific distance in the case where H is higher than Ho; and correct the first position in the retracting direction of the plunger by a specific distance in the case where H is lower than Ho. By thus automatically correcting the position of the plunger for opening the vacuum valve to the optimum state, the formation of cavities or blowholes in the die-cast product is prevented, and at the same time, by maintaining the degree of vacuum in a specific state, the product quality is stabilized.

Abstract: A valve assembly for venting diecasting moulds comprises a venting channel, a venting valve communicating with the venting channel and having an axially displaceable valve closure member, and an actuating member for operating the venting valve from an open position into a closed position. The actuating member includes a power pick up member exposed to the liquid casting material escaping during the casting operation from a casting chamber provided in the diecasting mould through the venting channel and being axially displaceable under the influence of the kinetic energy transmitted from the liquid casting material to the power pick up member when the liquid casting material hits the power pick up member.

Abstract: A method and apparatus capable of continuously discharging contaminated gas out of metal molds, the gas being generated prior to the casting step and including moisture. A gas vent valve is provided at a gas vent passage in communication with a mold cavity. A suction unit and a vacuum pump are selectively connected to the gas vent valve. After closure of the metal molds, the suction unit is connected to the gas vent valve to perform sucking interior of the mold cavity. By this suction, an external air is introduced into the metal molds through a pouring port of a shot sleeve. Thus, contaminated gas in the cavity is replaced with a clean air. During injection molding, the gas vent valve is connected to the vacuum pump for decompressing the mold cavity. Vapor explosion is avoidable since moisture content is removed from the mold cavity even if the molten metal is introduced into the cavity.

Abstract: A gas venting system is connected to a downstream side of a gas vent valve through a gas exhaust line. An electromagnetic valve and a suction unit are connected to the gas exhaust line. A pressure switch is directly connected to the gas exhaust line to detect the pressure variation within the line. By the suction through the suction unit and the opening of the electromagnetic valve, the gas exhaust line is decompressed. If the line has a perforation, the pressure does not reach a predetermined pressure. If clogging occurs, the pressure reaches a predetermined pressure while the metal molds are open and the gas vent valve is open. Thus, accurate detection to the defects can be achieved regardless of the state of the metal molds and the internal volume of a vacuum tank.

Abstract: A casting mold has a main body provided with a vent hole opened up in a casting space of said main body. The improvement is characterized in that the vent hole is provided with air discharging means and air feeding means which are disposed at the vent hole and the air discharging means and air feeding means are suitably selected so that air within the casting space can be discharged and a pressurized air can be fed toward the casting space through the vent hole.

Abstract: The vacuum valve apparatus is used in die casting equipment of the type which utilize a source of vacuum pressure in an internal die cavity for making a casting. The apparatus includes a valve body that has components that are separable along a split line that is positioned to facilitate removal of casting material from internal ports that may result in the event of a malfunction.

Abstract: A mold casting process comprises, after pouring of a molten metal into a mold, rapidly cooling that surface layer of a cast product which is in contact with a mold, and releasing the resulting product from the mold when the surface layer thereof has been converted into a shell-like solidified layer. Such process is used for casting a mechanical part blank and apparatus for carrying out the process is provided.

Abstract: A vacuum die-casting machine has a bellows forming a sealed enclosure between the rear of the fill chamber and the piston rod. A vacuum is applied to the enclosure during evacuation of the die cavity and charging of the fill chamber with molten metal. As the piston moves forward, an inert gas at about atmospheric pressure is introduced into the enclosure and extends into the feed tube.

Abstract: The apparatus is used in die casting equipment of the type which utilizes a source of vacuum pressure in an internal die cavity for making a casting. The apparatus includes a valve body that has components that are separable along a split line that is positioned to enable easy cleaning of casting material from internal ports. The apparatus has a valve, a trap operatively connected to the valve body and a closed chamber with an inlet thereto. The chamber is adapted to receive and contain casting material that may enter the inlet thereof.

Abstract: The apparatus has a generally cylindrically shaped rotating collar for sealing the chamber after casting material has been poured into it. The apparatus has a slidable plunger mechanism with an enlarged tip for forcing casting material through a shot sleeve toward the die. A flat annular collar retainer plate is located at right end of the collar. A sleeve seal tube is attached to the collar retainer plate adapted to receive the plunger tip. A seal housing is carried by and is slidable on the plunger stem, has an enlarged left end portion in which a sleeve seal is located so that when the plunger mechanism is moved to the left, the plunger tip enters the chamber and the seal housing and plunger stem move to the left until the seal engages the seal tube during leftward movement of the plunger. Further movement of the plunger stem results in the stem sliding relative to the seal housing while the plunger tip forces material in the chamber toward the die cavity.

Abstract: A die casting vacuum valve has a cover die block and ejector die block. A cushion member is positioned in the cover die block and a reciprocating member is positioned in the ejector die block such that upon reciprocation of the reciprocating member, it contacts the cushion member and cover die block to seal the reciprocating member with the cover die block and the surrounding surface. A controller mechanism controls the reciprocation of the reciprocating member such that the reciprocating member contacts the cushion when the molten material enters the mold cavity and slot to prevent further flow of the molten material in the slot past the reciprocating member.

Abstract: This invention relates to a casting control system of a die cast machine, and more particularly to a system for controlling a high speed injection real stroke of an injection plunger and controlling valve closing timing for degassing gas in a mold cavity. The high speed injection real stroke is measured by an arithmetic unit from a signal output from a position detector, and the high speed injection real stroke is then compared with a certain preset value. When arithmetic unit determines that the high speed injection real stroke and the preset value do not coincide with each other, a pretest action delay time of the injection plunger is .+-. incrementally or decrementally corrected until both values coincide.

Abstract: A degassing apparatus for a mold includes a degassing valve, an acoustic wave detecting unit, and a valve closing unit. The degassing valve is located at an end portion of a degassing passage extending from a mold cavity. The acoustic wave detecting unit is arranged midway along the degassing passage and detects an acoustic wave generated when a molten metal collides against a wall surface of the passage, and thereby detecting passing of the molten metal. The valve closing unit closes the valve when a detection signal level is higher than a reference signal level.

Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly.

Abstract: A gas vent system of a mold improves timing of closing the gas vent passageway, in particular in die castings or in moldings. The gas vent passageway is formed on mating surfaces of a pair of mold halves and communicating a mold cavity with the outside of a mold when the mold is closed. The gas vent valve is mounted on one of the mold halves and disposed intersecting perpendicularly to the gas vent passageway and is provided with a concave portion on its end surface receiving the pressure from the molten pressure charged. The other mold half is provided with a projection which can be fitted tightly in the concave portion of the gas vent valve, and the projection is provided with part of the gas vent passageway so as to direct a flow of the molten material passed through the gas vent passageway from the mold cavity toward the concave portion of the gas vent valve. The gas vent valve is operated to close the gas vent passageway in response to a pressure from the molten material forced into the mold cavity.

Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly.

Abstract: An improved gas venting valve is provided for use with a material-forming mold or die cavity to control venting of gas through a gas conduit communicating with the cavity. The gas venting valve includes a hollow piston axially movable in a housing and having a valve head connected thereto for movement between open and closed positions relative to a valve seat. The valve seat is disposed in a portal of the housing communicating with the gas conduit. In the open position, a gas venting passage internal of the piston is communicated to the portal by the open valve for venting gas from the cavity as material is introduced therein. In the closed position, the valve head is sealed against the valve seat to prevent material introduced into the mold cavity from escaping. The piston is axially moved in the housing by application of pressurized fluid to respective pressure responsive surfaces on the piston.

Abstract: A gas venting arrangement in a high speed injection molding apparatus such as a high speed die casting machine. The gas venting arrangement includes a gas vent control valve which is closable at an optimum timing and at high speed. This valve closure is achievable by providing an improved combination of a control circuit and a valve driving mechanism. The control circuit is connected to a molten metal sensor and sends a high voltage output drive signal to the valve driving mechanism when the sensor detects a first molten metal or a metal splash. The valve driving mechanism includes an electromagnetic valve connected to a pneumatic source and a pneumatically operated valve connected between the electromagnetic valve and the gas vent control valve. The pneumatically operated valve is also connected to the pneumatic source. The electromagnetic valve performs prompt change-over operation upon receiving the drive signal, and supplies driving pneumatic pressure to the pneumatically operated valve.

Abstract: There are disclosed a method and an apparatus for forming disk wheel like formed parts, in a manner that the forming work is carried out by placing, in the vertical direction, the mold axis of a metal mold cavity, which corresponds to the axis of rotation of a disk wheel, thus to inject hot molten metal from the bottom in the mold axis direction, characterized in that the control mode of the injection speed comprises: a first phase to allow an injection speed when the hot molten metal has reached the inlet of the metal mold cavity to be low, a second phase to allow an injection speed from the time when the hot molten metal passes a disk wheel hub equivalent portion of the metal mold cavity until it passes the greater part of a disk wheel rim portion thereof via a disk wheel disk portion thereof to be, at the end portion of said rim equivalent portion, equal to a speed corresponding to a lower speed or less, which corresponds to a gas discharge ability of a degassing unit provided in association with the metal

Abstract: The present invention relates to a method of detecting a degassed state in a mold and a system therefor. A gas release opening is formed between a movable mold part and stationary mold part, and a diffuser block having a path for releasing the gas to atmosphere is disposed on the mold. A secondary flow path capable of generating a secondary flow when the gas is released is formed in this diffuser block, and a wind velocity sensor is disposed in this path. Wind velocities of the secondary flow, which are detected by the wind velocity sensor, serve as indications of a cast state and the like in a die cast machine or the like. The secondary flow path is suitably shut off by a shut-off mechanism, and connected to an air cleaner, so that the wind velocity sensor can be effectively protected from dust and the like.

Abstract: Disclosed is a gas venting arrangement in an injection molding apparatus, and a method for venting gas out of the injection molding apparatus. The gas venting arrangement includes mold halves formed with a gas vent passage in fluid communication with a mold cavity and positioned downstream thereof, a gas vent control valve disposed at a downstream end portion of the vent passage, a detection member disposed at the vent passage for detecting injected material exceeding over the mold cavity, a valve driving mechanism connected to the gas vent control valve, and an electric control means connected between the detection member and the valve driving mechanism. The detection member generates a detection signal upon contact with the injected material and the valve driving mechanism is operated in response to the detection signal through the electric control means to operate the vent control valve.

Abstract: A gas removal system for a mold cavity of a die casting or other molding machine includes a vacuum line connecting the mold cavity to a vacuum pump when a valve therebetween is open to evacuate gas from the mold cavity prior to injection of molten material therein and further includes a gas flow indicator disposed in the vacuum line between the valve and vacuum pump. The gas flow indicator includes a mechanical flapper movable in a particular manner in response to evacuation of gases from the mold cavity and in another noticeably different manner when little or no gas is evacuated from the mold cavity as a result of the valve being improperly closed. The flapper is visible to a machine operator through a window to indicate whether the gas evacuation system is operative to remove gas from the mold cavity.

Abstract: A gas removal system for a mold cavity of a die casting or other molding machine includes a valve movable to an open position to interconnect the mold cavity to a gas venting or evacuating device or to a closed position. A portion of the valve is movable relative to a fluid pressure supply inlet port to establish a first pressure condition represented by back pressure in the supply line when the valve is in one of the open or closed positions and a second pressure condition represented by substantial absence of back pressure in the supply line when the valve is in the other of those positions. The presence or absence of back pressure in the supply line is sensed to determine valve position. A control unit compares the second valve position and a scheduled valve position and indicates when the valve is improperly positioned to prevent injection of a melt into the mold cavity.

Abstract: In a casting apparatus, an electromagnetic pump is installed above a mold cavity. A molten metal contained in a crucible is forced into the mold cavity. The electromagnetic pump acts not only to exhaust gas or air in the mold cavity but also applies a downward force to the molten metal rising above the upper surface of the mold cavity.

Abstract: This invention concerns an improvement in a molding die for use in casting in which a metal article is molded by charging a molten metal to the inside of a molding die comprising paired male and female dies, and then cooling the temperature of the molten metal to a solidification region and a solidification range where the solid phase and the liquid phase are present together, wherein one or both of paired male and female dies constituting the molding die equipped retractably with a pressurizing insert for applying the pressure to the molten metal charged to the molding die is made of ceramics thereby obtaining a molding die that can facilitate the control for the temperature distribution over the entire molding die, particularly, within the molding die upon cooling to solidify the molten metal, as well as having sufficient strength such as thermal shock resistance, shock resistance and durability enabling to mold a high temperature metal article by solidifying the high temperature molten metal of about 600.

Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly through the gas vent passages than expected.

Abstract: Disclosed is a degassing apparatus incorporated with a molding apparatus having a mold cavity, which includes a spool having a bore formed therein. The spool further has formed therein a gas inlet opening adapted to be communicatively coupled to the mold cavity of the molding apparatus, and a gas outlet opening, the gas inlet and outlet openings being in selective communication and non-communication with each other. Means for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings, are provided. Also provided is a flanged piston mounted in the bore and coupled to the communication controlling means, the piston being reciprocatingly slidable between a first position and a second position, the bore being further formed with an upper chamber and a rod-side chamber situated on opposite axial sides of the piston, and a lower chamber radially surrounding a portion of said piston.

Abstract: A degassing apparatus for a metal mold comprises a valve body and a bypass. The valve body is slidably provided between an end of a vent groove communicating with a metal mold cavity and a valve opening/closing portion before an exhaust hole. When a molten metal flowing from the cavity acts on a surface of the valve body, the valve body moves toward the exhaust hole and blocks a path toward the exhaust hole. The bypass bypasses a valve head of the valve body from the vent groove and guides gas to the exhaust hole. The valve head of the valve body has a substantially head-cutting conical outer shape projecting in the direction of the vent groove. The vent groove has a gas vent path extending from a top portion to the vicinity of the base of the valve head along an outer surface of the valve head. An end portion of the gas vent path corresponding to the base of the valve head communicates with a start portion of the bypass which bypasses the valve head.

Abstract: A mold-release agent injection nozzle is provided in the portion of the die casting machine leading to the mold cavity or in the mold. A mold-release agent is then spray applied to the surfaces of the mold through the nozzle while the mold is closed. The surplus mold-release agent is then discharged through a vent port having a displaceable valve.

Abstract: A process for casing a fiber-reinforced metal body by placing a shaped fibrous article made of a reinforcing fiber into a cavity in a casting mold and filling a molten metal into the shaped fibrous article to solidify it, the process further including the steps of pouring the molten metal into the cavity from the lower portion thereof, while venting gas present within the cavity through a gas vent passage having a very small opening communicating with the upper portion of the cavity, and closing the gas vent passage and completely solidifying the molten metal under a higher pressure.

Abstract: There are disclosed a method and an apparatus for forming disk wheel like formed parts, in a manner that the forming work is carried out by placing, in the vertical direction, the mold axis of a metal mold cavity, which corresponds to the axis of rotation of a disk wheel, thus to inject hot molten metal from the bottom in the mold axis direction, characterized in that the control mode of the injection speed comprises: a first phase to allow an injection speed when the hot molten metal has reached the inlet of the metal mold cavity to be low, a second phase to allow an injection speed from the time when the hot molten metal passes a disk wheel hub equivalent portion of the metal mold cavity until it passes the greater part of a disk wheel rim portion thereof via a disk wheel disk portion thereof to be, at the end portion of said rim equivalent portion, equal to a speed corresponding to a lower speed or less, which corresponds to a gas discharge ability of a degassing unit provided in association with the metal

Abstract: A process for casting a cylinder block blank made of light alloy provided with a cylinder barrel reinforced around its cylinder bore with a reinforcing tubular body and a crankcase provided continuous to the cylinder bore, which includes placing the reinforcing tubular body in a first cavity formed for shaping a cylinder barrel at the lower portion of a mold which is formed at its upper portion with a second cavity for shaping a crankcase communicating with the first cavity, and pouring a light alloy molten metal from the lower portion of the first cavity into the first and second cavities while simultaneously venting gas from the first and second cavities.

Abstract: A mold-release agent injection nozzle is provided in the portion of the die casting machine leading to the mold cavity or in the mold. A mold-release agent is then spray applied to the surfaces of the mold through the nozzle while the mold is closed. The surplus mold-release agent is then discharged through a vent port having a displaceable valve.

Abstract: A mold and method for producing, or casting a high-melting metal article from a high-melting metal having a melting point of about 900.degree. to 1600.degree. C.

Abstract: A deflator for injection molding in a cavity. Two exhaust passages connect the cavity to a detection valve and an exhaust valve, which is being pumped. The exhaust passages are arranged so that the molten metal reaches the detection valve before the exhaust valve. Closing of the detection valve triggers the pneumatic closing of the exhaust valve. Also included in the invention is a bounce reduction means for the exhaust valve and a rockable connection for approaching the deflator to the mold.

Abstract: A degassing apparatus, adapted for use in a molding apparatus having a mold cavity, includes a spool having a bore, a gas inlet opening and a gas outlet opening. The gas inlet and outlet openings are in selective communication and non-communication with each other. A reciprocatingly slidable valve body engages a conforming valve seat formed on the spool for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings. A piston is mounted in the bore and coupled to the valve body. The piston is reciprocatingly slidable between a first position and a second position. First and second chambers are situated on opposite axial sides of the piston. First, second and third fluid ports are formed in the spool. The first and second ports are in communication with the first and second chambers, respectively.

Abstract: This invention relates to a metal mould for use in die casting. Such a metal mould is required to have a venthole arrangement through which a gas within a cavity is discharged out of the metal mould as molten metal is poured into the cavity. The invention is characterized by a venthole arrangement which comprises inclined grooves (5, 6) being formed in the facing surfaces of two half portions (1, 2) of the metal mould having the cavity defined therebetween, communicating with the cavity and a safe cavity (7), and inclining in a direction opposite to each other. With the arrangement of the invention, a gas can be effectively discharged out of the metal mould without spouting out molten metal.

Abstract: A method of producing a fiber-reinforced composite material in which a fiber body is mounted on mounting surfaces in a mold cavity, which mounting surfaces are in fluid communication with the outside of the mold through air relief passages. A molten matrix metal is poured into the mold cavity and then subjected to a high hydrostatic pressure so as to be filled into the fiber body while expelling the air from the fiber body to the outside of the mold through the air relief passages. The molten metal is thereafter filled into the air relief passages and solidifies immediately to seal the mold cavity from the ambient atmosphere whereby the molten matrix in the mold cavity is rapidly solidified under high pressure to form a fiber-reinforced composite material of high quality with inclusion of substantially reduced voids or cavities.

Abstract: A die-casting apparatus is used to carry out a die-casting method in which an injection plunger is moved forwardly at a lower speed and then is temporarily stopped at a forward stroke intermediate position in which a space defined by the injection plunger and an injection sleeve is substantially filled with an amount of molten metal. Then, evacuation of a product cavity and the injection sleeve is commenced and, after the lapse of a predetermined time period, the injection plunger is again moved forwardly at a higher speed to inject the molten metal from the injection sleeve into the product cavity. Compared with the prior art, the method provides an increased evacuation time period and assures a reduction in the volume to be evacuated. In addition, the higher injection stroke reduces possibility that air and gases are trapped in the molten metal to provide die-cast products of a high quality.

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 gas venting arrangement incorporated into a mold for use in a die casting or injection mold machine, having a passage for venting gases including by-pass passages and a valve chamber consisting of a forward portion formed in the mold where the valve is slidably received and a rear portion formed by a member separate from the mold. The valve and the passage are designed so that the valve is forced to move from an opened position to a closed position to shut the passage upon axial impingement of a melt from a cavity of the mold. The arrangement has a first system for biasing the valve into the opened position, a second system for biasing the valve into the opened position upon the melt impingement, and a system for releasing the valve from the second biasing means to return from the opened position to the closed position.

Abstract: A method for injecting molten metal in a vertical diecasting machine. In order to efficiently produce high quality castings, a molten metal is injected into a mold cavity with the upper part of the mold cavity communicating with the atmosphere, the mold cavity is occluded before the completion of the injection, and then the molten metal is pressurized to suppress the trapping of air or gases in the casting.

Abstract: A gas-venting valve includes a sliding valve and either a fixed or movable valve chamber. The valve is closed by impingement of molten metal or melt flowing out of a cavity defined by the mold, in such a manner that the valve is forced to move relative to the valve chamber from a first position to a second position. The invention further includes a device for urging the valve to move relative to the valve chamber from the first position to the second position; a device for restraining the valve at the first position and preventing it from moving toward the second position, against the force of the urging device, until a part of the melt impinges against the valve; and a device for actuating the valve to return from the second position to the first position against the force of the urging device.

Abstract: A diecasting process for producing cast pieces for metals or their alloys by means of a horizontal cold chamber diecasting machine. The diecasting machine includes a diecasting mold held under a vacuum, a fill chamber coupled to the diecasting mold, a holding furnace containing metal melt, a suction pipe partially immersed in the holding furnace and coupled to the fill chamber, means for transporting metal melt from the holding furnace through the suction pipe into the fill chamber under a vacuum, and means for moving the metal melt from the fill chamber into the diecasting mold. During the dosaging phase when the fill chamber is filled with metal melt, gases and lubricant vapors are developed upon entry of the melt into the fill chamber.

Abstract: A method and apparatus for casting molten metal in a die casting machine having matching die assemblies movable between open and closed positions, a plunger for injecting molten metal into the die cavity, a vacuum system for evacuating the die cavity during injection of molten metal and a vacuum control valve for opening and closing the exhaust passage through which the air is evacuated. A fluid cylinder is mounted on one die assembly with its piston rod coupled to the valve rod of the vacuum control valve. The fluid cylinder has a solenoid-operated control valve actuated by an electric switch operated by movement of the molten metal injection piston so that the vacuum control valve begins to close at a predetermined point during the injection stroke. The injection plunger also actuates a timer at the same time it actuates the solenoid-operated control valve.

Abstract: An arrangement incorporated with a mold for use in a die casting machine or an injection mold machine comprising: a gas vent passage formed in the mold communicating with a cavity of the mold; two symmetrical by-pass passages branched from the gas vent passage; a gas discharge passage communicating with the outside of the mold; and valve means including a valve chamber formed in the mold having a valve located therein and communicating with the above-mentioned passages. The valve in a first position cooperates with the valve chamber to prevent the gas vent passage from communicating with the gas discharge passage, but prevents both the gas vent passage and the by-pass passages from communicating with the gas discharge passage when in a second position.