Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/20—Accessories: Details
  • B22D17/32—Controlling equipment

Definitions

• the invention relates to a hot chamber die casting machine according to the preamble of claim 1.
• Hot chamber die casting machines of this type are known (DE-AS 21 43 937).
• the casting tank immersed in the melt is provided with a casting cylinder with a riser hole and with a mouthpiece body attached to it, which can be guided up to the mold.
• the die casting process is one of the most economical manufacturing processes in the foundry industry. It is carried out with die casting machines which carry out the press-in process in three phases in order to achieve the highest possible product qualities. It is known (DE-PS 29 22 914) to either use path-dependent signals to control the press-in process or signals dependent on the press-in pressure, from which in turn the respective position of the casting piston and the degree of filling of the mold can be concluded.
• the bath level is one of the main disturbances in these hot chamber die casting machines.
• a different bath level can lead to different filling processes in the printing form. Is the bathroom mirror e.g. too high, the mold cavity is filled during the first phase. If it is too low, the start of the second phase comes already in the casting container or in the mouthpiece body and an empty shot is created which can lead to high pressure peaks.
• the object of the invention is to avoid these disadvantages.
• the characterizing features of claim 1 are provided in a hot-chamber die casting machine of the type mentioned at the outset. With this measure, the position of the metal front can be detected exactly, so that from this point in time the further material flow via sprue pins and sprue channels can be clearly determined.
• the press-in process can be controlled via - per se known - highly dynamic continuous valves with switching times between 1 to 5 ms, which are actuated by the control device and a Enable customized speed and pressure control. This configuration makes it possible, in particular when the control device is designed as digital control electronics, to achieve digital speed and pressure control which makes it possible to approach different points at different speeds over the entire filling process.
• the reprint is also freely selectable. You can work with screens in a manner known per se to monitor the casting parameters (pressure, speed and path). It is also possible to compare the different shapes or sprue designs with the aid of an additional flexible time. It is thus possible, for example, that when the sensor detects material, the casting parameters on the screen show that the first phase has to be extended somewhat in order to ensure optimum ventilation.
• the great advantage here is that, in contrast to the previously mentioned arrangement of a metal sensor in the mold, the sensor is now assigned to the machine at a location which is close to the sprue bush of the mold, so that it is not necessary is to provide different shapes with a sensor in a cumbersome manner.
• the formation of the various forms can, as indicated, be taken into account by setting an empirically determined flexible time.
• an evacuation device with a vacuum pump and with a valve connected upstream thereof, which is additionally actuated by the control device can also be assigned to the mold. It can also be provided that the nozzle tip can be inserted into a receptacle of the mouthpiece body, so that the metal sensor is then inserted in this receptacle of the mouthpiece body. It then also remains possible to provide different nozzle tips without having to change the arrangement of the metal sensor.
• metal sensors that work in a non-contact manner, such as, for example, on the metal front Magnetic field sensors or ultrasonic sensors, then there are no sealing problems during installation, as can occur with sensors that are triggered when they come into contact with the metal front because of the high pressures and temperatures.
• FIG. 1 shows a schematic representation of the end of a riser bore of a casting container of a hot-chamber die casting machine with an attached mouthpiece body which extends into the mold and has a metal sensor at its end provided with a nozzle tip, and
• FIG. 2 shows a schematic block diagram of the control device for the press-in process of the hot-chamber die-casting machine of FIG. 1.
• FIG. 1 shows the upper end of a casting tank (2) which is immersed in a casting trough (1) and which is provided in a manner not shown with a casting piston which can be moved via a drive rod (3).
• the casting container (2) has a riser bore (4), the upper end of which has a conical receiving opening for inserting a mouthpiece body (5) which can be heated in a known manner and which is connected to the insertion opening (6).
• opposite end has a conical receptacle (7) for a nozzle tip (8), which in the form
• FIG. 2 shows that the piston rod (3) of the casting piston is guided by a press cylinder (16), on the outflow side of which a valve (17) is arranged, which is designed as a highly dynamic continuous valve known per se.
• This valve (17) is actuated via a two-stage pilot valve (18) when a corresponding pulse comes from the control device (15).
• the control device (15) is designed as digital control electronics and, for example, the setpoints for six phases of the press-in process, which are provided to produce a specific product, can be stored in it.
• the control device (15) enables real-time control and receives start pulses for this time control on the one hand from the metal sensor (13), but can also receive it from a displacement-dependent scanning device (19), for example as a rotary encoder can be designed and is connected via a suitable device (20) to the plunger of the press cylinder (16) so that its position within the press cylinder (16) can be detected. There is also the possibility of detecting the pressure increase at the nozzle tip by means of a sensor in the hydraulics and thus initiating the signal for the start of the second phase, in which the pressure is increased significantly.
• Both the path-dependent values and the signals of the metal sensor (13) can also be additionally fed to a screen (21) in a manner known per se, which displays a graphic display of the respective Casting parameters enabled.
• the control device (15) can also be connected to a valve (22) which is connected upstream of a vacuum device (not shown) connected downstream of the mold (11) and which can prevent the metal flowing from the evacuated mold into the ventilation channels reaches the vacuum pump.
• the control valve (17) which is installed on the outflow side of the casting cylinder, works in the filling phase as a speed control valve.
• the speed is programmed as a function of the casting piston position and the corresponding actual values can be given on the screen and to the control device via the device (19).
• the continuous valve works as a pressure control valve.
• the corresponding setpoints for distance, speed and pressure are entered into the control device.
• the control device (15) can bring about an exact real-time regulation of the press-in process, which is independent of the bath level inside the tub (1).

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Casting Devices For Molds (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Press Drives And Press Lines (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=6519979

Family Applications (1)

Country Status (7)

Families Citing this family (9)

Family Cites Families (11)

• 1994
  • 1994-06-07 DE DE4419848A patent/DE4419848C1/de not_active Expired - Fee Related
• 1995
  • 1995-05-23 EP EP95920872A patent/EP0714331B1/fr not_active Expired - Lifetime
  • 1995-05-23 ES ES95920872T patent/ES2144612T3/es not_active Expired - Lifetime
  • 1995-05-23 DE DE59508044T patent/DE59508044D1/de not_active Expired - Lifetime
  • 1995-05-23 JP JP50026896A patent/JP3824171B2/ja not_active Expired - Lifetime
  • 1995-05-23 AT AT95920872T patent/ATE190880T1/de active
  • 1995-05-23 US US08/592,348 patent/US5699849A/en not_active Expired - Lifetime
  • 1995-05-23 WO PCT/EP1995/001963 patent/WO1995033588A1/fr not_active Ceased

Non-Patent Citations (1)

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