EP1153680B1 - Process and apparatus for supplying mold-release agent to a die casting machine - Google Patents

Abstract

Process for feeding a separating agent into casting mold (1, 2) having a casting chamber (3) and a ventilating channel and into the casting cylinder (5) of a pressure casting machine comprises injecting the agent into the mold via a channel and additionally sucking the agent via an opening (8) arranged in the casting cylinder. An Independent claim is also included for a pressure casting machine. Preferred Features: The separating agent is a powder or a liquid.

Description

The invention relates to a method for entering a release agent in a Die casting machine according to the preamble of claim 1 and a die casting machine to carry out the process.

WO-A1-9301910 discloses a method for operating a die-casting machine known, located in the reservoir in a molten metal In metered quantity passes into a casting cylinder and from there by means of a Casting piston is pressed into a mold cavity. After a selectable number of casting cycles, the supply of the molten metal to the casting cylinder or Filling chamber interrupted, after which via injection means, the casting cylinder in the Area associated with a molten metal filling opening of the casting cylinder, a cleaning of the molten metal filling opening and a gassing of the cylinder and the mold cavity for the purpose of cleaning and / or release coating can be introduced. The mold is provided with a vent channel, over the during casting of the molding in the mold cavity existing air can flow out.

However, if more complicated shapes need to be cast, it is not secured that the cleaning or separating agent Also, all parts of the mold cavity achieved, so that the cleaning imperfect is and the sprue is difficult to solve. Another disadvantage is in that a powder is used as release agent and residues of this powder after opening the mold as a powerful cloud affect the environment.

A similar method is known from DE-A1-35 18 635, in which additionally during the injection process for the sprue in the mold cavity Existing air is sucked through the vent channel.

From EP-A1-0 983 812 a method for the application of a separation or Lubricant known on the surface of a casting piston and / or the Inner wall of a casting chamber, a pouring channel and / or a mold cavity a die casting machine is given. This is the separation or Lubricant evaporates outside the die casting unit and this substance is added closed mold passed into the die casting unit. It is then waited until this substance condenses on the said surface before the casting process can start. This substance consists of one or more substances, their respective evaporation temperature higher than the temperature of surface is mentioned. The vaporized separating or lubricant occurs in the casting cylinder and is at the same time by means of a venting channel aspirated connected vacuum system. A similar procedure is known from DE-A1-199 06 770. The distribution of the separating agent or lubricant However, in the casting cavity is in these two known methods imperfect.

By DE-A1-38 42 720 is also a device for aspirating Pollutants known by casting machines for metal parts, which is a the casting machine Having shielding against the environment air barrier. Compressed air nozzles and suction openings of this device are close to the opening gap adapted to the mold halves and are only during opening hours the mold halves activated. This device constitutes a considerable, additional effort for the casting machine and does not stop all pollutants from away from the surroundings.

By EP 0 230 660 is also an injection molding according to the preamble of claim 1, wherein a casting machine with a fixed Mold half and a movable mold half is used. In the movable mold half is arranged an ejector pin which the solidified molding ejects. The release agent is over a sprue supplied, which connects the casting mold space with the injection cylinder. For the Release agent injection may additionally also use an injection channel be provided in particular in the ejector.

The object of the invention is a method that in the preamble of Claim 1 type to create, with the addition of an environmentally friendly Disposal of the release agent better distribution of the release agent under Low material and cost is possible.

This object is achieved with the features of claim 1.

By entering the release agent via a special channel, for example runs approximately in the middle of a mold half, and the suction operation of the release agent at at least two different locations of the casting mold space a better distribution of this agent in the casting mold space is achieved, so that the amount required for a release agent injection can be reduced can. At the same time excellent lubrication of the casting cylinder and the pressure piston, since the release agent also acts as a lubricant.

According to a further embodiment of the invention is a powdery or liquid release agent used. In particular, the use of a liquid Release agent already leads to the fact that when you open the mold halves the Smoke caused by the burned release agent is low. The powdery or liquid release agent mainly carries for cooling the mold, while with the highly heated release agent as in the EP-A1-0 983 81 the mold in the course of the casting operation to impermissible Temperatures threaten to heat up. The temperature of the mold should but under be kept about 200 ° C. The cooling problem is thus reduced if that Release agent is injected in the form of aqueous suspensions. As a result of high evaporation enthalpy of the water, the mold is cooled so far, that in conjunction with an internal, practice-standard casting cooling at simple parts the mold temperature can be kept in the desired range. An interruption of the casting process for introducing an external coolant is ideally not necessary. The amount of injected release agent could therefore also within certain limits to the regulation of Mold temperature can be used.

In order to improve the distribution of the release agent, takes place according to a further training of the process the suction also over additional Suction ducts, on the one hand in the mold cavity and on the other hand in the vent channel lead.

Alternatively, according to another embodiment of the method, the Extraction of the release agent made via special suction channels become.

The invention also proposes a die casting machine for carrying out the Method before, in which the special injection channel closable by means of a valve is. This avoids that in this injection channel casting material can penetrate.

The invention also proposes a die casting machine for carrying out the Method before, in which the special injection channel axially into the casting mold space is guided channel, which is arranged in the stationary mold half. This axial injection channel may be alone or in addition to a radial injection channel be provided and improves the distribution of the release agent.

According to a further advantageous embodiment of the invention, the axial Injection channel formed with an injection device consisting of a cylinder-piston unit and a nozzle head in communication with the piston consists.

According to a further embodiment of the invention, the connection of the Piston with the nozzle head via a nozzle head holder into which the nozzle head exchangeable is inserted. Therefore, depending on the type of mold cavity different length nozzle heads used or the nozzle heads for cleaning be replaced.

According to a further expedient embodiment of the invention, the nozzle head formed as a cylindrical part, which at one end of a Ring flange for insertion into the nozzle head holder and at its other end Having associated with the injection channel in communication, radial nozzle channels.

According to a further embodiment of the invention, all suction channels are over and the same filter connected to a vacuum source. This will be are derived from the casting particle away from the vacuum source held.

Fig. 1

eine schematische Ansicht einer Druckgießmaschine zur Erläuterung des Verfahrens gemäß der Erfindung,

Fig. 2

eine Draufsicht auf eine Gießformhälfte mit Absaugkanälen der Druckgießmaschine nach Fig. 1,

Fig. 3

einen Vertikalschnitt durch einen Teil der orrtsfesten Gießformhälfte und eine Einspritzvorrichtung zur axialen Trennmittelzuführung zum Gießformraum,

Fig. 4

eine Stirnansicht einer Zylinder-Kolben-Einheit der in Fig. 3 gezeigten Einspritzvorrichtung,

Fig. 5

einen Schnitt längs der Linie V-V in Fig. 4,

Fig. 6

einen Schnitt längs der Linie VI-VI in Fig. 4,

Fig. 7

eine Stirnansicht eines Düsenkopfhalters der Einspritzvorrichtung der Fig. 3,

Fig. 8

eine Seitenansicht des Düsenkopfhalters der Fig. 7,

Fig. 9

eine Stirnansicht eines Düsenkopfs der Einspritzvorrichtung der Fig. 3 und

Fig. 10

einen Vertikalschnitt durch den Düsenkopf der Fig. 9.

The invention will now be explained in more detail with reference to exemplary embodiments. Show it:

Fig. 1

a schematic view of a die casting machine for explaining the method according to the invention,

Fig. 2

1 is a plan view of a mold half with suction channels of the die casting machine according to FIG. 1,

Fig. 3

FIG. 2 a vertical section through part of the fixed mold half and an injection device for the axial release agent supply to the mold cavity, FIG.

Fig. 4

an end view of a cylinder-piston unit of the injection device shown in Fig. 3,

Fig. 5

a section along the line VV in Fig. 4,

Fig. 6

a section along the line VI-VI in Fig. 4,

Fig. 7

an end view of a nozzle head holder of the injection device of FIG. 3,

Fig. 8

a side view of the nozzle head holder of Fig. 7,

Fig. 9

an end view of a nozzle head of the injection device of Fig. 3 and

Fig. 10

a vertical section through the nozzle head of Fig. 9.

In the figures 1 and 2 are of the die casting machine only those for the invention essential parts shown. Two mold halves 1, 2 close one Mold cavity 3, which receives the molten metal and the shape of the molding certainly. The mold half 1 is movable while the mold half 2 is stationary.

The casting mold space 3 is above pouring channels 4 with a through the mold half 2 guided casting cylinder 5 in conjunction, in which a pressure piston 6 is arranged is. The casting cylinder 5 is provided with a rotatable locking ring 22 provided, which has a pouring opening 7, via which a metered amount of Molten metal in the casting cylinder 5 can be entered. The casting cylinder points Furthermore, a suction opening 8, which can be closed by the locking ring 22 is. The locking ring 22 can on the other hand by rotation a connection between the suction opening 8 and a connected to the lock ringn Make suction pipe 9.

The casting mold space 3 is on the other hand formed in the mold half 1 special suction channels 10, 11, via a vent channel 12 and over a in both mold halves 1, 2 formed, so-called washboard 13 with a filter 14 in connection, to which a vacuum source, not shown connected. The suction channels 10, 11 open on the one hand to ge suitable places left and right of the vent channel 12 in the mold cavity 3 and on the other hand in the vent channel 12. These suction channels have while an approximately meander-shaped structure, so that the penetrating molten metal can cool down quickly. About these suction channels is also the release agent distributed in the casting space 3. The washboard 13 is used for fast Cooling of the rising molten metal and guarantees a flawless Formation of the molding, while the filter 14 resulting from the casting process Keep particles away from the vacuum source. To the filter 14 is also the Suction tube 9 connected. The control for the vacuum source is not shown. It is only a valve 15 shown, the suction before the Filter 14 can interrupt.

Furthermore, opens laterally into the mold cavity 3 in the mold half 1 a special injection channel 16, to the outside of a separating agent container 17 via a solenoid valve 18 and a metering container 19 is connected. At this Dosing is a solenoid valve 20, a compressed air source, not shown connected. The injection channel 16 can be closed with a valve 21 become. The release agent in the release agent container is preferably liquid.

A release agent injection cycle proceeds as follows, with the individual Operations are effected by a control device, not shown. First, the mold 1, 2 is closed and the pouring opening 7 by means of Lock ring 22 closed. The injection channel 16 is by means of a channel closure pin the valve 21 is closed. The solenoid valve 18 then opens for a given time interval, leaving a certain, relative small amount of release agent in the dosing 19. The valve 21st then opens for a given time interval. At the same time it opens Solenoid valve 20 corresponding to a predetermined time interval, so that in the Dosierbehälter 19 existing release agent via the injection channel 16 in the Gießformraum 3 passes. About 0.2s after that, a vacuum valve opens at the Vacuum source for a given time interval, the injected Release agent under swirling on the one hand via suction channels 10, 11, 12 and the washboard 13 and on the other hand is sucked through the suction pipe 9. The Release agent is by atomization (aerosol formation) on the wall in Mold cavity 3 evenly distributed and cools the mold. Then can the pouring 7 are opened and start the casting process.

Since the release agent is sucked through the suction pipe 9, casting cylinders 5 and pressure piston 6 lubricated excellent. There will be a good lubrication and good demolding, a reduction in environmental impact, an improvement in the working environment and a low release agent consumption reached.

Also conceivable are instead of the suction channels 10, 11 suction channels that are not in lead the vent channel 12, but separated from the mold half. 1 led out and then connected via its own filter to the vacuum source are. These channels may conveniently also each by means of a be closed at their mouths in the mold cavity acting valve so that no molten metal, but only the release agent in these channels can penetrate.

In the same way is the injection and the suction of a cleaning agent possible.

As indicated in Fig. 2, the injection of the release agent over a special, axially into the mold cavity 3 leading injection channel 22nd take place, which is arranged in the stationary mold half 2. This release agent injection can alone without the injection channel 16 or in addition to Injection channel 16 done. Figures 3 to 10 show how one for such Separating agent injection necessary injector formed by way of example can be.

According to Fig. 3, a cavity 23 is provided in the injection mold half 2, in which an injection device 24 by means of screws, such as the screw 25, attached is. The injection device 24 consists of a cylinder-piston unit with a cylinder 26 and a piston 27 and a nozzle head 28 and a nozzle head holder 29. The nozzle head holder 29 is in the left end of the Piston 27 is screwed and takes the nozzle head 28 interchangeable. The Control of the piston 27 is carried out in a conventional manner hydraulically via a indicated connection 30 and is not shown in detail. The adjustment of the Piston 27 is only a few millimeters. The injection channel 22 is axial bores through the nozzle head 28, the nozzle head holder 29 and formed the piston 27 up to a release agent connection 31, wherein the Release agent supply to this release agent connection 31 is not shown. The time sequences of the release agent injection via the injection channel 22 take place in a similar manner, as already with reference to Figures 1 and 2 for the injection channel 16 has been described.

The individual parts of the injection device 24 are shown in FIGS. 4 to 10 shown enlarged.

The cylinder-piston unit shown in Figures 4 to 6 has a cylinder 26 with two flanges 33, 34, each with three mounting holes, such as the mounting hole 35 on. By means of these fastening holes plugged screws, such as the screw 25 (FIG. 3), the cylinder-piston unit 26, 27 can be fastened to the mold half 2.
The cylinder 26 has not shown channels 30 'for the piston control. The piston 27 has a coaxial with the injection channel 22 guided threaded bore 36 for screwing the nozzle head holder 29.

The nozzle head holder 29 shown in FIGS. 7 and 8 consists of a essentially cylindrical part 37 and a coaxially aligned with this Threaded stub 38 for screwing into the threaded hole 36 (Fig. 5). The part 37 has the front side an upwardly open, U-shaped recess 39, to the threaded stub 38 towards a wider, upwardly open, U-shaped Recess 40 connects. Both recesses 39, 40 are used for Inserting and receiving the nozzle head 28 from above. At the bottom of the Part 37 is a small hole 41 is provided, which is not for receiving a serves shown locking pin.

The nozzle head 28 shown in Figures 9 and 10 has a cylindrical Part 42 and an annular flange 43, located at the right end of the part 42nd located. The annular flange 43 has an annular groove 44 for insertion of a front side not shown O-seal, the sealing of the injection channel 22 on the part 37 serves. The annular flange also has a semicircular recess in the lower region 45 for the rotationally secure locking of the nozzle head 28 on the nozzle head holder 29 by means of said locking pin. At the left end of the Part 42 of the injection channel has connection with four radial nozzle channels, such as the nozzle channel 46. These nozzle channels are 27 with retracted piston closed by the mold half 2 and with extended piston 27 for Mold cavity 3 open.

Claims (10)

1. Method for feeding a releasing agent into a mould assembly (1, 2), which includes a mould assembly chamber (3) and a ventilation duct (12), and into the mould cylinder (5) of a pressure moulding machine, where air is sucked out of the mould assembly (1, 2) via the ventilation duct (12) during the moulding operation for the injection-moulded component and where the releasing agent is injected into the mould assembly (1, 2) between such moulding operations, and means are provided for sucking out the releasing agent, wherein the separating agent (17) is injected with the mould assembly (1, 2) closed and at the same time this agent is sucked out of the mould assembly chamber (3) via the ventilation duct (12), characterised in that the releasing agent is injected via a specific duct (16), which is disposed in the mould assembly, and the releasing agent is sucked out in addition via an opening (8), which is disposed in the mould cylinder.
2. Method according to claim 1, characterised in that the separating agent (17) is powdery or liquid.
3. Method according to claim 1 or 2, characterised in that the sucking out is effected via additional suction ducts (10, 11), which on one side terminate into the mould assembly chamber (3) and on the other side terminate into the ventilation duct (12).
4. Method according to one of claims 1 to 3, characterised in that the agent is additionally extracted via specific suction ducts.
5. Pressure moulding machine for the accomplishment of the method according to one of claims 1 to 4, characterised in that the specific injection duct (16) is closable by means of a valve (21).
6. Pressure moulding machine for the accomplishment of the method according to one of claims 1 to 4, characterised in that the specific injection duct is a duct (22) which is guided axially into the mould assembly chamber and is disposed in the fixed mould assembly half (1).
7. Pressure moulding machine according to claim 6, characterised in that the injection duct (22) is formed with an injection apparatus (24), which is produced from a cylinder-piston unit (26, 27) and a nozzle head (28), which communicates with the piston (27).
8. Pressure moulding machine according to claim 7, characterised in that the connection between the piston (27) and the nozzle head (28) is effected via a nozzle head holder (29), into which the nozzle head (28) is insertable in a replaceable manner.
9. Pressure moulding machine according to claim 8, characterised in that the nozzle head (28) is in the form of a cylinder-shaped part (42), which has at its one end an annular flange (43) for inserting into the nozzle head holder (29) and at its other end radial nozzle ducts (46), which communicate with the injection duct (22).
10. Pressure moulding machine according to one of claims 5 to 9, characterised in that all the suction ducts (9 -13) are connected to a vacuum source via one and the same filter (14).

Images