DE1191522B - Die casting machine with a device for the simultaneous evacuation of the mold cavity and the charging chamber - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

B22d

German class: 31c -26/01

1191522
B63219VI a / 31c
July 11, 1961
April 22, 1965

The invention relates to die casting machines for casting metals under pressure, one at a time Mold cavity and a charging chamber as well as a device for simultaneous evacuation this mold cavity and this charging chamber.

There are already die-casting machines known which have an evacuable mold cavity, the Evacuation takes place via a valve body arranged in a mold half. The batch will in this case fed to the mold cavity via a spray nozzle without the interposition of a charging chamber. This direct feed has the disadvantage that, on the one hand, the entire, in the Melting pot available metal must be put under the high processing pressure and that on the other hand, when the mold cavity is evacuated, the casting compound flows in prematurely in the mold cavity cannot be avoided. In addition, the casting material foams when it enters Mold cavities of these known die casting machines heavily, making the die casting process strong and the quality of the products is deteriorated.

Other known die-casting machines have charging chambers into which the casting charge can be sucked in by pulling back a charging piston. In these known die casting machines however, the mold cavities cannot be evacuated, which affects the quality of the cast parts has a detrimental effect. If there is insufficient evacuation of a mold cavity, in particular at small castings produce undesirable inclusions.

Finally, die-casting machines with a mold cavity that can be evacuated and that can be evacuated are also available Charging chamber known in which a vacuum line provided with a shut-off valve to the Mold cavity is connected. The charging chamber is also located in these known die-casting machines without interposed throttle parts directly on the vacuum pump or an upstream one Recipients, so that the liquid casting material is sucked into the charging chamber very quickly and in doing so strongly foams, billows and splatters. Foaming and spraying in the charging chamber hampers the die casting process very much. In addition, the melt injects into the mold, before the charging piston is moved.

The invention aims to improve and further develop die casting machines, in which the molten casting compound before being pressed into the mold cavity by a die casting machine with a device for
simultaneous evacuation of the mold cavity
and the charging chamber

Applicant:

The British Oxygen Company Limited, London

Representative:

Dipl.-Ing. R. Holzer, patent attorney,

Augsburg, Philippine-Welser-Str. 14th

Named as inventor:

Harold Robert Henry Adams, London

Claimed priority:

Great Britain July 15, 1960 (24 806) -

Crucible is brought into a charging chamber. The aim is to feed the molten Casting compound are controlled so that a surge and splashing of the casting compound, which leads to an undesirable Penetration and premature solidification of the casting compound in parts of the mold cavity could be avoided.

The invention is based on a die casting machine with a device for simultaneous Evacuation of the mold cavity and the charging chamber is equipped, in which liquid metal is sucked out of a crucible, whereby to control the negative pressure in the mold cavity and in the charging chamber and the filling of the charging chamber with liquid metal in one of the mold halves and / or a valve is arranged in the evacuation line or valves are arranged with whose valve body or valve bodies connect the mold cavity to the vacuum source is to be locked. The die casting machine according to the invention is characterized in that the in of the one mold half arranged valve which connects the charging chamber with the mold cavity Supply channel is assigned such that the valve body in its open position with respect to the other mold half forms a narrow channel. According to an advantageous further development of this inventive concept, the

509 540/290

protruding end of a supply line for the fluid around the charging piston 8 leaves free. This sige metal contain a charging nozzle. In addition, circular space 17 is provided with a first sub-can to seal the charging chamber connected to the pressure line 18, which leads to the top Implementation of a charging piston is guided under a horizontal line 19. Latter pressure seal be provided on the penetrating 5 contains a vacuum valve 20, with the help of which the Gases are sucked off. Vacuum system to a vacuum pump 21

According to the invention, the mold cavity will be closed or separated from the same and the charging chamber via the vacuum control can. Between the vacuum pump 21 and the valve evacuated for a specified period of time. A vacuum chamber 22 is located under the vacuum valve 20.

The supply of the molten metal into the io A second vacuum line 33 leads from the hori charging chamber takes place through the negative pressure effect of the zontal line 19 downstream of the negative pressure valve 20 and can according to the invention by the between downwards.

the mold cavity and the charging chamber - two sleeves 23 and 24 are each in a drilling

gene control opening can be influenced. in the fixed and movable form

In detail, the supply of the molten half 2 or 3 is let in, with the sleeves 23 and the metal in the charging chamber being coaxial with the charging chamber 7 through under 24. The first pressure effect of the already mentioned first, between sleeve 23 has the same diameter as the batches of the mold cavity and the charging chamber yaw chamber7 and forms their continuation. At the adjacent control opening and a second, at the end of the sleeve, there is an incision 25, which protrudes into a crucible end of a 20 which continues into the feed channel 6 and provides a feed line for the liquid metal. The incision 25 goes into an inclined exterior controlled opening. Furthermore, an undercavity 26 on the inner surface of the sleeve 23 is above.
pressure seal for sealing the charging chamber. The second sleeve 24 takes a cylindrical one

on the implementation of a valve body 27 in the charging chamber, which for example by displaceable charging piston provided. 35 a mechanical drive or a hydraulic

The vacuum control valve body forms with an actuator 28 can be displaced. Mold half the first control opening when the control Fig. 1 shows the valve body 27 in its open valve in its open state the mold cavity position. When the valve body is closed, lies space and the charging chamber with a vacuum an end surface 30 of the valve body 27 at a source connects. 30 contact surface29 of sleeve24. In the shown in Fig. 1

Details of the invention emerge from the opened position of the valve body 27 The following description of individual embodiments has an end 31 of a vacuum line 32 over the play on the basis of the drawings. It represents the feed channel 6 and the sprue 5 with the

Fig. 1 is a schematic section of a pressure mold cavity 4 and also across the inclined casting machine, 35 cavity 26 of the first sleeve 23 with the charging

2 shows a corresponding section of a wide-chamber 7 connection. The other end of the Unterren Embodiment of a die casting machine. pressure line 32 is to the already mentioned sub-

One recognizes in FIG. 1, a fixed form pressure line 33 is connected. When the valve body plate 1, on which a fixed casting mold per 27 is moved into its closed position, half 2 is attached. Another, in known 40 the end 31 of the vacuum line 32 by the movable mold half 3 works with the walls of the bore in the sleeve 24 closed.
fixed half 2 together. If the two- F i g. 1 shows the individual parts of the die casting

the mold halves 2 and 3 in the machine shown in FIG. 1 according to the invention in their starting position position against each other, leave them between at the beginning of a work cycle. First of all, this will A mold cavity 4, a sprue space 5 and 45 vacuum valve 20 pass through the actuating member 28 a feed channel 6 free. The movable form - opened. Since the lower half in the vacuum line 3 contains the ejection pressure chamber 22 is switched on in a manner known per se, almost arises fixing pins 3 '. immediately in the two vacuum lines 18 and 33

The fixed mold plate 1 takes a cylindrical negative pressure. This will be the one with the second drical, horizontally lying charging chamber 7. 50 vacuum line 33 connected rooms evacuated, Inside the charging chamber 7 there is a charging, namely the mold cavity 4, the charging chamber 7 piston 8 displaceable, which in its output and the supply line 11. The molten Position is drawn. A heatable crucible 9 occurs evenly over the metal without bulging takes the molten metal 10, for example feed line 11 into the charging chamber 7, an aluminum or zinc alloy. The 55 because the molten metal 10 through the on his Melting crucible 9 is below the charging chamber 7 atmospheric pressure acting in the surface arranged and is conveyed with the same through a line 11 charging chamber. The Chargierkam connected, the lower end 12 of which is melted into the mold 7 up to the height of the mold cavity 4 zene metal 10 protrudes and the upward into a leading cavity 26 with molten metal Opening 13 in the bottom surface of the charging chamber 7 60 is filled.

flows out. At the lower end 12 of the feed line feeding the molten metal into the

11 is a nozzle 14 with a control opening to the regulating charging chamber 7 is controlled by the control effect of the adjustment of the flow. inclined cavity 26 controlled so that a

The line 11 can mix from the outside by gas flames or spraying of the molten metal are heated, which are indicated at 15. 65 is avoided, which leads to a premature penetration

In order to seal the implementation of the charging process, the same could lead into the mold cavity 4. The piston 8 in the charging chamber 7 provides a seal. The cavity 26 forms with the valve body 27 processing ring 16, which has a circular space 17 in its open, in F i g. 1 position shown

a control opening, which ensures a uniform evacuation of the charging chamber 7 and the supply line 11 guaranteed. By evacuating the annular space 17 via the first vacuum line 18 a vacuum seal is obtained to seal the feed-through of the charging piston 8 into the charging chamber 7. This vacuum seal prevents air from entering the Charging chamber over the sealing ring 16, since such an ingress of air causes a surge or splashing of the Could cause molten metal fed into the charging chamber 7 via the opening 13.

At the end of the charging period, the movement of the piston 8 is initiated and, at the same time, the valve body 27 is moved into its closed position by the actuator 28, and the Vacuum valve 20 closed. The molten metal is drawn from the piston 8 through the feed channel 6 and the sprue 5 pressed into the mold cavity, so that the desired cast body arises. The movements of the individual parts are controlled in a known manner.

The amount of molten metal fed into the charging chamber 7 depends on the Duration of the evacuation period during which the metal is conveyed into the charging chamber takes place, further on the size of the negative pressure and finally on the size of the control opening in the nozzle 14. The latter can be interchangeable to control the batch. Fine tuning the Charge can then be reached by changing the duration of the evacuation period.

It should be noted that even with a maximum filling of the charging chamber 7, the metal spreads on the bottom of the charging chamber 7 as long as the piston 8 is in its starting position Remains, and that the surface of the supplied metal is not that formed by the cavity 26 Control opening at the upper outlet end of the charging chamber approaches until the piston 8 moves and pushes the molten metal into the mold cavity.

In the exemplary embodiment according to FIG. 2, parts which fulfill the same function are given the same reference numerals as in FIG. 1 referred to. The charging chamber 7 merges into an extension 7 α, which leads to a cylinder Ib immersed in the molten metal 10. The charging piston 8 is shown in its starting position and can be displaced within the cylinder 1b. In this exemplary embodiment, the feed line 11 lies below the surface of the molten metal 10. The end 12 of the feed line 11 allows the molten metal 10 to enter and can be closed by a slide 34 which is displaceable in the sleeve 35. The other end of the supply line opens into an opening 13 in the wall of the cylinder 7 b.

Two sleeves 23 and 24 are also embedded in the two mold halves 2 and 3. The first case 23 has a conical inner bore 37 which forms an extension of the charging chamber 7. A Incision 25 on the sleeve neck establishes a connection to the feed channel 6.

The second sleeve 24 receives the cylindrical valve body 27, which is shown in FIG. 2 in its open End position is shown. The closed end position of the valve body corresponds to that in the context with F i g. 1 described end position. The valve body 27 of FIG. 2 runs at its end 38 conical, this conical end portion 38 of the conical bore 37 of the first sleeve 23 adapted is. However, a narrow connecting space 39 remains free between these two conical shaped parts, when the valve body 27 is in its open end position. The narrow connecting space 39 represents a connection between the charging chamber 7 and the end 31 of the opening in the valve body 27 Vacuum line 32 ago.

Fig.2 shows the individual parts of an injection molding machine in a position at the beginning of a work cycle. First, the vacuum valve 20 is by means of of the actuator 28 is open. As a result of the action of the vacuum chamber 22 arises almost immediately a good negative pressure in the negative pressure line 33. The one with the negative pressure line 33 in connection standing spaces, namely the mold cavity 4 and the charging chamber 7, are evacuated. When the slide 34 is moved upward, the molten metal flows under the action of the the surface of the molten metal contained in the crucible 9 Constant pressure and not rising into the charging chamber 7.

The flow of molten metal into the charging chamber 7 can be controlled so that no bulging or splashing occurs and no molten metal prematurely enters the mold cavity 4 can penetrate. The narrow connecting space 39, which acts as a control opening, is used for control purposes Ensures evacuation of the charging chamber 7.

At the end of the charging period, the slide 34 is lowered so that it is the end 12 of the supply line 11 shut off. The charging piston 8 is set in motion and at the same time the valve body 27 is moved into its closed end position by the actuating member 28, as is the vacuum valve 20 closed. The molten metal is from the piston 8 via the feed channel 6 and the sprue space 5 is pressed into the mold cavity 4, whereby the desired cast body is produced. Even in this embodiment of the invention, the timing of the movements of the various Individual parts in a known manner.

Claims (3)

Patent claims: 1. Die casting machine with a device for the simultaneous evacuation of the mold cavity and the charging chamber, into which liquid metal is sucked from a crucible, whereby to control the negative pressure in the mold cavity and in the charging chamber as well as the filling of the charging chamber with liquid metal in one of the mold halves and / or a valve is arranged in the evacuation line or valves are arranged, with the valve body or valve body of which the connection of the mold cavity with the vacuum source is to be shut off, characterized in that the valve (27 to 31 or respectively) arranged in one mold half (3) . 38) is assigned to the feed channel (6) connecting the charging chamber (7 or 1a, 7b) to the mold cavity (4) in such a way that the valve body (27 or 38) is narrow in its open position relative to the other mold half (2) Channel (26 or 39) forms. 2. Die casting machine according to claim 1, characterized by a charging nozzle (14) at the end (12) of a supply line (11) for the liquid metal which projects into a crucible (9). 3. Die casting machine according to claim 1 or 2, characterized in that on the implementation tion of the charging piston (8) a vacuum seal of the charging chamber is provided. References considered: U.S. Patent Nos. 2837792, 2668985; Precision Metal Molding, June 1959, p. 28 and 1 sheet of drawings 509 540/290 4.65 © Bundesdruckerei Berlin