JPS5956959A - Vacuum die casting device - Google Patents

Abstract

PURPOSE:To prevent the generation of blowholes by sucking beforehand the air from a cavity by a vacuum device, and pressing a molten metal in this state by a punch thereby packing the molten metal into the cavity. CONSTITUTION:A titled device is constituted of a cavity 2 in a die 1, a suction hole 4 communicating with the same, a vacuum pump 24 which sucks air from the cavity 1, a solenoid valve 22 which blocks the molten metal to be fed into the hole 4 from the cavity 2 side by opening and closing the hole 4, a punch 17 which packs the molten metal into the cavity 2, the 1st switch 18 which detects the point of the time when the pressing of the molten metal by the same is started, the 2nd switch 19 which detects the point of the time just before the pressing of the molten metal ends, and a control unit 20 which opens the valve 22 in accordance with the signal of the switch 18 outputted at the point of the time when the pressing of the molten metal is started and closes the valve 22 in accordance with the signal of the 2nd switch outputted at the point of the time when the pressing of the molten metal ends.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an apparatus for die-casting by filling a cavity with molten metal by injecting it through a sprue and using a punch and a vacuum device.

Conventionally, in pre-non-yaar die casting equipment that presses and fills molten metal into a cavity with a punch, when pouring molten metal, the air that enters from the sprue and the air that exists in the cavity becomes bubbles and mixes into the molten metal. , cavities occur in cast products. In order to prevent the formation of the above-mentioned blowholes, the punch can be operated slowly to gradually expel the air present in the cavity and the air that has entered from the sprue from the joint of the mold. However, the casting yield was poor, and the cavities could not be completely removed.

Connect the vacuum device to the cavity via the suction pipe 1
~ There has also been proposed a method in which the cavity is filled with molten metal by applying negative pressure to the cavity, but according to this, the cavity is filled and the molten metal flows out into the suction pipe and then dies. This was a practical problem because it caused clogging of the suction tube.

The purpose of the present invention is to press the molten metal with a punch when the air inside the cavity is sucked in advance by a vacuum device.
In order to eliminate the above-mentioned drawbacks, the above-mentioned drawbacks will be eliminated by filling the cavity with the same material.

The drawing is a simplified configuration diagram showing an embodiment of the vacuum die-casting apparatus according to the present invention, and in the drawing, 1 indicates molds 1a and 11.
) are mutually combined, and the above-mentioned mold 1
a and 11], a cavity 2 consisting of a predetermined molding space is formed. This two-cavity mold 1 communicates with a molten metal inlet 3 and a suction hole 4 formed in the mold 1. The molten metal inlet 3 communicates with the outside outlet 5 (discharge port 8 of the sleeve 7 with sprue 6 at 1111).
The suction hole 4 communicates with a hole 10 that accommodates an off-off pin 9 [7, and one end of the accommodation hole 10 communicates with a suction port 12 side to which a suction pipe 11 is connected. It is driven by and reciprocates inside the hole 10, and when the /-ru portion 13 provided on the tip side moves forward and moves at the position corresponding to the suction hole 4, the When the hole 10 side of the suction hole 4 is closed and the knoll portion 13 moves backward, the suction hole 4 is opened [7, and this suction hole 4 is communicated with the suction pipe 11 through the hole 10 7. become. The air cylinder device 12 is controlled by a solenoid valve 14.

A punch 17 is accommodated in the sleeve 7, and this punch 17 is connected to a rod 16 driven by a hydraulic cylinder device 15, and the tip 17a of the punch 17 is located at a position where six molten metals are opened to the maximum extent. From the side 6a, it passes through the position 61)--(the point at which suppression of the molten metal starts) where the sprue 6 is completely blocked, and moves to the position 6dl where the molten metal completely fills the cavity 2 and the suction hole 4. Two position detection switches 18.19 are arranged along the moving direction of the rod 16, and these switches 18.19 are controlled by a flange 16a provided on the rod 16. &, When the tip 7a of the J-punch 17 completely blocks the sprue 6 at the position 6b-1, the flange 16
a, outputs the position detection signal S1, and the tip 17a of the punch 17 is just before the position 6d where the tip 17a finishes completely injecting the molten metal into the two cavities! When the S'L device 6 is moved, it is turned on by the flange 16a and outputs a position detection signal S. Each of the above signals S, , S, is supplied to the control unit 20 .

The exhaust pipe 11 is connected to a tank 23 via a filter 21 and a solenoid valve 22. The pressure in the tank 231' is constantly reduced by the pump 24.

The electromagnetic valve 22 and the valve 14 are controlled by the outputs Sa and Sb from the control unit 20.

Note that when the reset switch 20a of the control unit 20 is turned on, the solenoid valve 22 is closed, the seal portion 13 of the tip-off pin 9 is opened, and the punch 17 is returned to the state shown in the drawing. The operation starts when the start switch 20b is turned on.

25 id: Detects a failure in the f-7 cylinder device 12,
This is a protective device that displays this and prevents the hydraulic cylinder 15 from operating in the event of a failure.
a switch 26 that responds to the rear end 9a of the shut-off pin protruding from the shut-off pin 9 and turns on when the shut-off pin 9 moves forward and turns off when the shut-off pin 9 moves backward; and a relay coil 28 connected between the switch 26 and a power source 27. The start switch 20 is controlled by the relay coils 28 of and .
+) and a normally open contact 28b connected in series to a confirmation switch 30. When the shutoff pin 9 moves forward and the seal portion 13 closes the suction hole 4, the switch 26 is turned on, so the relay coil 2
8 is excited, and the contact 28a is turned off. Therefore, even if the start switch 20b is turned on L7, the control unit 20 is not driven. When the sole portion 13 opens the suction hole 4, the switch 26 is turned off and the contact 28a is turned on, contrary to the above. For this reason, start switch 2obz. - The control unit 20 is driven by turning on. Normally, when the cylinder device 12 breaks down, the
Even if the valve 147 is controlled and the off pin 9 is moved back, the off pin 9 does not move back and the suction hole 4 remains closed. At this time, when the hydraulic cylinder device 15 is driven and the punch fills the molten metal, air is present in the cavity 2, so air bubbles are generated in the molten metal, resulting in the production of a defective cast product. Therefore, in such a case, even if the 1d scooter tip 20b is turned on, the hydraulic cylinder device 15 will not operate, thereby preventing the production of defective products. Lamp 29 makes a complete judgment as to whether the air/cylinder device 12 operates or not.With the confirmation switch 3o turned on, turn on and off the valve 14 to drive the cylinder device J2, and move the cylinder off pin 9 back and forth. Since the 77 button 29 lights up each time the movement bolt and the shutoff pin 9 move forward, it can be confirmed that the cylinder device 29 is operating normally.

The entire operation of vacuum die casting with the above configuration will be explained below.

The vacuum pump 2o is driven once in advance to reduce the pressure in the tank 23. First, molten metal is poured from the sprue 6 and then poured into the sleeve 7.

Next, the reset switch 20a is turned on, the off-pin 9 is moved back, the suction hole 4 is opened, and the solenoid valves 22 are closed. Next, when the start switch 201 is turned on, the opening side) unino
, move the injection port forward in three directions. Tip 17a of punch 17
When reaches the position 6b, the switch 18 is turned on, so the control unit yh 20 opens the solenoid valve 22 to open the cavity 2.
When the air in the suction hole 4 is sucked, the punch 17 starts pressing the molten metal, and as the punch 17 moves forward, the molten metal is pressed and filled into the cavity 2 and the suction hole 4. When the tip 17a of the punch 17 reaches the position 6dK, the cavity 2 and the suction hole 4 are completely filled with the molten metal. When punch 17 reaches position 6cVC, switch 1 is pressed.
9 is turned on, the control unit 20 outputs a signal Sa to close the solenoid valve 22, and also outputs a signal Sb to control the valve 14, and moves the off pin 9 forward to enter the collection hole 10 by the seal part 13. Completely fill the suction hole 4 without leaking. ftYi, the molten metal is separately stopped at the exit of the suction hole 4 by the seal part 1:3, and is filled into the cavity 2 and the suction hole 4 at a predetermined ratio. After filling the molten metal, open the mold 1a, 11) and fill the cavity 2.
The casting inside can be taken out.

According to the device according to the present invention, since the air inside the cavity 2 is filled with molten metal, no air bubbles are generated in the molten metal, thereby preventing the formation of cavities in the cast product. It is possible to obtain high quality castings.

In addition, when filling the above cavity with molten metal, punch 1
7 can be moved at high speed and filled from 7,
Filling can be performed reliably and in a short time, and the casting yield can be improved. Further, the solenoid valve 22 is opened by the switch 18 which detects the point in time when the pressing by the punch 17 begins, and the solenoid valve 22 is closed by the switch 18 which detects the point in time when the suppression starts to end. , and the pump 24 can be omitted from unnecessary operations.

In addition, when the set amount of molten metal is filled into the cavity 2, the shirt off pin 90 and the sole opening 13 close the suction port 4, so that only the required amount of molten metal is supplied, thereby preventing loss of molten metal. The molten metal flows through the hole 10 and the suction pipe 11 (
It is possible to prevent 1] 2 from leaking to i]ll. It's ox.
The protection device causes the shutoff pin 9 to close the suction hole 4 to prevent the inside of the gap from being filled with molten metal.
”-shi, it is possible to prevent the occurrence of defective products. It is possible to check whether the cylinder device 12 is operating properly using indicators such as the lamp 29, and maintenance and inspection of the device can be carried out smoothly.

[Brief explanation of the drawing]

The drawing is a simplified configuration diagram showing an embodiment of a vacuum die casting apparatus according to the present invention. ■Mold, 2 Cavity, 3 Inlet, 4 Suction hole, 6 Sprue, 7 Sleeve, 9 Shut-off pin, 10 Hole, 11 Suction W, 15 Air/linda Device, 17... Punch, ]-8, 19 Suinochi, 2
0...! ti control unit, 22... solenoid valve, 23.
Tank, 24-3'j, empty pump. Patent IQl'1 Person Nissin Kogyo Co., Ltd. agent Patent attorney Jun- Procedural amendment 2 Title of the invention Vacuum die-casting device 3 Supplementary relationship with the person doing the process Patent applicant 4, agent 297-

Claims (1)

[Claims] A cavity provided in the mold, an air intake hole communicating with this cavity, a vacuum device that sucks air in the cavity through this air intake hole, and a vacuum device that opens and closes the air intake hole to send air from the cavity side to the air intake hole. an opening/closing valve mechanism that prevents the molten metal from reaching t, a punch and a drive device that pressurize and fill a certain amount of molten metal into the cavity, a first switch that detects when the punch starts suppressing the molten metal, and a first switch that detects when the punch starts suppressing the molten metal; a second switch for detecting a point immediately before the end of suppression of the molten metal;
The on-off valve mechanism is opened based on a signal from the first switch that is output at the time when suppression of the molten metal starts, and the on-off valve mechanism is opened based on a signal from the second switch that is output at a time immediately before the end of suppression of the molten metal. A vacuum die casting apparatus comprising: a closing control unit; and a protection device that detects the operation of the opening/closing valve mechanism and controls the punch driving device or the display state of a safety indicator.