JPH0413463A - Temperature control method and device for casting die - Google Patents

Abstract

PURPOSE:To improve the heat exchange rate with a die by feeding a fixed volume of the cooling water in a tank by high-pressure air into a cooling hole to cool the die, thereby assuring the effective contact with the inner peripheral surface of the cooling hole while destroying steam films. CONSTITUTION:The fixed volume of the cooling water is stored in the cooling water tank a1 by a liquid level sensor 5 and the closing operation of an air discharge solenoid valve 16 and is pressurized and held by the opening operation of a high-pressure air supplying solenoid valve 15. The fixed volume of such cooling water is supplied into the cooling hole 1 of the die B by the high- pressure air at every casting shot of a die casting machine. The cooling water comes into contact with the inner peripheral surface of the cooling hole 1 while destroying the steam films generated on the inner perpheral surface to surely deprive the die B of its heat, thereby enhancing the cooling effect of the die B. The high-pressure air is successively fed into the cooling hole 1 to rapidly extrude and discharge the cooling water remaining in the cooling hole 1 to the outside of the cooling hole 1 when the supply of the fixed volume of the cooling water in the storage tank a1 ends. The temp. drop of the die B by the remaining of the cooling water is thus prevented.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method and device for controlling the temperature of a casting mold used for aluminum die casting, etc., and more specifically to a method and device for controlling the temperature of a casting mold used for aluminum die casting, etc. The present invention relates to a method and apparatus for cooling and controlling the temperature of a mold that is heated up by high heat.

<Prior art and problems> In general, mold temperature cooling control uses a reciprocating cooling pipe that is inserted into the cooling hole of the mold and has an outward circulation path and a return path. The product material molten metal filled in the mold cavity, such as aluminum (AA') molten metal, is cooled down to its solidification temperature by being heated by the high heat of the molten metal, and the temperature of the mold is increased. The temperature of the rising mold is controlled by cooling it.

However, in the conventional method, even after the molten metal has solidified, that is, after the product has been removed from the mold, the cooling water remains in the cooling hole, so the mold is heated by the cooling water remaining in the cooling hole. As a result, the mold cools down more than necessary, which hinders the flow of molten metal in the mold cavity during the next casting shot, and causes problems such as molten metal wrinkles and shrinkage cracks. There is a risk that defects will occur more easily and the number of defective products will increase.

In addition, mold protrusions on the cavity surface such as core pins that receive a large amount of heat from the filled molten metal and are easily overheated to high temperatures (
Inner circumferential surface (large surface) of the cooling hole in the case of a protruding part
A vapor film (gas film) is formed on the surface of the product, and this vapor film prevents the cooling water from coming into contact with the inner circumferential surface, preventing effective cooling and causing problems such as seizing and galling of the product due to overheating. It was something that could not be prevented.

However, in the conventional method, the supply pressure of cooling water into the cooling hole is a low pressure (water pressure) of about 1 to 3 kg1/cffl.
Since the cooling process is carried out in a vacuum, it is not possible to destroy the steam film that forms between the inner peripheral surface of the cooling hole and the cooling water, resulting in problems such as seizure.

<Problem to be solved by the invention> The present invention has been made in view of the above conventional circumstances, and the technical problem to be solved is to supply a fixed amount of cooling water to the cooling holes for each casting shot. In the cooling section (high-temperature overheating section) where a vapor film that inhibits cooling is generated during feeding, the cooling effect is enhanced while destroying the vapor film, and the cooling control is ensured. It is an object of the present invention to provide a temperature control method and device which achieve equilibrium maintenance of the mold temperature by discharging cooling water from the cooling hole after the completion of solidification to prevent the mold from becoming too cold.

<Means for Achieving the Technical Problem> The technical means taken by the present invention to achieve the above-mentioned problem is to store a fixed amount of water in a cooling water storage tank for each casting shot, and to use a fixed amount of cooling water in the tank. This is a temperature control method in which high-pressure air is sent into the cooling hole, and when the constant supply of cooling water is finished, the high-pressure air that flows into the cooling hole is used to discharge the cooling water from the cooling hole to the outside. A cooling water storage tank that stores a fixed amount of cooling water using a sensor and holds the stored fixed amount of cooling water under pressure, and a cooling water storage tank that is equipped with a check valve and branched piping from the cooling water storage/supply port provided at the bottom of the storage tank. A cooling water supply line equipped with a cooling water supply solenoid valve and a high pressure air supply line and an air discharge solenoid valve branched from the air supply and discharge port provided at the top of the storage tank and equipped with a high pressure air supply solenoid valve. It consists of an air discharge line equipped with a

<Example> An example of the implementation of the present invention will be described below. FIG. 1 is a circuit diagram of a temperature control device A that implements the temperature control method of this example, in which a indicates a cooling water storage tank;
2 is a cooling hole 1 for external water or mold B in the storage tank a1.
A cooling water storage line that stores (supplies) return water from
3 is a cooling water supply line that sends the cooling water stored in the storage tank a to the cooling hole 1, a4 is a high pressure air supply line that sends high pressure air to the storage tank a1, and a5 is a line that discharges the air in the storage tank a1 to the outside. This is an air discharge line for (discharging) the external water or return water for each casting shot, while storing a certain amount in the cooling water storage tank a, and pumping the internal amount of cooling water into the cooling hole 1 by high pressure air. Continuing to supply the fixed amount of cooling water, the cooling hole 1 is
The temperature of the mold B is controlled by flowing high-pressure air into the mold B and exhausting the residual cooling water in the cooling holes 1 to the outside.

The above-mentioned cooling water storage tank a is a pressure-resistant tank having a desired internal volume, and has a cooling water storage/supply port 2 at its lower part, an air supply/discharge port 3 at its upper part, and further has a side wall of tank a1. is equipped with a liquid level gauge 4 extending over approximately the entire length (total height) and a liquid level sensor 5 which can be moved up and down, and a cooling water storage line a is connected from the cooling water storage and supply port 2 to
2 and the cooling water supply line a3 are branched,
A high pressure air supply line a4 and an air discharge line a are branched from the air supply/discharge port 3.

The liquid level sensor 5 is for quantitatively controlling the storage amount of external water or return water, so-called cooling water, which is stored in the cooling water storage tank a1 for each casting shot by the cooling water storage line a2. In the example, the liquid level gauge 4
The liquid level gauge 4 is equipped with an optical sensor, a magnetic sensor, etc., which has a function of electrically or mechanically detecting the rising approach of the float 6, which moves up and down according to the change in the amount of stored cooling water in the tank a1. Alternatively, it can be attached to the storage tank a and mounted on the side of the liquid level gauge 4 so as to be vertically movable.

The cooling water storage line a2 is a line for feeding and storing cooling water at a desired water pressure into the cooling water storage tank a1 for each casting shot, and one end thereof is connected to the cooling water storage/supply port 2 of the storage tank a1. A cooling water intake locoupler is connected at the other end to an external water source such as tap water or industrial water or a return water source such as a return water storage tank that circulates and stores the return water from the cooling hole 1 via a connecting hose or the like. -7,
Further, a check valve 8 for preventing backflow due to high pressure of the cooling water inside the storage tank a is connected and provided in the middle of the piping.

The cooling water supply line a3 is a line that sends a fixed amount of cooling water stored in the cooling water storage tank a1 and kept under pressure by supplying high-pressure air to the cooling hole 1 with the high-pressure air supplied in the tank a1, One end of the cooling water storage line a2 is connected to the cooling water storage/supply port 2 of the storage tank a to form a branch pipe, and the other end is a cooling pipe C inserted into the cooling hole 1 of the mold B. Cooling water circulation population 9
A cooling water supply port coupler 10 is provided for connection via a connection hose or the like, and a cooling water supply port coupler 10 is provided in the middle of the piping.
A check valve 11, a cooling water supply solenoid valve 12, and a flow rate adjustment valve I3 are connected and arranged in order from the side, and the storage tank a is connected by the opening operation of the cooling water supply solenoid valve 12 and the high pressure air supply line a4.
A fixed amount of cooling water in the tank a1 is sent and supplied to the cooling hole 1 of the mold B by air pressure applied in the tank a1.

The high-pressure air supply line a4 is locally superheated by the heat from the molten product material filled in the high-pressure air mold cavity created by an air generation source such as a compressor, and is connected to the inner peripheral surface of the cooling hole 1 and the cooling water. 6 to 7 kg of high-pressure water is used to break down the vapor film (gas film) that forms between
This is a line that sends high-pressure air of 1/Ci or more into the storage tank a1. One end of the line is connected to the air supply/discharge port 3 of the storage tank a1, and the other end is connected to a connecting hose (pressure resistant hose) across the air generation source. ), and a high-pressure air supply solenoid valve 15 is further connected in the middle of the piping.

The air discharge line a is connected to the high pressure air supply line a4, which is used to collect 6 to 7 kg1/c added into the storage tank a1.
This is a line that releases the air in the tank a1 to the outside so that the high pressure area above i is lower than the inflow water pressure area of the cooling water stored in the storage tank a1 through the cooling water storage line a2, and one end of the line is connected to the high pressure A branch pipe is connected to the air supply line a4 from the air supply/discharge port 3 of the storage tank a1, the other end is open to the outside, and an air discharge solenoid valve 16 is connected to the middle of the pipe.

In addition, the above-mentioned liquid level sensor 5, cooling water supply solenoid valve 12,
The high-pressure air supply solenoid valve 15 and the air discharge solenoid valve 1 are electrically connected via a control unit (not shown), and are operated at the operation timing and operation time set in advance to the control unit. A fixed amount of cooling water is stored in the cooling water storage tank a, and 6 to 7 kg1/ci of cooling water is stored in the tank a1.
The above-mentioned pressurization is maintained, a fixed amount of cooling water is supplied to the mold B cooling hole 1, and high-pressure air is sent.

Specifically, when storing a fixed amount of cooling water in the cooling water storage tank a1, the cooling water supply solenoid valve 12 and the high pressure air supply electrode valve 15 are kept closed, and the air discharge solenoid valve 16 is kept open. The cooling water intake coupler is closed or opened according to the output signal from the control unit so that the
Cooling water is supplied from the cooling water storage tank a1 through the cooling water storage line a2 and is stored in the cooling water storage tank a1 up to the height where the liquid level sensor 5 is installed, and as the float 6 approaches the rising position, the liquid level sensor 5 operates for detection. As a result, a closing operation signal is output from the control section to the air discharge solenoid valve 16, and the solenoid valve 16 is brought into a closed state, and the storage tank a is closed.

A predetermined amount of cooling water is stored in the tank.

When a certain amount of cooling water is stored in the cooling water storage tank a1 by the water storage control operation and the air discharge solenoid valve 16 is closed, an opening operation signal is output from the control section to the high pressure air supply solenoid valve 15, and the solenoid valve 15 is closed. The valve is open and the storage tank a
1 is supplied with high pressure air of 6 to 7 kg1/ci or more from the air intake coupler 14 and sent through the high pressure air supply line a4.
It is pressurized and maintained at a pressure of ~7 kg1/cd or more.

A fixed amount of water is stored in the cooling water storage tank a1 and 6
When supplying cooling water held at a pressure of ~7 kg1/cnf or higher to the cooling hole 1 of mold B, the control unit receives a high-speed injection signal output from the control panel (not shown) of the die-casting machine. When input (received), an opening operation signal is output from the control unit to the cooling water supply solenoid valve 12, the solenoid valve 12 becomes open, and the cooling hole 1 is injected with a pressure of 6 to 7 kg1/cnf or more. A fixed amount of cooling water is supplied to 6-7
High-pressure air flows into the cooling hole 1 at a pressure of kg1/ci or more, and after a fixed amount of cooling water is supplied from the cooling hole 1, the remaining cooling water is discharged to the outside. In this case, the high-pressure air supply solenoid valve 15 is kept open to continuously supply high-pressure air to the cooling water storage tank a1, and the remaining cooling water after the fixed amount of cooling water is supplied to the cooling hole 1 is removed from the outside. After the set time elapses, the cooling water supply solenoid valve 1
2, the valve is closed by the output of a closing operation signal from the control section.

Next, according to the temperature control method using the temperature control device A configured as described above, the liquid level sensor 5 and the air discharge solenoid valve 16 are
A fixed amount of cooling water is stored in the cooling water storage tank a1, which is stored in a fixed amount by the closing operation of the tank a1, and which is kept under pressure of 6 to 7 kg1/a (or more) by the opening action of the high-pressure air supply solenoid valve 15. A fixed amount is supplied to the cooling hole 1 of the mold B, and while breaking the vapor film generated on the inner peripheral surface of the cooling hole 1, it contacts the inner peripheral surface and reliably removes heat from the mold B, which has been superheated to a high temperature. After increasing the cooling effect of mold B, and after supplying the internal amount of cooling water to storage tank a, continue from 6 to 7
kg Ila! The above high-pressure air is sent into the cooling hole 1, and the cooling water remaining in the cooling hole 1 is quickly pushed out and discharged to the outside of the cooling hole 1, thereby preventing a drop in the temperature of the mold B due to the remaining cooling water.

In addition, the return water returned from the cooling water circulation outlet 17 of the cooling pipe C as the fixed amount of cooling water is supplied to the cooling hole 1 in the cooling water storage tank a1 is returned to the return water storage tank etc. in the same manner as a well-known cooling control device. You are free to reuse it or discharge it outside.

Furthermore, the temperature control device A of this embodiment is connected and incorporated into a part of a well-known cooling control device and is used for local cooling to control cooling of only several cooling holes 1 in a large number of cooling holes 1. Of course, it is also free to use it alone as a device for controlling cooling of several cooling holes 1.

<Effects of the Invention> Since the present invention is configured in a diagonal manner, it exhibits the following effects.

■ A fixed amount of water is stored in a cooling water storage tank for each casting shot, and a fixed amount of cooling water is supplied to the tank using high-pressure air to break the vapor film (gas film) formed on the inner peripheral surface of the cooling hole. Since the mold is cooled by sending high-pressure air of 6 to 7 kgf/cm or more into the cooling hole as described above, the amount of cooling water for each casting shot can be controlled uniformly under the same cooling conditions. It can be fed into the cooling hole by supply, and in the cooling part (high temperature superheated part) where a steam film that inhibits cooling occurs, it can effectively contact the inner circumferential surface of the cooling hole while destroying the steam film. The heat exchange rate with the mold can be improved more and more reliably. Moreover, after the fixed amount of cooling water is fed into the cooling holes, high-pressure air is flowed into the cooling holes and the cooling water remaining in the cooling holes is discharged to the outside, so that the heat is released after the molten product material has solidified. The mold will not get too cold due to being stolen.

Therefore, according to the temperature control method of the present invention, cooling control is ensured by supplying a constant amount of cooling water for each casting shot, while preventing the occurrence of defective products due to seizure etc., and achieving an equilibrium that minimizes temperature changes. The mold temperature can be maintained and controlled.

■ The cooling water stored in the cooling water storage tank through the cooling water storage line is stored in a fixed amount in the storage tank for each casting shot by controlling the operation of the liquid level sensor and the air discharge solenoid valve installed in the air discharge line. High-pressure air is supplied into the storage tank by controlling the operation of a high-pressure air supply solenoid valve disposed in a high-pressure air supply line. It is possible to pressurize and maintain the high-pressure air with air at a pressure higher than cnf and send it to the cooling hole by controlling the operation of a cooling water supply solenoid valve installed in the cooling water supply line.

Therefore, according to the temperature control device of the present invention, a fixed amount of cooling water is stored in the cooling water storage tank for each casting shot, and the cooling hole is maintained at a pressure that breaks the steam film that inhibits cooling. Since the cooling water and high-pressure air can be sent to the cooling hole through one cooling water storage tank, the above-mentioned effect (2) can be obtained. This will not complicate the piping system.

Therefore, the intended purpose can be achieved.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the method and device for controlling the temperature of a casting mold according to the present invention, in which Fig. 1 is a circuit diagram and Fig. 2 shows a state in which it is connected to a cooling pipe inserted into a cooling hole of the mold. It is a schematic diagram. In addition, al in the figure: Cooling water storage tank A2: Cooling water storage line A3: Cooling water supply line A4: High pressure air supply line A5: Air discharge line 1・Cooling hole 2: Cooling water storage and supply port 3・High pressure air supply Combined discharge port 5: Liquid level sensor 8. II: Check valve 12:
Cooling water supply solenoid valve 15, high pressure air supply solenoid valve 16, air discharge solenoid valve Figure 1

Claims (1)

[Claims] 1. While storing a fixed amount of water in a cooling water storage tank for each casting shot, the fixed amount of cooling water in the tank is sent into the cooling hole by high pressure air, and when the fixed amount of cooling water supply is finished, the cooling water is sent to the cooling hole. A method for controlling the temperature of a casting mold, characterized in that cooling water is discharged from the inside of the cooling hole to the outside by high-pressure air flowing in. 2. A cooling water storage tank that stores a fixed amount of water using a liquid level sensor and holds the stored fixed amount of cooling water under pressure, and a check valve that is branched from the cooling water storage/supply port provided at the bottom of the storage tank. A cooling water storage line equipped with a cooling water supply line, a cooling water supply line equipped with a cooling water supply solenoid valve, and a high pressure air supply line equipped with a high pressure air supply solenoid valve, which is branched from the air supply/discharge port provided at the top of the storage tank. 1. A temperature control device for a casting mold, comprising an air discharge line and an air discharge line equipped with an air discharge solenoid valve.