WO2014091532A1

WO2014091532A1 - Method for operating hot chamber die casting machine

Info

Publication number: WO2014091532A1
Application number: PCT/JP2012/081904
Authority: WO
Inventors: 武宏梅木; 剛士石川; 達義宮崎
Original assignee: Ykk株式会社
Priority date: 2012-12-10
Filing date: 2012-12-10
Publication date: 2014-06-19
Also published as: CN104870122B; TW201422338A; CN104870122A; TWI519363B

Abstract

The present invention is a method for operating a hot chamber die casting machine that, in addition to not generating blow holes in the injection molding, is capable of injection molding in a short time and has excellent durability and with which the size of the space can be set freely. The method is configured so that: injection molding is performed by moving an injection plunger (7) to an injection completion position; the injection plunger (7) is then moved to a molten metal supply position and after waiting for a set period at the molten metal supply position, is moved to a set position to form a continuous space (10) between a nozzle (8) and a molten metal path (6); subsequently, the injection plunger (7) is moved to a filling completion position to fill molten metal in the space (10); after opening the mold (9) and removing the injection molding (11), the injection plunger (7) is moved to the injection molding start position to form a space (10) of a set size; and the mold is closed in this state and the injection plunger (7) is moved to the injection completion position.

Description

Operation method of hot chamber die casting machine

The present invention relates to an operation method of a hot chamber die cast machine.

Conventionally, a hot chamber die casting machine shown in FIG. 10 is known.
That is, a gooseneck 3 is provided in a molten metal 2 of a melting pot 1 called a pot or crucible filled with a molten metal. And a runner 6 communicating with the injection chamber 5.
An injection plunger 7 is fitted into the injection chamber 5 so as to be movable up and down, and the hot water supply port 4 is opened and closed by moving the injection plunger 7 up and down by an injection cylinder (not shown).
The leading end 6 a of the runner 6 is positioned above the upper surface of the molten metal 2, that is, the pot hot bath surface 2 a, and a nozzle 8 is provided at the leading end 6 a of the runner 6.
The nozzle 8 is continuous with the cavity 9 a of the mold 9. In this mold 9, the fixed mold 9b and the movable mold 9c are closed and opened by a mold clamping mechanism (not shown).

The above-described hot chamber die casting machine operates as follows.
In the state shown in FIG. 10, the mold 9 is closed, and the injection plunger 7 opens the hot water supply port 4 and supplies the molten metal 2 to the injection chamber 5. The hot water surface 2b is the same height as the pot hot water surface 2a.
By moving the injection plunger 7 downward from the state shown in FIG. 10, the hot water inlet 4 is closed and further moved downward to pressurize the molten metal 2 in the injection chamber 5. Then, it is injected into the cavity 9a of the mold 9 (injection process).
FIG. 11 shows the state where the injection is completed, and the injection plunger 7 is at the lower injection completion position.

When the injection plunger 7 is moved upward from the injection completion state shown in FIG. 11 and returned, the inside of the injection chamber 5 becomes a negative pressure, and the metal due to the pressure difference between the tip of the nozzle 8 and the tip of the injection plunger 7 Since the molten metal 2 moves upward together with the injection plunger 7, as shown in FIG. 12, the molten metal 2 at the tip of the mold 9 and the nozzle 8 is separated, and the molten metal 2 is separated from the inside of the nozzle 8 and the distal end portion of the runner 6. It becomes a space 10 that does not exist. The injection molded product 11 in the cavity 9a of the mold 9 is cooled.
When the injection plunger 7 moves further upward from the state shown in FIG. 12 and reaches the above-mentioned hot water supply position as shown in FIG. 13, the hot water supply port 4 is opened and the inside of the above-mentioned space 10 is under negative pressure. The molten metal 2 in 1 sequentially flows into the injection chamber 5 from the hot water supply port 4 (hot water supply), the molten metal surface 2b of the molten metal 2 in the runway 6 rises sequentially, and the space 10 becomes gradually smaller.
When a predetermined time elapses, the molten metal 2 is filled up to the nozzle 8 as shown in FIG. In this state, the pressure inside the nozzle 8 is lower than the atmospheric pressure.

From the state shown in FIG. 14, the movable mold 9c of the mold 9 is moved and opened as shown in FIG. 15, and the injection molded product 11 in the cavity 9a is taken out.
As a result, the inside of the nozzle 8 communicates with the atmosphere, so that the molten metal 2 in the injection chamber 5 sequentially flows out of the hot water inlet 4 into the melting pot 1 due to the difference in height between the nozzle 8 and the pot hot water surface 2a, for a predetermined time. As shown in FIG. 16, the hot water surface 2b in the runner 6 becomes the same height as the pot hot water surface 2a, and the space 10 becomes larger.
From this state, the movable die 9c is brought into contact with the fixed die 9b and the die is closed, and the state where the die clamping is completed is the state shown in FIG.

Since the operation method of injection molding an injection molded product with a conventional hot chamber die casting machine is as described above, it continues to the end of the runner 6 and the nozzle 8 in a state where the mold clamping is completed as shown in FIG. When the injection plunger 7 is moved downward at high speed from the mold clamping completion state shown in FIG. 10 and the injection operation is performed, the air in the space 10 enters the cavity 9a of the mold 9 and is injected. Since a cast hole is generated in the molded product and the quality of the injection molded product is deteriorated, the injection plunger 7 is slowly moved downward from the mold clamping completion state shown in FIG. The nest is not generated.

For this reason, in the conventional operation method described above, the time required for injection molding becomes long.

Patent Document 1 discloses an operation method of a hot chamber die cast machine that solves this problem, does not generate a cast hole in an injection molded product, and shortens the time required for injection molding.
In other words, a metal sensor for detecting the molten metal is provided in the nozzle, and the amount of the molten metal in the nozzle (the height of the molten metal surface) is detected by the metal sensor so that the size of the space can be known. When the molten metal in the nozzle reaches the set amount, it is possible to detect that the space has reached the set size.
Then, in a state where the mold is opened (for example, the state shown in FIG. 15 and FIG. 16 described above), the injection plunger is moved slowly downward to send the molten metal in the injection chamber to the runner and the nozzle. When it is detected that the molten metal has reached the set amount, stop the injection plunger, close the mold and move the injection plunger downward at high speed to inject the molten metal into the mold chamber. This is an operation method in which injection molding is performed.

With this operation method, since the injection plunger is moved downward at a high speed and injection molding is performed after the space in the nozzle becomes the set size, a casting hole due to air mixing does not occur in the injection molded product. At the same time, the time required for injection molding can be shortened.

JP 2003-53507 A

In the conventional operation method described above, since the metal sensor detects the molten metal, the metal sensor has a problem in durability because it touches the molten metal at a high temperature.
Moreover, since the amount of the molten metal in the nozzle is detected based on the detection of the molten metal by the metal sensor, the size of the space is set to the set size. The size of cannot be set freely.

The object of the present invention is to prevent the occurrence of a cast hole due to air mixing in an injection molded product, to shorten the time required for injection molding, and to be excellent in durability and to freely set the size of the space. The operation method of the hot chamber die-casting machine.

According to the present invention, the molten metal 2 in the melting pot 1 is moved up and down the injection plunger 7 of the gooseneck 3, so that the cavity of the mold 9 passes through the filler port 4, the injection chamber 5, the runner 6, and the nozzle 8. The operation method of the hot chamber die-casting machine which injects into 9a and inject-molds the injection molded article 11,
With the mold 9 closed, the injection plunger 7 is moved downward from the injection molding start position to the lowest injection completion position, and the molten metal in the injection chamber 5 is injected into the cavity 9 a of the mold 9. A first step of moving the injection plunger 7 upward to the uppermost hot water supply position that opens the hot water supply port 4 communicating with the injection chamber 5 and the melting pot 1;
A second step of forming a space 10 in the nozzle side part by moving the injection plunger 7 downward to a set position for closing the hot water supply port 4 below the hot water supply position after waiting for a set time at the hot water supply position; ,
Filling the injection plunger 7 from the set position in a state where the injection molded product 11 exists in the cavity 9a of the mold 9 and filling the molten metal in the space 10 below the set position to eliminate the space 10 A third step of moving downward to a completion position;
A fourth step of forming the setting space 10 in the nozzle side portion by moving the injection plunger 7 upward from the filling completion position to the injection molding start position for closing the fuel filler port 4 above the filling completion position; ,
A hot chamber die casting machine operating method comprising a fifth step of closing the mold 9 after taking out the injection molded product 11 from the mold 9.

In the present invention, in the third step, the injection plunger 7 is moved downward from the set position to fill the space 10 with the molten metal, so that the injection plunger 7 stops at the filling completion position,
In the fourth step, the operation method of the hot chamber die cast machine can be set such that the injection plunger 7 is moved upward by a set stroke from the filling completion position to the injection molding start position.

In this way, the size of the space 10 can be made to match the set stroke from the filling completion position of the injection plunger 7 to the injection forming start position, and the size of the space 10 can be changed by changing the set stroke. be able to.

In the present invention, the stroke detecting means 30 for detecting the movement stroke of the injection plunger 7 detects the stroke in which the injection plunger 7 has moved upward from the filling completion position, and the injection plunger when the detected stroke is the set stroke. 7 can be used as the operation method of the hot chamber die cast machine in which the injection molding start position is stopped.

In this way, the injection plunger 7 can be accurately set to the injection molding start position.

In the present invention, the setting position of the injection plunger 7 is detected based on the movement stroke of the injection plunger 7 detected by the stroke detection means 30 and the injection plunger 7 is moved according to the detected position. It can be set as the operation method of the hot chamber die-cast machine which controls and sets to a set position.

In this way, the injection plunger 7 can be stopped at the set position with high accuracy.

In the present invention, in the third step, the filling completion position of the injection plunger 7 is set as a target position, and when the set target position and the actual filling completion position are different, the first injection molding operation is performed at the next time. The operation method of the hot chamber die-casting machine in which the filling completion position is corrected by increasing / decreasing the waiting time in the two steps can be obtained.

In this way, when the filling completion position is changed by repeating the injection molding operation a plurality of times, the filling completion position can be corrected to the target position.

In the present invention, the operation of the hot chamber die cast machine is such that the injection plunger 7 is moved from the filling completion position to the sagging prevention position to form the space 10 in the nozzle side portion, and then the mold 9 is opened. It can be a method.

In this way, the molten metal does not flow down from the nozzle 8 when the mold 9 is opened.

In the present invention, the size of the space 10 formed in the nozzle side part in the second step is the operation method of the hot chamber die cast machine in which the molten metal in the nozzle 8 is separated from the mold 9. Can do.

In this way, the molten metal in the nozzle 8 is not easily cooled by the cooling of the mold 9.

In the present invention, the fixed mold 9b of the mold 9 is a hot chamber die cast machine in which the hot water inlet 9d is always in contact with the nozzle 8, the movable mold 9c is moved, the mold is closed, and the mold is opened. The operation method can be as follows.

In this way, since the fixed mold 9b does not move, the hot water inlet 9d and the nozzle 8 do not repeat contact and separation, and a gap is generated between the hot water inlet 9d and the nozzle 8 of the fixed mold 9b, The molten metal does not leak.

In the present invention, the operation method of the hot chamber die cast machine can be set such that the setting position of the injection plunger 7 is changed after performing the injection molding operation a plurality of times.

In this way, since the injection plunger 7 moves over the entire area of the injection chamber 5, the entire area of the injection chamber 5 can be used effectively.

According to the present invention, the space 10 at the start of injection molding has a set size, and even if the injection plunger 7 is moved to the injection completion position at a high speed, a cast hole due to air mixing does not occur in the injection molded product. The time required for injection molding can be shortened.
Moreover, since only the movement of the injection plunger 7 is controlled and no sensor or the like affected by the high-temperature molten metal is used, the durability is excellent.
Furthermore, the size of the space 10 can be freely set by changing the injection molding start position of the injection plunger 7.

It is explanatory drawing at the time of the start of the 1st injection molding operation | movement of this invention. It is explanatory drawing when the injection plunger of this invention is an injection completion position. It is explanatory drawing when the injection plunger of this invention is in the middle of a return. It is explanatory drawing when the injection plunger of this invention is a hot-water supply position. It is explanatory drawing when the injection plunger of this invention is a setting position which closes a hot-water supply port. It is explanatory drawing when the injection plunger of this invention is a filling completion position. It is explanatory drawing when the injection plunger of this invention is a sagging (drawing) prevention position. It is explanatory drawing when the injection plunger of this invention is an injection molding start position. It is explanatory drawing when the metal mold | die of this invention is closed. It is explanatory drawing at the time of completion of the conventional mold clamping. It is explanatory drawing when the conventional injection plunger is an injection molding completion position. It is explanatory drawing when the conventional injection plunger is in the middle of a return. It is explanatory drawing when the conventional injection plunger is a hot-water supply position. It is explanatory drawing at the time of the completion of the conventional hot water supply. It is explanatory drawing when the mold opening of the conventional metal mold | die is started. It is explanatory drawing when mold opening of the conventional metal mold is completed.

As shown in FIG. 1, the hot chamber die cast machine of the present invention is similar to the conventional hot chamber die cast machine shown in FIG. 10 and includes a melting pot 1, a gooseneck 3, a nozzle 8, and a mold 9. , An injection cylinder 20 for moving the injection plunger 7 up and down, and means 30 for detecting the movement stroke of the injection plunger 7 are provided. In the hot chamber die casting machine, the gooseneck 3 which is an injection part is submerged in the molten metal 2 of the melting pot 1 and the molten metal in the mold 9 (for example, an alloy such as zinc, aluminum, magnesium, copper, etc.) Is press-fitted.
The injection cylinder 20 is extended, contracted, and stopped by a command from the controller 40. For example, by supplying the fluid pressure of the fluid pressure source 21 of air or oil to the expansion chamber 23 and the contraction chamber 24 by switching the valve 22, the expansion operation and the contraction operation are performed. The valve 22 is switched by a command from the controller 40. It is done.
When the injection cylinder 20 is extended, the injection plunger 7 is moved downward, and is moved upward by being contracted.
The stroke detection means 30 is a sensor using, for example, a laser, and the detected stroke value is sent to the controller 40.

The injection plunger 7 moves up and down as will be described later. In order to control the movement speed of the injection plunger 7 as described later, the supply amount of the fluid pressure source 21 per unit time is increased or decreased, or the fluid pressure source 21 is moved. The amount of fluid pressure supplied per unit time to the expansion chamber 23 and the contraction chamber 24 of the injection cylinder 20 can be increased or decreased by providing a throttle in the connection circuit between the injection cylinder 20 and the opening area of the valve 22. good.

Next, an example of the operation method of the present invention will be described.
The state shown in FIG. 1 is obtained when the first injection molding operation starts after the long-term stop or after the mold replacement, that is, when the first injection molding operation starts.
That is, the mold 9 is closed, and the molten metal in the runner 6 of the gooseneck 3 is at a height up to the middle of the runner 6, and its molten metal surface 2 b is the same height as the pot molten metal surface 2 a, and the nozzle 8 The space 10 formed continuously inside the nozzle 8 or the tip of the runner 6, that is, the size of the space 10 formed in the nozzle side portion is the same as the state shown in FIG. is there.

The first injection molding operation is as follows.
1, the injection cylinder 20 is extended from the state where the first injection molding operation is started, and the injection plunger 7 is moved downward to inject the molten metal in the injection chamber 5 into the cavity 9a of the mold 9. Then, the injection molded product 11 is molded by the injection plunger 7 being at the injection completion position shown in FIG.

The injection completion position of the injection plunger 7 in the injection completion state shown in FIG. 2 is determined by the pressing force of the injection plunger 7 (extension thrust of the injection cylinder 20) and the volume of the cavity 9a of the mold 9.
That is, when the molten metal 2 is filled in the cavity 9a of the mold 9 at a predetermined pressure, the injection plunger 7 does not move any further, and as shown in FIG. Since the upper hot water supply position is always the same (for example, top dead center), the injection completion position of the injection plunger 7 is determined as described above.

The return operation after the completion of injection is as follows.
The injection cylinder 20 is contracted and operated from the injection completion state, and the injection plunger 7 is moved upward to return. As shown in FIG. 3, the molten metal at the tip of the nozzle 8 is separated from the mold 9, and the inside of the runner 6 The molten metal surface 2b of the molten metal gradually falls, and a negative pressure space 10 is generated at the nozzle side portion.
Further, the injection plunger 7 is moved upward to the hot water supply position shown in FIG.
The above-described operation is the first step.

When the injection plunger 7 moves upward to the hot water supply position (top dead center) shown in FIG. 4, the hot water supply port 4 is opened, and the injection chamber 5 and the inside of the melting pot 1 communicate with each other through the hot water supply port 4. The molten metal 2 in 1 is supplied into the injection chamber 5 from the hot water supply port 4, and the molten metal surface 2b in the runner 6 rises sequentially as time passes. That is, it becomes a hot water supply state.

The injection plunger 7 is waited at a hot water supply position for a set time so that a space 10 is formed in the nozzle side portion. That is, when waiting at the hot water supply position for a long time, the space 10 is filled with the molten metal.
Then, after the set time has elapsed, the injection plunger 7 is moved downward again to stop at the set position where the hot water supply port 4 is closed as shown in FIG.
This set position is above the injection completion position shown in FIG.
The above-described operation is the second step of forming the space 10 in the nozzle side portion.

As a result, the molten metal 2 in the melting pot 1 is not supplied into the injection chamber 5 and a space 10 is formed in the nozzle side portion.
That is, if the aforementioned hot water supply state continues for a long time, the molten metal fills the nozzle 8 and the space 10 is not formed in the nozzle side portion, but the nozzle side portion (inside the nozzle 8 is controlled by controlling the time of the hot water supply state. Since the amount of the molten metal filled in the top of the runner 6) can be adjusted, the time of the hot water supply state (that is, the time of waiting the injection plunger 7 at the hot water supply position) is set as the set time, so that the nozzle side portion A space 10 can be formed.

For example, in the hot water supply state, the size of the space 10 that changes per unit time depends on the amount of hot water supplied from the hot water supply port 4 into the injection chamber 5 per unit time, the volume of the runner 6, and the volume of the nozzle 8. Can be calculated.
Moreover, the size of the space 10 when the injection plunger 7 moves to the hot water supply position shown in FIG. 4 and starts hot water supply from the hot water inlet 4 into the injection chamber 5 is the volume of the injection chamber 5 and the runner 6. And the volume of the nozzle 8 and the movement stroke of the injection plunger 7 from the injection completion position to the hot water supply position.

From this, from the size of the space 10 at the start of hot water supply and the size of the space 10 that changes per unit time, it is possible to calculate the waiting time in the hot water supply state that can form the space 10, and the calculated time When the input time has elapsed after the hot water supply state shown in FIG. 4 has been entered, the controller 40 switches the valve 22 to extend the injection cylinder 20 and starts to move the injection plunger 7 downward. To set position.

As shown in FIG. 5, the size of the space 10 described above is preferably such that the molten metal in the nozzle 8 is not in contact with the mold 9, for example, the injection molded product 11 in the cavity 9a.
In this way, the molten metal in the nozzle 8 is not easily cooled by the cooling heat for cooling the injection molded product 11 in the cavity 9a of the mold 9, and the injection molding operation described later is easy to perform.

The operation of stopping the injection plunger 7 at the aforementioned set position (position where the injection plunge 7 shown in FIG. 5 closes the hot water supply port 4) can be performed as follows.
The set position is set in advance with reference to the hot water supply position shown in FIG.
The stroke detecting means 30 detects the movement stroke of the injection plunger 7 from the hot water supply position, and obtains the position of the injection plunger 7 from the detected stroke.
When the position of the injection plunger 7 matches the set position, the injection cylinder 20 is stopped using the valve 22 as a neutral position, and the injection plunger 7 is set to the set position shown in FIG.

For example, a hot water supply position and a set position of the injection plunger 7 are set in advance, and a position difference (height difference) between the hot water supply position and the set position is obtained by calculation or actual measurement and input to the controller 40.
The stroke detecting means 30 detects the movement stroke in which the injection plunger 7 has moved downward from the hot water supply position, and when the movement stroke becomes the difference between the aforementioned positions, the controller 40 sets the valve 22 to the neutral position, and the injection cylinder 20 To stop the injection plunger 7 at the set position.
Since the movement stroke of the injection plunger 7 can be detected by the stroke of the injection cylinder 20, that is, the flow rate of the fluid pressure to be supplied, the supply amount per unit time is constant and the time for which the valve 22 is set to the fluid pressure supply position is controlled. By doing so, the injection plunger 7 can be set to the set position.

As described above, after the injection plunger 7 stops at the set position, the molten metal is filled into the space 10 described above.
This operation is as follows.
The injection cylinder 20 is extended to move the injection plunger 7 downward, and the molten metal in the injection chamber 5 is sequentially fed into the space 10 and filled.
When the molten metal is filled into the space 10, the molten metal is pressurized and the injection plunger 7 stops at the filling completion position shown in FIG. This operation is the third step.
At the time of the above-described operation, since the injection molded product 11 exists in the cavity 9a of the mold 9, the molten metal is not injected into the cavity 9a of the mold 9.

The filling completion position of the injection plunger 7 is detected and input to the controller 40.
For example, the stroke detecting means 30 detects a movement stroke until the injection plunger 7 moves downward from the set position and stops, and the filling completion position is detected based on the set position based on the detected movement stroke.

If the above-described filling completion position of the injection plunger 7 is different from the target position, an accurate injection molding operation cannot be performed, so that it can be confirmed whether the filling completion position is the target position.
For example, the filling completion position of the injection plunger 7 described above is determined by the size of the space 10 at the set position shown in FIG. 5, and the actual filling is completed if the space 10 has a size that matches the target filling completion position. Although the position coincides with the target filling completion position, if the size of the space 10 is different from the above-described size, the actual filling completion position differs from the target filling completion position.
That is, since the setting position of the injection plunger 7 shown in FIG. 5 is always constant, if the size of the space 10 is larger than the size corresponding to the target filling completion position, the downward movement stroke of the injection plunger 7 is increased. It becomes longer, the filling completion position is closer to the lower part than the target position, and if it is smaller, the downward movement stroke of the injection plunger 7 is shorter, and the filling completion position is closer to the upper part than the target position.

Paying attention to this, the filling completion position when the size of the space 10 is the target size is obtained by calculation or measurement, and that position is input to the controller 40 as the target position.
This target position is compared with the detected filling completion position. If they are the same, the filling completion position is the target position. If they are different, the filling completion position is different from the target position.
Then, when the filling completion position is not the target position, the filling completion position is set as the target position by controlling the waiting time in the hot water supply state during the next injection molding operation.
For example, an error of the molten metal to be filled in the space 10 is calculated based on the difference between the target position and the detected filling completion position and the volume per unit stroke of the injection plunger 7, and the time of the hot water supply operation state (hot water supply) by the error. The filling completion position is corrected by increasing or decreasing (time).

The mold 9 may be opened after the injection plunger 7 has been moved to the filling completion position. However, the mold 9 is molded in a state where the molten metal is filled in the nozzle 8 as shown in FIG. When opened, a phenomenon called dripping (drawing), that is, the molten metal in the nozzle 8 may flow down, so that the mold 9 is opened after performing the dripping (drawing) preventing operation.
That is, as shown in FIG. 6, since the inside of the nozzle 8 is sideways and the hot water inlet 9d of the fixed mold 9b is also sideways, when the mold 9 is opened with the molten metal filled in the nozzle 8, the fixed mold The molten metal may flow down through the hot water inlet 9d of the mold 9b.

The aforementioned sagging (drawing) prevention operation is as follows.
The injection plunger 7 is moved upward by a few millimeters from the filling completion position shown in FIG. 6 to obtain a sagging (drawing) prevention position shown in FIG.
As a result, the space 10 in the injection chamber 5 has a negative pressure, and the molten metal is drawn back into the injection chamber 5. As shown in FIG. 7, the space 10 is formed in the nozzle side portion, and the molten metal in the nozzle 8 Even when the mold 9 is opened, the molten metal in the nozzle 8 does not flow down to the hot water inlet 9d of the fixed mold 9 with the molten metal surface 2b positioned lower than or at the same position as the lower peripheral edge of the outlet of the nozzle 8. Like that.

For example, an upward movement stroke from the filling completion position of the injection plunger 7 is detected by the stroke detection means 30, and the injection is performed when the detected stroke matches a preset lifting stroke (set stroke) of several mm. The plunger 7 is stopped.
The pulling stroke is determined by the size of the space 10 and the amount of movement of the molten metal per unit stroke of the injection plunger 7.

When the above-described sagging (drawing) prevention operation is completed, the mold 9 is opened, and as shown in FIG. 8, the fixed mold 9b and the movable mold 9c are separated from each other and the inside of the nozzle 8 is communicated with the atmosphere. .
Since the mold 9 is moved and closed by moving the movable mold 9c while the hot water inlet 9d of the fixed mold 9b is in contact with the nozzle 8, the fixed mold 9b does not move. The hot water inlet 9d and the nozzle 8 do not repeat contact and separation, and a gap is formed between the hot water inlet 9d and the nozzle 8, so that the molten metal does not leak.

In the state described above, the size setting operation of the space 10 is performed.
The size setting operation of the space 10 is as follows.
After the injection plunger 7 has moved to the sagging (drawing) prevention position, the injection plunger 7 is moved upward, and the molten metal surface height 2b of the nozzle side portion is sequentially decreased to sequentially increase the size of the space 10. .
When the size of the space 10 reaches the set size, the injection plunger 7 is stopped, and the set size space 10 is formed in the nozzle side portion as shown in FIG.
This operation is the fourth step.

As described above, the position where the injection plunger 7 is stopped is the injection molding start position. This injection molding start position is set in advance with reference to the filling completion position, and the position of the injection plunger 7 is obtained by the stroke detected by the stroke detection means 30. When the position of the injection plunger 7 reaches the set injection molding start position, the injection plunger 7 is stopped.

That is, the size of the space 10 is determined by the upward movement stroke from the filling completion position (sagging (drawing) prevention position) of the injection plunger 7. Based on the amount of change in the molten metal due to the unit movement distance, the upward movement stroke from the filling completion position or the dripping (drawing) prevention position of the injection plunger 7 is calculated and obtained, and the stroke is input to the controller 40.
When the stroke detected by the stroke detection means 30 matches the stroke set above, the controller 40 switches the valve 22 to the neutral position, and stops the injection cylinder 20 so that the injection plunger 7 is injection molded as shown in FIG. The start position is set, and the size of the space 10 on the nozzle side portion is set as a set size.

The operation of stopping the injection plunger 7 at the injection molding start position may be controlled by the time for moving the injection plunger 7.
For example, the time for switching the valve 22 to the fluid pressure supply position is the time required for the injection plunger 7 to move from the filling completion position (sagging (drawing) prevention position) to the injection molding start position. Is the neutral position.

In the operation described above, the injection molded product 11 is taken out from the mold 9 and the mold 9 is closed as shown in FIG.
This operation is the fifth step.
After the above-described mold closing and mold clamping are completed, the injection plunger 7 is moved downward at a high speed to reach the injection completion position as shown in FIG. 2, thereby completing the second injection molding operation.

When the injection molded product 11 cannot be sufficiently cooled during the injection molding operation as described above, the injection plunger 7 is stopped at an arbitrary position to increase the time from the start of injection molding to the removal of the injection molded product. By doing so, the injection molded article 11 can be sufficiently cooled.

The operation for setting the size of the space 10 may be performed before the mold 9 is opened.
For example, as shown in FIG. 6, when the plunger 7 moves to the filling completion position, the operation of setting the size of the space 10 is performed.
Then, the mold is opened and the injection molded product 11 is taken out.

Thereafter, the operations shown in FIGS. 3 to 9 and 2 are repeated to perform the third and subsequent injection molding operations.
At this time, if the filling completion position deviates from the target position during the previous injection molding operation, the target filling is performed by controlling the time of the hot water supply state shown in FIG. 4 (time for waiting the injection plunger 7 at the hot water supply position). Try to be the completion position.

When the injection molding operation is repeated a plurality of times as described above, the setting position of the injection plunger 7 is changed.
By doing in this way, since the injection plunger 7 moves over the whole region of the injection chamber 5, the whole region in the injection chamber 5 can be used effectively.

In the above description, the opening area of the hot water supply port 4 when the injection plunger 7 is at the hot water supply position is constant. However, the opening area of the hot water supply port 4 is adjusted, and the molten metal 2 in the melting pot 1 is replaced with hot water supply. The flow rate of hot water supplied from the port 4 into the injection chamber 5 per unit time may be increased or decreased.
For example, the hot water supply port 4 has a circular shape, an oval shape, or a slit shape, the lower end surface of the injection plunger 7 is positioned in the middle of the hot water supply port 4 in the vertical direction, and the lower end surface of the injection plunger 7 is moved vertically. By changing to, the opening area of the hot water supply port 4 can be adjusted.

DESCRIPTION OF SYMBOLS 1 ... Melting pot, 2 ... Molten metal, 3 ... Gooseneck, 4 ... Hot water inlet, 5 ... Injection chamber, 6 ... Runway, 7 ... Injection plunger, 8 ... Nozzle, 9 ... Mold, 9a ... Cavity, 9b ... Fixed mold, 9c ... movable mold, 9d ... hot water inlet, 10 ... space, 11 ... injection molded product, 20 ... injection cylinder, 21 ... fluid pressure source, 22 ... valve, 30 ... stroke detection means, 40 ... controller.

Claims

By moving the molten metal (2) in the melting pot (1) up and down the injection plunger (7) of the gooseneck (3), the filler port (4), injection chamber (5), runner (6) , An operation method of a hot chamber die cast machine for injecting an injection molded product (11) by injection into a cavity (9a) of a mold (9) through a nozzle (8),
With the mold (9) closed, the injection plunger (7) is moved downward from the injection molding start position to the lowest injection completion position, and the molten metal in the injection chamber (5) is moved to the mold (9 ) Is injected into the cavity (9a), and the injection plunger (7) is moved upward to the uppermost hot water supply position for opening the hot water supply port (4) communicating with the injection chamber (5) and the melting pot (1). A first step of moving;
The injection plunger (7) waits for a set time at the hot water supply position and then moves downward to the set position for closing the hot water supply port (4) below the hot water supply position, thereby forming a space (10) in the nozzle side portion. A second step of:
The injection plunger (7) is moved from the set position into the cavity (9a) of the mold (9) with the injection molded product (11) in the space (10) below the set position. A third step of filling the molten metal and moving downward to a filling completion position to eliminate the space (10);
The injection plunger (7) is moved upward from the filling completion position to the injection molding start position for closing the fuel filler opening (4) above the filling completion position to form a setting space (10) in the nozzle side portion. A fourth step of
A method of operating a hot chamber die casting machine, comprising: a fifth step of closing the mold (9) after taking out the injection molded product (11) from the mold (9).
In the third step, the injection plunger (7) is moved downward from the set position and the molten metal is filled into the space (10), so that the injection plunger (7) stops at the filling completion position,
The operation method of the hot chamber die-casting machine according to claim 1, wherein in the fourth step, the injection plunger (7) is moved upward by a set stroke from a filling completion position to be an injection molding start position.
The stroke detecting means (30) for detecting the movement stroke of the injection plunger (7) detects the stroke in which the injection plunger (7) has moved upward from the filling completion position, and the injection is performed when the detected stroke is the set stroke. The operation method of the hot chamber die-casting machine according to claim 2, wherein the plunger (7) is stopped to be an injection molding start position.
The setting position of the injection plunger (7) is detected based on the movement stroke of the injection plunger (7) detected by the stroke detection means (30), and the injection plunger is determined by the detected position. The method of operating a hot chamber die cast machine according to any one of claims 1 to 3, wherein (7) is controlled to move to a set position.
In the third step, the filling completion position of the injection plunger (7) is set as a target position, and when the set target position is different from the actual filling completion position, the second step is performed during the next injection molding operation. The operation method of a hot chamber die cast machine according to any one of claims 1 to 4, wherein the filling completion position is corrected by increasing or decreasing the waiting time.
The injection plunger (7) is moved from a filling completion position to a sagging prevention position to form a space (10) in the nozzle side portion, and then the mold (9) is opened. A method of operating the hot chamber die cast machine according to claim 1.
The space (10) formed in the nozzle side portion in the second step is sized so that the molten metal in the nozzle (8) is separated from the mold (9). Method of hot chamber die casting machine.
The fixed mold (9b) of the mold (9) has its hot water inlet (9d) always in contact with the nozzle (8), moves the movable mold (9c), closes the mold, and opens the mold. The operation method of a hot chamber die cast machine according to any one of claims 1 to 7.
The operation method of the hot chamber die cast machine according to any one of claims 1 to 8, wherein the setting position of the injection plunger (7) is changed after performing the injection molding operation a plurality of times.