JPS591060A - Method and device for controlling vacuum suction casting - Google Patents

Abstract

PURPOSE:To enable the manufacture of a stable product by detecting the difference between either one of the temp. while a casting mold is at an ordinary temp. and the temp. when the mold is immersed in molten metal and the temp. of the molten metal without contact, immersing the casting mold into the molten metal down to the prescribed depth and stopping the same. CONSTITUTION:A vacuum suction casting device is so constituted that the state when a casting mold 12 is immersed in the molten metal 19 in a crucible 18 is detected, the relative movement of the mold 12 and the crucible 18 is stopped and after the molten metal 19 is sucked therein is allowed to solidify and the mold 12 is parted relatively from the metal 19. This device 1 is controlled by the method of detecting the difference between either one of the temp. while the mold 12 is at an ordinary temp. and the temp. when the mold is immersed in the molten metal with a temp. detector 32 without contact, immersing the mold 12 in the metal 19 down to the prescribed depth and stopping there.

Description

DETAILED DESCRIPTION OF THE INVENTION The disclosed technology belongs to a technical field in which a product is produced by vacuum suction of molten metal into a mold.

Therefore, the invention of this application stops the relative movement between the mold and the crucible in a state in which the tip of the mold, which is vertically installed in the clamp device of the suction casting device, is immersed in the molten metal in the crucible, and sucks the molten metal. The present invention relates to a vacuum suction casting control method in which the mold and the crucible are fixed, and then the mold and the crucible are relatively separated from each other, and an apparatus directly used in the method. A non-contact temperature detection device attached to the clamp device detects the temperature difference between the preset room temperature of the mold, the temperature at the time of immersion, and at least one of the molten metal temperature. A reduced pressure suction casting control method in which the relative movement between the mold and the crucible is stopped, the suction and solidification time is measured at the same time, and then the mold and the crucible are separated from each other, and a device directly used in the method. It is an invention.

As is well known, vacuum casting technology uses a vacuum device to suck the molten metal in a crucible into the cavity of a mold to perform predetermined casting molding. Since the capacity of the molten metal is constant, it is necessary to immerse the mold in a predetermined amount in accordance with the decrease in the amount of molten metal due to repeated suction, and the manner in which this is done is as follows.

That is, one electrode is attached near the sprue at the tip of the mold, and the other electrode is inserted into the molten metal in the crucible, and when the mold is immersed in the molten metal to a predetermined depth, both of the electrodes are able to absorb the molten metal. The relative movement between the mold and the crucible is stopped by creating a short circuit through the media, and then a vacuum device is activated to draw the molten metal into the mold cavity.

After that, the molten metal in the cavity is cooled and solidified after a predetermined amount of suction, and then the mold and the crucible are separated from each other.

Therefore, the amount of relative proximity movement between the mold and the crucible during a new casting operation increases by the amount of molten metal reduced in the previous operation.

However, both electrodes are of a contact type, and when used repeatedly for pouring, they are gradually eroded and damaged, resulting in poor detection. There was a drawback that the amount changed and it was not possible to stabilize the product.

Furthermore, in the worst case scenario, there is a problem in that the mold is excessively immersed into the molten metal, resulting in damage to both electrodes or the mold. - On the other hand, when the molten metal adheres firmly to the tip of the electrode, problems similar to those described above occur, and in the worst case, the mold stops without coming into contact with the molten metal, making it impossible to perform casting.

To deal with this, the electrodes have to be replaced or cleaned in a short period of time, making maintenance and inspection cumbersome and increasing maintenance costs.

The purpose of the invention of this application is to solve the problems of the suction casting control method and apparatus based on the above-mentioned prior art, and to uniquely produce a stable product suitable for mass production. It is an object of the present invention to provide an excellent vacuum suction casting control method and apparatus useful for casting applications in the parts manufacturing industry, which reduce equipment maintenance costs.

The structure of the invention of this application in accordance with the above-mentioned object is to solve the above-mentioned problems by controlling the clamping device installed in the vacuum suction casting device, which vertically suspends the mold, to control the temperature of the mold at room temperature, the temperature at the time of immersion, and the molten metal. A non-contact temperature detection device for detecting a temperature difference on one side is attached to the tip of the mold, and when the mold and crucible are moved relative to each other by a lifting device,
When the tip of the mold is immersed in a predetermined amount of molten metal in the crucible, the non-contact temperature detection device senses one of the temperature rise in the mold tip region due to the molten metal and the temperature of the molten metal, and sends a signal to the elevation control device. □, stop its operation, measure the immersion time, and after a predetermined elapsed time, reversely operate the lifting device to separate the mold and the crucible from each other. It is something.

Next, one embodiment of the invention of this application will be described below with reference to the drawings.

Reference numeral 1 denotes a vacuum suction device, in which a rod 5 with clamp devices 4 erected on both sides of the upper surface is attached to a piston 3' of a hydraulic cylinder 3 as a lifting device vertically installed on an upper frame 2. It is inserted into and connected to the balance arm 6.

On the other hand, the clamp device 4 includes a kump cylinder 8 suspended inside the clamp arm 1 connected to the piston 3'.
A vacuum hood 9 is connected to the piston 8', and has a hook 10 at its open end, and the upper surface of the mold 12 for hooking the norange portion 11 to the hook 10 is not shown in the vacuum hood 9. They are closely connected via the 0 ring.

Further, the mold 12 is set in the flask 13 with an air permeable mold 14 made of organic binder sand having a cavity 15 and a sprue 17 facing the tip 16 of the mold 12 as usual. The end portion 16 is directed toward a molten metal 19 in a crucible 18 set in a lower frame (not shown).

Further, a decompression device 20 connects a decompression chamber 22 and a vacuum pump 23 to a flexible hose 21 that communicates with the decompression hood 9.

24 is a vacuum suction casting control device which constitutes the gist of the invention of this application, and an elevation control device 25 engages with supply/discharge pipes 26 and 27 connected to the hydraulic cylinder 3 and a cam 28 attached to the outside of the clamp arm 7. a limit switch 29 which is possible and fixed to the frame 2'; and the clamp arm 7.
They are pivotally fixed to the tips of brackets 30 extending outward, and are connected in parallel to non-contact optical temperature detection devices 32 having photodiodes 31, respectively.

The photodiode 31 is provided to face the immersion portion 16' as the tip region of the flask 13, and its detection field of view Δχ is set in accordance with the amount of molten metal sucked into the mold 12. The temperature difference between the mold 13 and the molten metal 19 is detected to control the lifting and lowering of the hydraulic cylinder 3.

In the above configuration, the illustrated embodiment shows a state in which the mold 12 is set in a predetermined manner in the clamping device 4, but the mold 12 is placed in the mold 13 in advance in the cavity 15 and the sprue 17.
The flange portion 11 of the flask 13 is inserted through the clamp cylinder 8 between the hook 10 of the clamp arm 7 having a gap and the vacuum hood 9, and then the clamp cylinder 8 is loaded. screw 8'
is activated, and the seventh lunge portion 11 is held between the hook 10 and the vacuum hood 9.

The casting process after the mold 12 is set in a predetermined manner will be explained based on the circuit of the elevation control device 250 shown in FIG. 2. First, when the start switch (S) 33 is turned on, the start relay (CR1) 34 is activated, the lowering solenoid (SLl) 35 is energized, oil is supplied to the hydraulic cylinder 3 from one supply/discharge via 26, oil is drained from the other supply/discharge pipe 27, and the piston 3' is gradually projected downward. .

Then, the clamping device 4 connected to the piston 3' descends with the mold 12 suspended, and the tip 1 of the mold 12 is lowered.
6. That is, the sprue 17 is made to face the molten metal 19 in the crucible 18.

During this time, since the temperature detecting device 32 is attached to the bracket 30 extending from the clamp arm 7, the field of view from the photodiode 31 moves down while detecting only the flask immersion portion 16' of the mold 12.

Therefore, in this state, the temperature detection device 32 detects the room temperature of the flask 13, so its output is weak.

Then, when the tip 16 of the mold 12 faces the molten metal 19 and the immersed part 16' of the mold 13 is gradually immersed,
The temperature of the molten metal 19 is gradually input to the temperature detection device 32, which has a detection field of view Δχ corresponding to the immersion portion 16'.

The detection field of view Δχ, that is, the immersion portion 16'
When all of the molten metal is poured into the molten metal 19, the photoode 31 receives only the radiated light from the molten metal 19, so the output from the temperature detection device 32 increases in accordance with the molten metal temperature. , the high output activates the relay (CR2>36), which closes the relay (OR2) 36 and activates the other relay (CR3) 37, which opens the starting relay (CR1) 34 and closes the lowering solenoid ( SLI) 35 and hydraulic cylinder 3.
The oil supply to the hydraulic cylinder 3 is stopped, and at the same time, the pressure reducing device 20 starts suction to reduce the pressure inside the mold 12, and the timer relay (TR)
38 starts measuring the suction time.

As a result, the mold 12 maintains the initial posture in which it is immersed in the molten metal 9 to a predetermined depth, and the pressure reducing device 20
The molten metal 19 is sucked up from the sprue 17 into the cavity 15 by the suction force.

After a predetermined amount of the molten metal 19 is sucked and solidified,
That is, the timer relay (TR) 38 closes after measuring a predetermined casting time, and the relay (CR4) 39 is activated to energize the ascending renoid (SL2) 40, and the hydraulic cylinder 3 is connected to the hydraulic cylinder 3 from the one supply/discharge pipe 126. The mold 12 is lifted away from the crucible 18 by draining the oil and supplying oil from the other supply/discharge pipe 27 to move the piston 3' backward.

Thus, in the predetermined rising range, the limit switch 28 attached to the clamp arm 1 engages with the limit switch (LS) 29, the contacts of the limit switch (LS) 29 are short-circuited, and the relay (CR5) 41 operates, and as a result, the relay (CR4) 39 opens and the lifting solenoid (S L
2 > 40 is returned to its original position, the oil supply to the hydraulic cylinder 3 is cut off, and the mold 12 is returned to its initial position and stopped.
Then, the mold 12 is removed in the reverse process to the above-mentioned set state, and a new mold is set to complete one process.

Although not shown, in another embodiment, the detection field of the photodiode 31 shown in FIG. The temperature detection device 32 can detect the temperature rise of the flask 13 and stop the hydraulic cylinder 3 from lowering.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments. For example, the non-contact temperature detection device is not limited to optical measurement, but may also be heat-ray measurement, and a lifting device may be used as a crucible. The molds may be connected to each other so that the molds are fixed and moved closer to each other, or the sprue of the mold may be exposed from the tip of the flask.

As mentioned above, according to the invention of this application, in a vacuum suction casting control method and a device directly used in the method, the immersion depth of the mold into the molten metal is determined by the temperature of the mold at room temperature;
Since the temperature difference between the immersion temperature and the molten metal temperature is detected, and the relative movement between the mold and the crucible is stopped, the immersion depth is always kept constant from the molten metal surface regardless of the increase or decrease in the amount of molten metal, making it possible to perform repeated casting. As a result, the excellent effect of uniquely guaranteeing the stability of the quality of the product is achieved.

In addition, since the above-mentioned temperature difference is detected in a non-contact manner, there is no melting damage or adhesion of molten metal during repeated casting compared to the conventional contact method, there is no detection failure, and maintainability is greatly improved. However, the excellent effect of easy maintenance is achieved.

On the other hand, a non-contact temperature detection device is attached to a clamp device that vertically installs a mold, pointing toward the mold tip area, and the detection position is physically fixed, so vibrations caused when the mold and crucible move relative to each other, A steady state is maintained regardless of periodic errors, etc., and the excellent effect is that the immersion depth of the mold can be accurately measured.

Then, the operation of the lifting device is controlled and stopped by the output transmitted from the temperature detection device that detects the depth of immersion of the mold in the melt, and then, after a period of time, the mold and the crucible are separated from each other. This has the excellent effect of completely automating the casting process.

[Brief explanation of drawings]

The drawing is one of the fruits of the invention of this application...111! FIG. 1 is a schematic explanatory diagram of an embodiment, and FIG. 2 is an explanatory diagram of a circuit of an elevation control device. 12... Mold, 18... Crucible, 19...
Molten metal, 1... Decompression suction casting device, 4... Clamp device, 3... Lifting device, 24... Control device, 32...
-Temperature detection device, 16'...Tip region. Applicant: Toyota Motor Corporation, -32m

Claims (2)

[Claims] (1) Detecting the state in which the mold is immersed in the molten metal in the crucible, stopping the relative movement between the mold and the crucible, suctioning and solidifying the molten metal, and then vacuuming to separate the mold and the molten metal relative to each other. In the casting control method, the difference between the temperature of the mold at room temperature, the temperature at the time of immersion, and the temperature of the molten metal is detected in a non-contact manner, and the mold is immersed and stopped at a predetermined depth in the molten metal. Characteristic vacuum suction casting control method. (2) In a control device connected to an elevating device connected to one of a crucible and a clamp device for vertically disposing a mold, which is provided in a vacuum suction casting control device, a non-contact temperature detection device is attached to the clamp device to hold the mold vertically. Attached toward the tip area,
A vacuum suction casting control device, characterized in that the non-contact temperature detection device is connected to the lifting device.