JP2000301314A - Casting method and casting apparatus - Google Patents

Abstract

(57) [Problem] To provide a casting method and a casting apparatus capable of easily determining the occurrence of defective products due to a shift in the timing of pulling out a slide core and preventing outflow of defective products. A pair of molds (1) forming a cavity (2).
The hollow portion 8 is formed by using a casting apparatus 1 having
Cast a casting with a zero. With the slide core 3 advanced into the cavity 2, the molten metal 88 is inserted into the cavity 2.
Fill. After the molten metal 88 around the slide core 3 solidifies, the slide core 3 is withdrawn before the mold opening time. The pulling force acting when the slide core 3 is withdrawn from the cavity 2 is measured, and the quality of the casting 8 is determined by comparing the measured value with a preset appropriate value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a casting method and a casting apparatus for, for example, die casting.

[0002]

2. Description of the Related Art In recent years, cast products such as die-cast parts have been required to have a near net shape closer to the final shape in order to reduce the number of cuts in post-processing. On the other hand, in general, a cast product has a shape in consideration of draft in advance in order to facilitate release of a product or release of a core from a product.

For example, when a cylindrical hollow portion is provided inside a product, the core is usually provided with a shape such that the outer diameter gradually increases in the core removing direction.
In such a case, in order to realize the near-net shape, it is necessary to reduce the draft as much as possible. However, the hollow part (the core cast-out part)
When the draft angle of the core is reduced, the release force when the core is released from the product is greatly increased. Also, due to the increase in the releasing force, the product may seize to the mold at the time of releasing.

[0004] Therefore, the applicant filed Japanese Patent Application No. 10-1058.
As indicated in No. 12, a method of casting the slide core before the molten metal around the slide core and before opening the pair of dies is proposed. did. As a result, the above-mentioned cast product reduces the force for restraining the slide core, preventing the release force from increasing,
The near net shape of a casting having a hollow portion can be achieved.

[0005]

However, in the conventional casting method according to the above proposal, the timing of pulling out the slide core is delicate, and it is difficult to completely prevent the occurrence of defects. That is, if the timing of pulling out the slide core is shifted, the slide core is broken,
There is a possibility that a disadvantage that the slide core is cast out in an unsolidified state of the molten metal may occur. Further, even if such a defect occurs, it is difficult to judge it at a manufacturing stage, and there is a possibility that a defective product may flow out to a subsequent process.

The present invention has been made in view of such a conventional problem, and a casting method capable of easily determining occurrence of a defective product due to a shift in timing of pulling out a slide core and preventing outflow of the defective product. And a casting apparatus.

[0007]

According to a first aspect of the present invention, there is provided a casting apparatus having a pair of molds for forming a cavity and a slide core disposed to be able to advance and retreat with respect to the cavity. The molten metal is filled into the cavity while the slide core is inserted into the cavity, and then the molten metal around the slide core solidifies.
A method of casting a casting having a hollow portion by retreating the slide core from the cavity before the mold opening time of the pair of molds, wherein the slide core is retreated from the cavity. The casting method is characterized in that the pulling force acting on the casting is measured, and the measured value is compared with an appropriate value having preset upper and lower limits to determine the quality of the casting.

What is most notable in the present invention is that a pulling force acting when the slide core is withdrawn from the cavity is measured, and the measured value is compared with an appropriate value having predetermined upper and lower limits. To determine the quality of the casting.

The quality of the cast product is, for example, the quality of the shape of the hollow portion formed by the slide core. The solidification of the molten metal around the slide core means at least when the molten metal located in a cavity portion formed between the slide core and a mold facing the slide core has solidified. Therefore, it does not matter whether the molten metal such as the solid portion where the slide core is not located is completely solidified. Further, the mold opening time of the mold means a time when the molten metal is completely solidified and becomes a cast product, which can be released from the mold.

Next, the operation and effect of the present invention will be described.
In the casting method of the present invention, as described above, the pulling force acting when the slide core is withdrawn from the cavity is measured, and the measured value is compared with an appropriate value having a preset upper limit and lower limit. The quality of the casting is determined by comparison. That is, if the measured value is at the appropriate value,
If it is determined that the casting is good, and if the measured value is not at the appropriate value, it is determined that the casting is defective.

If the timing of pulling out the slide core deviates during the casting, problems such as breakage of the slide core and cast-out of the slide core in an unsolidified state of the molten metal occur. I do. And the cast product cast at this time becomes a defective product. When such a defect occurs, as described above, the quality of the casting can be determined by comparing the measured value with the appropriate value. Therefore, it is possible to easily determine the occurrence of a defective product due to a shift in the slide core withdrawal timing, and it is possible to prevent the defective product from flowing out to a subsequent process.

As described above, according to the present invention, it is possible to provide a casting method capable of easily determining the occurrence of defective products due to a shift in the timing of pulling out the slide core and preventing the outflow of defective products.

Next, the pulling force of the slide core can be measured by a pressure sensor attached to a hydraulic cylinder for moving the slide core forward and backward. That is, by measuring the hydraulic pressure of the hydraulic cylinder, the pulling force applied when the slide core is pulled out of the cavity can be indirectly measured. Therefore, it is possible to easily and accurately measure the pulling force.

Next, it is preferable to issue an alarm when the measured value of the pull-out force is not at the proper value, as in the third aspect of the present invention. As a result, the operator can be easily notified of the abnormality, and the outflow of defective products to the next process can be reliably prevented.

Next, when the measured value of the pulling force is not at the proper value, it is preferable to exclude the cast product. As a result, the outflow of defective products to the next process can be prevented more reliably.

Next, it is preferable that the casting apparatus is stopped when the measured value of the drawing force exceeds the upper limit of the appropriate value. When the measured value of the pulling force exceeds the upper limit, there is a high possibility that the slide core is broken. In such a case, if the casting device is operated continuously with the slide core broken, a large number of defective products will be cast. According to the present invention, such mass casting of defective products can be reliably prevented.

Next, according to the invention as set forth in claim 6, there is provided a casting apparatus having a pair of molds for forming a cavity, and a slide core disposed so as to be able to advance and retreat with respect to the cavity. The casting device comprises an actuator for moving the slide core forward and backward, a measuring means for measuring a drawing force when the slide core is pulled out of the solidified molten metal, and a measurement value obtained by the measurement means and a preset upper limit. There is a casting apparatus characterized by having a judgment unit for judging the quality of a casting by comparing a value with an appropriate value having a lower limit.

The casting apparatus has the measuring means and the judging section, and the judging section can judge occurrence of a defective product. Therefore, as described in the description of the first aspect of the present invention, it is possible to obtain a casting apparatus that can easily determine the occurrence of defective products due to a shift in the timing of pulling out the slide core and prevent the outflow of defective products. it can.

Next, it is preferable that the actuator is a hydraulic cylinder and the measuring means is a pressure sensor attached to the hydraulic cylinder. Thus, as described in the description of the second aspect of the present invention, it is possible to easily and accurately measure the pull-out force.

Next, as in the invention according to claim 8, the casting apparatus has an alarm which is activated when the determination section determines that the measured value of the drawing force is not at the appropriate value. Is preferred. As a result, the operator can be easily notified of the abnormality, and the outflow of defective products to the next process can be reliably prevented.

Next, as in the ninth aspect of the present invention, the casting device is configured to stop when the determination unit determines that the measured value of the drawing force exceeds the upper limit of the appropriate value. It is preferred that As a result, as described in the description of the fifth aspect of the present invention, it is possible to reliably prevent mass casting of defective products.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment A casting method and a casting apparatus according to an embodiment of the present invention will be described with reference to FIGS. The casting method in this example is
As shown in FIG. 1, a casting apparatus 1 having a pair of molds 11 and 12 forming a cavity 2 and a slide core 3 arranged to be able to advance and retreat with respect to the cavity 2 is used.

With the slide core 3 advanced into the cavity 2, the molten metal 88 is inserted into the cavity.
(FIG. 1). Next, after the molten metal 88 around the slide core 3 is solidified, the slide core 3 is withdrawn from the cavity 2 before the pair of dies 11 and 12 open. As a result, a cylindrical casting 8 having a hollow portion 80 shown in FIG. 2 is cast. The hollow portion 80 is a cylindrical deep concave portion.

In the casting, the slide core 3
Of the casting 8 is measured by comparing the measured value with an appropriate value having a preset upper limit and lower limit.

The casting apparatus 1 of this embodiment will be described below with reference to FIG.
It will be described based on. The casting apparatus 1 is provided with a hydraulic cylinder 30 for moving the slide core 3 forward and backward, and a temperature sensor 4 for measuring the temperature of the dies 11, 12 or the slide core 2; And a control unit 5 for instructing the exit time of the slide core 3. The control unit 5 temperatures T ₁ measurement said actual is compared with the measured temperatures T ₁ sent from the set temperature T ₀ and the temperature sensor set in advance of the slide core 3 at the time when reached the set temperature T ₀ It is configured to issue an exit instruction.

As shown in FIG. 1, the pair of dies 11 and 12 are die-casting dies provided with an injection cylinder 15 and an injection plunger 16.
The molten metal 88 guided into the cavity 2 is pressurized and filled into the cavity 2 through the sprue 17 by the injection plunger 16. In the dies 11, 12, the reference numeral 12 in FIG. 1 denotes a fixed type, and the reference numeral 11 denotes a movable type.

Further, as shown in FIG. 1, the temperature sensor 4 provided on the mold 12 is constituted by a thermocouple, and is buried in a portion facing the slide core 3. The temperature sensor 4 is electrically connected to the control unit 5, and is configured to detect the temperature of the mold 12 every moment and send the detected value to the control unit 5.

As shown in FIG. 1, the slide core 3 is provided with a hydraulic cylinder 3 provided above dies 11 and 12.
It extends downward from zero and is provided so as to move up and down by the action of the hydraulic cylinder 30.
The hydraulic cylinder 30 is electrically connected to the control unit 5, and is configured to move the slide core 3 forward and backward based on an instruction from the control unit 5.

As shown in FIG. 1, a pressure sensor 31 for measuring the pulling force of the slide core 3 is attached to the hydraulic cylinder 30. The pressure sensor 3
1 is electrically connected to the determination unit 6 via the amplifier 32. Further, the casting apparatus 1 includes an alarm 61 that emits an alarm sound and an alarm light based on a signal from the determination unit 6.
Having.

Next, a series of casting operations in this embodiment will be described more specifically with reference to FIGS. FIG. 3 is a flow chart showing a time series of a series of casting operations from closing of the molds 11 and 12 to opening of the molds. 4, the horizontal axis represents time, and the vertical axis represents the temperature, is an explanatory diagram showing a transition of the measured temperature T ₁ of the mold 12 which is measured by the temperature sensor 4. For convenience of explanation, the step numbers (S1 to S1) in FIG.
The time corresponding to S10) is shown using the same number in FIG.

As shown in FIG. 3, first, in steps S1, the molds 11 and 12 are clamped to form the cavity 2, and the slide core 3 is advanced into the cavity 2. Next, the melt 2 is filled in the cavity 2 in step S2. Thus, as shown in FIG. 4, the measured temperature T ₁ of the a mold 12 toward time S1~S2 the cooling process, rapidly increase in temperature molten metal filling (S2) opportunities.

[0032] Then, the measured temperature T ₁ is to determine whether the peaked at step S3, S4. In other words, the measured temperatures T ₁ was raised after the molten metal filling is monitored whether or not to start the cooling. Then, after the peak of the measured temperatures T ₁ in the step S4 is confirmed, step S5,
Found temperatures T ₁ in S6, it is determined whether the host vehicle has reached the set temperature.

Then, in step S4, the measured temperature T
_{After 1} confirms that it has reached the set temperature T _0, carrying out the exit of the slide core 3 in step S7. Thus, the slide core 3 can be pulled out of the casting 8 with a small releasing force without breaking the solidified state of the molten metal 88 in the cavity 2.

At this time, the pulling force of the slide core 3 is measured by measuring the oil pressure of the hydraulic cylinder 30 by the pressure sensor 31 (S8). This measured value is sent to the determination section 6 via the amplifier 32 (S9).
Then, in step S10, the molds 11 and 12 are opened, and one cycle of a series of casting operations is completed.

Further, the determination section 6 determines in step 9
As shown in FIG. 5, when the measurement value sent in step P1 is received in step P1, the quality of the casting 8 is determined by comparing the measurement value with the appropriate value. That is, in step P2, the measured value is compared with the upper limit of the appropriate value. If the measured value is equal to or smaller than the upper limit, the process proceeds to Step P3.

On the other hand, when the measured value is larger than the upper limit, the casting 8 cast at that time is determined to be defective, and the casting 8 is discharged in step P4. In this case, it is determined that the slide core 3 has been broken, the casting apparatus 1 is stopped in step P5, and the alarm 61 is activated in step P6.

In step P3, the measured value is compared with the lower limit of the appropriate value. And
If the measured value is equal to or greater than the lower limit, it is determined that casting is being performed normally, and one cycle is completed. On the other hand, if the measured value is smaller than the lower limit, the casting 8 cast at that time is determined to be defective, and the casting 8 is discharged in step P7, and the alarm 61 Activate

The measured value of the pulling force of the slide core 3 temporarily changes from the start to the end of drawing as shown by waveforms H ₁ , H ₂ and H ₃ in FIG. Therefore, the measured value to be compared with the appropriate value as described above is the maximum value K
₁ , K ₂ and K ₃ are used. Therefore, when the waveform of the measured values of the waveform shown in H ₁ in FIG. 6, the slide core 3
Is determined to be broken. The waveform of the measured values in the case of the waveform shown in H _2, it is determined that the slide core 3 is pulled out in a non-solidified state of the molten metal 8. Further, when the waveform of the measured value of the waveform shown in H _3, since the maximum value K ₃ is between the upper limit value and the lower limit value, is determined to be normal.

Next, the operation and effect of this embodiment will be described. In the casting method of this embodiment, as described above, the pulling force acting when the slide core 3 is withdrawn from the cavity 2 is measured, and the measured value is set to an appropriate value having a preset upper limit value and lower limit value. And the quality of the casting 8 is determined.

In the casting, if the timing of pulling out the slide core 3 is shifted, the slide core 3 is broken or the slide core 3 is cast out in a state where the molten metal 88 is not solidified. Problem occurs. Then, the cast product 8 cast at this time becomes a defective product. When such a problem occurs, as described above, the quality of the casting 8 can be determined by comparing the measured value with the appropriate value. Therefore, it is possible to easily determine the occurrence of a defective product due to a shift in the timing of pulling out the slide core 3, and it is possible to prevent a large amount of the defective product from flowing to a subsequent process.

The pulling force of the slide core 3 is measured by a pressure sensor 31 attached to the hydraulic cylinder 30. That is, by measuring the hydraulic pressure of the hydraulic cylinder 30, the pulling force applied when the slide core 3 is pulled out of the cavity 2 can be indirectly measured. Therefore, it is possible to easily and accurately measure the pulling force.

When the measured value of the pulling force is not at the proper value, the alarm 61 is activated, so that the operator can be easily informed of the abnormality and the outflow of the defective product to the next process can be surely performed. Can be prevented. Further, when the measured value of the pulling force is not at the proper value, the cast product 8 is excluded, so that the outflow of the defective product to the next step can be more reliably prevented.

Further, the casting apparatus 1 stops when the measured value of the pulling force exceeds the upper limit of the appropriate value, so that mass casting of defective products can be reliably prevented.
That is, when the measured value of the pulling force exceeds the upper limit, there is a high possibility that the slide core 3 is broken. In such a case, if the casting device 1 is continuously operated with the slide core 3 broken, a large number of defective products will be cast. According to this example, it is possible to reliably prevent such a defective product from being mass-cast.

In the above embodiment, the pull-out force of the slide core was measured using a pressure sensor. However, a strain gauge was embedded in the slide core, and the force acting on the slide core was directly measured. Is also good.

As described above, according to the present embodiment, it is possible to provide a casting method and a casting apparatus which can easily determine the occurrence of a defective product due to a shift in the timing of pulling out the slide core and prevent the outflow of the defective product. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a casting apparatus in an embodiment.

FIG. 2 is a perspective view of a casting in the embodiment.

FIG. 3 is a flowchart showing a flow of a casting operation in the embodiment.

FIG. 4 is a diagram showing a change in a mold temperature in the embodiment.

FIG. 5 is a flowchart showing the flow of a non-defective product determination and subsequent processing in the embodiment.

FIG. 6 is a diagram showing a change in the pulling force of the slide core in the embodiment.

[Explanation of symbols]

 1. . . Casting equipment, 11,12. . . Mold, 2. . . Cavity, 3. . . Slide core, 30. . . Hydraulic cylinder, 31. . . Pressure sensor, 5. . . Control section, 6. . . Judgment unit, 61. . . 7. Alarm, . . Castings, 80. . . Hollow, 88. . . Molten metal,

Claims (9)

[Claims] 1. A slide core is made to enter the cavity by using a casting device having a pair of molds forming a cavity and a slide core which can be advanced and retracted with respect to the cavity. After the molten metal is filled in the cavity in a state where the molten metal is solidified around the slide core, the slide core is removed from the cavity before the mold opening time of the pair of molds. In the method of casting a casting having a hollow portion by withdrawing, a pulling force acting when the slide core is withdrawn from the cavity is measured, and the measured value is compared with a preset upper limit and lower limit. A casting method characterized in that the quality of a cast product is determined by comparing with a proper value of the casting. 2. The casting method according to claim 1, wherein the pulling force of the slide core is measured by a pressure sensor attached to a hydraulic cylinder for moving the slide core forward and backward. 3. The casting method according to claim 1, wherein an alarm is issued when the measured value of the pull-out force is not at the appropriate value. 4. The method according to claim 1, wherein:
When the measured value of the pulling force is not at the appropriate value, the casting is removed. 5. The method according to claim 1, wherein:
When the measured value of the drawing force exceeds the upper limit of the appropriate value, the casting device is stopped. 6. A casting apparatus comprising: a pair of molds forming a cavity; and a slide core disposed so as to be able to advance and retreat with respect to the cavity, wherein the casting apparatus advances and retreats the slide core. Actuator, a measuring means for measuring a pulling force when the slide core is pulled out of the solidified molten metal, and comparing the measured value of the measuring means with an appropriate value having predetermined upper and lower limits. And a judgment unit for judging the quality of the casting. 7. The casting apparatus according to claim 6, wherein said actuator is a hydraulic cylinder, and said measuring means is a pressure sensor attached to said hydraulic cylinder. 8. The casting apparatus according to claim 6, wherein the casting device has an alarm that is activated when the determination unit determines that the measured value of the pulling force is not at the appropriate value. apparatus. 9. The method according to claim 6, wherein:
The casting apparatus is configured to stop when the determination unit determines that the measured value of the pulling force exceeds the upper limit of the appropriate value.