JP2003103344A - Manufacturing method for molding mold and molding mold manufactured thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a convenient manufacturing method for a molding mold capable of forming a degassing groove with satisfactory accuracy and at a low cost, easily, and without being restrained by the forming place of the degassing groove, the shape of the groove, and size, and a molding mold provided with the degassing groove, excellent in a degassing effect, free from generation of a burr. SOLUTION: In the manufacturing method for the molding mold for molding a metal and a resin, when pouring either of a molten metal, semi-molten metal, semi-solidified metal, molten resin, and semi-molten resin in a mold cavity by gravity or pressure, the degassing groove for discharging gas in the cavity to the outside of the mold on at least either mold members constituting the mold, and the degassing groove is formed by embossing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of manufacturing a molding die used when molding a metal or a resin, and a molding die manufactured by the method.

[0002]

2. Description of the Related Art When a molten metal or the like is filled into a mold cavity by using a mold such as a mold casting method, a semi-melt molding method, a semi-solidification molding method and a die casting method, or a molten resin is molded into a metal mold. When filling and molding in the mold cavity, it is important to effectively discharge the gas in the mold cavity out of the mold. As the gas in the mold cavity, the gas originally generated in the mold is generated from the core in the case of the mold casting method, or the mold blown into the mold cavity in the case of the die casting method. It is a gas mixed with evaporative gas of the agent. A defect caused by the gas caught in the cast product during casting may occur, and a gas defect portion may become a problem in a machining process such as screwing of the cast product in a subsequent process. Further, problems such as poor appearance and poor quality of the cast product also occur. The same applies to resin molding.

Therefore, in the case of the gravity casting method or the low pressure casting method, as described in JP-A No. 11-221656, the depth of the outer peripheral surface of the extrusion pin attached to the mold is 0.3 to An invention has been presented in which a large number of 0.4 mm grooves are provided. Further, in Japanese Unexamined Patent Publication No. 2000-102851, in a semi-solid forming method of filling a cavity with a semi-solid metal billet to produce a metal molded product, a groove width on the outer peripheral surface of an extrusion pin is a solid phase of the semi-solid metal billet. An invention has been proposed in which a gas vent groove having a size smaller than the particle size is provided.

All of these gas vent grooves have been formed by machining or electric discharge machining. Molding method, shape of molded product, temperature of molten metal to be injected into the mold cavity,
It is necessary to properly set the formation position of the gas vent groove in the mold, the shape, and the size of the groove by the injection pressure and the like. It is important to form a degassing groove that has a degassing effect, does not generate burrs due to the insertion of molten metal into the groove, and does not hinder the movement of the extrusion pin.

Depending on the set location of the gas venting groove in the mold, the shape and size of the groove, when forming the gas venting groove, there is a limit to the machinable range in the machining, and it is generally V-shaped. Is the formation of grooves. It is difficult to form the gas vent groove quickly and at low cost without being restricted by the location of the gas vent groove, the shape of the groove, and the dimensions. Similarly, in the electric discharge machining, it is necessary to prepare an electrode according to the formation location of the gas vent groove, the shape and size of the groove, which requires a long time and cost, and requires a corresponding device.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and its object is to be restricted by the location of the gas vent groove, the shape and size of the groove. It is an object of the present invention to provide a simple method for producing a molding die that can easily form a gas vent groove with high dimensional accuracy and at low cost without any need. Another object of the present invention is to provide a molding die that is provided with a gas vent groove that is excellent in gas venting effect and that does not generate burrs.

[0007]

According to the present invention, in a method of manufacturing a molding die for molding a metal or a resin, a molten metal, a semi-molten metal, a semi-solidified metal, a molten resin, a semi-solid resin, or a semi-solid metal in a die cavity. When at least one of the molten resins is injected by gravity or pressure, a gas vent groove for discharging the gas in the mold cavity to the outside of the mold is formed in at least one of the mold members constituting the mold. In addition, there is provided a method for manufacturing a molding die, characterized in that the gas vent groove is formed by texturing.

In the present invention, it is preferable that the mold member in which the gas vent groove is formed is an extrusion pin and the gas vent groove is formed on the outer peripheral surface thereof. Further, the mold member is a pair of molds forming a mold cavity, and the degassing groove can be formed on at least one mold mating surface.

Further, in the present invention, the mold member is a pair of molds forming a mold cavity, and a mold insertion hole for inserting an extrusion pin provided in at least one mold is provided. A gas vent groove can be formed on the inner wall.

Further, in the present invention, the mold member is a pair of molds forming a mold cavity, and the gas vent groove is formed in at least one mold, and a vent hole is formed in an inner wall of the cavity. It is possible to form the gas vent groove communicating with each other.

Furthermore, in the present invention, the molding die may be a die casting die.
Preferably, it is an extrusion pin and it is preferable to form the gas vent groove on the outer peripheral surface thereof.

According to the present invention, in a molding die for molding a metal or a resin, any one of a molten metal, a semi-molten metal, a semi-solidified metal, a molten resin, and a semi-molten resin is gravity or applied in a mold cavity. At the time of injecting by pressure, a gas vent groove for discharging the gas in the die cavity out of the die is formed in at least one of the die members constituting the die, and the gas vent groove is There is provided a molding die, which is a groove formed by texturing.

[0013]

Embodiments of the present invention will be described below, but it goes without saying that the present invention is not limited to the following embodiments. The method for producing a molding die of the present invention is a method for producing a molding die for molding a metal or a resin, in which any of molten metal, semi-molten metal, semi-solidified metal, molten resin and semi-molten resin is contained in the die cavity. When the gas is injected by gravity or pressure, a gas vent groove for discharging the gas in the die cavity out of the die is formed in at least one of the die members constituting the die, and the gas vent groove is formed. It is characterized in that it is formed by texturing.

The mold is composed of a plurality of mold members including a movable mold and a fixed mold, and a plurality of extrusion pins inserted in one mold member and the other mold member, and has a shape of a molded product. The mold cavity is formed by assembling these mold members. At least one of these mold members is formed with a degassing groove for discharging the gas in the mold cavity to the atmosphere outside the mold by embossing, and these mold members are assembled to form a molding die. Use as a mold.

The present invention is particularly characterized in that the gas vent groove is formed by texturing. For example, in the case of forming a gas discharging groove having a depth of 30 μm and a width of 1 mm in a round rod-shaped extruding pin having a material of SKD61 and a diameter of 10 mm in a straight line in the axial direction (longitudinal direction) of the round rod, the width is 1
mm masking tape 1mm on the outer peripheral surface of the extrusion pin
Those axially attached at intervals are immersed in a nitric acid-based corrosive liquid for 3 minutes, taken out from the corrosive liquid, the masking tape is peeled off, washed with water, and rust preventive oil is applied to complete the process. A plurality of extruding pins can be collectively formed to form a gas vent groove.

The formation of the gas vent groove by the embossing is extremely simple and the dimensional accuracy of the gas vent groove is extremely high. The cost is low and the required work time is extremely short. Furthermore, a major feature is that it can be easily formed regardless of the shape and size of the required gas vent groove. No special equipment is required. It can be easily formed by ordinary workers without the need for special techniques when and as needed at work sites such as casting.

It is very difficult to machine a shallow vent having a depth of 30 μm, a width of 1 mm, and a wide gas vent groove into a round bar having a diameter of 10 mm at equal intervals of 1 mm, and even if it is possible, many It takes time, and the dimensional accuracy of the created gas vent groove is poor. Even in electrical discharge machining, a special electrode is required,
It takes a lot of time.

The degassing groove can be formed by means other than the extrusion pin. For example, the gas vent groove can be formed on the mating surface of one of the pair of molds forming the mold cavity and the other mold. In this case, both molds may be formed, but either one may be formed. A place where gassing failure is a problem, that is, a place where gas in the mold cavity is likely to accumulate can be further formed as a pair of molds, and a gas discharging groove can be formed in the mating surface by graining. The shape of the gas vent groove is 10 μm to 500 μ in depth.
m, and the width is preferably in the range of 0.1 mm to 5 mm.

In addition, a gas vent groove is formed in the inner wall of the mold insertion hole into which the extrusion pin provided in each of the one mold and the other mold of the pair of molds forming the mold cavity is inserted. It can also be formed. In this case, since the molds are generally large, instead of immersing them in the corrosive liquid, one end of the mold insertion hole is sealed and the corrosive liquid is injected into the mold insertion hole. Done.

Further, a degassing groove communicating with a vent hole is formed on the inner wall of the cavity by texturing in at least one of the pair of molds forming the mold cavity wall and the other mold. it can.

In the die casting method, conventionally, no gas vent groove is provided in the extruding pin, and a gas vent hole of about 0.2 mm is provided in the mating surface of the mold (split die). A mold having a structure in which a basin is provided under the mold has been used.

However, even in the die casting method, gas is likely to accumulate in the boss portion, and a gas vent groove was required on the outer peripheral surface of the extrusion pin. However, in the die-casting method, it is not possible to form the degassing groove due to the fact that the molten metal is inserted into the degassing groove having a depth of about 0.2 mm by ordinary machining, burrs are generated, and the movement of the extrusion pin is obstructed. Was not done.

In the die casting method, the inventors of the present invention also obtained an extremely excellent degassing effect and formed burrs when the groove was formed by forming an extremely shallow and wide groove by embossing. However, the inventors have found and invented that a high-quality cast product can be obtained with a high yield. The shape of the gas vent groove with a shallow bottom and a wide width is rectangular in cross section and has a depth of 10
It is a groove having a size range of μm to 50 μm, preferably 20 μm to 30 μm and a width of 0.1 mm to 5 mm.

It is presumed that the shallow bottom prevents the molten metal from being inserted, and the wide bottom provides a gas venting effect. Further, the degassing groove formed by the texturing is an uneven surface having a gently curved surface (etching surface), and it is presumed that this surface state also prevents the molten metal from being inserted. It ’s extremely shallow like this,
It is difficult to machine a wide gas vent groove by machining or the like, and it becomes possible to form a round bar-shaped extrusion pin or the like only by texturing.

A molding die formed by using a die member having a gas vent groove formed by texturing, for example, an extruding pin or the like enables the production of extremely high-quality molded products with a high yield.

[0026]

As described above, according to the method for manufacturing a molding die of the present invention, the dimensional accuracy is high and the cost is low without being restricted by the formation position of the gas vent groove, the shape and the size of the groove. Thus, a simple method for producing a mold for forming a gas vent groove can be obtained. Further, there is provided a molding die having a gas venting groove which is excellent in gas venting effect and does not cause burrs.

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Claims (8)

[Claims] 1. A method of manufacturing a molding die for molding a metal or a resin, wherein any one of a molten metal, a semi-molten metal, a semi-solidified metal, a molten resin and a semi-molten resin is gravity or pressurized in a mold cavity. Forming a gas vent groove for discharging the gas in the mold cavity to the outside of the mold when injecting the gas into the mold cavity, and forming the gas vent groove by embossing. 1. A method for manufacturing a molding die, which comprises forming. 2. The molding die according to claim 1, wherein the die member forming the gas vent groove is an extruding pin, and the gas vent groove is formed on an outer peripheral surface thereof. Production method. 3. The mold member is a pair of molds forming a mold cavity, and the degassing groove is formed on at least one mold mating surface.
The method for producing a molding die according to item 1. 4. The mold member is a pair of molds forming a mold cavity, and a gas vent groove is formed in an inner wall of a mold insertion hole into which an extrusion pin provided in at least one mold is inserted. The method for manufacturing a molding die according to claim 1, wherein the molding die is formed. 5. The pair of molds, wherein the mold members form a mold cavity, wherein the gas vent groove is formed in at least one mold, and the gas communicating with the vent hole is formed on the inner wall of the cavity. The method for manufacturing a molding die according to claim 1, wherein a groove is formed. 6. The method of manufacturing a molding die according to claim 1, wherein the molding die is a die casting mold. 7. The molding die according to claim 6, wherein the die member forming the gas vent groove is an extruding pin, and the gas vent groove is formed on the outer peripheral surface thereof. Production method. 8. In a molding die for molding a metal or a resin, any one of a molten metal, a semi-molten metal, a semi-solidified metal, a molten resin and a semi-molten resin is injected into a mold cavity by gravity or pressure. At this time, a gas vent groove for discharging the gas in the die cavity to the outside of the die is formed in at least one of the die members constituting the die, and the gas vent groove is formed by texturing. A mold for molding, which is a groove formed.