JP2018111124A - Metal mold device, vent pin and method for molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal mold device, vent pin and method for molding that can drastically improve gas emission amount and maintain work efficiency as well.SOLUTION: A metal mold device 1 comprises a metal mold 4 configuring a mold cavity 3 in which a molten material is poured and a cylindrical extrusion pin 9 inserted in a pin hole 8 provided in the metal mold 4 so that after a molten material is poured in the mold cavity 3, a solidified molding is pushed out by the extrusion pin 9. In a gap between the extrusion pin 9 and the pin hole 8, a vent part 13 is configured with an annular gas introduction port 21 having a diameter difference r of 0.02-0.50 mm between a tip outer peripheral surface 9a of the extrusion pin 9 and an inner peripheral surface 8a of the pin hole 8 and an exhaust passage 22 configured broad from the gas introduction port 21 toward a rear of the extrusion pin. The gas introduction port 21 is given an axial length n of 1.00-11.00 mm.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a molding die apparatus used for casting of light metals such as aluminum and molding of resin, and a molding method, and in particular, a high-quality molded product can be obtained by quickly exhausting gas existing in a runner or cavity to the outside. The present invention relates to a mold apparatus, a vent pin, and a molding method that can be obtained.

  For example, in casting by die casting, gas such as air and water vapor existing in the mold enters the cavity by the molten metal pushed by the plunger. It is known that defects such as a nest of a die-cast molded product can be reduced by molding in a state where the gas in the cavity is discharged as much as possible to the outside. As a technique for reducing defects in a die cast product, a vacuum die casting method in which die casting is performed in a state where the inside of a cavity is decompressed is widely used.

  In the vacuum die casting method, there is a problem that equipment and maintenance for increasing the degree of vacuum in the cavity are required and the cost increases. As a method not using the vacuum die casting method, providing a vent portion for discharging gas to a molding die is performed. FIG. 13A is a schematic cross-sectional view of a general molding die 100. In this molding die 100, molten metal passes through a runner 101 and a gate 102 and is filled into a cavity 105 constituted by a fixed die 103 and a movable die 104. At that time, the gas existing in the cavity 105 or the like passes through the overflow portion 106 and is discharged to the outside of the mold.

  The overflow part 106 is provided with a vent part 107 through which gas is discharged to the outside of the mold. As shown in FIG. 13B, the vent portion 107 is usually provided with a gap of about 0.5 mm on the opposite side of the overflow portion 106 from the cavity 105. As the distance from the cavity 105 increases, the gap gradually becomes about 0.1 mm. It has become a shape that can be narrowed to. By setting it as such a vent part 107, gas is discharged | emitted and a molten metal shall not be blown off by casting pressure.

  However, since the conventional vent part 107 becomes narrow as it leaves | separates from the cavity 105, the exhaust_gas | exhaustion resistance of gas is large. Further, the molten metal enters the vent portion 107 and solidifies, thereby inhibiting gas discharge. For this reason, it cannot be said that the gas is exhausted sufficiently by the conventional vent portion 107, and accordingly, it is difficult to further improve the quality of the die cast product.

  In Patent Document 1, a wedge-shaped notch that narrows toward the rear is provided at the tip of an extrusion pin for extruding a molded product molded in a cavity, and gas is provided by providing a groove behind the notch. The extrusion pin to be discharged is described. Patent Document 2 describes a method of discharging gas by providing a similar notch at the tip of an extrusion pin that pushes out a runner connected to a cavity. As disclosed in Patent Document 3, a method of discharging gas by a chill vent provided in a cavity is also known.

Japanese Patent No. 4085182 Japanese Patent No. 5431780 JP 2003-132656 A

  When the method of Patent Document 2 was used for aluminum casting by die casting, and gas was discharged by a runner in front of the cavity, a better die cast product was obtained than when gas was discharged at a conventional vent part. However, the amount of gas discharged by this method is not sufficient, and it is difficult to obtain a high-quality die-cast product. Even with the method using the chill vent of Patent Document 3, the amount of gas discharge cannot be dramatically improved, and the quality of the die-cast molded product is also accompanied by this.

  Extrusion marks pressed by the extrusion pin remain in the molded product obtained at the time of mold opening. In the gas discharge method of Patent Document 2, for example, as shown in FIG. 14, the wedge-shaped trace at the tip of the extrusion pin remains on the runner in a sharp shape, and there is a risk that the hand may be damaged during the excision work of the runner. There has been a problem of lowering work efficiency.

  Therefore, in view of the problems of the prior art, the present invention provides a molding die device, a vent pin, and a molding method that can dramatically improve the amount of gas discharged and maintain work efficiency. Objective.

  A molding die apparatus according to the present invention includes a molding die that forms a cavity filled with a molten material, and a pin hole that is provided in the molding die and communicates with the cavity or a flow path of molten material that enters and exits the cavity. A vent portion for discharging gas along the longitudinal direction of the vent pin is formed in a gap between the vent pin and the pin hole into which the vent pin is inserted. The portion is configured by an outer peripheral surface of the tip of the vent pin and an inner peripheral surface of the pin hole, and an annular gas inlet having a diameter difference of 0.02 to 0.50 mm between the outer peripheral surface of the tip and the inner peripheral surface. And a discharge path that is configured to have a gas ventilation resistance that is smaller than that of the gas introduction port from the gas introduction port toward the rear of the vent pin, and the axial length of the gas introduction port. One in which there is a 1.00~11.00mm.

  According to the present invention, the vent portion configured by the gap between the vent pin and the pin hole is configured by the tip outer peripheral surface of the vent pin and the inner peripheral surface of the pin hole, and the diameter difference between the tip outer peripheral surface and the inner peripheral surface. An annular gas introduction port having a diameter of 0.02 to 0.50 mm, and a discharge passage that is configured to be wider from the gas introduction port toward the rear of the vent pin so that the gas ventilation resistance is smaller than that of the gas introduction port. have. Unlike the conventional one provided in the overflow part, the vent part directly communicates with the flow path such as the cavity and the runner, and the gas inlet near the cavity and the flow path is thin, and the cavity and the flow path Discharge path far from is wide. In this vent part, since it is once throttled at the gas inlet that communicates directly with the cavity and the flow passage, the gas discharge speed increases, and in the discharge path that is wider than the gas inlet, The gas ventilation resistance after passing through the gas inlet can be reduced. Thereby, the discharge | emission amount of gas can be improved. The molded product has no sharp profile and does not damage the hand during post-processing operations. Thereby, work efficiency can be maintained.

  Since the length of the gas inlet is set to 1.00 to 11.00 mm, an appropriate ventilation resistance can be obtained, and blowing of molten metal can be prevented.

The maximum depth h in the vent pin radial direction of the discharge path preferably satisfies the following formula and is 2.00 mm or less.
r <h <(D / 4)
Where r is the difference in diameter between the outer peripheral surface of the tip of the vent pin and the inner peripheral surface of the pin hole, and D is the diameter of the vent pin. In this case, it is possible to effectively reduce the gas ventilation resistance after passing through the gas inlet and to prevent the molten material from blowing out.

  For example, the discharge path includes a plurality of chamfered portions extending in the longitudinal direction formed at a predetermined interval in the circumferential direction on the peripheral surface of the vent pin, and a plurality of exhaust air configured by an inner peripheral surface of the pin hole. What is necessary is just to have a channel | path. In this case, it is possible to obtain an appropriate gas flow resistance after passing through the gas inlet.

  The width of each exhaust passage in the direction orthogonal to the axial direction is preferably 1 to 20 mm. By setting the width of each exhaust passage in the direction orthogonal to the axial direction to 1 to 20 mm, the gas after passing through the gas inlet can be quickly discharged.

  As another discharge path, the discharge path is composed of a single chamfered portion extending in the longitudinal direction formed on the peripheral surface of the vent pin and an inner peripheral surface of the pin hole. It is good also as what has. In this case, it is possible to obtain an appropriate gas flow resistance after passing through the gas inlet.

  You may form the groove | channel over the vent pin longitudinal direction full length of the said gas introduction port in the front-end | tip outer peripheral surface of the said vent pin. In this case, it is possible to increase the amount of gas flow while maintaining an appropriate gas flow resistance at the gas inlet.

  It is preferable that the range of at least 3 mm from the gas inlet side end portion in the discharge path to the opposite side has the same cross-sectional shape. By not providing, for example, a concave portion or a convex portion in the vicinity of the gas inlet side end of the discharge path, gas can be discharged smoothly.

  It is preferable that the tip of the vent pin penetrates axially rearward from the inner surface of the flow passage, or protrudes axially forward from the inner surface of the flow passage. In this case, a pressure change occurs in the molten material such as the molten metal, the molten metal and the gas are separated, and the degassing efficiency by the vent pin can be improved.

  It is preferable that the vent portion is provided so that gas is discharged at a high change portion where a change in flow rate or pressure of the molten material increases. In the high-change part where the flow rate of the molten material and the pressure change accordingly, the gas is separated and discharged due to the difference in specific gravity between the gas and the molten material, so that the gas can be discharged more effectively and the amount of gas discharged is further increased. be able to.

  An overflow portion having a weight of 1/4 or more of a product weight for accumulating molten material is provided in the cavity via the flow passage, and the high change portion is a portion where the flow velocity changes depending on the product shape. Preferably there is. When the flow of the molten material such as molten metal stops, solidification progresses, and when solidification progresses, degassing becomes impossible. For this reason, a large overflow is provided, a flow of the molten metal is created in the cavity, the gas and the molten metal are separated, the high change portion is set as a portion where the flow velocity changes depending on the product shape, and the vent portion is appropriately arranged. Thereby, degassing is performed efficiently and product quality can be improved.

  The high change portion is, for example, a bent portion of the runner. In the case where a runner that introduces the molten material serving as the flow path and a gate that serves as an inlet for the molten material into the cavity exist, the high change portion is a boundary portion between the runner and the gate. It is. The high speed changing portion is a flow path of the overflow portion.

  The vent pin of the present invention is a vent pin used in the molding die device described above, and includes a front end outer peripheral surface constituting the gas introduction port between the pin hole and an inner peripheral surface of the pin hole, and an axial direction on the front end outer peripheral surface. And an outer side surface which is formed continuously toward the rear and forms the discharge path with the inner peripheral surface of the pin hole.

  According to the molding die apparatus using the vent pin of the present invention, the vent part constituted by the gap between the vent pin and the pin hole is constituted by the tip outer peripheral surface of the vent pin and the inner peripheral surface of the pin hole, and the tip An annular gas inlet having a diameter difference between the outer peripheral surface and the inner peripheral surface of 0.02 to 0.50 mm, and a gas ventilation resistance smaller than that of the gas inlet from the gas inlet toward the rear of the vent pin. And a discharge path that is widely configured. Unlike the conventional one provided in the overflow part, the vent part communicates directly with the introduction path such as the cavity and the runner, and the gas inlet near the cavity and the introduction path is thin, and the cavity and the introduction path Discharge path far from is wide. In this vent part, since the gas introduction port that directly communicates with the cavity and the introduction path is once throttled, the gas discharge speed increases, and the exhaust path that is wider than the gas introduction port beyond that The gas ventilation resistance after passing through the gas inlet can be reduced. Thereby, the discharge amount of gas can be improved dramatically. The molded product has no sharp profile and does not damage the hand during post-processing operations. Thereby, work efficiency can be maintained. Moreover, since the length of the gas inlet is set to 1.00 to 11.00 mm, an appropriate ventilation resistance can be obtained, and blowing of molten metal can be prevented.

  The molding method of the present invention is a molding method in which molding is performed using the molding die apparatus of the above invention, wherein the gas introduction speed is increased at the gas inlet, and the gas inlet is passed through the outlet. It is characterized by reducing the gas flow resistance afterwards.

  In the molding die apparatus used in the molding method of the present invention, the vent portion constituted by the gap between the vent pin and the pin hole is constituted by the tip outer peripheral surface of the vent pin and the inner peripheral surface of the pin hole, and the tip outer peripheral surface. And an annular gas inlet having a diameter difference between the inner peripheral surface of 0.02 and 0.50 mm, and a discharge path that is wider than the gas inlet from the gas inlet toward the rear of the vent pin. Have. Unlike the conventional one provided in the overflow part, the vent part communicates directly with the introduction path such as the cavity and the runner, and the gas inlet near the cavity and the introduction path is thin, and the cavity and the introduction path Discharge path far from is wide. In this vent part, since the gas introduction port that directly communicates with the cavity and the introduction path is once throttled, the gas discharge speed increases, and the exhaust path that is wider than the gas introduction port beyond that The gas ventilation resistance after passing through the gas inlet can be reduced. Thereby, the discharge amount of gas can be improved dramatically. The molded product has no sharp profile and does not damage the hand during post-processing operations. Thereby, work efficiency can be maintained. Moreover, since the length of the gas inlet is set to 1.00 to 11.00 mm, an appropriate ventilation resistance can be obtained, and blowing of molten metal can be prevented.

  According to the present invention, the gas discharge speed is increased by the gas inlet, and the gas ventilation resistance after passing through the gas inlet in the previous discharge path can be reduced. Thereby, the discharge amount of gas can be improved dramatically. Since the molded product does not have a sharp deformed portion and does not damage the hand during the post-processing operation, the work efficiency can be maintained.

It is a schematic cross section of a die casting apparatus provided with the molding die apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the molding die apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the state in which the extrusion pin is inserted by the pin hole. It is a front view of an extrusion pin. It is a perspective view of an extrusion pin. It is a principal part expanded sectional view of the state by which the extrusion pin is inserted by the pin hole. It is a microscope picture of a molded article cross section. It is a perspective view of the flow path of the example which provided the vent part in the bending location of the runner which is a high change part. (A) is sectional drawing of the example which provided the vent part in the boundary part of the runner and the gate 51 which is a high change part. (B) is sectional drawing of the example which provided the vent part in the flow path of the overflow part which is a high change part. It is a perspective view of the front-end | tip part which shows the modification of a vent pin. (A) And (b) is a perspective view which shows the other modification of a vent pin. It is a perspective view which shows the other modification of a vent pin. (A) is a schematic cross-sectional view of a conventional molding die, and (b) is a schematic cross-sectional view of an overflow portion in the conventional molding die and its vicinity. It is a principal part photograph of the conventional die-cast molded product shape | molded using the extrusion pin in which the vent part was formed.

  An embodiment of the present invention will be described by taking die casting as an example. FIG. 1 is a schematic cross-sectional view of a die casting apparatus 2 including a molding die apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the molding mold apparatus 1 according to an embodiment of the present invention. This die casting apparatus 2 is a casting apparatus for obtaining a die cast product, and a molding die apparatus 1 having a molding die 4 constituting the cavity 3 and a molten metal as a molten material in the cavity 3 in a pressurized state. A pressurizing mechanism 5 for filling and a material supply unit 7 for supplying molten metal to a supply path 6 between the molding die 4 and the pressurizing mechanism 5 are provided.

  The molding die apparatus 1 includes a molding die 4 constituting a cavity 3 filled with a molten material, and a cylindrical extrusion pin (vent pin) 9 fitted in a pin hole 8 provided in the molding die 4. And. The pressurizing mechanism 5 includes a molten metal reservoir, a hydraulic cylinder 10, a plunger 11 introduced into the hydraulic cylinder 10, and the like. Molten metal introduced into the supply path 6 between the molding die 4 and the pressurizing mechanism 5 is filled into the cavity 3 by the pressure of the plunger 11.

  The molding die 4 includes a main mold 15 and a nest 16 fitted into the main mold 15. The main mold 15 includes a fixed main mold 17 and a movable main mold 18. A fixed side insert 19 is fitted into the fixed main mold 17, and a movable side insert 20 is fitted into the movable main mold 18. The nesting 16 includes a fixed nesting 19 and a movable nesting 20 that can be moved back and forth with respect to the fixed nesting 19 and can be changed between a mold closed state and a mold open state. The fixed side insert 19 and the movable side insert 20 constitute a cavity 3, and a flow path such as a gate or a runner serving as a runner is formed in the molding die 4.

  After the mold 4 is closed, molten aluminum (hereinafter referred to as molten metal) is poured into the supply path 6 from the material supply unit 7, the plunger 11 of the pressurizing mechanism 5 moves forward, and the molten metal in the supply path 6 is molded. It is transferred to the mold 4. The molten metal flows into the cavity 3 through a runner, a gate, etc. and is filled. Thereafter, the molten metal is solidified in the cavity 3 to form a molded product. After the molding die 4 is opened, the solidified molded product is pushed out by the extrusion pin 9 and released from the molding die 4.

  3 is a cross-sectional view of a state where the push pin 9 is inserted into the pin hole 8 provided in the runner 12, FIG. 4 is a front view of the push pin 9, and FIG. 5 is a perspective view of the push pin 9. FIG. 6 is an enlarged cross-sectional view of the main part in a state where the push pin 9 is inserted into the pin hole 8. In the gap between the push pin 9 and the pin hole 8 into which the push pin 9 is inserted, a vent portion 13 for discharging the gas from the runner 12 and the cavity 3 is formed along the longitudinal direction of the push pin 9.

  The vent portion 13 has an annular gas inlet 21 formed by the tip outer peripheral surface 9a of the push pin 9 and the inner peripheral surface 8a of the pin hole 8, and gas ventilation from the gas inlet 21 toward the rear of the push pin. It has a discharge path 22 that is wider than the gas inlet 21 so as to reduce the resistance. Here, being wider than the gas introduction port 21 means that the cross-sectional area of the gas flow passage in the flow direction (the cross-sectional area perpendicular to the left-right direction in FIG. 3) is made larger than that of the gas introduction port 21. The cross-sectional area of the discharge passage 22 is larger than the cross-sectional area of the gas introduction port 21, and the length of the discharge passage 22 in the axial direction rearward is sufficiently longer than the gas introduction port 21. Can flow quickly toward the rear in the axial direction.

  The tip portion 9s of the push pin 9 that is a part of the gas inlet 21 is cylindrical, and the diameter difference r between the tip outer peripheral surface 9a of the push pin 9 and the inner peripheral surface 8a of the pin hole 8 is 0.02 to 0. .50 mm is preferable, and 0.05 to 0.35 mm is more preferable. In the case of this embodiment in which the tip 9s of the extrusion pin 9 that is a vent pin enters the axial direction rearward from the inner surface 12a of the runner 12 that is a flow passage, the tip portion of the extrusion pin 9 that becomes a part of the gas inlet 21 The axial length n of 9s is preferably 1.0 to 11.0 mm, more preferably 3.0 to 7.0 mm. Accordingly, the gas inlet 21 is a cylindrical space having a diameter difference r between the inner and outer diameters of 0.02 to 0.50 mm and an axial length n of 1.0 to 11.0 mm. As the diameter difference r between the distal outer peripheral surface 9a of the push pin 9 and the inner peripheral surface 8a of the pin hole 8 is increased, the axial length n of the distal end portion 9s of the push pin 9 may be increased.

  The discharge passage 22 that is configured to be wider than the gas introduction port 21 so that the gas ventilation resistance is smaller is a plurality of chamfers extending in the longitudinal direction formed at predetermined intervals in the circumferential direction on the peripheral surface of the push pin 9. It has a plurality of exhaust passages 24 composed of a portion (outer surface) 23 and an inner peripheral surface 8 a of the pin hole 8. The chamfered portion 23 is continuously formed on the distal end outer peripheral surface 9a toward the rear in the axial direction. The gas passage on the axially rear side of the gas inlet 21 is expanded by the amount of the chamfer 23. That is, the discharge path 22 includes a space between the outer peripheral surface portion 23 a where the chamfered portion 23 of the push pin 9 is not formed and the inner peripheral surface 8 a of the pin hole 8, and the plurality of exhaust passages 24 described above. Has been.

  The plurality of exhaust passages 24 are configured at equal intervals in the circumferential direction of the push pin 9. The discharge passage 22 of the present embodiment has four exhaust passages 24 provided at equal intervals with an angle of 90 °. The number of exhaust passages constituting the discharge path is not limited.

Each exhaust passage 24 is formed in a vertically long rectangular shape in plan view by chamfering a part of the peripheral surface of the push pin 9. The maximum depth h of each exhaust passage 24 in the radial direction of the push pin preferably satisfies the following formula and is 2.00 mm or less.
r <h <(D / 4)
Where r is the difference in diameter between the outer peripheral surface of the tip of the vent pin and the inner peripheral surface of the pin hole, and D is the diameter of the vent pin.

  1-20 mm is preferable and, as for the width m of the direction orthogonal to the axial direction in each exhaust passage 24, 5-15 mm is more preferable. The maximum depth h in the direction of the push pin diameter is more advantageous for degassing, but is limited to 2 mm from the viewpoint of pin strength. For this reason, degassing can be more effectively performed by increasing the pin hole 8 from a position 10 mm above the product end surface to 1.2 to 2.0 times the pin diameter.

  Gases such as air existing in the runner 12 and the cavity 3 are discharged to the outside of the molding die 4 through the vent portion 13 and the flow path ahead. The transferred molten metal slightly flows into the vent portion 13, but solidifies in the vicinity of the inlet of the gas inlet 21 and does not enter deep into the gap space of the gas inlet 21. By configuring the vent portion 13 with a gas introduction port 21 in a thin gap space and a plurality of exhaust passages 24 having a gap space wider than that, the following action can be obtained.

  When the molten metal flows into the runner 12, the vicinity of the inlet of the gas inlet 21 configured by a narrow gap space is depressurized, and the discharge speed of the gas existing in the runner 12 increases. Since the plurality of exhaust passages 24 ahead are wider than the gas inlet 21, the gas ventilation resistance after passing through the gas inlet 21 can be reduced. That is, it is possible to perform a molding method that increases the gas discharge speed of the runner 12 at the gas inlet 21 and reduces the gas ventilation resistance after passing through the gas inlet 21 through the plurality of exhaust passages 24. By performing this molding method, the amount of gas discharged can be dramatically improved.

  By setting the length n in the axial direction of the gas inlet 21 to 1.0 to 11.00 mm, an appropriate ventilation resistance can be obtained, and the blowout of molten metal can be prevented. By setting the maximum depth h in the radial direction of the extrusion pin of each exhaust passage 24 constituting the discharge passage 22 to satisfy the above formula and not more than 2.00 mm, the gas ventilation resistance after passing through the gas inlet 21 is reduced. It can reduce effectively and the blowing of molten material can be prevented with it.

  By setting the width m of each exhaust passage 24 in the direction orthogonal to the axial direction to 1 to 20 mm, the gas after passing through the gas inlet 21 can be quickly discharged. The flow path of the main mold 15 further ahead of the end of each exhaust passage 24 may be a larger flow path than each exhaust passage 24. By setting the dimensions of each part of the gas inlet 21 and each exhaust passage 24 within the above ranges, the gas in the runner 12 and the cavity 3 can be efficiently discharged while preventing the molten metal from being blown out.

  As shown in the present embodiment, the tip 9s of the push pin 9 enters the rear side in the axial direction with respect to the inner surface 12a of the runner 12, which is a flow path, and, as shown by the phantom line in FIG. You may make it the front-end | tip 9s of a certain extrusion pin 9 protrude in the axial direction front rather than the inner surface 12a of the runner 12 which is a flow path. In this case, a pressure change occurs in the molten material such as the molten metal, the molten metal and the gas are separated, and the gas venting efficiency by the vent portion 13 can be improved. Thus, even when the tip 9s of the extrusion pin 9 that is a vent pin protrudes forward in the axial direction, the axial length n of the tip portion 9s of the extrusion pin 9 is preferably 1.0 to 11.0 mm. Preferably it is 3.0-7.0 mm.

  For example, when the extrusion pin 9 is arranged in the molding die device 1, a range d1 that is allowed to enter the axial direction with reference to the inner surface 12a of the runner 12 is 5 mm, and a range d2 that is projected is 5 mm. Adjust the position with. By doing in this way, a pressure change arises in a molten metal, separation of a molten metal and gas is achieved and the degassing efficiency by the vent part 13 becomes favorable. Conventionally, the tip 9s of the push pin 9 is inserted axially rearward from the inner surface 12a of the runner 12, but the tip 9s of the push pin 9 is protruded forward in the axial direction from the inner surface 12a of the runner 12.

  The tip 9s of the extruding pin 9 that is a vent pin is protruded, and the flow rate of the molten material that is a molten material is narrowed. Therefore, the flow rate is increased and the pressure is decreased, so that bubbles are increased and separation is facilitated by buoyancy. Thereby, the improvement of the degassing effect can be expected. When the vent portion 13 is configured as a product portion, the tip 9s of the extrusion pin 9 and the inner surface 12a of the runner 12 are flush with each other, and when used in the runner or overflow portion, the inner surface 12a of the runner 12 as described above. The position may be adjusted in the range of −5 mm to +5 mm with reference to the above.

  When the tip 9s of the push pin 9 as a vent pin protrudes axially forward from the inner surface 12a of the runner 12, it is preferable to provide a tapered draft portion 40 at the tip of the push pin 9 as shown in FIG. . If the draft angle portion 40 is provided, the runner 12 and the extrusion pin 9 can be easily released from each other. The angle of the draft portion 40 is, for example, about 10 °. Moreover, when the extrusion pin 9 is disposed in the product portion, the product and the extrusion pin 9 can be easily released from each other.

  Referring to FIG. 6, a range k of at least 3 mm from the gas inlet side end in the discharge path 22 toward the opposite side has the same cross-sectional shape. The range k having the same cross-sectional shape is preferably 3 mm, more preferably 5 mm, and still more preferably 10 mm. Thus, the vicinity of the gas inlet side end of the discharge path 22 has the same shape and, for example, no recess or protrusion is provided, so that gas can be discharged smoothly.

  Even when the extruding pin 9 as a vent pin is installed and gas is discharged, if an overflow portion is not provided, an island-like structure (initial solidified piece) may occur in the molded product as shown in the photograph of FIG. This phenomenon is considered to be due to a part of the molten metal being instantaneously cooled on the inner surface of the mold. If there is no overflow portion, the initial solidified piece solidifies inside the cavity 3. Therefore, it is only necessary to provide an overflow portion for storing the molten material in the cavity 3 through the flow passage in a state where the vent portion 13 is provided.

  By providing the cavity 3 with the overflow part for storing the molten material, the island-like structure (initial solidified piece) can be guided to the inside of the overflow part, and a flow of molten metal is created inside the cavity 3. By arranging the extrusion pin 9 that is a vent pin at the site where the flow velocity varies depending on the product shape, it is possible to efficiently vent the gas and to suppress the generation of the island structure as described above. Products can be manufactured.

  Regarding the location where the vent portion 13 is provided, the pin hole 8 and the extrusion pin 9 constituting the vent portion 13 may be provided so that gas is discharged at a high change portion where the flow rate or pressure of the molten material increases. In the high-change part where the flow rate of the molten material and the pressure change accordingly, the gas is separated and discharged due to the difference in specific gravity between the gas and the molten material, so that the gas can be discharged more effectively and the amount of gas discharged is further increased. be able to.

  An overflow part having a weight of 1/4 or more of the product weight for storing the molten material is provided in the cavity 3 through the flow path, and the high change part is a part where the flow velocity changes depending on the product shape. Is preferred. When the flow of the molten material such as molten metal stops, solidification progresses, and when solidification progresses, degassing becomes impossible. For this reason, a large overflow is provided, a flow of the molten metal is created in the cavity, the gas and the molten metal are separated, the high change portion is set as a portion where the flow velocity changes depending on the product shape, and the vent portion 13 is appropriately arranged. Thereby, degassing is performed efficiently and product quality can be improved.

  When the flow stops, the molten metal begins to solidify, and the gas in the molten metal that cannot be removed at the runner part becomes a nest as it is. For this reason, on the opposite side of the main gate, a large overflow of 1/4 or more of the product weight (if it is too large, solidification cannot be made in time and it will explode after opening the mold) is provided. By making a flow of the molten metal in the cavity 3 and disposing the extrusion pin 9 as a vent pin at a portion where the flow rate changes depending on the product shape, the gas can be efficiently vented. This makes it possible to manufacture high quality die cast products. In addition, it is thought that separation of a molten metal and gas will be accelerated | stimulated by the buoyancy increase by the volume of gas increasing by the pressure reduction and the specific gravity difference of a molten metal and gas if the flow velocity of a molten metal becomes high.

(Separation of molten aluminum and gas)
In order to efficiently degas the die casting, it is necessary to separate the molten aluminum and the gas mixed in the sleeve. For this purpose, the following method may be used.
1. Thin the runner. 2. Make the gate smaller. 3. Bend the runner. 4). Provide a pool in the vent pin. 1.2. Then, the flow rate is increased, separation is performed by the difference in specific gravity between the molten metal and the gas, and the pressure of the molten metal is decreased, the gas volume is increased, and separation from the molten metal is performed by buoyancy. 3.4. Then, the flow path of the molten metal is bent to increase the flow resistance, and the separation is achieved by the difference in specific gravity from the gas.

  For example, as shown in FIG. 8, the high change portion 50 is a bent portion of the runner 12, and the bent portion 13 may be provided at this bent portion. As shown in FIG. 9A, the boundary portion between the runner 12 that introduces the molten material that becomes the flow path and the gate 51 that becomes the injection port of the molten material into the cavity 3 becomes the high change portion 50, and this boundary portion A vent portion 13 may be provided in As shown in FIG. 9B, the flow passage 55 of the overflow portion 52 is the high change portion 50, and the vent portion 13 may be provided in this flow passage 55. In these cases, the gas can be discharged more effectively, and the amount of gas discharged can be further increased.

  In the molding die device 1 and the molding method of the present embodiment, the vent portion 13 constituted by the gap between the extrusion pin 9 and the pin hole 8 is formed by the tip outer peripheral surface 9 a of the extrusion pin 9 and the inner peripheral surface 8 a of the pin hole 8. And an annular gas inlet 21 having a diameter difference r between the tip outer peripheral surface 9a and the inner peripheral surface 8a of 0.02 to 0.50 mm, and from the gas inlet 21 toward the rear side of the extrusion pin. And a discharge passage 22 that is wider than the gas inlet 21 so that the gas ventilation resistance is smaller. Unlike the conventional one provided in the overflow portion, the vent portion 13 communicates directly with the introduction path such as the cavity 3 and the runner 12, and the gas inlet 21 near the cavity 3 and the introduction path is thin. The discharge path 22 far from the cavity 3 and the introduction path is wide.

  In the vent portion 13, since the gas introduction port 21 that directly communicates with the cavity 3 and the introduction path is once throttled, the gas discharge rate increases and is wider than the gas introduction port 21 beyond that. The gas passage resistance after passing through the gas inlet 21 in the discharge path 22 can be reduced. Thereby, the discharge amount of gas can be improved dramatically. The molded product has no sharp profile and does not damage the hand during post-processing operations. Thereby, work efficiency can be maintained. By using the molding die device 1 and the molding method of the present embodiment, a high-quality die-cast molded product with extremely few defects such as a nest can be obtained.

  A plurality of discharge passages 22 are constituted by a plurality of chamfered portions 23 extending in the longitudinal direction formed at a predetermined interval in the circumferential direction on the peripheral surface of the extrusion pin 9, and an inner peripheral surface 8 a of the pin hole 8. Therefore, it is possible to obtain an appropriate gas ventilation resistance after passing through the gas inlet 21. Since the plurality of exhaust passages 24 are configured at equal intervals in the circumferential direction of the extrusion pin 9, there is no bias in the discharge state of the gas after passing through the gas introduction port 21, and around the gas introduction port 21. The gas can be introduced evenly along.

  The present invention is not limited to the above embodiment. The said embodiment is illustration of the shaping die apparatus which concerns on this invention, a vent pin, and the shaping | molding method, and is not restrictive. The molding die device, the vent pin, and the molding method of the present invention can be applied not only to aluminum but also to other metals, and can also be applied to injection molding for molding a synthetic resin. In particular, high-quality magnesium molded products can be obtained by molding magnesium using the molding die apparatus, vent pin and molding method according to the present invention. In the said embodiment, although the vent part is provided in the runner, you may provide a vent part in the other introduction path or cavity of molten material. You may provide a vent part in both introduction paths and cavities of molten materials, such as a runner.

  The vent pin in the present invention includes any pin shape used for molding, and is not limited to an extrusion pin for releasing a molded product from a mold. Any cylindrical pin may be used as long as it is inserted into a cavity or a pin hole communicating with a molten material introduction path into the cavity. As another form of the vent pin, for example, a cast pin for forming a pilot hole of a bolt hole in advance in casting of a cast product having a bolt hole or the like can be mentioned. Moreover, the pin etc. which were inserted by the pin hole provided in the metal mold | die only for providing a vent part are also contained.

  FIG. 10 is a perspective view showing a modification of the push pin (vent pin). As shown in FIG. 10, a plurality of grooves 31 may be formed on the distal end outer peripheral surface 30 a of the extrusion pin (vent pin) 30 over the entire length of the gas inlet in the longitudinal direction of the vent pin. The plurality of grooves 31 may be provided so as to correspond to the chamfered portions 23 as shown in FIG. The size and number of grooves are not limited, and a plurality of grooves may be provided corresponding to one chamfer 23. In this case, it is possible to increase the amount of gas flow while maintaining an appropriate gas flow resistance at the gas inlet.

  The shape of the exhaust passage is not limited. FIGS. 11A and 11B are perspective views showing another modification of the push pin (vent pin). In the extrusion pin 32 shown in FIG. 11A, the number of chamfered portions 33 is larger than that in the first embodiment shown in FIG. As shown in FIG. 11 (b), the discharge path is not composed of a plurality of exhaust passages, and the outer peripheral surface 35b having a diameter smaller than the outer peripheral surface 35a of the push pin 35 and the inner peripheral surface of the pin hole. It may be configured. The discharge path may have a wider shape as it goes rearward of the vent pin.

  FIG. 12 is a perspective view showing another modification of the push pin (vent pin). In contrast to the push pin 9 of the first embodiment shown in FIG. 5 provided with four chamfered portions 23, the push pin 35 is provided with only one chamfered portion 36. In other words, in this example, the discharge path has only one exhaust gas constituted by only one chamfered portion 36 formed in the peripheral surface of the push pin 35 and extending in the longitudinal direction and the inner peripheral surface of the pin hole. Has a passage. In this example, a tapered draft portion 40 is provided at the tip of the extrusion pin 35. As still another modification, only two chamfered portions may be provided in an opposing manner (at intervals of 180 °). In the case of an extrusion pin having a diameter smaller than about 8 mm, the influence on the strength is increased by providing a chamfered portion. When the present invention is applied to an extrusion pin having a small diameter, if the number of chamfered portions is reduced as in the modified example of FIG. 9, strength reduction can be prevented.

  The cross-sectional shape of the vent pin and the pin hole constituting the vent portion may be not only circular but also polygonal, and in this case, it becomes a polygonal annular gas inlet. The shape of the molding die, the shape of the fixed side insert and the shape of the movable side insert, the shape of the main die, the shape of the runner, the number and shape of the vent portions, and the portion of the die where the vent portions are provided are not limited. When using the molding die of the present invention provided with a vent portion, the various members provided as necessary may have any form as long as the effects of the present invention are not impaired.

DESCRIPTION OF SYMBOLS 1 Molding device 2 Die-casting device 3 Cavity 4 Molding die 5 Pressurizing device 6 Supply path 7 Material supply part 8 Pin hole 8a Inner peripheral surface 9 Extrusion pin (vent pin)
9a tip outer peripheral surface 9s tip portion 12 runner 13 vent portion 16 nesting 21 gas introduction port 22 discharge path 23 chamfering portion 23a outer peripheral surface portion 24 exhaust passage 30, 32, 35 Extrusion pin (vent pin)
30a Tip outer peripheral surface 31 Groove 33, 36 Chamfered portion 40 Draft portion r Diameter difference between the outer peripheral surface of the push pin and the inner peripheral surface of the pin hole n Length in the axial direction of the tip portion of the push pin h Maximum of each exhaust passage Depth m Width in the direction perpendicular to the axial direction in the exhaust passage

Claims (15)

Molding die constituting a cavity filled with a molten material, and a cylindrical vent pin provided in the molding die and fitted into a pin hole communicating with the cavity or a flow path of the molten material entering and exiting the cavity And
In the gap between the vent pin and the pin hole into which the vent pin is inserted, a vent portion for discharging gas along the longitudinal direction of the vent pin is configured.
The vent portion is composed of an outer peripheral surface of the tip of the vent pin and an inner peripheral surface of the pin hole, and an annular gas introduction in which a difference in diameter between the outer peripheral surface of the tip and the inner peripheral surface is 0.02 to 0.50 mm. An outlet, and a discharge passage that is widely configured so that the gas ventilation resistance is smaller than that of the gas inlet toward the rear of the vent pin from the gas inlet,
The molding die apparatus whose axial direction length of the said gas inlet is 1.00-11.00 mm. The molding die apparatus according to claim 1, wherein the maximum depth h of the discharge path in the radial direction of the vent pin satisfies the following formula and is 2.00 mm or less.
r <h <(D / 4)
Where r is the difference in diameter between the outer peripheral surface of the tip of the vent pin and the inner peripheral surface of the pin hole, and D is the diameter of the vent pin.   The discharge path includes a plurality of exhaust passages configured by a plurality of chamfered portions extending in the longitudinal direction formed at predetermined intervals in the circumferential direction of the vent pin and an inner peripheral surface of the pin hole. The molding die apparatus of Claim 1 or 2 which has.   The molding die apparatus according to claim 3, wherein a width of each exhaust passage in a direction orthogonal to the axial direction is 1 to 20 mm.   The discharge path has a single exhaust passage formed of a single chamfered portion extending in the longitudinal direction formed on the peripheral surface of the vent pin and an inner peripheral surface of the pin hole. The molding die apparatus according to claim 1 or 2, wherein   The molding die device according to any one of claims 1 to 5, wherein a groove is formed on the outer peripheral surface of the tip of the vent pin over the entire length of the gas inlet in the longitudinal direction of the vent pin.   The molding die device according to any one of claims 1 to 6, wherein a range of at least 3 mm from the gas inlet side end portion in the discharge path to the opposite side has the same cross-sectional shape.   The molding die device according to any one of claims 1 to 7, wherein a tip end of the vent pin enters an axially rearward side from an inner surface of the flow passage or protrudes an axially forward side from an inner surface of the flow passage. .   The molding die device according to any one of claims 1 to 8, wherein the vent portion is provided so that gas is discharged at a high change portion where a change in flow rate or pressure of the molten material increases.   An overflow portion having a weight of 1/4 or more of a product weight for accumulating molten material is provided in the cavity via the flow passage, and the high change portion is a portion where the flow velocity changes depending on the product shape. The molding die apparatus according to claim 9.   The molding die device according to claim 9, wherein the high change portion is a bent portion of the runner. There is a runner that introduces a molten material that serves as the flow path, and a gate that serves as an inlet for the molten material into the cavity.
The mold apparatus according to claim 9, wherein the high change portion is a boundary portion between the runner and the gate.   The mold apparatus according to claim 9, wherein the high change portion is a flow path of the overflow portion. It is a vent pin used for the molding die device according to any one of claims 1 to 13,
A tip outer peripheral surface constituting the gas inlet with the inner peripheral surface of the pin hole;
A vent pin formed on the outer peripheral surface of the tip continuously toward the rear in the axial direction and having an outer surface that forms the discharge path with the inner peripheral surface of the pin hole. A molding method for performing molding using the molding die device according to claim 1,
A molding method for increasing the gas discharge speed at the gas inlet and reducing the gas ventilation resistance after passing through the gas inlet through the discharge passage.