JP2007245160A - Reduced pressure die-casting apparatus and reduced pressure die-casting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduced pressure die-casting apparatus and a reduced pressure die-casting method with which the entrapment of the air by jumping ahead molten metal from a runner to a cavity for product, is restrained and the stable quality product can be formed, with a simple constitution. <P>SOLUTION: This reduced pressure die-casting apparatus is provided with: a die 1 forming the cavity 10 for product in the inner part; a plunger for injecting the molten metal M into the cavity 10 for product through a runner 11 and a gate 12 in the die 1; and a pressure reducing means 2 for reducing the pressure in the cavity 10 for product in the die 1. An air passing-through hole 30 through which the air in a sleeve, the runner 11 and the gate 12 can be sucked with the pressure reducing means 2, is provided at the position corresponding to the gate 12 and the molten metal M is prevented from causing to flow into the cavity 10 for product till filling up in the gate 12, and a parting member 3 which allows to cause to flow into the cavity 10 for product when the molten metal M is filled up into the gate 12, is arranged in the gate 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum die casting apparatus and a vacuum die casting method, and in particular, a molding die in which a product cavity is formed, a plunger for injecting molten metal into the product cavity through a runner and a gate of the molding die, and the molding Depressurization die-casting device equipped with decompression means for decompressing (evacuating) the inside of the product cavity of the mold, and a state in which the product cavity is formed inside the mold and the inside of the product cavity of the mold is decompressed (evacuating) The present invention relates to a vacuum die casting method in which a molten metal is injected into a product cavity through a runner and a gate to form a product having a predetermined shape.

  Depressurization (vacuum) die-casting equipment and decompression (vacuum) for injecting molten metal by depressurizing the inside of the product cavity to prevent defects such as casting holes and blowholes due to gas entrainment when the molten metal is injected into the product cavity ) Die casting methods are conventionally known (see, for example, Patent Documents 1 and 2).

Patent Document 1 discloses a sleeve communicating with a (product) cavity of a mold, a plunger chip that is slidably fitted in the sleeve, pushes out molten metal in the sleeve, and injects the molten metal into the cavity, and the cavity A vacuum die casting apparatus having a pressure reduction control means for controlling the degree of pressure reduction in accordance with the position of the plunger tip, wherein the pressure reduction control means comprises a high vacuum pressure reduction means, a low vacuum pressure reduction means, and the plunger tip is Having a switching means for communicating the low vacuum depressurizing means and the cavity when reaching the first position, and for communicating the high vacuum depressurizing means and the cavity when the plunger tip reaches the second position, etc. A vacuum die casting apparatus characterized by the above is disclosed.
Further, Patent Document 1 discloses an injection process in which molten metal in the sleeve is injected into a cavity of a mold by a plunger tip slidably fitted in the sleeve, and the degree of pressure reduction in the cavity is determined by the plunger. A vacuum die casting method having a pressure reduction degree control step controlled according to the position of the tip, wherein the pressure reduction degree control step sets the inside of the cavity to a reduced pressure when the plunger tip reaches the first position, A vacuum die casting method is disclosed, which is a step of increasing the pressure in the cavity when the plunger tip reaches the second position.
That is, Patent Document 1 states that “the molten metal in the sleeve space is blown off by the flow of air that leaks into the sleeve space through the gap existing on the sliding surface between the plunger tip and the sleeve, and is advanced into the product cavity. As it solidifies as it is, it cannot be fused with the molten metal injected later, and a hot water defect occurs. In addition, defects such as cast holes and blowholes generated by the air flowing in from the gap being caught in the molten metal increase. (0005), and Patent Document 1 divides the degree of decompression in the product cavity into two stages according to the position of the plunger, thereby providing a clearance on the sliding surface between the plunger tip and the sleeve. In this way, air is prevented from leaking into the sleeve space and flowing, thereby preventing the molten metal from entering the product cavity.

On the other hand, Patent Document 2 discloses a vacuum die casting apparatus for injecting molten metal in an injection sleeve into a product cavity in a vacuum state by an injection end face of an injection tip that slides in the injection sleeve. There is disclosed a vacuum die casting apparatus including a decompression chamber formed on the back surface side of the injection chip and continuing to the back surface of the injection chip, and a vacuum generating means connected to the decompression chamber.
Patent Document 2 discloses a vacuum die casting method that uses the vacuum die casting apparatus to inject the molten metal in a state where the decompression chamber is decompressed.
That is, in Patent Document 2, the molten metal is injected in a state where the decompression chamber formed on the back side of the injection tip is decompressed, whereby the gap between the inner periphery of the injection sleeve and the outer periphery of the injection tip is accompanied by the decompression in the cavity. This prevents the air on the back side of the chip from leaking to the cavity side from the minute gaps to prevent the air from being entrained in the molten metal or being drawn into the cavity at once.

JP 2003-062652 A JP 2002-224807 A

  However, in the above prior art, in Patent Document 1, the decompression control means includes a high vacuum decompression means, a low vacuum decompression means, and a high vacuum decompression means and a low vacuum decompression means according to the position of the plunger tip. Since switching means for selecting one and communicating with the product cavity is required, the structure becomes complicated, and thus there are problems such as high cost and complicated control.

  Further, in Patent Document 2 of the above-described conventional technique, a decompression chamber connected to the back of the decompression chamber injection tip is provided on the back side of the injection tip in the injection sleeve, and the decompression means is connected to the decompression chamber. Since this circuit needs to be newly provided, the structure becomes complicated, and there are problems such as high cost and complicated control.

  Furthermore, in the above conventional technique, the pressure reduction in the cavity is controlled according to the moving speed (position or time) of the plunger (Patent Document 1), and between the pressure reducing chamber on the back side of the injection tip and the cavity. Since the pressure reduction is controlled for each part (Patent Document 2), in both Patent Documents 1 and 2, it is necessary to maintain various seal structures for securing and maintaining the degree of pressure reduction. In addition to labor and cost, there is a problem that it is difficult to accurately control the degree of decompression because it is difficult to properly maintain the seal structure.

  The present invention has been made in view of the above-mentioned problems, and with a simple configuration, the molten metal is prevented from preceding the runner into the product cavity and entraining air, thereby causing the occurrence of a hot water boundary, a ball defect, etc. It is an object of the present invention to provide a reduced pressure die casting apparatus and a reduced pressure die casting method capable of preventing the above and forming a product of stable quality.

In order to achieve the above object, a vacuum die casting apparatus according to a first aspect of the present invention provides a molding die in which a product cavity is formed, and a plunger for injecting molten metal into the product cavity via a runner and a gate of the molding die. And a decompression means for decompressing the inside of the product cavity of the mold, wherein the air in the sleeve, the runner and the gate is sucked by the decompression means in a state where the plunger is sealed. A partition member that has a vent hole capable of preventing the molten metal from flowing into the product cavity until the gate is filled, and allowing the molten metal to flow into the product cavity when the gate is filled , Provided at the gate between the product cavity and the runner.
According to a second aspect of the present invention, there is provided a vacuum die casting method in which a product cavity is formed in a mold, and the product cavity of the mold is decompressed by a decompression means. A reduced pressure die casting method in which a molten metal is injected into a product cavity through a gate to form a product having a predetermined shape, and the air in the sleeve, the runner and the gate is sealed by the pressure reducing means while the plunger is sealed. A partition member having a vent hole capable of suction is provided at a gate between the product cavity and the runner, the partition member prevents the molten metal from flowing into the product cavity until the gate is filled; and When the molten metal fills the gate, it is allowed to flow into the product cavity.

According to the first aspect of the present invention, the partition member is provided at the gate between the product cavity of the mold and the runner, and the mold is closed to form the product cavity inside. At positions corresponding to the gates of the partition members, air holes that allow air to flow but not to allow molten metal to flow are provided. Next, the pressure in the product cavity is reduced by the pressure reducing means in a state where the plunger is sealed, and the molten metal in the plunger sleeve is injected into the product cavity through the runner and the gate by the forward drive of the plunger tip. The injection of the molten metal by the plunger is set at a relatively low speed and a low pressure until the runner and the gate are filled, and is set at a relatively high speed and a high pressure after the runner and the gate are filled with the molten metal. By providing the partition member at the gate of the mold, the molten metal in the plunger sleeve is prevented from flowing into the product cavity until the runner and the gate are filled. The air in the plunger sleeve, the mold runner, and the gate flows from the vent hole provided in the partition member to the product cavity and is sucked by the pressure reducing means. When the molten metal fills the runner and the gate, the partition member is melted and destroyed by the heat and injection pressure of the molten metal, and the molten metal is filled into the product cavity. Therefore, it is possible to prevent the molten metal from entraining air or pre-running into the product cavity, and a stable quality die-cast product free from so-called hot water boundaries and ball defects is manufactured.
In the invention of claim 2, a partition member is provided at the gate between the product cavity of the mold and the runner, and the mold is closed to form a product cavity inside. A vent hole through which air can be circulated and molten metal cannot be circulated is provided in advance at a position corresponding to the gate of the partition member. Next, the product cavity is decompressed by the decompression means in a state where the plunger is sealed, and the molten metal in the plunger sleeve is injected by the forward drive of the plunger tip. The injection of the molten metal by the plunger is set at a relatively low speed and low pressure until the runner and the gate are filled, and is set at a relatively high speed and high pressure after the runner and the gate are filled. By providing the partition member on the gate of the mold, the molten metal in the plunger sleeve is prevented from flowing into the product cavity until the runner and the gate are filled. The air in the plunger sleeve, the mold runner, and the gate flows from the vent hole provided in the partition member to the product cavity and is sucked by the pressure reducing means. When the molten metal fills the runner and the gate, the partition member is melted and broken by the heat and injection pressure of the molten metal, and the molten metal is filled into the product cavity. Therefore, it is possible to prevent the molten metal from entraining air or pre-running into the product cavity, and a stable quality die-cast product free from so-called hot water boundaries and ball defects is manufactured.
In addition, since the partition member melts into the molten metal after being melted and destroyed, it is desirable that the partition member be made of a material that does not affect the elements of the material (alloy) that constitutes the die-cast product. In addition, when there are a plurality of gates, the partition member is configured to be melted and broken so that the molten metal is simultaneously injected into the product cavity from each gate according to the shape of the die-cast product to be manufactured. In addition, the partition member can be melted and broken so that the molten metal is sequentially filled through the gate at a position far from the decompression means in the product cavity. For that purpose, the thickness of the partition member in the flowing direction of the molten metal and the number, size, and position of the holes to be provided can be adjusted. A product cavity for molding the partition member in the molding die may be formed continuously with the product cavity of the die-cast product, and the partition member may be molded simultaneously with the molding of the die-cast product.

According to the first aspect of the present invention, the sleeve has the vent hole capable of sucking the air of the sleeve, the runner and the gate by the pressure reducing means in a state where the plunger is sealed, and the molten metal fills the gate. A partition member is provided at the gate between the product cavity and the runner to prevent the product from flowing into the product cavity and to allow the molten metal to flow into the product cavity when the gate is filled. Depending on the configuration, it is possible to prevent the molten metal from leading into the product cavity from the runner and entraining the air, thereby preventing the occurrence of hot water boundaries, defective balls, etc., and forming a stable quality product. A vacuum die casting apparatus can be provided.
According to the second aspect of the present invention, the partition member having the vent hole capable of sucking the air of the sleeve, the runner, and the gate by the pressure reducing means in a state where the plunger is sealed is provided between the product cavity and the runner. With a simple configuration that is provided on the gate and prevents the molten metal from flowing into the product cavity until the gate fills the gate, and allows the molten metal to flow into the product cavity when the gate fills the gate, Depressurization die casting method that prevents molten metal from leading into the product cavity from the runner and entraining air, thereby preventing the occurrence of hot water and ball defects and forming a product with stable quality Can be provided.

First, an embodiment of a vacuum die casting apparatus according to the present invention will be described in detail mainly based on FIGS. In the drawings, the same reference numerals are given to similar or corresponding parts.
The reduced pressure die casting apparatus of the present invention generally includes at least a product mold 10 in which at least a product cavity 10 is formed (hereinafter referred to as a mold 1), and at least the product cavity 10 through a runner 11 and a gate 12 of the mold 1. And a pressure reducing means 2 for reducing the pressure inside the product cavity 10 of the mold 1, and the air in the sleeve, the runner 11 and the gate 12 is kept in a sealed state. A vent hole 30 capable of being sucked by the decompression means 2 is provided at least at a position corresponding to the gate 12, and prevents the molten metal M from flowing into the product cavity 10 until the gate 12 is filled; The partition member 3 that allows the molten metal M to flow into the product cavity 10 when the gate 12 is filled is formed between the product cavity 10 and the runner 11. Provided to the gate 12.

  As shown in FIG. 2, the mold 1 in this embodiment is composed of a fixed mold 1A and a movable mold 1B, which are attached to a fixed platen and a movable platen, respectively, and are moved closer to and away from each other. The mold closing and clamping and mold opening can be performed. When the mold 1 is in a closed state, a product cavity 10 having a shape corresponding to the die-cast product, a runner 11 for introducing molten metal from the plunger into the product cavity 10, a product cavity 10, A gate 12 located between the runners 11, a biscuit forming part 13, and a decompression path 14 connected to the decompression means 2 are formed. A recess 15 for holding the plate-like partition member 3 is formed in a groove shape at a position corresponding to the fixed mold 1A of the mold 1 and the gate 12 of the movable mold 1B. In this embodiment, a plurality of gates 12 are provided. However, the present invention can also be applied to the case where a single gate 12 is provided. Further, the mold 1 has a runner 11 via a gate 12 with respect to a product cavity 10 as shown in FIG. 4 according to the shape of a die-cast product to be molded, for example, when a cylinder block of a V-type engine is molded. A plurality can be provided.

  Since the partition member 3 melts into the molten metal after being melted and destroyed as will be described later, the partition member 3 can be made of the same material as the molten metal M supplied into the plunger sleeve, and is molded in the product cavity 10. It can be formed from a material that does not affect the elements of the alloy (material) that constitutes the die-cast product. That is, for example, when the ADC 12 that is an aluminum alloy is used as a material for forming a die-cast product, the composition elements of the ADC 12 include Si and Cu. Therefore, as the material of the partition member 3, the same ADC 12 as the material of the die-cast product can be used, and a material selected from Al, Si, and Cu can be used. For example, the partition member 3 is formed into a plate shape having a plate thickness of 1 mm or less, and a vent hole 30 having a diameter of 0.5 mm or less is formed at a position corresponding to the gate 12 by machining such as a drill.

  Further, when the partition member 3 is made of the same material as the molded die-cast product, as shown in FIG. 4, the partition member 3 is formed through the product cavity 10 formed in the mold 1 and the communication portion 16. You may comprise so that the cavity 17 may be formed and the partition member 3 may be shape | molded simultaneously with shaping | molding of a die-cast product. The partition member forming cavities 17 are arranged so that the width direction of the plate-like partition member 3 is positioned in the vertical direction of FIG. 4 as shown in the left and right sides different from the center line of FIG. It may be arranged (shown to the left of the center line), or may be arranged so that the plate thickness direction of the plate-like partition member 3 is positioned in the vertical direction in the figure (shown to the right of the center line). The decompression path 14 connected to the decompression means 2 may be formed to extend to the side of the partition member molding cavity 17 (shown on the left), and on the opposite side to the product cavity 10. It may be formed so as to extend upward (shown to the right of the center line).

  Further, when there are a plurality of gates 12, the partition members 3 are melted and melted so that the molten metal M is simultaneously injected into the product cavities 10 from the gates 12 according to the shape of the die cast product to be manufactured. The partition member 3 can be melted and destroyed so that the molten metal M can be sequentially filled through the gate 12 at a position far from the decompression means 2 in the product cavity 10. Can do. That is, the partition member 3 is formed in a wedge shape so that the plate thickness is gradually changed according to the gate 12 at the corresponding position, and the size, number, and arrangement of the vent holes 30 may be varied. it can.

Next, the decompression die casting method of the present invention will be described in detail along with the operation of the decompression die casting apparatus configured as described above.
The reduced pressure die casting method of the present invention generally includes a product cavity 10 formed inside a mold 1, and the decompression means 2 depressurizes the inside of the product cavity 10 of the mold 1 with a plunger and a runner 11 and a gate of the mold 1. 12 is a vacuum die casting method in which a molten metal is injected into a product cavity 10 through 12 to form a product of a predetermined shape, and the sleeve, the runner 11 of the mold 1 and the gate 12 are sealed while the inside of the plunger is sealed. A partition member 3 having a vent hole 30 through which air can be sucked by the decompression means 2 is provided in the gate 12 between the product cavity 10 and the runner 11, and the partition member 3 allows the molten metal M to reach the runner 11 and the gate 12. The product cavity 1 is prevented from flowing into the product cavity 10 until it is full, and when the molten metal M fills the runner 11 and the gate 12. It is intended to allow the flow into.

  When die-casting a product of a predetermined shape, as shown in FIG. 4, when the partition member 3 is a partition member-forming cavity 17 together with the product in the previous molding cycle, the excess molding material is removed to form a plate shape. And a predetermined number of vent holes 30 having a predetermined diameter are formed at predetermined positions at positions corresponding to the gates. When the partition member 3 is formed, the vent hole 30 does not need to be drilled by machining in a later step if it can be formed at the same time by providing a core in the partition member forming cavity 17.

  Next, in a state where the movable mold 1B is opened from the fixed mold 1A, the partition member 3 is inserted and held in one holding portion 15 thereof. The insertion of the partition member 3 into the holding portion 15 can be performed manually, but can also be performed automatically by a robot or the like. Thereafter, when the movable mold 1B is moved close to the fixed mold 1A and the mold is closed, a product cavity 10, a runner 11 and a gate 12 are formed in the mold 1, as shown in FIG. The partition member 3 is held by the holding portions 15 of both the fixed mold 1A and the movable mold 1B. Then, when the molten metal is poured into the plunger sleeve with the plunger tip of the plunger retracted, and the plunger tip is advanced forward from the pouring port, the inside of the plunger sleeve communicating with the runner 11 is sealed. . When the decompression means 2 is driven in this state, the air in the product cavity 10 is sucked and decompressed through the decompression path. At this time, the air in the plunger sleeve, the runner 11, and the gate 12 is sucked and decompressed through the vent hole 30 of the partition member 3.

  Subsequently, when the plunger tip is further advanced at a relatively low speed and low pressure, as shown in FIG. 5, the molten metal M supplied into the plunger sleeve flows into the product cavity 10 by the partition member 3. Since it is in a blocked state, the runner 11 and the gate 12 are filled. The mold 1 is clamped at a predetermined pressure until the runner 11 and the gate 12 are filled with the molten metal M.

  When the runner 11 and the gate 12 are filled with the molten metal M, the forward drive of the plunger tip is switched to a relatively high speed and high pressure. The switching of the plunger tip forward drive from the relatively low speed / low pressure to the high speed / high pressure is based on the inner diameter of the plunger sleeve or the outside of the plunger tip based on the volume of the gate 12 to the surface of the runner 11 and the partition member 3. It can be set by the advance position of the plunger tip relative to the diameter. When the runner 11 and the gate 12 are filled with the molten metal M, and the forward drive of the plunger tip is switched to a relatively high speed and high pressure, the partition member 3 is melted and broken by the heat and injection pressure of the molten metal M, as shown in FIG. Thus, the product cavity 10 in a state where the molten metal M in a state where the flow into the product cavity 10 is blocked by the partition member 3 until then, that is, the preceding run is suppressed and is reduced in pressure from each gate 12 simultaneously or sequentially in a predetermined order. It is allowed to flow in and is filled. For this reason, there is no conventional hot water boundary or ball defect due to the previous run, and a product with stable quality can be formed.

  As shown in FIG. 4, when the partition member molding cavity 17 is formed via the product cavity 10 and the communication portion 16, the molten metal M is formed from the product cavity 10 via the communication portion 16 for partition member molding. The partition member 3 that is filled in the cavity 17 and can be used in a molding cycle subsequent to the molding cycle can be molded.

It is the fragmentary sectional view showing the important section of one embodiment of the decompression die-casting device of the present invention. It is a cross-sectional plan view of FIG. It is a front view which shows a partition member. It is the fragmentary sectional view which showed the principal part of another embodiment of the pressure reduction die-casting apparatus of this invention. It is principal part sectional drawing shown in order to demonstrate the state with which the molten metal was prevented from flowing in into a product cavity by the partition member, and the runner and the gate were filled. FIG. 6 is a cross-sectional view of an essential part for explaining a state in which the partition member is melted and broken from the state of FIG. 5 and the molten metal flows into and fills the product cavity.

Explanation of symbols

1: Mold (molding die), 2: Depressurization means, 3: Partition member, 10: Product cavity, 11: Runner, 12: Gate, 30: Vent

Claims (2)

A mold having a product cavity formed therein, a plunger for injecting molten metal into the product cavity via a runner and a gate of the mold, and a decompression unit for decompressing the product cavity of the mold. A vacuum die casting apparatus,
The plunger has a vent hole that can suck the air of the sleeve, the runner, and the gate by the pressure reducing means in a sealed state, and flows into the product cavity until the molten metal fills the gate. A decompression die casting apparatus, wherein a partition member is provided at a gate between the product cavity and the runner so as to prevent the molten metal from flowing into the product cavity when the molten metal fills the gate. A product cavity is formed inside the mold, and molten metal is injected into the product cavity through the runner and gate while the pressure inside the product cavity of the mold is reduced by the pressure reducing means, thereby forming a product having a predetermined shape. A vacuum die casting method,
A partition member having a vent hole capable of sucking the air of the sleeve, the runner, and the gate by the pressure reducing means in a state where the inside of the plunger is sealed is provided at the gate between the product cavity and the runner,
A reduced pressure die casting method characterized in that the partition member prevents the molten metal from flowing into the product cavity until the gate is filled, and allows the molten metal to flow into the product cavity when the gate is filled.

Images