JP2000052017A - Low-speed filling die-cast method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-speed filling die-cast method and equipment to maintain the air vent passages in cavities in the same state and to make the air pressure in the cavities uniform. SOLUTION: When cavities 2 of a multi-cavity mold are filled with molten metal at a low speed, a gas vent groove 5 to push out air in the cavities 2 is formed in the dividing surface 4 of a mold 3 in such a way as to surround the cavities 2. The gas vent groove 5 is provided with multiple push-out pins 7 and the air in the cavities 2 is discharged from a clearance 8 between the push-out pin 7 and its inserting hole 6. By means of the gas vent groove 5, the cavities 2 are connected and the air pressure is made uniform, thus smoothing the run of the molten metal to a bottom die 11 of the cavities 2 by adjusting the clearance 8 to control the air vent rate and applying back pressure to the molten metal without filling the gas vent groove 5 with the molten metal or leaving the solidified portion of the molten metal in the gas vent groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-speed filling die-casting method and apparatus, and more particularly to a low-speed filling die-casting method and apparatus such as melt forging and laminar flow die casting.

[0002]

2. Description of the Related Art In a usual low-speed filling die casting method, when a multi-cavity mold, for example, a 4-cavity mold 50 as shown in FIGS. 3 is formed, the slide core 15 is mounted along the inclined pin 16, and when the molten metal is injected into the cavity 51 of the formed mold by the injection piston 12, the air in the cavity 51 is quickly spilled to the outside. In order to discharge the gas, each cavity 51 has a gas vent groove 52 communicating with the outside. Reference numeral 4 denotes a mold dividing surface, 7 denotes an extrusion pin for extruding a cast product, and 6 denotes an insertion hole for the extrusion pin 7.

The air in the four cavities 51 and the runners 53 is pushed by the molten metal, so that the gas vent grooves 52,
In other words, the air enters the chill vent 56 through the air vent runner 55 from the connecting portion 54 in each cavity 51, and is further discharged through the air vent slit 57 to the outside of the mold 50 for each of the four cavities 51. A shut-off valve (not shown) may be used for the gas vent groove 52.

However, when the chill vent 56 is used in the gas vent groove 52, the air is allowed to pass through but not through the molten metal. Therefore, the clearance is reduced from large to small, so that the molten metal stops in the middle of the chill vent 56. With respect to all the chill vents 56, the molten metal was not stopped at a certain position, and the melt was uneven, and the air vent was uneven. The molten metal is solidified in the middle of the chill vent 56 communicating with the cavity 51, and the solidified slab may remain in the chill vent 56 when the product is extruded. Therefore, if the slab remains, it cannot function as an air vent.

[0005] In addition, a release agent is used in die casting, but the release agent used in low-speed injection laminar flow casting needs to have a heat retaining property. Therefore, since the release agent contains a solid content, the molten metal is filled. The solid content will be deposited in the portions where no treatment is performed.
Therefore, when the chill vent 56 is used for the gas vent groove 52, the molten metal is not filled at the tip of the chill vent 56, so that the solid content of the release agent is deposited on the tip of the chill vent 56 and changes the cross-sectional area of the chill vent 56. Therefore, the air release from each cavity 51 is unbalanced, and the air pressure in each cavity 51, that is, the residual air pressure is different.

If an unbalance occurs in the air bleeding of each cavity 51 and a difference occurs in the residual air pressure in each cavity 51, a difference occurs in the flow rate of the molten metal into each cavity 51. In the low-speed filling die casting method, the casting quality is maintained by preventing the entrainment of air by keeping the inflow speed of the molten metal below a certain value. Each time, the inflow speed of the molten metal changes, causing poor running of the molten metal and entrainment of air due to turbulence, resulting in poor casting quality.

When a shut-off valve is used for the gas vent groove 52, cast burrs remain in the valve portion, which often causes malfunctions, and the air vents of the cavities 51 are imbalanced. This causes a difference in the residual air pressure in each cavity 51.

As described above, in the above-described conventional method, it is difficult to always keep the gas release grooves 52 of each cavity 51 in the same state because the gas release grooves 52 are independent for each cavity 51. However, the air pressure in each cavity 51 could not be made uniform.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems in low-speed filling die casting, and an object of the present invention is to include a mold release agent in an air vent passage in each cavity. Eliminate the accumulation of solid matter and the residual flash of castings, keep the air vent passage in the same condition, and make the air pressure of each cavity uniform, maintain good casting quality, and increase the operation rate. And a low-speed filling die casting method and apparatus.

[0010]

According to the present invention, there is provided a low-speed filling die casting method and apparatus according to the present invention.
It is characterized by having the following configuration. That is, the low-speed filling die-casting method according to claim 1 is a die-casting method in which a molten metal is charged at a low speed into a cavity of a plurality of molds.
When the molten metal is filled in the cavity, a gas vent groove for extruding air in the cavity is formed by connecting the divided surfaces of the mold so as to surround each cavity, and the gas formed by the connection is formed. Arrange multiple extrusion pins in the groove,
The air in each cavity is discharged from the gap between the push pin and the insertion hole of the push pin.

In this configuration, since the gas vent groove is connected so as to surround each cavity, the air pressure in each cavity becomes uniform, and no problem occurs even if the gas vent groove is filled with the molten metal. Since solids of the release agent are no longer accumulated, and a plurality of extrusion pins are provided in the gas vent groove, no solidified fragments of the molten metal or solids derived from the mold release agent remain in the gas vent groove. By adjusting the gap between the pin and its insertion hole, the amount of air bleeding can be adjusted, thereby applying back pressure to the molten metal and discharging air from the cavity while maintaining a constant back pressure. It is possible to make the hot water flow to the lower mold part smooth.

According to a second aspect of the present invention, there is provided a low-speed filling die casting apparatus, comprising: a mold having a plurality of cavities; and a gas vent groove formed in the dividing plane of the mold so as to communicate with each cavity and surround each cavity. A plurality of extruding pins provided continuously in the gas vent groove, and an extruding pin which can reciprocate in the inserting hole. When the molten metal is filled in the cavity, air in the cavity is removed. It is characterized in that it is discharged from the gap between the push pin and the insertion hole of the push pin. Therefore, the above-described low-speed filling die casting method can be efficiently realized.

According to a third aspect of the present invention, there is provided a low-speed filling die casting apparatus, wherein a connecting portion between the gas release groove and the cavity is provided at a final filling portion of the molten metal into the cavity. Since it is provided in the final filling section, the air pushed by the molten metal does not remain in the cavity.

[0014]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a vertical sectional view of a low-speed filling die casting apparatus showing an embodiment of the present invention, and FIG. 2 is a plan layout view of the low-speed filling die casting apparatus showing an embodiment of the present invention. The same components as those in the related art are denoted by the same reference numerals.

1 to 4, a low-speed filling die casting apparatus 1 includes a mold 3 having a plurality of cavities 2 and a divided surface 4 of the mold 3 connected to each cavity 2 and surrounding each cavity 2. A gas vent groove 5 formed by connection, and a plurality of push-pin insertion holes 6 provided continuously with the gas vent groove 5.
(Hereinafter, simply referred to as an insertion hole 6) and an extrusion pin 7 that can reciprocate in the insertion hole 6. When the molten metal is filled into the cavity 2 by the injection piston 12, the air in the cavity 2 is removed. It is configured to be discharged from the gap 8 between the push pin 7 and the insertion hole 6.

The mold 3 is divided into an upper mold 10 and a lower mold 11 at a dividing surface 4. In this embodiment, the mold 3 is provided with four cavities 2. However, the number of the cavities 2 may be two, six, or eight. Can be applied.

The lower die 11 is provided with an injection piston 12 for injecting the molten metal into the mold 3 slidably facing the biscuit 13. The mold 3 has a runner 14 communicating between the biscuit 13 and the four cavities 2, and the slide core 15 is slidable along an inclined pin 16 provided on the lower mold 11. It is provided so that it can be attached to the mold 3.

The gas vent groove 5 is connected to each cavity 2 in a loop through a gate of the cavity 2, that is, a connecting portion 20. Therefore, since all four cavities 2 are in communication, the molten metal is filled in each cavity 2 and after reaching the final filling portion, reaches the connecting portion 20, so that the air pressure in each cavity 2 is uniform. Become.

The gas vent groove 5 has a thickness of 3 to 1
A range of 0 mm and a width of 4 to 10 mm is preferable. In addition, the connecting portion 20 is provided at the final filling portion of the molten metal into the cavity 2 and may be a single or a plurality. The connecting portion 20 has a rectangular cross section, and the size thereof is 0.3 to 1.5 m in thickness.
m, a width of 3 to 30 mm and a length of 5 to 20 mm are preferable.

The upper die 10 is provided with insertion holes 6 and 6a into which extrusion pins 7 and 7a for taking out products are inserted, and the extrusion pins 7 and 7a are inserted into the insertion holes 6 and 6a. Inside, it can be moved up and down by an extruder 21. The insertion hole 6 is provided with the connecting portion 20 and the gas release groove 5.
And the insertion hole 6a is directly associated with the four cavities 2 and the runners 14 described above.

Each of the push pins 7 and 7a inserted into the insertion holes 6 and 6a has a function of removing a product cast in the mold 3, and among them, the insertion holes 6 and In addition to the above-described role, the gap 8 has a role of venting the air. Therefore, the insertion hole 6 is opened to the outside when the molten metal is filled, and the air in the cavity 2 is discharged. (FIGS. 3 and 4)

The number of the insertion holes 6 and the number of the push-out pins 7 can be appropriately changed, and the gap 8 between them can be changed by changing the inner diameter of the insertion hole 6 and the outer diameter of the push-out pin 7. Since it can be changed freely, the amount of air bleeding can be adjusted, and back pressure can be applied to the molten metal. Therefore, in the low-speed filling die casting apparatus of the present invention, only gravity can be applied to the lower mold 11 in the process of injecting the molten metal. It can be better.

Next, the low-speed filling die-casting method using the low-speed filling die-casting apparatus 1 having the above configuration will be described. The low-speed filling die-casting apparatus in which the number of the insertion holes 6 and the number of the push-out pins 7 are changed according to the material and purpose of the product. After selecting 1 and preparing the injection of molten metal, such as applying a release agent to the mold surface,
The mold 3 is closed.

Next, when the molten metal is slowly filled from the hot water supply port by the injection piston 12, the molten metal is filled in the biscuit 13.
From each of the cavities 2 through the respective runners 14, and at the same time, the air in each of the runners 14 and the cavities 2 is pushed by the molten metal, and enters the loop-shaped degassing groove 5 through the respective connecting portions 20. By the loop-shaped portion 5a,
The inside of each cavity 2 is brought into a communicating state through each connecting portion 20.

At this time, a part of the air is discharged to the outside through the gap 8 between the insertion hole 6 and the push-out pin 7 which are directly associated with the connecting portion 20, and the remaining air is associated with the loop-shaped portion 5a. It is discharged to the outside through the gap 8 between the insertion hole 6 and the push pin 7. Therefore, the air pressure applied to each cavity 2 becomes uniform, the inflow speed of the molten metal becomes constant for each cavity 2, and there is no occurrence of imperfect hot water or air entrainment due to turbulence.

After smoothly filling each cavity 2, the molten metal reaches the inside of the connecting portion 20 located at the final filling portion of the molten metal, and further fills the air vent groove 5 having a sufficient sectional area to solidify. Therefore, the solid of the release agent does not accumulate in the air vent groove 5. After completion of the casting, the mold is opened by cooling, the extrusion board 21 is lowered, and the extrusion pins 7, 7a are inserted into the insertion holes 6,
6D, the product is removed from the mold 3.

At this time, the extruding pin 7 serving as an air vent passage
8 is to be cleaned by the lowering of the extrusion pins 7 and 7a, solid matter and casting burrs derived from the release agent are eliminated, and the cross-sectional area of the gap 8 is constant. Is held. In addition, by adjusting the size of the gap 8 to adjust the amount of air bleeding, back pressure can be applied to the molten metal to improve the run of the molten metal in the lower mold 11 of the cavity 2.

An embodiment for confirming the effect of the present invention will be described below. Example 1 Al-Cu based aluminum alloy was used as a molten metal,
A mold release agent containing a solid material for giving heat retention was selected, and the low-speed filling die casting apparatus shown in FIGS.
It was used 0 times and 40 manifolds were cast.

Comparative Example 1 Forty manifolds were cast by using the same aluminum alloy and mold release agent as in Example 1 using the conventional low-speed filling die-casting apparatus shown in FIGS. Table 1 shows the failure status and operation rate of the products generated in Example 1 and Comparative Example 1.

[0030]

[Table 1]

As shown in Table 1, each of the manifolds cast by the method of the present invention has a constant filling time into each cavity and a uniform air back pressure, compared to the manifold cast by the conventional method. Due to the improvement of the balance, the incidence of poor running and poor blistering is reduced to 1/10 to 1/3 of the conventional rate. In addition, the operation rate of the method of the present invention is about 10% lower than that of the conventional method because periodic cleaning of the chill vent and the gas vent groove is not required, and the superiority of the method of the present invention was confirmed.

Although the preferred embodiment of the present invention has been described above, the specific configuration is not limited to this, and modifications and additions without departing from the gist of the present invention are within the scope of the present invention.

[0033]

As described above in detail, according to the first aspect of the present invention, since the gas vent groove is connected so as to surround each cavity, the air pressure in each cavity becomes uniform, and the gas vent groove is formed. Even when the molten metal is filled, no solid matter of the release agent is deposited and the plurality of extrusion pins are arranged in the gas vent groove. No solids derived from the release agent remain,
By adjusting the gap between the extrusion pin and its insertion hole,
The amount of air bleeding can be adjusted, whereby a back pressure is applied to the molten metal, and the molten metal can smoothly flow to the lower mold portion of each cavity. Therefore, in the case of the cast product, the occurrence of defective products due to poor running water or swelling is extremely reduced, and the operation rate is greatly improved.

According to the second aspect of the present invention, the above-described low-speed filling die-casting method can be efficiently realized, and it is possible to extremely reduce the occurrence of defective products and greatly improve the operation rate.

According to the third aspect of the present invention, since the connecting portion is provided in the final filling portion of the molten metal, the air pushed along with the molten metal does not remain in the cavity, so that the above effect is further enhanced. Achieved reliably.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a low-speed filling die casting apparatus showing an embodiment of the present invention.

FIG. 2 is a plan view of a low-speed filling die casting apparatus according to an embodiment of the present invention.

FIG. 3 is a layout view of an air vent groove in the low-speed filling die casting device along the line AA in FIG. 2;

FIG. 4 is an arrangement diagram of air vent grooves in the low-speed filling die casting device along the line BB in FIG. 2;

FIG. 5 is a longitudinal sectional view showing a conventional example.

FIG. 6 is a plan view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-speed filling die-casting apparatus 2 Cavity 3 Die 4 Dividing surface 5 Gas release groove 5a Loop-shaped part 6, 6a Insertion hole of extrusion pin 7, 7a Extrusion pin 8 Gap 10 Upper mold 11 Lower mold 12 Injection piston 13 Biscuit 14 Runner 15 Slide core 20 Communication part 21 Extruder

Claims (3)

[Claims] In a die casting method in which a molten metal is filled into a cavity of a multi-cavity mold at a low speed, a gas vent groove for extruding air in the cavity when the molten metal is filled in the cavity, surrounding each cavity. And a plurality of extrusion pins are disposed in the gas vent groove formed by the coupling, and each cavity is formed through a gap between the extrusion pin and the insertion hole of the extrusion pin. A low-speed filling die-casting method characterized by discharging air from inside. 2. A mold having a plurality of cavities, a gas vent groove connected to each cavity and continuously formed in a divided surface of the mold so as to surround each cavity, and a gas vent groove continuously. A plurality of push-out pins provided, and a push-out pin which can reciprocate in the insert-through holes, and when the molten metal is filled in the cavity, the air in the cavity is filled with the push-out pin and the push-in hole. A low-speed filling die casting apparatus characterized in that the apparatus is discharged from a gap of the die. 3. A communication part between the gas vent groove and the cavity,
3. The low-speed filling die-casting apparatus according to claim 2, wherein the low-speed filling die casting apparatus is provided at a final filling portion of the molten metal into the cavity.