JPH01233057A - Manufacture of transferring mold - Google Patents

Abstract

PURPOSE:To enable using of low pressure proof of a mold vessel and transfer of complicate and fine shape by exhausting air in the mold vessel before pouring molten metal at the time of obtaining the transferring mold with pressurized casting complex method by presetting a model pattern in the mold vessel and blowing the pressurized air into the vessel after pouring the molten metal. CONSTITUTION:The gypsum-made model pattern 34 having permeability is set so as to plug venting holes 24 in bottom plate 14 of the mold vessel 10 and granular material 30 is packed into the vessel 10. Successively, the granular material 36 is preheated to the temp. higher than the critical preheating temp. to be permissible, to which the molten metal 38 poured into the vessel 10 penetrates into gap between the granular grains 36, and further lower than the solidified temp. of the molten metal 38. Under this condition, while sucking air in the vessel 10 through a suction hose 28, the molten metal 38 is poured and after pouring, the opening part of the vessel 10 is immediately closed and the pressurized air is blown in the vessel 10 through a pressurized air introducing hose 32. Then, this suction and pressurized air introduction are continued till solidifying the molten metal 38.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for manufacturing a mold such as an injection mold or a press mold, and in particular, a method for manufacturing a mold, such as an injection mold or a press mold, using a predetermined model mold.
The present invention relates to a new method for manufacturing a transfer mold that transfers the shape of the model mold.

(Prior art) Conventionally, as one of the methods for manufacturing molds such as injection molds and press molds, a desired mold is created by using a predetermined model mold and transferring the shape of the model mold. (
A method for obtaining a transcription type is known. According to such a transfer method, cutting jJl for manufacturing a mold by cutting a mold material
Compared to the 'l method, molds can be manufactured in a shorter time and at lower cost.

By the way, a typical transfer mold manufactured by such a transfer method is the ZAS type (zinc alloy mold), which is manufactured by pouring molten zinc alloy into a mold container in which a model mold is set. However, such ZAS molds have the problem of large shrinkage during solidification and large shrinkage distortion, which makes post-processing troublesome.Also, they do not have sufficient mechanical strength and are not durable as molds. There was also the inherent problem of low performance.

On the other hand, in recent years, a transfer mold has been manufactured using a pressure casting composite method proposed in the Bulletin of the Japanese Society of Wood and Metals, Vol. 25, No. 12 (1986), pp. 1026-1033. That is what is being considered.

This pressure casting composite method involves filling a mold container with ventilation holes in the bottom wall with a predetermined granular material, and then pouring the molten metal into the core mold container. The critical preheating temperature that allows penetration into the gap (the newsletter tube 1208
(see lines 16 to 19 on the left side of the page; the same applies hereinafter) and below the freezing point of the molten metal, the molten metal is poured into a nuclear mold container and zested, and the molten metal is After pouring the molten metal, a large pressing force is immediately applied to the molten metal with a punch press to allow the molten metal to penetrate into the gaps of the granular material, thereby producing a metal matrix composite material using the molten metal as a metal base. It is a method to
(Refer to Publication No. 8), when manufacturing a metal matrix composite material according to the pressure casting composite method, if a model mold is set in the mold container in advance before filling with granular material, the model mold can be set after solidification of the molten metal. By removing the model mold, a transfer mold is obtained in which the shape of the model mold is transferred.

According to the transfer mold manufactured using the pressure casting composite method of such a metal matrix composite material, since the proportion of molten metal is small, shrinkage strain can be reduced compared to the above-mentioned ZAS mold. In addition, the mechanical strength is intermediate between that of granular material and molten metal, so the combination of granular + A rice grains and molten metal produces i, which has greater mechanical strength than the ZAS type.
A transcription mold with excellent J durability can be obtained.

(Problem to be solved) However, as mentioned above, the method of manufacturing a transfer mold using the pressure casting composite method of metal matrix composite + A has superior transfer accuracy and surface durability compared to the ZAS mold. Although it is possible to obtain a transfer mold, the molten metal is 3 to 6 MPa (#30 to 60 kg/
Since a large pressing force of 2 degrees or more is applied,
It is necessary to use a mold container that is strong enough to withstand the applied pressure, and since such a large pressure is applied, there is a problem that it is difficult to transfer complex or minute shapes. .

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and its gist is to provide ventilation holes in a predetermined type container having ventilation holes in the bottom wall. A model mold having air permeability is set so as to cover the pores, and a predetermined granular material is filled into the mold container so as to cover the model mold, and then suction and exhaust is performed through the ventilation hole of the mold container. On the other hand, the granular material is preheated to a temperature higher than the critical preheating temperature that allows the molten metal poured into the mold container to penetrate into the gaps of the granular material. pouring the molten metal into the mold, then blowing pressurized gas into the mold container to apply a predetermined pressing force to the molten metal, thereby causing the molten metal to penetrate into the gaps between the granular materials, and After solidifying the molten metal, the solidified metal is removed from the mold container and the model mold is removed from the solidified metal, thereby obtaining a transfer mold to which the model mold is transferred. be.

Here, the model mold has heat resistance that can withstand the temperature of the molten metal, and pressure resistance that can withstand the pressure exerted by the particulate material, the weight of the molten metal, and the pressurized gas, and the molten metal is substantially contained in its pores. For example, when using a low melting point metal such as zinc, tin, lead, aluminum, copper or an alloy thereof as the molten metal,
If a plaster mold or a high melting point metal such as iron or its alloy is used as the molten metal, a sand mold can be suitably used as the model mold.

In addition, the granular material may be any material as long as it does not disappear at the temperature of the molten metal or deform due to the temperature of the molten metal or pressurizing force, and depending on the intended characteristics, various inorganic powder materials, metal powders,
Although it is possible to use I material, it is necessary to use a material with a particle size in which the gaps between the granular materials are larger than the pores of the model mold and allow penetration of the molten metal. Note that it is desirable to use such a granular material having a particle size as uniform as possible.

Furthermore, the suction pressure of the gas such as air sucked and exhausted from the vents of the mold container and the blowing pressure of the gas blown into the mold container may be any pressure that allows the molten metal to penetrate into the gaps of the granular material. Although it depends on various conditions such as the particle size of the material, - For boat fishing, the suction pressure is 1 kg/cnl.
Combination of degree and blowing pressure of 5 to 6 kg/cM-U
will be suitably adopted.

Hereinafter, the method of the present invention will be explained in more detail based on the accompanying figures.

That is, in the attached drawings, 10 is a mold container,
Container body 1 consisting of a side wall 12 and a double bottom wall 14.16
8 and a lid 20 for opening and closing the opening of the container body 18. Further, a sealed space 22 is formed between the bottom walls 14 and 16, and air inside the mold container 10 is provided in the sealed space 22 through an appropriate number of ventilation holes 24 formed in the upper bottom wall 14. The spaces are communicated with each other, and a suction hose 28 is connected through a through hole 26 formed in the lower bottom wall [6]. And the ventilation hole 24. Closed space 222
Gas such as air within the mold container 10 can be forcibly sucked and exhausted through the through hole 26 and the suction hose 28. On the other hand, in the upper space inside the mold container 10, the lid body 2
A pressurized air introduction hose 32 for introducing pressurized air as pressurized gas can be connected through a through hole 30 formed in the hole 30.
Pressurized air led through can be blown into the mold container 10 through the opening 30 .

To manufacture a transfer mold using such a mold container 10,
First, as shown in the figure, a breathable model mold 34 with minute pores, such as a plaster mold or a sand mold, is placed on the bottom wall 14 while blocking the opening of the ventilation hole 24. set on top. After setting the model type 34,
A predetermined granular material 36 such as an inorganic powder material or a metal powder material selected according to the intended characteristics of the transfer mold is filled into the mold container 10 so as to cover the model mold 34, and the mold is heated by heating means (not shown). Preheat all 10 containers. At this time, if the preheating temperature of the granular material 36 is too low, the molten metal 38 described later will not penetrate into the gaps of the granular material 36 and the desired transfer mold will not be obtained. Particulate material 36 is preheated such that the temperature of particulate material 36 is above a critical preheat temperature that allows penetration of molten metal 38.

In addition, such granular material? When preheating 436, it is possible to heat the granular material 36 to a temperature higher than the freezing point of the molten metal 38, but if the preheating temperature of the granular material 36 is too high, the time required for displacing the molten metal 38 becomes long. Generally, the granular material 36 is not preheated to a temperature lower than the freezing point of the molten metal 38 to avoid problems such as the heat resistance required for the granular material 36 and the model mold 34 increasing or decreasing. Become. Further, as the granular material 36, it is possible to use one that has been preheated to some extent.

Next, while the granular material 36 is preheated, gas such as air in the mold container 10 is sucked and exhausted through the suction hose 28 at a predetermined suction pressure, and the molten metal selected according to the required characteristics of the transfer mold is heated. 38 is poured into the mold container 10. After pouring the molten metal 38, the opening of the container body 18 is promptly closed, and pressurized air at a predetermined pressure guided through the pressurized air introduction hose 32 is blown into the mold container 10, and the molten metal 38 is Pressurize. Note that the combination of the suction pressure when sucking and exhausting gas such as air in the mold container 10 and the blowing pressure of pressurized air blown into the mold container 10 is such that the molten metal 38 is The combination will be set in advance to allow the penetration of

In this way, since the model mold 34 has air permeability, the molten metal 38 is pressurized by the pressurized air blown into the mold container 10, and the model mold 34 and the ventilation hole 24 are Based on the suction effect of the molten metal 38 based on the depressurization effect of the gap between the granular materials 36 due to the suction and exhaust,
The molten metal 38 is effectively infiltrated into the interstices of the granular material 36 to fill the interstices. Therefore, after the operation of infiltrating the molten metal 38 into the granular material 36, the molten metal 38 is solidified, and the metal matrix composite which is the solidified product of the molten metal 38 is removed from the mold container 10, and the model mold 3
4 from its metal matrix composite, the model 34
A transcription form is obtained in which the molecule is transcribed.

It goes without saying that the structure of the mold container 10, the formation form of the ventilation holes 24 in the mold container 10, etc. can be changed as appropriate depending on the necessity. Also, as the pressurized gas blown into the mold container 10, in addition to the pressurized air such as the one above, N2. It is also possible to use a pressurized inert gas such as hydrogen.

(Effects of the Invention) As is clear from the above description, the transfer mold manufactured according to the method of the present invention has the same effect as the transfer mold manufactured using the pressure composite casting method, in which the granular material (36) is Since it is composed of a metal matrix composite material with molten metal (38) infiltrated into the gap, it has superior transfer accuracy compared to the ZAS type. )
In combination with this, it can have superior durability than the ZAS type. Furthermore, in the method of the present invention, the operation of penetrating the molten metal (38) into the gaps between the granular materials (36) can be performed under the suction effect through the model mold (34). Even under the low pressure action of pressurized gas, the molten metal (38) can be sufficiently infiltrated into the gaps between the granular materials (36) and in a manner that it is in close contact with the model mold (34). Therefore, it is possible to use a mold container (10) with a simpler structure and poorer pressure resistance than when a pressure casting composite method is used.

Also, in this way, the pressing force on the molten metal (38),
Furthermore, since the pressure applied to the model mold (34) is small, it is possible to manufacture a transfer mold with a more complex or minute shape than when using the conventional pressure casting composite method. be.

Examples of the present invention will be given below to clarify the present invention more specifically.

(Example) A breathable model mold 34 made of plaster was set in a mold container 10 as shown in the attached drawing so that the ventilation hole 24 formed in the bottom wall 14 of the mold container 10 would be kept cool. Then, in the mold container 10 in which the model mold 34 is set,
As the powder + A material 36, iron powder of approximately uniform particle size with a minimum particle size of 150 mesosius is filled, and this iron powder is packed into the mold container 10 at a temperature between the critical preheating temperature and the solidification point of tin. I 8
Preheated to 0'c.

Next, under the preheated state of the iron powder, molten tin as the molten metal 38 was poured while sucking the air inside the mold container with a suction pressure of 1 kg/ct through the suction port 28. , After pouring the molten tin, the mold container 10
Immediately close the opening and blow out pressurized air of 5 to 6 kg/c+A into the nuclear mold container 1o through the pressurized air introduction bow 32, and continue blowing out the pressurized air until the molten tin solidifies. And the suction operation of the air inside the mold container 10 was continued.

After solidifying the molten tin, the solidified product was taken out from the mold container 1o, and the plaster mold, which was the model mold 34, was removed from the solidified product.

As a result, a transfer mold was obtained in which the shape of the plaster mold, which is the model mold 34, was transferred with better transfer precision than the ZAS mold, and which had greater mechanical strength and excellent durability than the ZAS mold.

[Brief explanation of the drawing]

The attached figure is a principle diagram for explaining the method of the present invention. 10; Mold container 24: Vent hole 28: Suction port 32: Pressurized air introduction bow 34: Model mold 36; Granular material 38; Molten metal

Claims (1)

[Claims] A model mold with air permeability is set in a predetermined mold container having a ventilation hole in the bottom wall so as to cover the ventilation hole, and a predetermined granular shape is placed in the mold container while covering the model mold. After filling the material, suction and exhaust are carried out through the ventilation holes of the mold container, while the granular material is heated to a critical temperature that allows the molten metal poured into the mold container to penetrate into the gaps of the granular material. Pouring the molten metal into the mold container in a state preheated to a temperature higher than the preheating temperature, and then blowing pressurized gas into the mold container to apply a predetermined pressing force to the molten metal. by infiltrating the molten metal into the interstices of the granular material and solidifying the molten metal, and then removing the solidified metal from the mold container and removing the model mold from the solidified metal. A method for producing a transfer mold, comprising obtaining a transfer mold onto which the model mold is transferred.