JPH0331543B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a refractory mold.

The methods of producing cast products with accurate dimensions and smooth casting surfaces are generally referred to as precision casting methods, but these precision casting methods include shell mold casting, investment casting (using wax as a disappearing model material), etc. In some cases, there are methods such as lost wax casting method), plaster casting method, and the show process.

Among the above, the present invention relates to a method for manufacturing a refractory mold used in an investment casting method. Conventionally, when manufacturing this refractory mold, as shown in FIG. Disappearance model material 2 (wax, plastic, mercury, etc.) in a fluid state is press-filled into the interior 1a by injection or the like, and the necessary number of dissipation models having substantially the same shape as the cast product are manufactured. At the same time, as many disappearing models as necessary are made in substantially the same manner as shown in FIG. 1, corresponding to the sprue and runner parts of the mold to be made.
Next, as shown in FIG. 2, a vanishing model tree 5 is manufactured by melting and joining a vanishing model 3 having the same shape as the cast product and a vanishing model 4 corresponding to the sprue and runner parts. In addition, when manufacturing the disappearing model 4 corresponding to the sprue and runner parts, a nut 6 is buried inside. Next, as shown in FIG. 3, a sealing material 7 such as paper is pasted on the gate of the disappearing model tree 5, and a holder 8 is screwed into the nut 6 to fix it. At this time, the sealing material 7 is attached by using a suitable adhesive or by partially melting and joining the disappearing model around the outer periphery of the sprue.

Next, as shown in FIG. 4, the disappearing model tree 5 is immersed in a dipping tank 11 containing a refractory slurry 10 to attach the slurry.
Subsequently, as shown in FIG. 5, a refractory material (refractory sand) 12 is applied to the vanishing model tree 5 to which the slurry is attached, and then dried to remove the slurry, the refractory material, and the refractory material.
The drying process is repeated several times to produce a mold pattern 13 coated with a refractory material of a required thickness. Then the 6th
As shown in the figure, the refractory coating attached to the sprue part of the mold master 13 is removed, the holder 8 is removed, and at the same time, the sealing material 7 is removed to expose the disappearing model material at the sprue part. As shown in FIG. 7, the mold master 13 is placed in a heating furnace 15 equipped with a heating element 14 and heated to cause the disappearing model material to melt and fall. After that, by performing firing, a casting space 20 as shown in FIG.
A refractory mold 20 having a runner a, a runner 20b, and a sprue 20c was obtained.

However, in such a conventional manufacturing method, the process of pasting the sealing material 7 such as paper on the sprue part of the vanishing model tree 5 using adhesive or partial melting is troublesome, and the process of pasting the sealing material 7 such as paper on the sprue part of the vanishing model tree 5 is troublesome. The process of removing the refractory from the sprue of the mold master 13 afterwards is very inefficient, and the sealing material 7 is also removed at the same time, so it cannot be reused. was.

This invention was made by focusing on the above-mentioned conventional problems, and it is possible to easily seal the sprue part of the vanishing model tree, and it is possible to easily seal the sprue part of the mold master after being coated with refractory material. The removed refractories can be removed very easily, and the subsequent removal of the lost model can be done smoothly.
It is an object of the present invention to provide a method for producing a refractory mold that has a number of advantages, such as the ability to use both sealing means.

This invention provides a method for producing a refractory mold by applying a refractory coating to the surface of the vanishing model and then vanishing the vanishing model. After abutting a sealing material, a refractory coating is applied to the surface of the disappearing model, and then the elastic sealing material is removed and the disappearing model is made to disappear, thereby producing a refractory mold. It is a feature. In this case, it is more desirable that the external shape of the elastic sealing material be larger than the opening of the sprue portion of the refractory mold.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 9 to 13 show one embodiment of the present invention, which will be sequentially explained below.

When manufacturing a refractory mold according to this embodiment, first, a disappearing model tree 5 is manufactured in the same manner as shown in FIGS. 1 and 2. As for the disappearing model materials used at this time, as in the past,
Heat-melting wax, plastics (polystyrene, polyethylene, vinyl chloride, etc.), mercury, water-soluble urea resin, etc. can be used.

Next, as shown in FIG. 9, an elastic sealing material 21 is applied to the disappearing model tree 5 at a portion corresponding to the sprue of the mold to be manufactured.
Applying the pressing member 22 to this elastic sealing material 21,
Holder 2 with stopper 24 fixed with screw 23
By screwing the threaded part 5 into the nut 6,
The elastic sealing material 21 is fixed. As shown in FIG. 10, this elastic sealing material 21 has a flat ring shape and is made of natural rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, polyurethane rubber, acrylonitrile-butadiene rubber,
It is molded from materials such as chloroprene rubber, neoprene rubber, silicone rubber, and fluorine rubber. In this case, the outer shape of the elastic sealing material 21 is larger than the outer shape of the sprue portion of the disappearing model tree 5.

Note that the holder 25 is structured to be screwed into the nut 6, so loosen the screw 23 and remove the stopper 2.
By adjusting the fixing position of 4, when the holder 25 is screwed into the nut 6, the holding member 22
The elastic sealing material 21 can be fixed well by the above-described method. In this case, slight deviations in the position of the holding member 22 or the screwing depth of the holder 25 can be absorbed by the elasticity of the elastic sealing material 21, and the elastic sealing material 21 can be fixed well. . From this perspective, the thickness of the elastic sealing material 21 depends on its hardness (for example, shear A).
A hardness of about 40 is good), but it is best to have a hardness of about 4 mm or more.

In this way, as shown in FIG. 9, the elastic sealing material 21 is fixed to the disappearing model tree 5, and as shown in FIG. Then, as shown in FIG. 12, a refractory material (refractory sand) 12 is attached to the vanishing model tree 5 to which the slurry has been attached, and then it is dried, and the above-mentioned slurry is attached. The steps of , adhering the refractory and drying are repeated several times to produce a mold prototype 26 coated with the refractory to a desired thickness.

Next, the operator bends the elastic sealing material 21 by hand to remove the refractory material attached around the elastic sealing material 21, and then removes the holder 25 from the nut 6 and removes the elastic sealing material from the mold master 26. 21, the holding member 22, and the holder 25 are removed to obtain a mold master 26 in which the disappearing model of the sprue part is exposed, as shown in FIG.

Thereafter, the mold master 26 is placed into the seventh mold in the same manner as described above.
The mold is placed in a heating furnace 15 shown in the figure, and the disappearing model material is melted and dropped by heating, followed by firing to obtain a refractory mold 20 as shown in FIG.

In this way, in the process of attaching the refractory slurry and the refractory (refractory sand), if the elastic sealing material 2
1. Even if a refractory coating is formed around the holding member 22, by appropriately bending the elastic sealing material 21, the refractory coating can be removed extremely easily, and the subsequent holder 25, The elastic sealing material 21 and the pressing member 22 can be removed extremely easily.

FIG. 14 shows another embodiment of the present invention, in which a space 5a is provided inside the sprue of the disappearing model tree 5 to save on expensive disappearing model materials such as wax. That is, in this case, the elastic sealing material 31 is not formed into a flat ring shape as shown in FIG. 10, but is formed into a flat circular shape so that the space 5a of the disappearing model tree 5 can be completely sealed. . Further, the pressing member 32 is attached to the elastic sealing material 31.
Except for the parts that are particularly necessary when pressing
As shown in the figure, the elastic sealing material 32a is formed in the hollow part 32a, and when the refractory is covered with the refractory, the elastic sealing material 31
I try to make it stick more.

In the case of the embodiment shown in FIG. 14, the refractory slurry and the refractory material (refractory sand) are applied several times to the vanishing model tree 5 with the elastic sealant to obtain a refractory coating of the required thickness. However, by bending the elastic sealing material 31 by hand after the refractory coating is completed, the refractory attached around the elastic sealing material 31 can be easily removed, so that the subsequent elastic sealing material 31, pressing member 32,
The holder 25 can be removed extremely easily.

In addition, by using elastic sealing materials 21 and 31 made of fluorocarbon rubber and having mirror-finished surfaces, it is possible to almost prevent refractories from adhering to the elastic sealing materials 21 and 31. Pressing member 22,
Since the refractory adheres only to the portion 32, it becomes unnecessary to remove the refractory coating and at the same time it becomes possible to save the refractory. At this time, even if the refractory adheres to the presser members 22, 32, there is almost no problem in removing the elastic sealing materials 21, 31, the presser members 22, 32, and the holder 25; Refractories should be removed at an appropriate time.

Furthermore, in the case of the embodiment shown in FIG. 14, a case has been described in which the entire disappearing model tree 5 is made of the disappearing model material. The present invention can also be applied to a vanishing model tree in which a ceramic cup is joined to a runner made of vanishing model material and a cast product part.

As explained above, according to this invention,
After contacting an elastic sealing material with the part of the vanishing model corresponding to the sprue part of the mold to be manufactured, a refractory coating is applied to the surface of the vanishing model, and then, after removing the elastic sealing material, the vanishing model is Since a refractory mold is manufactured by extinguishing, it is possible to seal the part of the extinguishing model corresponding to the mold sprue well, and it is possible to seal the part of the extinguishing model that corresponds to the mold sprue part, and to prevent the adhesion of the elastic seal material around the elastic sealing material after being coated with refractory material. The refractory can easily fall off by bending the elastic seal material appropriately, so the subsequent removal of the elastic seal material can be carried out very smoothly, and at the same time, the exposed model at the mold sprue can be prevented. Since it is made well and there is no unnecessary refractory attached to the mold sprue part, it is possible to make the flow of the disappearing model extremely smooth during the disappearing process of the disappearing model,
It is possible to prevent refractories from being mixed in the leaked lost model, which creates a favorable situation for repurifying the lost model, and it is also possible to easily reuse the elastic sealing material, making it possible to create a refractory mold. It has many excellent effects such as significantly increasing production efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of a mold used to manufacture a vanishing model by filling it with vanishing model material, and FIG. 2 is a front explanatory diagram showing how a vanishing model tree is manufactured from a plurality of vanishing models. Figure 3 is an explanatory front view of the state in which the sealing material is pasted on the sprue part of the vanishing model tree in the conventional method, and Figures 4 and 5 are
An explanatory diagram of the situation in which refractory slurry and refractory material (refractory sand) are attached to the surface of the vanishing model tree shown in the figure, respectively. Figure 6 is a front view of the mold prototype made from the vanishing model tree of Figure 3, and Figure 7 The figure is a cross-sectional explanatory diagram of the heating furnace showing the state in which the disappearing model material disappears,
FIG. 8 is a cross-sectional explanatory diagram of a refractory mold produced after firing, and FIG. 9 is a partial cross-sectional explanatory diagram of a state in which an elastic sealing material is brought into contact with the sprue portion of a vanishing model tree in one embodiment of the present invention. Fig. 10 is a plan view of the elastic sealing material, Figs. 11 and 12 are explanatory diagrams of the situation in which refractory slurry and refractory material (refractory sand) are attached to the surface of the disappearing model tree in Fig. 9, respectively, and Fig. 13 is a plan view of the elastic sealing material. The figure is a front view of a mold prototype made from the disappearing model tree shown in FIG. 9, and FIG. 14 is a partial cross section of another embodiment of the present invention in which an elastic sealing material is brought into contact with the sprue part of the disappearing model tree. The explanatory diagram, FIG. 15, is a plan view of the holding member. 2...Disappearance model material, 3, 4...Disappearance model, 5
... Disappeared model tree, 10 ... Refractory slurry,
12... Refractory material (fireproof sand), 20... Refractory mold,
21, 31... Elastic sealing material, 22, 32... Pressing member, 25... Vanishing model holder.

Claims (1)

[Claims] 1 After applying a refractory coating to the surface of the vanishing model,
When producing a refractory mold by causing the disappearance model to disappear, an elastic sealing material is brought into contact with a portion of the disappearance model corresponding to the sprue portion of the mold, and then a refractory coating is applied to the surface of the disappearance model. A method for manufacturing a fire-resistant mold, characterized in that the fire-resistant mold is manufactured by removing the elastic sealing material, and then causing the disappearing model to disappear.