JPS58157547A - Manufacture of refractory casting mold - Google Patents

Abstract

PURPOSE:To improve the working efficiency in molding of casting molds for investment casting in the stage of molding said molds by bringing an elastic sealing material to abut to the sprue of expendable patterns and covering the same with refractories then removing the sealing material and expending the expendable patterns. CONSTITUTION:With an expendable tree 5 consisting of plural expendable patterns and a sprue and runners made of hot meltable wax or the like, an elastic seal 21 made of natural rubber is placed in the position corresponding to the sprue of the casting mold to be manufactured, and is fixed by means of a retaining member 22, a screw 23, a stopper 24, a holder 25, a nut 6, etc. The assembly is immersed in the refractory slurry 10 in a tank 1 to stick the refractory slurry on the surface, and in succession, refractory sand is stuck thereon and is dried. The matrix of the casting mold is manufactured by repeating the above-mentioned operations a number of times, whereafter the material 21 is deflected to dislodge and remove the refractories from the circumference. The matrix is put into a furnace where the same is heated to melt away the expendable pattern material; thereafter, the mold is calcined, whereby a precision casting mold 20 consisting of the refractories is molded.

Description

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

The methods of manufacturing 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 method, investment casting method (where wax is applied to the disappearing model material). When used, there are lost wax casting method) 1 plaster casting method, show process, etc.

Among the above, the present invention relates to a method for manufacturing a refractory mold used in an investment casting method. Conventionally, when making this refractory mold, as shown in FIG. Disappearance model material 2 (wax, plastics, mercury, etc.) in a fluid state is press-fitted into 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 Figure 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.
Screw the holder 8 into place 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 refractory slurry IJ-10t
- The vanishing model tree 5 is dipped in the dipping tank 11 in which the slurry is attached, and then, as shown in FIG. 5, the vanishing model tree IJ-51 with the slurry attached
After adhering C refractory material (refractory sand) 12, it is dried, and slurry and refractory material adhere.

The drying process is repeated several times to produce a mold pattern 16 coated with a refractory material of a required thickness. Thereafter, as shown in FIG. 6, the refractory coating adhering to the sprue part of the first mold master 13 is removed, the holder 8 is removed, and at the same time, the sealing material 7 is removed and the model material at the sprue part disappears. expose the
Next, as shown in FIG. 7, the mold master 16 is placed in a heating furnace 15 equipped with a heating element 14 and heated to melt and cause the disappearing model material to fall. Thereafter, firing is performed to form a casting space 20a as shown in FIG.

A refractory mold 20 having a runner 20b and a sprue 20e 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 disappearing model tree 5 using adhesive or partial melting is troublesome.
The work of removing the refractory from the sprue of the mold master 13 after applying the refractory coating is extremely inefficient, and in addition, the sealing material 7 is also removed at the same time, making it impossible to reuse. It had some problems.

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. A refractory mold that has numerous advantages, such as being able to very easily remove the refractory material that has been removed, smoothing out the subsequent removal of the lost model, and allowing the sealing means to be reused. The purpose is to provide a manufacturing method.

This invention provides a method for producing a fire-resistant mold by applying a figure-resistant coating to the surface of a vanishing model and then causing the vanishing model to disappear. After abutting a sealing material, a refractory coating is applied to the surface of the disappearing model, and then, after removing the elastic sealing material, the disappearing model is made to disappear, thereby producing a refractory mold. 'are doing. □In this case, it is more desirable that the external shape of the elastic sealing material be larger than the opening of the sprue of the refractory mold.

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

No figure 9! FIG. 13 shows one embodiment of the present invention, which will be sequentially explained below.

When producing a refractory casting according to this embodiment, first a disappearing model tree 5 is produced in the same manner as shown in FIGS. 1 and 2. As the disappearing model material used in this case, heat-melting wax, plastics (polystyrene, polyethylene, vinyl chloride, etc.), mercury, water-soluble area resin, etc. can be used as in the past.

Next, as shown in FIG. 9, for the vanishing model 17-5K, an elastic sealant 21 is applied to a part corresponding to the sprue part of the mold to be manufactured, and a press is applied to the elastic sealant 21. The elastic sealing material 21 is fixed by applying the member 22 and screwing the threaded portion of the holder 25 to which the cyst collar 24 is fixed with the screw 26 into the nut 6. The elastic sealing material 21 has a flat ring shape as shown in FIG. 10, and is made of natural rubber, styrene-butadiene rubber, butadiene rubber, imprene rubber, polyurethane rubber, acrylonitrile-butadiene rubber, chloroprene rubber, or neoprene rubber. It is molded from materials such as , silicone rubber, and fluoro 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 since the holder 25 has a structure that is screwed into the nut 6, it is recommended that the fixing position of the stopper 24 be adjusted by loosening the screw 26. The elastic sealing material 21 can be fixed well. In this case, the presser member 22
A slight deviation in the position of the holder 25 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 point of view, the thickness of the elastic sealing material 21 is preferably about 4 mm or more, although it depends on its hardness (for example, about 40 is good).

In this way, the elastic sealing material 21 is fixed as shown in FIG.
The slurry is applied by immersing the disappearance model tree 5 in 1, and then, as shown in FIG.
2 is applied and then dried, and the above-described steps of slurry adhesion, refractory adhesion, and drying are repeated several times to produce a mold prototype 26 coated with refractory to a desired thickness.

Next, after bending the elastic sealing material 21 and causing the refractory attached around the elastic sealing material 21 to fall off, the holder 25 is removed from the nut 6, and the elastic sealing material 21. Pressing member 22. By removing the holder 25, a mold master 26 with an exposed model of the sprue portion as shown in FIG. 13 is obtained.

Thereafter, the mold master 26 is placed in the heating furnace 15 shown in FIG. 7 in the same manner as described above, and the disappearing model material is melted and dropped by heating, followed by firing. A sex mold 20 is obtained.

In this way, in the step of attaching the refractory slurry 1 and the refractory (fireproof sand), the elastic sealing material 21, the pressing member 2
Even if a refractory coating is formed around the holder 252, the refractory coating can be removed very easily by bending the elastic sealing material 21 appropriately, and the subsequent holder 252 elastic sealing material 21. It is possible to remove the holding member 22 with great ease.

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 61 is not made into a flat ring shape as shown in FIG. 10, but is made into a flat circular shape so that the space 5IL portion of the disappearing model tree 5 can be completely sealed. There is. Further, the pressing member 62 is attached to the elastic sealing material 3.
As shown in FIG. 15, hollow portions 32a are formed except for the parts particularly necessary when holding down the refractory material 61, so that more of the refractory material adheres to the elastic sealing material 61 during subsequent refractory coating. .

In the case of the embodiment shown in FIG. 14, the refractory slurry and the refractory (refractory sand) are applied several times to the vanishing model tree 5 with the elastic sealant to obtain the refractory coating of the required thickness. However, by bending the elastic sealing material 61 after the refractory coating is completed, the refractory attached around the elastic sealing material 61 can be easily removed, so that the subsequent elastic sealing material 61. Pressing member 62. The holder 25 can be removed with great ease and effort.

In addition, the elastic sealing material 21.31 is made of fluoro rubber,
By using a material with a mirror-finished surface, it is possible to almost prevent refractories from adhering to the elastic sealing material 21.31, and to prevent refractories from adhering only to the holding member 22°62. Therefore, it becomes unnecessary to remove the refractory coating and at the same time it becomes possible to save on refractories. At this time, even if the refractory adheres to the holding member 22.32, there is almost no problem in removing the elastic sealing materials 21, 31, the holding member 22.62, and the holder 25, and the holding member 22.
．． Refractories attached to the holder 32 and the holder 25 may be removed at an appropriate time.

In addition, 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, but in addition, the sprue part of the disappearing model tree 5 may be made of a ceramic cup. 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 the present invention, after an elastic sealing material is brought into contact 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, Next, after removing the elastic sealing material, the disappearing model is made to disappear, thereby producing a fire-resistant mold. Therefore, the part of the disappearing model corresponding to the mold sprue can be well sealed, and the fire-resistant mold can be made. The refractories attached around the elastic sealing material after covering the object can be easily removed by appropriately bending the elastic sealing material, so that the subsequent removal of the elastic sealing material can be performed very smoothly. Since the extinguished model is well exposed at the mold sprue and there is no unnecessary refractory attached at the mold sprue, the extinguished model can flow out extremely smoothly during the extinguishing process. ,
It is possible to prevent refractories from being mixed in the leaked lost model, creating a favorable situation for repurifying the lost model, and it is also possible to easily reuse the elastic sealing material, which improves the production efficiency of refractory molds. It has many great effects, such as being able to significantly increase

[Brief explanation of the drawings] Figure 1 is a perspective explanatory diagram of a mold used to manufacture a vanishing model by filling it with vanishing model material, and Figure 2 is a diagram for producing a vanishing model tree from multiple vanishing models. Figure 3 is a front explanatory diagram showing the state in which the sealing material is pasted on the sprue part where the vanishing model is free in the conventional method. Figures 4 and 5 are the diagram of the vanishing model tree in Figure 3. An explanatory diagram of the situation in which refractory slurry and refractory material (refractory sand) are attached to the surface, respectively. Figure 6 is a front view of the mold prototype made from the disappearing model tree in Figure 3. Figure 7 is an illustration of the disappearing model material. FIG. 8 is a cross-sectional view of the refractory mold manufactured after firing, and FIG. 9 is an explanatory cross-sectional view of the heating furnace showing the state of disappearance. FIG. 9 is an explanatory cross-sectional view of the refractory mold manufactured after firing. FIG. 10 is a plan view of the elastic sealing material, and FIGS. 11 and 12 are 9
An explanatory diagram of the situation in which refractory slurry and refractory material (refractory sand) are attached to the surface of the disappearing model tree shown in Figure 1.
Fig. 3 is a front view of a mold prototype manufactured using the disappearing model tree shown in Fig. 9, and Fig. 14 shows a state in which an elastic sealing material is brought into contact with the sprue portion of the disappearing model tree in another embodiment of the present invention. FIG. 15, a partial cross-sectional explanatory diagram, is a plan view of the holding member. 2-Disappearance model material, 3, 4.-Disappearance model, 5-Disappearance model tree, 10.-Large-resistant slurry-112.-Large-resistant (fire-resistant sand), 20.-Refractory mold, 21.31... Elastic sealing material, 22.32--Pressure member, 25--Disappearance model holder. Patent Applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Yutaka Oshio'; A1 Prisoner
No. 2i8i No. 5f Fig. 6 CJc

Claims (1)

[Claims] (1) After applying a refractory coating to the surface of the vanishing model,
In the method of manufacturing a refractory mold by causing the disappearing model to disappear, an elastic sealing material is brought into contact with a portion of the disappearing model corresponding to the sprue portion of the mold, and then the surface of the disappearing model is coated with a refractory material. A method for manufacturing a refractory mold, characterized in that the refractory mold is manufactured by removing the elastic sealing material and then extinguishing the extinguishable model.