JPH0716700A - Wax pattern used to manufacture of mold and method for coating refractory sand - Google Patents

Abstract

PURPOSE:To suitably execute coating on an investment material by bonding dry refractory sand to narrow and long holes and groove parts with binder slurry and closing one end or both ends of the holes and the grooves with the slurry. CONSTITUTION:After closing one side of the opening side end parts of the holes 16 in a wax pattern 14 with e.g. cloth-made adhesive tape 20, the wax pattern 14 is turned over and the closed side with the tape 20 is positioned downward. Further, the binder slurry having low viscosity and high fluidity is poured from the other end part coming to the opening upward in the hole 16 to form the slurry layer 21 and successively, the dry refractory sand 22 is charged from the opening end part in this hole 16 and filled in the inner part. As this refractory sand 22 is dried and has extremely high fluidity, even if the through-hole 16 in the wax pattern 14 is narrow and long, the refractory sand is quickly spread over in the inner part of the hole with the gravity. At the time of uniformly spreading the refractory sand 22 over into the inner part of the through-holes 16, the end part at the other side opened upward in the wax pattern 14 is closed with the binder slurry.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wax mold used for making a mold and a method for coating refractory sand,
More specifically, prior to casting a casting having a narrow and long hole or groove by the lost wax method, an improvement of the wax mold used for producing a lost wax casting mold,
The present invention relates to a method for coating the wax mold with refractory sand.

[0002]

2. Description of the Related Art As shown in FIG. 4, a work 10 used for a supercharger for an internal combustion engine has a large number of narrow elongated through holes 12 formed in the axial direction of a cylindrical body. This work is
Since heat resistance and low coefficient of thermal expansion are required, a special heat resistant alloy is used as the material. Since this special heat-resistant alloy is generally difficult to machine and requires a high degree of precision processing, the work is cast by the lost wax method, which is a type of precision casting technology. In this lost wax method, a model having the same shape and dimensions as the final product, a cast product, is molded by wax injection (this model is called a "wax mold"),
The surface of the wax mold is coated with an invest material to solidify it, the wax mold is heated to melt the wax, and the hollow invest material is baked at a high temperature to obtain a mold. Since the cavity in this mold matches the external shape of the final product, the cast product is manufactured by pouring a molten metal of the required metal into the mold, cooling and solidifying, and then releasing the mold. It Here, as the investment material to be coated on the surface of the wax type, a slurry (solution) in which a fine refractory powder such as zircon flour is mixed with a binder (binder) such as ethyl silicate or colloidal silica is used. used.

By the way, the above-mentioned workpiece has a special shape in which a narrow elongated through hole is formed in the cylindrical body in the axial direction. Therefore, as shown in FIG. 5, even if the wax mold 14 is coated with an investment material, since the through hole 16 is narrow and long, the circumference of the investment material is poor and a uniform coating cannot be applied. The current situation. Therefore, for such a special wax mold 14, the following special slurry is used. For example, first, ethyl silicate 40, pure water,
A binder is prepared by mixing piperidine and cyclohexylamine, but this preparation requires a long time (24 hours). By adding refractory sand to this binder, and further by adding a curing agent prepared from methyl alcohol and pure water thereto, a slurry having excellent fluidity is prepared. Then, this slurry is poured from above the wax mold 14. At this time, a suitable vibration is given by a vibrating device (not shown) so that the slurry is evenly distributed in the narrow long through hole 16, and at the same time, the rod 18 is used. Manual work is performed by pushing and pushing the slurry deeply. By subjecting the wax mold 14 coated with the investment material to the dewaxing process and the firing process described above, a mold for casting a casting having narrow and long holes and grooves is manufactured.

[0004]

As described above, in order to coat the wax type having the narrow and long holes and grooves with the investment material, after the special binder described above is prepared, it is fireproofed. Although it is necessary to add sand or a hardening agent, there is a drawback that it takes a long time to prepare and set up the binder. In addition, when the slurry is put into the wax mold, the work of pushing the slurry into the hole with a stick is manually performed, which is labor-intensive and tends to cause variations. Furthermore, in a mold using this special investment material as a base material, it is necessary to perform alkali treatment under pressure using an autoclave because it is difficult to collapse when releasing the mold after casting into the mold, It is also pointed out that it is costly and expensive.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned drawbacks of the prior art, and it is a mold for casting a casting having narrow and long holes and grooves. Regarding a wax mold used for manufacturing, an object of the present invention is to provide a wax mold suitably coated with an investment material without using a special slurry and without requiring manual work for pushing the slurry by a rod. . Another invention of the present application is an improved coating of refractory sand on a wax mold used for producing a mold having narrow and long holes and grooves, and both ends of the holes and grooves being open. The purpose is to provide a method.

[0006]

In order to solve the above-mentioned problems and preferably achieve the intended purpose, the present invention is a wax mold for producing a mold having narrow and long holes and grooves.
Dry refractory sand is bound to the narrow and long holes and grooves by a binder slurry, and one or both ends of the holes and grooves are closed with the slurry. A method for coating refractory sand on a wax mold according to another invention of the present application is a wax mold for producing a mold having narrow and long holes or grooves, and both ends of the holes or grooves are open. When coating the refractory sand on, the one end of the hole or groove is closed with the required closing material, and the closed side is positioned below and opened above the hole or groove. From the other end that is present, fill the inside of the hole or groove with dry refractory sand, and bind the refractory sand with the binder slurry that was previously applied to the inner surface of the hole or groove, and then to the above It is characterized in that the other open end is closed with a binder slurry. A method for coating refractory sand on a wax mold according to still another invention of the present application is used for producing a mold having narrow and long holes or grooves, and only one end of the holes or grooves is open. When coating the wax mold with refractory sand, dry refractory sand is filled into the inside of the hole or groove from one open end of the hole or groove, and is applied to the inner surface of the hole or groove in advance. It is characterized in that the refractory sand is coagulated by the binder slurry, and then the one end is closed by the binder slurry.

[0007]

EXAMPLES Next, a wax mold used for producing a mold according to the present invention and a method for coating the wax mold with refractory sand will be described below with reference to the accompanying drawings with reference to preferred embodiments. The main purpose of the present invention is to eliminate the use of the special binder slurry as described above and to fill the narrow and long holes and grooves of the wax mold with dry refractory sand. As the wax type having narrow and long holes and grooves, there are two types, one with both ends of the hole or groove open, and the other with only one end of the hole or groove open. Since it can be considered, the former will be explained first.

The wax mold 14 shown in FIG. 1 is penetrated by a narrow and elongated hole 16 and is open at both ends of the wax mold 14. After one end of the wax mold 14 on one open side of the hole 16 is closed with, for example, a cloth-type adhesive tape 20, the wax mold 14 is inverted and the tape 20 is turned over.
The obstruction side by is located below. Then, a binder slurry having a low viscosity and a high fluidity is poured from the other end that has opened above the hole 16 to form a slurry layer 21, and then the dried refractory sand 2 from the open end of this hole 16
Charge 2 to fill the inside. Since the refractory sand 22 is dry and extremely rich in fluidity, even if the through hole 16 in the wax mold 14 is narrow and long, it quickly and uniformly spreads inside the hole due to gravity. When filling the dried fireproof sand 22 with vibration by a vibration device (not shown) to the wax mold 14, the circumference of the fireproof sand 22 is further improved, which is preferable. When the refractory sand 22 is evenly distributed inside the through hole 16, the end of the wax mold 14 on the other side that is open upward is closed by the binder slurry 24. Zircon silica (ZrSi), fused silica, or the like is preferably used as the dried refractory sand 22. As the binder slurry 24, for example, a slurry having a low viscosity mixed with zircon flour or fused silica flour can be used.

Next, the wax mold 14 shown in FIG. 2 is of a type in which a narrow and elongated hole 16 is opened only on one end side of the wax mold 14. In this wax mold 14, the open side of the narrow and long hole 16 is set up, and the binder slurry is poured from the end of the hole 16 to form a slurry layer 21 and then dry fireproof sand 22 is applied. It is charged to fill the inside of the hole 16. Then the one hole 1
The end of 6 is closed with the binder slurry 24 as before. Fireproof sand 22 and binder slurry 2 used here
4 is the same as illustrated with respect to FIG.

As described above, the wax mold 14 in which the narrow and long hole 16 is filled with the dry refractory sand 22 and one or both ends of the hole 16 is closed by the binder slurry 24 is formed as described above. The wax is melted by heating. When the refractory sand 22 in the hollow state is fired at a high temperature, a mold suitable for casting a casting having narrow and long holes can be obtained. The work is manufactured by pouring a molten metal of a special heat-resistant alloy suitable for the material of the work into the mold, cooling and solidifying the melt, and then separating the mold. When the refractory sand 22 used is fused silica, it is easy to remove the mold from the mold after casting and the sand is easily collapsed, so that it is not necessary to carry out the alkali treatment in the autoclave system as described above. In the illustrated embodiment, the case where the narrow and long hole 16 is formed in the wax mold 14 has been described, but the present invention is not limited to this and the case of FIG.
As shown in (a) and (b), it may be a narrow and long groove portion.

[0011]

As described above, according to the wax mold used for manufacturing the mold and the method for coating the sand with the refractory sand according to the present invention, it is not necessary to prepare a special binder for a long time. The number of steps can be reduced, and labor can be saved by eliminating the manual work of pushing the binder with a rod. Further, there is an advantage that the obtained wax mold does not vary, no autoclave-type alkali treatment is required at the time of mold release, the work is simplified, and the amount of slurry used can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state in which a wax mold having a narrow and long through hole is subjected to a method for coating refractory sand according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state in which a method for coating refractory sand according to another embodiment of the present invention is applied to a wax mold that is narrow and long and has a hole that is open only at one end. .

FIG. 3 is a plan view showing a state where a narrow and long groove is formed in a wax shape.

FIG. 4 is a schematic perspective view showing an appearance of a work.

FIG. 5 is a schematic perspective view showing a state in which a worker is pushing the investment material by hand with a stick when the wax mold is coated with the investment material because the through hole is narrow and long. is there.

[Explanation of symbols]

 14 Wax type 16 Narrow and long hole 20 Adhesive tape 21 Binder slurry 22 Fireproof sand

Claims (4)

[Claims] 1. A wax mold for producing a mold having a narrow and long hole or groove, wherein dry refractory sand is bonded to a portion of the narrow or long hole or groove by a binder slurry, and the hole is further formed. A wax mold in which one or both ends of a groove is closed with the slurry. 2. When coating a refractory sand on a wax mold for making a mold, which has narrow and long holes or grooves, and both ends of the holes or grooves are open, one of the holes or grooves is used. While closing the open end with the required closing material, position the closed side downward, and from the other end open above the hole or groove, dry the refractory sand Or refractory sand is filled in the inside of the groove or groove, and the refractory sand is bound by the binder slurry that has been previously applied to the inner surface of the hole or groove, and then the other end that is open upward is closed with the binder slurry. A method of coating refractory sand on a wax mold characterized by the above. 3. A wax mold used for producing a mold having a narrow and long hole or groove, and only one end of the hole or groove being open, is coated with refractory sand. From one open end of the groove, dry refractory sand is filled into the inside of the hole or groove, and the refractory sand is bound by the binder slurry previously applied to the inner surface of the hole or groove. A method for coating refractory sand on a wax mold, characterized in that one end is closed with a binder slurry. 4. The method for coating refractory sand on a wax mold according to claim 2, wherein vibration is applied simultaneously when filling dry refractory sand into the narrow and long holes or grooves.