JPS61222659A - Molding method for wax pattern in lost wax casting method - Google Patents

Abstract

PURPOSE:To solve the problem that a spacing is formed at the boundary between a core and wax by using a ceramic type core for molding a wax pattern for use in a lost wax casting method and pouring wax while the core is kept heated. CONSTITUTION:The ceramic type core 11 is used for the wax pattern 10. The wax 12 is poured while the core 11 is kept heated in the stage of molding. The core 11 and the wax 12 are brought into tight contact with each other at a contact surface 13 while the wax 12 contacting with the core 11 is maintained in the molten state. The problem that the spacing is formed at the boundary between the core and the wax is solved and the need for a sealing stage is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wax molding method in a lost wax casting method that provides good product precision and does not mix impurities into hot water.

<Prior Art> Various casting methods have been used in the past in response to demands for improving the dimensional accuracy of cast products and improving production efficiency. Among these, the lost wax method involves forming a wax mold with the same shape as the product in advance and casting into the dewaxed part, so it is widely used as a suitable casting method when a complex shape or a high degree of dimensional accuracy is required. There is.

By the way, in the above-mentioned strike wax method, when casting a product having a hollow part for cooling, such as a plate, vane, or nozzle, with a hollow part, pore part, or a similar shape, these The wax mold is molded using conventional methods such as a) ceramic set injection method, and (b) ceramic core post-insertion method. Here 0) What is the ceramic set injection method?
First, a core is set on a wax mold board, and molten wax is injected into the mold to form a wax mold in which the core and wax are integrated. The post-insertion method with a core is a method in which a wax mold is formed in advance with a cavity for insertion, a core is inserted, and a p-shaped mold is finally formed.

However, conventionally, all of the above-mentioned methods have the disadvantage that a gap n is likely to be formed at the interface between the four-shaped core 21 and the wax n, as shown in FIG.

For example, when a core is placed in a mold in advance and wax is injected, the wax shrinks due to the temperature of the core being lower than that of molten wax. Further, when inserting the core into a wax mold, it is necessary to form a gap for insertion in advance, and in this case as well, it is impossible to avoid the formation of a gap at the interface between the wax and the core. If there is a gap between the core and the wax, the coating material will not only get into this gap and reduce the dimensional accuracy of the product, but also cause the refractory coating material that has penetrated into the gap to leak during pouring. It mixes into the molten metal and causes problems such as inclusion defects. For this reason, conventional measures have been taken, such as applying wax 24 between the ends of the core 21 and wax 22 of the wax mold 20 to seal the gap n, as shown in FIG. 3, but these measures are not sufficient.

<Structure of the Invention> The present invention uses a ceramic core in the above-mentioned wax molding, keeps the wax contact surface in contact with the core in a molten state by heating the core, and makes the wax adhere to the core to close the gap. This solves the conventional problem by preventing this from occurring.

That is, according to the present invention, in the wax molding of the lost wax method, a ceramic core is used as the core that forms the product cavity or pores, and when the straw 1 (wax) is injected, the core is heated. There is provided a method for forming a wax mold in a lost wax casting method, which is characterized by keeping wax in contact with the core in a molten state and bringing the core and wax into close contact.

In the present invention, a ceramic core is used for the core of the product, such as a core that forms cavities, pores, or shapes similar to these. The material of the ceramic is not particularly limited, and any material may be used as long as it does not deform when heated and can be easily removed when demolding the mold. These 95 cores are arranged in a wax mold according to the shape of the product. The mold may be assembled in the same manner as in normal wax molding.

The ceramic core is heated to a temperature between the melting or softening point of the wax, typically ω~80'C.

Various heating methods can be used6, for example,
By preheating the core to the above-mentioned temperature and incorporating it into the mold, the heated state can be easily achieved. Ceramic has good heat retention properties after heating, so the above temperature can be maintained sufficiently even during the assembly of the hardware. Of course, other heating means may be attached to the core as necessary. After assembling the mold, molten wax is injected to form the wax mold. In this case, in the present invention, since the core is heated, even if the wax comes into contact with the core, it remains molten, and a wax mold is formed in which the wax closely adheres to the core and has no gaps.

After forming the wax mold, the outer periphery of the wax mold is coated and spread with a coating material, filled with a sweet filler such as sand in the mold, heated to dewax, and then fired. Make a mold. After that, the molten metal is poured into the mold, and after the mold is removed,
Get the final product. After forming the wax base in this manner, casting may be performed according to the usual lost wax method.

The present invention will be described below with reference to the drawings.

The figure shows a wax type hollow wing with a cavity in the center of the product.
1 and 2 show a wax mold according to the present invention, with FIG. 1 being a side view thereof and FIG. 2 being a sectional view taken along the line 1 rIAA-A. As shown in the figure, the wax mold 10 of the present invention uses a ceramic core 11, and the wax mold 10 is formed by heating the core 11 and injecting wax 12.

For this reason, the surface 13 of the wax 12 that comes into contact with the core 11 during wax injection does not undergo thermal contraction due to rapid cooling, but remains molten and comes into close contact with the core, so that the surface 13 of the wax 12 that comes into contact with the core 11 does not shrink as a result of rapid cooling. No gaps are created.

<Effects of the Invention> As explained above, according to the wax molding method of the present invention, a ceramic core is used and wax is injected into the core while it is heated, so that the contact surfaces between the wax and the core are in close contact with each other.
No gaps caused by heat shrinkage. Therefore, there is no need to apply molten wax to the end faces of the wax and the core to seal the gap as in the past, and it is possible to easily form a wax mold without a sealing process. Furthermore, the coating material does not enter the interface between the wax and the coat as in the conventional method, making it possible to obtain a wax mold with extremely high precision. Further, since the coating material does not enter the interface between the wax and the core, there is no problem such as the coating material being mixed in as an impurity during pouring.

[Brief explanation of the drawing]

1 and 2 show a wax mold according to the method of the present invention, FIG. 1 is a side view thereof, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. 3 is a longitudinal cross-section of a conventional wax mold. It is a front view. In the figure, 10.20... Wax mold, 11, 21... Core, 12, 22... Wax, 13... Contact surface,
n...gap, fable...wax. Patent Applicant Mitsubishi Metals Co., Ltd. Agent Patent Attorney Masahiro Matsui Figure 3

Claims (1)

[Claims] In wax molding using the lost wax method, a ceramic core is used as the core that forms the product cavity or pores, and when injecting wax, the core is heated to keep the wax in contact with the core in a molten state. , a method for forming a wax mold in a lost wax casting method, which is characterized in that the core and wax are brought into close contact with each other.