JP2000233259A - Metallic mold for wax pattern and manufacture of wax pattern using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the reusing of a wax core and to reduce the manufacturing cost and manufacturing manhour by forming a recessed part for reducing the thickness of the wax core near an undercut part at the back surface side of the soft material-made wax core forming a part of the cavity surface containing an undercut part and fitting a hard material-made insert member so as to be possible to insert/pull out. SOLUTION: The wax is filled into a cavity 10 from a wax pouring hole 5 to form a wax pattern 2 having an undercut part 3. At this time, the filling pressure is loaded onto the inner wall surface of the cavity 10 but the wax core 1 is not largely deformed because the recessed part 1b is supported with an insert member 8, and further, a soft material is used, but the deformation of the thick portion can be disregarded because the soft material is of comparatively thin thickness. After the wax pattern 2 is cooled and solidified, the insert member 8 is pulled out to the right side. Successively, when a movable side pattern plate 7 is shifted to the right side, simultaneously, the wax core 1 is shifted and separated from the wax pattern 2 while deforming without developing any damaging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for forming a wax model in a lost wax casting method and a method for manufacturing a wax model, and more particularly to a case where a wax model having an undercut shape is formed.

[0002]

2. Description of the Related Art In a mold for forming a wax model in a lost wax casting method, a surface or a concave portion protruding laterally in the opening / closing direction of the mold or the product taking-out direction is provided on the surface of a target wax model. At this time, this portion becomes an undercut portion.

FIG. 4 shows an example of a mold for forming a wax model having such an undercut portion. In this example, the undercut portion 3 is formed using the water-soluble wax core 21 as a core. In the step of forming the wax model, wax is injected, and after the wax model 2 is solidified, the movable mold plate 27 is first removed, and then the divided mold plate 6 is removed.
Is removed, and the wax model 2 and the water-soluble wax core 21 are separated from the fixed mold plate 4 in a state of being united. Then, the wax model 2 is completed by dissolving and separating the water-soluble wax core 21 with a chemical.

In addition, a ceramic wax core may be used as the wax core. In this case, since it is difficult to separate the ceramic wax core from the wax model, in a state where the wax model and the ceramic wax core are integrated, these are included in a molding material to form a casting mold. Next, only the wax is melted and discharged to cast the metal, and after the casting mold is broken, the ceramic wax core is eluted with an alkaline solution and separated from the metal casting product.

[0005]

However, in any of the above methods, the wax core used is disposable one time at a time, which increases the cost of the wax core material, increases the number of man-hours for manufacturing the wax core, and reduces the cost of the wax core. There are problems that it takes a lot of man-hours to remove it, that it costs a lot of money when using a chemical, and that it costs a lot to dispose of the chemical.

The present invention has been made to solve such a problem, and provides a mold for forming a wax model using an inexpensive and reusable wax core, and a method for manufacturing a wax model using the same. The purpose is to.

[0007]

According to a first aspect of the present invention, there is provided a mold for forming a wax model having an undercut portion in a part of a cavity in a lost wax casting method. A part of the cavity surface including the core is formed of a wax core made of a flexible material, and a concave portion for reducing the thickness of the wax core near the undercut portion is formed on the back side of the wax core, and the concave portion is formed of a hard material. The insert member is detachably fitted.

[0008] The present invention described in claim 2 provides the present invention in claim 1.
The method for manufacturing a wax model, which is performed using a mold for forming a wax model according to the above, wherein after the wax is injected into the cavity, the insert member is removed, and the wax core is elastically deformed. Characterized by being separated from

According to the wax model forming mold and the wax model manufacturing method using the same, when the insert member is pulled out after solidification of the wax model, the wax core of the flexible material is deformed and easily separated from the wax model. be able to. Since the wax core is not damaged, it can be reused, and the manufacturing cost and the number of manufacturing steps can be reduced as compared with the case of the conventional disposable wax core.

The wax core according to claim 1 is
A flange portion extending outward near the open end of the concave portion is provided, and if the flange portion is fitted with a groove provided on the movable mold plate, automation in the production of the wax model is facilitated. Become.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section of a mold for forming a wax model according to the present invention. The cavity 10 of the mold for forming a wax model includes a fixed-side mold plate 4 having a wax inlet 5, a divided mold plate 6 that forms an outer peripheral portion of the wax model 2, and a fixed-side mold plate 4 viewed from the wax model. Is formed by being surrounded by a movable side mold plate 7 which is arranged on the opposite side to the movable side and a wax core 1 for forming the undercut portion 3. The undercut portion 3 of this embodiment is located at a position near the movable mold plate 7 of the cavity 10 and
It has a shape that protrudes to the side.

The material of the wax core 1 is a flexible material such as hard silicon rubber, and the thickness of the portion forming the cavity 10 is relatively thin, about 2 to 5 mm. I have. The wax core 1 has a flange portion 1a in a plane perpendicular to the moving direction of the movable mold plate 7, and the flange portion 1a
In the groove 7a. This fitting causes the flange portion 1a to move integrally with the movable mold plate 7, which facilitates, for example, automation of a production line.

On the other hand, an insert member 8 made of a hard material such as steel is fitted into the concave portion 1b of the wax core 1. The insert member 8 has a smooth distal end shape that fills the concave portion 1b of the wax core 1 without any gap, and moves in the center line direction of the wax core 1 (in this embodiment, coincides with the moving direction of the movable mold plate 7). It is possible.

Next, a process of forming the wax model 2 using the wax model forming die configured as described above will be described. When the cavity is filled with the wax from the wax inlet 5 in the state of FIG. 1 (excluding the wax model 2), the wax model 2 having the undercut portion 3 is formed. At this time, the filling pressure of the molten wax is applied to the inner wall surface of the cavity 10, but the wax core 1
Is not greatly deformed since the concave portion 1b is supported by the insert member 8. In addition, since a soft material is used, since it is relatively thin, the compressive deformation of the thick portion is negligible.

FIGS. 2A to 2C show the wax model 2
2 shows a step of separating the wax core 1 from the wax. After the wax model 2 is cooled and solidified, the insert member 8 is first pulled out in the direction A as shown in FIG. Since the tip of the insert member 8 has a smooth shape, the wax core 1 can be pulled out without damage. Next, as shown in FIG. 2B, the movable mold plate 7 is similarly moved in the direction A. As described above, since the flange portion 1a of the wax core 1 is fitted with the groove 7a of the movable mold plate 7, the wax core 1 also moves together with the movable mold plate 7.
Since the insert member 8 has already been pulled out, the concave portion 1b of the wax core 1 is hollow, and since it is made of a thin flexible material, its rigidity is extremely low. Separate from the wax model 2 while deforming inward. At this time, the wax core 1 itself and the undercut portion 3 are not damaged. FIG. 2C shows a state in which the movable mold plate 7 and the wax core 1 are further moved in the direction A, and the wax core 1 is completely separated from the wax model 2. In this way, the wax core 1 is not damaged and the wax model 2 is not damaged.
Can be reused because it can be separated from

Subsequently, the split template 6 is separated from the wax model 2, and finally the wax model 2 is separated from the fixed-side template 4 to complete the intended wax model 2.

FIG. 3 is a side view showing another embodiment of the present invention in which the wax core 11 and the insert member 8 are combined. In the present embodiment, the wax core 11 is divided into two parts by the dividing line 13. After the insert member 8 is pulled out as described above, the movable core 7 is moved to separate the wax core 11 from the wax model 12. The deformation of the wax core 11 to the inside becomes easier as compared with the case where it is not divided. Therefore, it is suitable for a case where the undercut shape is deep, a case where the wax volume near the undercut is small and there is a concern that the wax model may be damaged.

[0018]

As described above, according to the mold for forming a wax model according to the first aspect and the method for manufacturing a wax model according to the second aspect, a part of the cavity is undercut in the lost wax casting method. When forming the wax model having the portion, the wax core of the flexible material can be deformed and easily separated from the wax model. Since the wax core is not damaged, it can be reused, and the manufacturing cost and man-hour of the wax core can be reduced as compared with the case of the conventional disposable wax core. Further, since it is not necessary to remove the wax core with a chemical or the like, the man-hour, the cost of the chemical, and the cost of disposal of the chemical are eliminated.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mold scheme according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a wax core separating step according to an embodiment of the present invention in the order of (a), (b), and (c).

FIG. 3 is a side view of a wax core and an insert member according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a conventional mold scheme.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wax core 1a Flange part 1b recessed part 2 Wax model 3 Undercut part 4 Fixed mold plate 5 Wax inlet 6 Split mold plate 7 Movable mold plate 7a Groove 8 Insert member 10 Cavity

Claims (2)

[Claims] 1. A mold for forming a wax model having an undercut in a part of a cavity in a lost wax casting method, wherein a part of the surface of the cavity including the undercut is a wax core made of a flexible material. A concave portion is formed on the back side of the wax core to reduce the thickness of the wax core in the vicinity of the undercut portion, and an insert member made of a hard material is removably fitted into the concave portion. Mold for forming wax models. 2. A method for producing a wax model, which is performed using the mold for forming a wax model according to claim 1.
A method of manufacturing a wax model, comprising: after injecting wax into the cavity, extracting the insert member, elastically deforming the wax core, and separating the wax core from the wax model.