JPH09182936A - Metallic mold for forming wax formed product for precision casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold for forming a wax formed product for precision casting which can extend the service life of the metallic mold without increasing the wt. of the whole metallic mold and can improve the precision of the obtd. precision cast product. SOLUTION: The metallic mold is divided into a fixed metallic mold 11 and a movable metallic mold 12 with a metallic mold parting surface, and a cavity 28 having a wax forming product shape is formed on the metallic mold divided surface at the time of clamping the metallic molds and a sliding mold 41 for forming the poured wax into a prescribed shape is arranged so as to be freely advanced/retreated along the metallic mold divided surface in either one of the fixed metallic mold 11 or the movable metallic mold 12. Further, a pushing part 42 for advancing the sliding mold 41 along the metallic mold divided surface by sliding while pushing the back side of the sliding mold 41 at the time of clamping the metallic molds is arranged at the position corresponding to the other metallic mold to the mold with the sliding mold, and at least on each sliding surface of the sliding mold 41 and the pushing part 42, resin layer 44 impregnating and burning fluorocarbon resin is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for a wax product for precision casting, which is suitable for use in producing a precision casting product.

[0002]

2. Description of the Related Art Conventionally, there is a base portion 1 of a secondary combustion chamber of a diesel engine as shown in FIG. This base part 1
This is an example of a precision casting product having a complicated shape. A flange 3 is provided in one opening of a cylindrical main body 2, and a recess 4 along the axis and a bottom surface of the recess 4 and the outside are provided inside the main body 2. A communication hole 5 that communicates is formed. In the case of manufacturing this mouthpiece part 1, first, a wax molding product for the mouthpiece part having the same shape as the mouthpiece part 1 to be molded is produced by using wax, and a die for the mouthpiece part is produced based on the wax molding product. A method of manufacturing a desired die part 1 based on this mold is adopted. Such a method for producing a precision casting product via a precision casting wax molded product is a Co-based alloy that cannot be plastically worked because a mold having a complicated shape can be produced with high precision. It is preferably used when casting a heat-resistant alloy such as a Ni-based alloy. This wax product for precision casting is usually molded into a predetermined shape using a molding die.

FIG. 4 is a sectional view showing a main part of a molding die used in a conventional molding process of a wax molded product for a die,
5 is a plan view of the lower mold (fixed mold), and FIG. 6 is a plan view of the same mold (movable mold). In FIG. 5, 11 is a lower mold (fixed mold) made of an aluminum alloy. , 12 are molds (movable molds) same as above. On the mold dividing surface 11a of the lower mold 11, a groove portion 13a having a semicircular cross-section for injecting wax, a plurality of branch portions 13b to 13e, and a hemispherical basin portion 13f are formed in the central portion thereof. Branching parts 13b to 13e
Each of them has a concave portion 14 formed by dividing a wax molded product for a die portion to be molded into two in the axial direction, and a slide pin (sliding type) 1 for forming a communication hole in the wax injected into the concave portion 14.
5, a groove portion 16 for accommodating the lower half portion and a groove portion 18 for accommodating the lower half portion of the slide piece (sliding type) 17 for forming a recess in the wax injected into the recess 14 are formed. ing.

Further, on the mold dividing surface 12a of the upper mold 12, groove portions 21a are respectively provided at positions corresponding to the groove portions 13a of the mold dividing surface 11a, the plurality of branch portions 13b to 13e, and the molten metal pool portion 13f. , A plurality of branch portions 21b to 21e
And a basin 21f are formed, and these diverging parts 21b
˜21e, a concave portion 22 and a slide pin 15 each having a shape obtained by axially dividing a wax molded product for a die to be molded into two parts.
A groove 23 for accommodating the upper half of the slide piece 17 and a groove 24 for accommodating the upper half of the slide piece 17 are formed,
A pressing block (pressing portion) 25 for advancing the slide pin 15 along the mold dividing surfaces 11a and 12a at the time of mold clamping is provided in the groove 23, and a slide piece 1 is provided at the groove 24 for mold clamping.
Pressing blocks (pressing parts) 26 for advancing 7 along the mold dividing surfaces 11a, 12a are provided, respectively.
Then, the groove portions 13a and 21a, the branch portions 13b to 13e,
21b to 21e and the pool parts 13f and 21f constitute a runner, and the recesses 14 and 22 constitute a cavity 28.

The slide pin 15 is provided so as to be movable back and forth with respect to the cavity 28, and a pin 31 for forming a communication hole in the wax injected into the cavity 28.
And a slide block 32 to which the pin 31 is fixed and slides in the groove portion 16, and a direction which is interposed between the slide block 32 and the groove portion 16 to separate (retract) the slide block 32 from the cavity 28. And a spring 33 that urges the spring 33 toward.

The back side of the slide block 32 is an inclined surface 32a having a downward slope, while the front surface side of the pressing block 25 is an inclined surface 25a having an upward slope. As the upper die 12 descends during mold clamping. When the inclined surface 25a of the pressing block 25 slides while pressing the inclined surface 32a of the slide block 32, the slide block 32 slides in the groove portion 16 and advances along the mold dividing surfaces 11a and 12a, and the tip end is moved. The pin 31 provided in the portion projects into the cavity 28. The slide piece 17 has the same structure as the slide pin 15.

[0007]

The conventional molding die is
In order to facilitate handling, the mold is generally made of an aluminum alloy to reduce its weight. However, when the entire die is made of aluminum alloy, the slide pin 15, the slide piece 17, the pressing blocks 25, 26
There is a problem that the sliding surfaces of such parts are severely worn, so that the life cycle of these parts is shortened and the life of the mold is shortened.

When the wear of these parts becomes severe,
The precision of the molded wax product for the die is reduced, and thus the precision of the die, which is a precision cast product, is reduced, which reduces the yield of the product and causes a cost increase. Therefore, it may be considered that these parts are made of a metal material having more excellent wear resistance, but the weight of the entire mold increases and the handling becomes difficult, which causes a practical problem. Absent.

The present invention has been made in view of the above circumstances, and it is possible to extend the life of a die without increasing the weight of the die as a whole, and further improve the precision of the precision cast product obtained. It is an object of the present invention to provide a molding die for a wax molding for precision casting.

[0010]

In order to solve the above problems, the present invention employs the following molding dies for wax moldings for precision casting. That is, the molding die of the precision casting wax molded article according to claim 1 is a molding die which is used when molding a precision casting wax molded article and is made of aluminum or an aluminum alloy. The mold is divided into a fixed mold and a movable mold by a surface, and when the mold is clamped, the cavity of the wax molded product is formed on the mold dividing surface, and either the fixed mold or the movable mold is formed. On one side, a sliding die that forms the wax injected into the cavity into a predetermined shape is provided so as to be movable back and forth along the mold dividing surface, and at a position corresponding to the other sliding die, either A pressing portion that slides while pressing the back side of the sliding die to advance the sliding die along the mold dividing surface when tightening is provided, and at least the sliding surface of each of the sliding die and the pressing portion is provided. , Impregnated with fluororesin and baked It is obtained by forming a only resin layer formed.

According to a second aspect of the present invention, there is provided a molding die for a wax product for precision casting, wherein a resin layer formed by impregnating a fluororesin and baking is formed on the inner surface of the cavity.

In the molding die of the wax product for precision casting according to claim 1, at least the sliding surface of each of the sliding mold and the pressing portion is formed with a resin layer which is impregnated with a fluororesin and baked. As a result, these resin layers protect the sliding surfaces, improve the wear resistance and mechanical strength of these sliding surfaces, and extend the life of the mold.

In the molding die of the wax product for precision casting according to claim 2, a resin layer formed by impregnating a fluororesin and baking is formed on the inner surface of the cavity.
The releasing property of the wax in the cavity is improved and the amount of the releasing agent used is reduced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a molding die for a wax molded product for precision casting according to the present invention will be described below.
FIG. 1 is a cross-sectional view showing a main part of a molding die of this embodiment. The same components as those of the conventional molding die shown in FIG. . In FIG.
41 is a slide pin (sliding type), 42 is a pressing block (pressing part), and the slide pin 41 is a pin 31
The pin 31 is fixed and includes a slide block 43 that slides in the groove 16 and a spring 33.

The slide block 43 is a fluororesin layer 44 which is a tough film obtained by impregnating the entire surface of the conventional slide block 32 with a fluororesin and baking it.
Is formed. Further, the pressing block 42 is
A similar fluororesin layer 44 is formed on the entire surface of the conventional pressing block 25. Although not shown,
The slide piece 17 also has a fluororesin layer 44 formed on the entire surface thereof, just like the slide pin 41.

The fluororesin layer 44 is formed on the surface of the slide block 42 as follows. First, FIG.
As shown in (a), the surface 32 of the slide block 32 is
The surface 32 is removed by removing the dirt of a and performing anodizing treatment or the like.
An oxide film 51 made of porous aluminum oxide is formed on a. Then, as shown in FIG. 2B, the slide block 32 having the oxide film 51 formed thereon is immersed in an aqueous solution in which a fluorinated polymer which is a precursor of a fluororesin is dispersed, and the slide block 32 is formed on the oxide film 51. The fluorinated polymer 52 is laminated. Then, as shown in FIG. 3C, baking treatment is performed at a temperature equal to or higher than the melting temperature of the fluorinated polymer 52,
The fluorinated polymer 52 is used as the fluororesin layer 44 having a strong strength. By forming the fluororesin layer 44 on the surface of the pressing block 25 by the same method, the pressing block 42 can be obtained.

Next, the operation of this molding die will be described.
During mold clamping, the inclined surface (sliding surface) 42a of the pressing block 42 slides while pressing the inclined surface 43a (sliding surface) of the slide block 43 as the upper die 12 descends. The slide block 43 has the groove 16
Slides inside and advances along the mold dividing surfaces 11a and 12a,
The pin 31 provided at the tip portion projects into the cavity 28. At the time when the upper mold 12 comes into close contact with the lower mold 11, the heated and fluidized wax is injected into the cavity 28, and the wax is held at a predetermined temperature and a predetermined pressure for a predetermined time, and the inside of the cavity 28 is kept. The wax is cured to form a mouthpiece having a predetermined shape.

After a predetermined time has elapsed, as the upper die 12 is raised, the inclined surface 42a of the pressing block 42 also rises, and at the same time, the spring 33 urges the slide block 43 to press the inclined surface 42a of the pressing block 42. . As a result, the inclined surface 43a of the slide block 43 moves in a direction of moving away from (retracting from) the cavity 28 while sliding along the ascending surface 42a of the ascending pressing block 42, and when the movement ends, the pin 43a 31 is in a state of being completely taken out from the molded wax. Cavity 28
If the wax molded from is taken out, a highly accurate wax molded product can be obtained.

As described above, according to the molding die of this embodiment, the slide block 32 and the pressing block 2 are provided.
5 and the slide piece 17 on the entire surface of the fluororesin layer 4
4 is formed, the entire surface of each of the slide block 32, the pressing block 25 and the slide piece 17 can be protected and reinforced by the tough fluororesin layer 44,
The wear resistance and mechanical strength of these surfaces can be improved, and the life of the mold can be extended.

In this embodiment, the fluororesin layer 44 is formed on the entire surface of each of the slide block 32, the pressing block 25 and the slide piece 17, but the fluororesin layer 44 is formed on at least each sliding surface. It should have been done. Further, if the fluororesin layer 44 is formed on the inner surface of the cavity 28 as well, the releasability of the wax in the cavity 28 can be improved and the amount of the release agent used can be reduced.

[0021]

As described above, according to the molding die of the first aspect of the present invention, at least the sliding surfaces of the sliding die and the pressing portion are impregnated with a fluororesin and baked. Since the resin layer is formed, the sliding surface can be protected and strengthened by these resin layers, and therefore, the wear resistance and mechanical strength of these sliding surfaces can be improved,
The life of the mold can be extended.

According to the molding die of the second aspect, since the resin layer formed by impregnating and baking the fluororesin is formed on the inner surface of the cavity, the releasability of the wax in the cavity can be improved. Therefore, the amount of release agent used can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a molding die according to an embodiment of the present invention.

FIG. 2 is a process chart showing a method for forming a fluororesin layer of a molding die according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a mouthpiece of a secondary combustion chamber of a diesel engine, which is an example of a conventional precision casting wax molded product.

FIG. 4 is a cross-sectional view showing a main part of a conventional molding die.

FIG. 5 is a plan view showing a lower mold (fixed mold) of a conventional molding mold.

FIG. 6 is a plan view showing an upper die (movable die) of a conventional molding die.

[Explanation of symbols]

 11 Lower Die (Fixed Die) 11a Die Split Surface 12 Upper Die (Movable Die) 12a Die Split Surface 17 Slide Piece (Sliding Die) 25 Pressing Block (Pressing Part) 28 Cavity 31 Pin 33 Spring 41 Slide pin (sliding type) 42 Pressing block (pressing part) 42a Sloping surface (sliding surface) 43 Slide block 43a Sloping surface (sliding surface) 44 Fluororesin layer

Claims (2)

[Claims] 1. A molding die used for molding a wax product for precision casting, which is made of aluminum or an aluminum alloy and is divided into a fixed mold and a movable mold by a mold dividing surface. When the mold is clamped, the wax-molded cavity is formed on the mold dividing surface, and the wax injected into the cavity has a predetermined shape in either the fixed mold or the movable mold. The sliding die to be formed on the mold is provided so as to be movable back and forth along the mold dividing surface, and the back side of the sliding die is pressed at the position corresponding to the other sliding die at the time of mold clamping. A pressing portion is provided which slides while advancing the sliding die along the mold dividing surface, and at least the sliding surface of each of the sliding die and the pressing portion is impregnated with a fluororesin and baked. Resin layer is formed Mold precision casting wax molded article, characterized in that. 2. A mold for molding a wax molded product for precision casting according to claim 1, wherein a resin layer formed by impregnating a fluororesin and baking is formed on an inner surface of the cavity.