JPH079084A - Manufacture of mold for lost wax casting and manufacture of die for injection molding from this cast product - Google Patents

Abstract

PURPOSE:To manufacturing a mold for lost wax casting for producing a cast product provided with characters, etc., having ground pattern on their periphery with few man-hour and to reduce the cost thereof by easily mass-producing metallic products with the ground pattern or mold flasks for pouring the wax from a single original mold. CONSTITUTION:In the method for manufacturing the mold for lost wax casting, an original drawing having figure of characters, etc., is put on a photosensitive resin and exposed. A part where is not exposed and cured due to the figure in this photosensitive resin is removed by washing and a lost foam pattern 10 is formed. This pattern 10 is stuck onto combustible material 11 for forming the ground pattern larger than the outer shape of this pattern 10. Fine powdery refractory is applied on this stuck material 14 and dried, this dried material is heated to lose the material for forming the ground pattern and the lost foam pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lost wax casting mold in which a disappearing model made of a photosensitive resin is used to form a mold, and a method for producing an injection mold from this mold. More specifically, it relates to a lost wax casting mold suitable for producing a metal pattern plate with a ground pattern, and a method for producing an injection mold or a wax injection mold from the cast product.

[0002]

2. Description of the Related Art Conventionally, an image of characters and figures created on an original drawing by a photoengraving method is exposed to a photosensitive resin to wash and remove an uncured portion to form a disappearing model, and the disappearing model is fireproofed. There has been proposed a method for producing a lost wax casting mold in which the disappeared model is extinguished by heating after coating and drying the object (JP-A-61-238).
441). The exposure is performed on the second original drawing by printing the photographed original drawing on a transparent polyethylene-based printing paper, reversing the negative and positive as necessary to create a second original drawing. According to this method, it is not necessary to use an expensive mold, and even a small amount of various cast products can be manufactured at low cost, and the period required for manufacturing can be significantly shortened.

However, this method has a drawback in that the number of cast products required is equal to the number of vanishing models, and the cost reduction effect due to mass production cannot be sufficiently obtained. To solve this point,
As shown in FIG. 3, negative / positive reversal is performed to form a master 2 made of a photosensitive resin on which predetermined recessed characters 1 are formed (FIG. 3 (a)). The same figure (b)), the lost wax 4 which melted is poured into this mold 3 (the same figure (c)), the lost wax is solidified and taken out from the mold 3, and the lost wax casting mold having the convex character 5 is formed. A method of obtaining 6 ((d) in the figure) has been attempted.
According to this method, since the prototype 2 made of the photosensitive resin is not used as the disappearance model, the mold 6 can be repeatedly made from a single prototype.

[0004]

However, JP-A-61-161
In both the manufacturing method shown in Japanese Patent No. 238441 and the manufacturing method shown in FIG. 2, it is not necessary to use an expensive mold, and a mold for a casting product containing characters and figures can be easily manufactured, while the surrounding area is Cast products with patterns are very difficult to manufacture. Further, in the manufacturing method shown in FIG. 2, there is a problem in that a prototype in which predetermined characters are reversed is first required, and a lot of man-hours for producing the prototype 2 of the photosensitive resin are spent.

An object of the present invention is to provide a method for producing a lost wax casting mold with a small number of steps for producing a casting product containing a letter, a figure or a symbol having a ground pattern on the periphery or a combination thereof. is there. Another object of the present invention is to provide a method of manufacturing a metal mold for injection molding, which can easily mass-produce a metal product with a ground pattern from a single master mold to reduce the cost. Still another object of the present invention is to provide a method for manufacturing a wax injecting formwork capable of easily mass-producing a wax pattern for a lost wax with a ground pattern from a single master mold to reduce costs.

[0006]

A configuration of the present invention for achieving the above object will be described with reference to FIGS. 1 and 2 corresponding to the embodiments. The method for producing a lost wax casting mold of the present invention comprises the steps of exposing a photosensitive resin with an original image having characters, figures or symbols or an image of a combination thereof, and exposing the photosensitive resin with the above image. And a step of forming the disappearance model 10 by washing and removing the uncured portion (FIG. 1A), and the disappearance model 1
The process of adhering the disappearance model 10 on the flammable ground pattern forming object 11 which is larger than the outer shape of 0 (the same figures (b) and (c)), and the ground pattern forming object 11 and the disappearance. It is a method including a step of coating finely divided refractory material on the adhesive body 14 of the model 10 and drying it, and a step of heating the dried material to erase the ground pattern forming object and the disappeared model.

Further, the method for producing an injection molding die of the present invention comprises a step of injecting molten metal into the lost wax casting mold produced by the above method, and a metal product with a background pattern solidified in this mold. The step of removing the metal product 20 from the mold and the step of placing the metal product 20 in the mold 21 with the ground pattern portion 20a facing upward (FIG. 2 (a)) using the metal product 20 as a prototype, The step of pouring the molten metal 24 containing bismuth into the mold so as to be embedded (FIG. 6B), the bismuth alloy body 26 solidified in the mold is turned over, and the metal product 20 is removed from the alloy body 26. The step of taking out (FIG. 6C) and the upper die 29 in which the bismuth alloy body 26 from which the metal product 20 is taken out is used as the lower die and the lower die is provided with the injection port 28 at a position facing the metal product taking out portion 27. Attach Forming a mold 30 out the method comprising a (FIG. (D)).

Further, in the method of manufacturing the wax injecting frame of the present invention, the metal product takeout portion 27 is formed in the lower mold made of the bismuth alloy body 26 in which the metal product 20 obtained by the above method is taken out.
Is a method of forming a wax injecting frame 30 by attaching an upper die 29 having an injecting port 28 at a position opposed to.

[0009]

[Function] A mixture of fine metal powder and a binder such as resin or wax is injected from the injection port 28 to the injection molding die 30.
Then, the upper mold 29 is removed and the molded product is taken out and sintered to produce a metal product 31 (FIG. 2 (e)) of the same type as the metal product 20. can do. By pouring the melted wax into the wax injection mold 30 through the injection port 28, solidifying the wax and taking it out from the mold 30, a wax pattern 31 for lost wax of the same shape as the metal product 20 can be mass-produced.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, although not shown, a liquid photosensitive resin is poured into a predetermined mold, and a polyethylene film in which only the letter "L" is transparently made by the photoengraving method is covered on the mold, and the upper part of the film is covered. From UV light. As a result, the L-shaped portion is hardened and the other portions are uncured. When this photosensitive resin is washed, the uncured portion is removed, and the disappeared model 10 of L character shown in FIG. 1 (a) is formed.

As shown in FIGS. 1 (b) and 1 (c), a base plate 12 made of wax having an outer shape larger than that of the model 10 is prepared, and a flammable ground having the same size as the base plate is provided on the base plate 12. The pattern forming object 11 is overlaid. In this example, the ground pattern forming object 11 is a cloth 11 made of knitted fabric. The vanishing model 10 is placed on the ground pattern forming object 11. The model 10, the ground pattern forming object 11 and the base plate 12 are bonded to each other with an adhesive such as acrylic resin or epoxy resin to form an adhesive body 14.

Although not shown, similar to the known lost wax casting method, after the adhesive body 14 is dipped in a slurry tank and pulled up, a fine powder refractory material (stucco) is sprinkled and dried to obtain a predetermined thickness. To form a coating layer. Then, after sufficiently drying, the adhesive body 14 is burnt to be extinguished by burning, and further baked to form a mold. Molten metal is poured into this mold and cooled and solidified. Then, the mold is removed, and finishing is performed if necessary to obtain a cast metal product. Although not shown, a ground pattern having fine irregularities corresponding to the texture was formed around the letter L of the metal product.

As shown in FIGS. 2 (a) and 2 (b), the metal product 20 is used as a master in a mold 21 placed on a flat base plate 22 with its ground pattern portion 20a facing upward. After the placement, the molten metal 24 containing bismuth and lead is gently poured from the container 25 into the mold so that the metal product 20 is buried. 2A, the sectional view of the metal product 20 corresponds to the sectional view taken along the line AA of the adhesive body 14 of FIG. 1C. As shown in FIGS. 2C and 2D, after the bismuth alloy body 26 solidified in the mold is turned over and the metal product 20 is taken out from the alloy body 26, the metal product 20 is removed.
The bismuth alloy body 26 taken out is used as a lower mold, and an upper mold 29 of a thick plate having an injection port 28 provided at a position facing the metal product taking-out portion 27 is attached to the lower mold and the injection molding mold 3
Form 0.

A mixture of fine metal powder and a binder such as resin or wax is injected from an injection port 28 into an injection molding die 30 to be molded, and the binder is heated to remove the upper die 29. By removing the molded product, taking out the molded product, and sintering the molded product, a metal product 31 of the same type as the metal product 20 can be mass-produced. That is, an L character portion 32 having the same shape as the L character portion formed on the upper surface of the metal product 20 and a ground pattern 33 having the same shape as the ground pattern 20a are formed on the metal product 31.

In the above example, the injection mold is formed from the lower mold of the bismuth alloy pair 26 and the upper mold 29 having the injection port 28. The lower mold and the upper mold form a wax injection mold. However, a wax pattern for lost wax can be mass-produced from this mold. Further, in the above example, the cloth is used as the ground pattern forming object, but the present invention is not limited to this, and may be wood, leaves, grass, paper, leather, synthetic resin or the like. In the case of a plate having a certain thickness like wood, it is not necessary to provide a base plate made of wax. Further, the disappearance model is not limited to the L character, and may be another character, a figure or a symbol, or a combination thereof.

[0016]

As described above, according to the present invention, a lost wax casting mold for producing a cast product containing a letter, a figure or a symbol having a ground pattern on the periphery or a combination thereof is formed with a small number of steps. It can be manufactured. Also, by using the metal product made from this lost wax casting mold as a prototype, and making an injection molding die, it is possible to easily mass-produce metal products with a ground pattern from this single prototype and achieve cost reduction. it can. Further, instead of the injection molding die, a wax injecting frame can be made to mass-produce a wax pattern for lost wax.

[Brief description of drawings]

FIG. 1 is a view showing a manufacturing process of a lost wax casting mold according to an embodiment of the present invention.

FIG. 2 is a diagram showing a process of manufacturing an injection molding die by using a casting product made by this lost wax casting mold as a prototype.

FIG. 3 is a view showing a manufacturing process of a conventional lost wax casting mold.

[Explanation of symbols]

 10 Disappearance model 11 Ground pattern forming object 12 Base plate 14 Adhesive body 20 Metal product made with lost wax casting mold 20a Ground pattern part 21 Formwork 24 Molten metal 26 Bismuth alloy body 27 Metal product extraction part 28 Pouring port 29 Upper mold 30 Mold for injection molding (wax injection mold)

Claims (5)

[Claims] 1. A step of exposing a photosensitive resin with an original image having images of characters, figures or symbols or a combination thereof, and exposing a portion of the photosensitive resin which is not exposed to the image and is not cured. Disappearance model by washing and removing (10)
A step of forming the disappearance model (10) on the flammable ground pattern forming object (11) larger than the outer shape of the disappearance model (10), and the ground pattern forming object (11) ) And a step of coating finely divided refractory on the adhesive body (14) of the disappearance model (10) and drying, and heating the dried matter to form the ground pattern forming object (11) and the disappearance model (10). A method for manufacturing a lost wax casting mold, which comprises a step of causing the wax to disappear. 2. The ground pattern forming object (11) has one or more sheet-like materials selected from the group consisting of cloth, wood, leaves, grass, paper, leather and synthetic resin having irregularities on the surface. Claim 1
A method for producing the lost wax casting mold described. 3. The method for producing a lost wax casting mold according to claim 1, wherein a base plate (12) made of wax is adhered to the lower surface of the ground pattern forming object (11). 4. A step of exposing a photosensitive resin with an original image having an image of characters, figures or symbols or a combination thereof, and exposing a portion of the photosensitive resin which is not exposed to the image and is not cured. Disappearance model by washing and removing (10)
A step of forming the disappearance model (10) on the flammable ground pattern forming object (11) larger than the outer shape of the disappearance model (10), and the ground pattern forming object (11) ) And a step of coating the bonded body (14) of the disappearance model (10) with a fine powder refractory material and drying, and a step of heating the dried material to disappear the ground pattern forming object and the disappearance model, A step of injecting molten metal into the lost wax casting mold produced by the disappearance step, a step of taking out the metal product with a ground pattern solidified in the mold from the mold, the metal product (20) as a prototype and the metal Placing the product (20) in the mold (21) with the ground pattern portion (20a) facing upward, and a molten metal containing bismuth in the mold so that the metal product (20) is embedded ( The step of pouring 24) and turning over the bismuth alloy body (26) solidified in the mold before The step of removing the metal product (20) from the alloy body (26), and the bismuth alloy body (26) from which the metal product (20) is removed is used as a lower mold to face the metal product removal portion (27) to the lower mold. And a step of forming an injection mold (30) by attaching an upper mold (29) having an injection port (28) at a position where the injection mold (30) is formed. 5. A metal product take-out portion for a lower mold made of a bismuth alloy body (26) obtained by taking out the metal product (20) according to claim 4.
Upper mold (29) with inlet (28) provided at a position facing (27)
A method for manufacturing a wax injection mold, in which a wax injection mold is attached to form a wax injection mold (30).