JPS6320620B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a mold used in die casting, injection molding, press molding, or the like.

(Conventional technology) Conventionally, in order to cast this type of mold, SKD, Cr
- A block made of Mo steel or S50C is machined to close to the desired mold shape, and shapes that are difficult to machine are then subjected to electrical discharge machining to form the mold, and then the molds are matched to form the final mold. The mold is obtained, and the final step is hand finishing to obtain the mold.

First of all, such conventional methods require a large amount of machining;
Moreover, the time required for machining is extremely long, and furthermore, a troublesome manual finishing process is required after machining, resulting in high costs.

(Technical Problems to be Solved by the Invention) In order to improve the above-mentioned conventional methods, a method of manufacturing a shaped part of a mold by casting has been put into practical use, and the Full Mort method is known as such a method. In the Full Mort method, a mold model is made from foamed steel, and this model is set in a frame and filled with mold sand to create a mold.
By pouring molten metal into the mold, the heat of the molten metal causes the Styrofoam to vaporize and disappear. By pouring molten metal into the disappeared portion, a mold having the same shape as the model is obtained.

In this conventional technique, when manufacturing a mold model using polystyrene foam, it is necessary to make the mold model large enough to take into account processing costs for the mold obtained by casting. Since the entire mold is cast, there is a large amount of heat shrinkage, and therefore the mold must be cast in a larger size. It is necessary to perform machining, electric discharge machining, finishing machining, etc. on the mold obtained as a result to obtain the final shape, and post-casting requires a large amount of time and costs.

The present invention has been made to solve the above-mentioned technical problems, and its purpose is to create a mold that can be easily and inexpensively obtained by omitting machining in a short time. To provide a manufacturing method.

(Means for solving the technical problem) The means for solving the above technical problem consists of a female mold body that is formed to be larger than the product shape part by a predetermined thickness and has a concave surface on the surface; A female mold main body and a corresponding male mold are each provided, and a heat-resistant sheet having the same thickness as the product to be molded is attached to the surface of the product-shaped part of the male mold, and combined with the female mold main body, the male mold is formed. A space is formed at a predetermined interval between the shaped portion and the molten metal is injected and filled into the space to cast a female mold corresponding to the male mold.

(Operation by the above means) According to the above means, the molten metal poured between the female mold body and the male mold flows into the recesses provided on the surface of the mold body, and the molten metal solidifies and shrinks due to the recesses. , the heat shrinkage is mechanically regulated, suppressed, and restrained by the inflow into the recess and the protrusion biting into the molten metal, which reduces deformation and improves the forming part of the mold obtained by casting. A product that does not require machining or the like can be obtained.

(Embodiment) Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 shown in FIG. 1 is a female mold main body model, the model 1 is molded from polystyrene foam, and has a mold forming recess 1a consisting of a recess at the lower part, and the recess 1a is larger by a predetermined interval than the female mold part 1b shown by the imaginary line. The mold matching surface 1c is also formed into a concave shape to make it large.

A plurality of recesses 2 . . . are formed on the surface of the molding recess 1 a of the model 1, and portions adjacent to the recesses 2 . . . eventually become protrusions 3 . Such recessed portion 2...
The head 4a protrudes toward the surface of the recess 1a, the rod 4b faces the bottom of the recess 2, and the tip of the rod 4b is buried in the bottom of the recess 2. Plant so that 4 stands upright. This is shown in Figure 2.

The above model 1 is set in a mold, filled with casting sand, etc., and molten metal such as FC30 is poured into the mold at a temperature
The model 1 is vaporized by injecting at 1370°C to 1400°C to obtain a female mold body 5 as shown in FIG. A molding recess 5a is formed in the female mold body 5, and in the molding recess 5a, the recess 6... is formed by the previously described recess 2...
However, a plurality of protrusions 7 are formed by the protrusions 3, and bolts 4 are installed in each of the recesses 6, as shown in FIG.

FIG. 5 shows a male mold, and in the embodiment, the male mold 8 is a male mold for molding the product shape part cast on the outer surface of the molding protrusion 8b of the mold main body 8a cast with FC30 etc. in the same manner as described above. A mold part 9 is provided, and the male mold part is cast using a ceramic mold or the like into which the product shape is transferred. A heat-resistant sheet 10 having the same thickness as the product is attached to the outer surface 9a of the male mold part 9, and the sheet 10 is made of, for example, a ceramic sheet.

Next, with the male mold 8 facing down, a blank holder 11 is fitted around the main body 8a, and the female mold 5 is exposed above the male mold part 9, and the molding recess 5a of the mold 5 and the male mold A cavity 12 is formed by maintaining a predetermined space between the surface of the mold part 9 of 8, specifically the outer surface of the sheet 10, and the molds 5 and 8 are held by a back-up mold 15, Next, the cavity 12 is filled with molten metal 13. This is shown in Figure 6.

The back-up mold 15 of the molten metal is removed, and after solidification, the female mold main body 5 is separated from the male mold 8 as shown in FIG. part 14 will be cast, and the sheet 10 will separate the female mold part 14 and the male mold part 9.
A gap equivalent to the thickness of the product is formed between the molds when the molds are aligned.On the other hand, the sheet 10 prevents the surface from being damaged even when the male mold part 9 is used as part of a mold, and the sheet 10 Casting peels off.

By the way, during the above-mentioned casting, the molten metal is filled into the cavity 12 and also flows into the recesses 6 of the main body 5, and although the molten metal contracts during solidification, the contraction is caused by the inflow into the recesses 6. The protrusion of the protrusion 7 into the molten metal strengthens the bond between the main body and the molten metal, and in conjunction with the bolt 4..., the anchor effect regulates and restrains the molten metal, prevents deformation due to shrinkage, and prevents the entire molten metal from deforming. A molded part 14a having a highly accurate surface of the female mold part 14 is obtained, which prevents shrinkage and pull-out.

Therefore, after obtaining the female mold part as shown in Fig. 7, the molding part 1
A female mold that can be put into practical use immediately can be obtained by simply applying a finishing process such as polishing to the surface of 4a.

Incidentally, during casting, a sprue push end portion is solidified and formed around the periphery, but this shall be cut and removed after casting.

Although the embodiment has been described in detail above, the shape of the recess is not limited to the embodiment, and may be a dovetail groove, a protrusion, or the like, or an L-shaped anchor or the like instead of a bolt.

(Effects of the Invention) As is clear from the above, according to the present invention, since the concave protrusion is provided on the mold body side during casting of the female mold part, the solidification shrinkage and thermal contraction of the molten metal are prevented by the concave protrusion. It is possible to control, restrain, hold down, and obtain a female mold with extremely high precision by casting, and since a male mold is used as the mold, only polishing is required after casting, and the heat-resistant sheet allows for a mold with a thickness equivalent to the product wall thickness. It is possible to obtain a mold in which the parts are accurately secured, and it is possible to use a male mold without damaging it.Furthermore, due to the above, the processing time and man-hours required for mold production can be significantly reduced. can be easily manufactured in a short period of time, and costs can be significantly reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 is a diagram of a model of the female mold body, Fig. 2 is a diagram of the same recessed part and a bolt attached, and Fig. 3 is a diagram of the female mold body. 4
The figure is an enlarged view of the main part of this, Figure 5 is a figure of the male mold,
FIG. 6 is a diagram of the casting state, and FIG. 7 is a diagram after casting. In addition, in the drawing, 5 is the female mold body, 6 and 7 are protrusions, and 4
1 is an anchor member, 8 is a male mold, 10 is a heat-resistant sheet, 13 is a molten metal, and 14 is a female mold part.

Claims (1)

[Scope of Claims] 1. A female mold body formed to be larger than a product shape part by a predetermined thickness and having a concave surface, and a male mold corresponding to the female mold body, A heat-resistant sheet is pasted on the surface of the product-shaped part of the male mold to have the same thickness as the product to be molded, and combined with the female mold body to form a space at a predetermined distance between the male mold part and the male mold-shaped part. A method for manufacturing a mold, characterized in that a female mold corresponding to the male mold is cast by injecting and filling the space with molten metal. 2. The mold manufacturing method according to claim 1, wherein the recessed portion of the female mold body is a recessed portion provided with an anchor member in which a bolt or the like is implanted.