JPH0341245B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a press mold. Conventionally, as a method for manufacturing press molds for mass production, there is a method called a so-called full mold method. In this method, a mold having substantially the same shape as the desired press mold is formed using foamed polystyrene or the like, and this mold is filled with molding sand to obtain a casting mold. Then, by pouring the metal into this mold, casting is performed while vaporizing the Styrofoam portion, and as a result, the portion corresponding to the Styrofoam is cast. Then, the part of the casting that will become the press mold surface is cut using an NC machine tool, etc., and then hand-finished to form the press mold. However, this method requires hand finishing after cutting, which increases the production period and
Production costs increase. On the other hand, in order to shorten the manufacturing period for prototype press molds where the number of panels that can be molded is limited to a certain extent, zinc alloy is used or the surface of the zinc alloy is coated with epoxy resin to form the press mold. However, such press dies lack durability, and the dimensional accuracy of the pressed product is also poorer than that of the mass-produced dies. Therefore, in order to solve these problems, the following press mold manufacturing method has been proposed. That is, first, a thermal spray model for thermal spraying is made of plaster, synthetic resin, or a low melting point alloy, and metal is thermally sprayed onto the model surface, which will become the surface of the press mold, to form a thermal spray layer. Next, this sprayed layer is lined with concrete, sand core, resin, etc. to form a press mold. The advantage of this method is that the model surface of the sprayed model can be completely reproduced with the sprayed layer, so there is no need for manual finishing after making it into a press mold, thereby shortening the production period and reducing production costs. be able to. However, in order to improve the durability of this press mold, it is necessary to select the metal to be thermally sprayed. Therefore, the purpose of the present invention is to solve the above-mentioned drawbacks, and to obtain a durable press mold by using a self-fusing alloy as the metal to be thermally sprayed and then remelting it on the model surface of the thermally sprayed model. Features. An embodiment of the present invention will be described below with reference to FIGS. 1a to 1h. FIG. 1a shows a basic model 2 with a surface 1 to be transferred, the material of which is
Use plaster, synthetic resin, low melting point metal, etc. FIG. 1b shows a step in which a fence 3 is erected around the outer periphery of the basic model 2, and a slurry 4 is poured into the fence 3 and solidified. Slurry 4 is
Al ₂ O ₃・ZrO ₂・Has a low coefficient of thermal expansion and high refractoriness
It is a mixture of SiO ₂ -based powder and ethyl silicate as a binder, and can flow into the basic model 2's surface shape instantly. The slurry 4 solidified in the fence 3 is shown in Figure 1c.
As shown in FIG. 1, it is separated from the basic model 2 and the fence 3, fired in a firing furnace (not shown) to form a ceramic mold 4a, and the model surface is coated and impregnated with water glass 5 as shown in FIG. 1d to form a thermal spray model 6.
form. The reason why the water glass 5 is applied to the ceramic mold 4a is as follows. In other words, the model surface of the ceramic mold 4a is rough with protruding fine particles peculiar to ceramics. For this reason, if thermal spraying, which will be described later, is performed directly on this model surface, the sprayed layer will peel off, resulting in the inconvenience that only a thin thermal sprayed layer can be formed. Furthermore, the ceramic mold 4a itself has the disadvantage of being brittle, and in order to compensate for these defects, it is impregnated with 3 to 10 mm of water glass 5 and reacted and hardened in a carbon dioxide atmosphere to counteract this fragility. The sprayed layer 7 is formed by spraying a self-fusing alloy onto the model surface of the sprayed model 6 thus created, that is, the model surface whose shape has been transferred in the opposite shape to that of the basic model 2, as shown in FIG. 1e. Form. At this time, the spraying distance is kept longer than when performing normal gas powder spraying, and a sprayed layer 7 of about 0.4 to 1.7 mm is formed. The sprayed model 6 with the sprayed layer 7 formed in this way is kept in a furnace (not shown) at a temperature slightly higher than the melting temperature of the self-fusing alloy for 30 to 60 minutes to perform remelting treatment, and is gradually cooled down to form the melted model 6 shown in FIG. Set to state f. A backing material 8 is placed on the back side of the model surface of the thermal sprayed layer 7 that has undergone the remelting process of the thermal sprayed model 6.
They face each other with an interval of ~15 mm, and either inject synthetic resin 9 into the gap to fix them together, or directly line them with a backing material such as synthetic resin or concrete to form the state shown in Figure 1g. After the injected synthetic resin or directly lined backing material has solidified, the thermal spray model 6 is removed to complete the press mold as shown in FIG. 1h. In the above example, the reason for performing the remelting treatment is that normally, when spraying a self-fusing alloy onto a metal surface, it is treated by gas powder spraying, but in this example, the self-fusing alloy was sprayed onto a ceramic containing water glass. If a fusible alloy is thermally sprayed using a gas burner, the sprayed layer of the self-fluxing alloy will curl up, and to avoid this, the metal should be gently remelted in the furnace to avoid thermal shock to the entire surface. is being carried out. In addition, the reason why ceramic was used as the thermal spray model was that it needed to withstand high temperatures and pressures in the furnace in order to remelt the sprayed layer of self-fusing alloy formed on the model surface of the thermal spray model.
For this purpose, ceramics with temperature and pressure resistance are used. Furthermore, the reason why a self-fusing alloy is used is that when a self-fusing alloy is subjected to remelting treatment, it becomes a completely integrated alloy and its durability is greatly improved. Incidentally, examples of self-fusing alloys include those shown in Table 1.

[Table] A press mold is manufactured as described above, but in the above embodiment, a punch or die may be used directly as the backing material 8, and as shown in FIG. 2, it can be used as a mold as it is. Materials 10 of ferrous and non-ferrous metals can be formed. FIG. 3 shows a case where the die is used as a shearing die. The die is placed on top of the punch holder 11 with the backing material 8, and the material 10 placed on the die is held down by the plate holder 12 while the upper holder The material 10 is cut by the upper blade 14 supported by the blade 13. As explained above, according to the present invention, since a self-fusing alloy is used as the thermal spray material, an extremely durable press mold can be obtained by performing remelting treatment.

[Brief explanation of the drawing]

1A to 1H are process diagrams of the press mold manufacturing method according to the present invention, FIG. 2 is a cross-sectional view of the press mold used as a mold, and FIG. 3 is a cross-sectional view of the press mold used as a shear mold. 2... Basic model, 3... Fence, 4... Slurry, 4a... Ceramic mold, 5... Water glass, 6... Thermal spraying model, 7... Thermal spraying layer, 8... Backing material.

Claims (1)

[Claims] 1. A step of erecting a fence around the outer periphery of the basic model and pouring slurry into the fence to solidify it; and a step of separating the solidified slurry from the basic model and the fence and firing it to form a ceramic mold. , a process of impregnating the model surface of a ceramic mold with water glass to form a thermal spray model, a process of thermally spraying a self-fusing alloy onto the model surface of the thermal spray model to form a thermal spray layer, and a process of forming a thermal spray model with the thermal spray layer formed. A process of putting the model into a furnace and subjecting the sprayed layer to re-melting treatment, a process of taking the sprayed model with the sprayed layer formed from the furnace and lining the sprayed layer from the back of the model surface, and separating the sprayed model and the sprayed layer. A method for manufacturing a press mold, which is characterized by the following steps: