JPH11123700A - Manufacture of extrusion die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit original strength of a die material by cutting an original board for a die in a required shape by water jet work. SOLUTION: For example, in manufacturing a core 21 of a male die 4 of a combination die 2, an original board for a die is cut in a required shape by water jet work. Or while cutting the original board for the die in the required shape by laser beam machining, jet water is supplied to cutting part. Various kinds of cemented carbide and die steel are normally used as a die material, but not particularly limited to them. Therefore, since a thermal influence layer such as a discharge affected layer by electric discharge machining is not generated or since a generated thermal influence part is blown away, original strength of the die material can be exhibited in a surface layer part of the die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an extrusion die used for extrusion molding, and more particularly to a method for manufacturing an extrusion die which can be suitably used for extrusion molding of a small and fine hollow material.

[0002]

2. Description of the Related Art For example, when a flat porous tube (1) as shown in FIG. 1 is manufactured by extrusion molding, generally, a male mold for forming a hollow portion (1a) in the tube and a tube of the tube are used. A combination die is used which is combined with a female mold for forming an outer peripheral portion. And furthermore, the manufacture of a small and elaborate flat perforated tube used as a tube for a heat exchanger facilitates the manufacture of a miniaturized die,
In order to reduce the cost of replacing the dies due to wear and the like, a combination of a male die and a core that forms the hollow portion (1a) of the tube (1) and a holding die that holds the core. Dice are used.

In the combination die (2) illustrated in FIGS. 2 and 3, the female die (3) has an elliptical flat forming hole (11) for forming the outer periphery of the flat porous tube (1). Welding for joining and welding extruded materials which are arranged adjacent to the rear part of the female main body mold (12) having the core part and the female main body mold (12) and have passed through the male mold (4). It comprises a welding chamber forming mold (14) for forming the chamber (13) and a cylindrical housing mold (15) for housing both the molds (12) and (14).

[0004] In the male mold (4), (21) is a core, (22) is a core holding mold, and (23) is a lid.

As shown in FIG. 3, the core (21) has a flat shape, and a plurality of hollow forming portions (24) (24) for forming the hollow portion (1a) of the flat porous tube (1) at its tip. Are formed in a comb shape, and a support protrusion (25) projecting in the width direction is formed at a base end portion.

The core holding die (22) is provided with a bridge (26) in such a manner as to cross an extruded material conducting hole (not shown) in the axis of the core. This is an integrally molded mold divided into (not shown). And
The bridge (25) has a flat core holding hole (2) for holding the core (21) in a mode penetrating the bridge (25) in the extrusion direction.
7) is provided. The core holding hole (27) has a support step (28) (28) formed at a base end thereof, and the projecting portion (2) of the core (21) when the core (21) is inserted and arranged.
5) and (25) are to be supported by the bearing steps (28) and (28).

[0007] The rear end face of the bridge (26) of the core holding mold (22) is retracted into the mold (22), and the lid (23) is fitted therein. A lid fitting recess (29) is formed.

By the way, as the material of the core (21), a cemented carbide or the like is used in order to secure wear resistance and durability.
In general, a flat master is cut out into a required shape and manufactured. Conventionally, since the dies are precise and small dies, the comb-shaped hollow molded portion (24) has been cut out by electric discharge machining such as wire-cut electric discharge machining with high machining accuracy.

[0009]

However, in the above-mentioned combination die (2), there is a problem that the die (2) is liable to be broken at the base of the tip forming portion (24) of the core (21). This is because the discharge-altered layer formed on the machined surface due to heat generated during electric discharge machining is a layer containing many pores and microcracks, so the core material surface does not have the original material strength of the super hard and the stress during extrusion is reduced. It is presumed that it will break at the base where it concentrates. Also, if there is a discharge alteration layer, the superhardness is easily eluted during caustic cleaning after use of the die, which also causes a decrease in the strength of the core.

The present invention has been made in view of such technical background,
An object of the present invention is to provide a method for manufacturing an extrusion die capable of exhibiting the original strength of a die material.

[0011]

In order to achieve the above object, a first method for manufacturing an extrusion die according to the present invention is characterized in that a die master is cut into a required shape by water jet processing. is there. Further, the second aspect of the present invention
The method of manufacturing an extrusion die is characterized in that a jet master is cut into a required shape by laser processing and jet water is supplied to the cut portion.

The material of the die to which the method of the present invention can be applied is various cemented carbides and various die steels which are usually used as a die material, and is not particularly limited.

The water jet processing used in the first method is to cut a die master by injecting pressurized water through a thin nozzle, and the heat affected layer such as a discharge altered layer formed by electric discharge machining. Does not generate itself. Therefore, the original strength of the die material can be developed in the surface layer portion of the die.

The processing method combining laser processing and jet water supply in the second method is described in SYN of Switzerland.
This is a method developed by OVA. According to this method, a heat-affected zone (degraded layer) is generated by heat generated during laser cutting, and the heat-affected zone is blown off and removed by a water jet, which is jet water supplied simultaneously with cutting. Therefore, similarly to the method of the first invention, the original strength of the die material can be developed in the surface layer after processing. This processing method is described in SMM
Details are reported in Schweizer Maschinemarkt 13/1997.

A comparison of these two extrusion die manufacturing methods reveals that the heat-affected layer is not formed on the cut surface and the original strength of the die material can be exhibited by either method. The second method, which combines laser cutting and jet water, allows the heat-affected zone generated at the time of laser fusing to be removed by shearing with a water jet, so that harder and thicker masters can be processed than the first method used. It is. For example, in the case of a carbide die, if the thickness of the master exceeds 2 mm, the latter method is preferably employed. In addition, any of these methods can achieve dimensional accuracy equal to or higher than that of the conventional electric discharge machining, and is suitable for manufacturing precise and small dies. Above all, the second method can be recommended for forming a high-quality extruded material because the surface roughness and dimensional accuracy of the cut surface are particularly excellent.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A combination die (2) shown in FIGS.
, A core (21) of a male type (4) was manufactured. The core was produced by cutting a 40 mm square, 2.5 mm thick master made of WC-Co into a required shape by changing the processing method.

(Example 1) Water jet processing was performed at a pump pressure of 400 bar.

Example 2 Jet water was supplied at a pump pressure of 500 bar while cutting with a YAG laser having an average output of 500 W.

(Conventional example) Wire cut electric discharge machining was performed.

Then, for each manufactured core, the presence or absence of a heat-affected zone on the cut surface was examined, and the surface roughness (Ra) was examined. The time required for these processes was compared.

Next, these cores are assembled in a combination die, and the flat porous tube (1) shown in FIG. 1 is extruded using A1100 aluminum. The sex was evaluated. Table 1 shows the results.

[0022]

[Table 1]

From the results shown in Table 1, it was confirmed that the heat-affected zone was not present on the cut surface in the example, and the durability was good. In addition, it was confirmed that the smoothness of the cut surface can be obtained by combining the laser processing and the gentle water jet. On the other hand, in the conventional example, since the discharge alteration layer was formed on the cut surface, the durability was poor. Further, it was also found that the machining method of the embodiment can drastically reduce the machining time as compared with the conventional wire cut electric discharge machining.

As in this embodiment, if the core in which the stress during extrusion is concentrated is processed by the method of the present invention, the durability of the die can be improved. By manufacturing the female mold by the method of the present invention, the extrusion die can be made harder to break and the durability can be further improved.

[0025]

As described above, according to the first method for manufacturing an extrusion die of the present invention, a die master is cut into a required shape by water jet processing. Is not generated and the original strength of the die material is exhibited.

In the second method of manufacturing an extrusion die according to the present invention, a jet master is cut into a required shape by laser processing and jet water is supplied to the cut portion. The heat affected zone is blown off and removed, and the original strength of the die material is developed in the same manner as in the first method.

As described above, by developing the original strength of the material in the surface layer portion of the die, the durability of the die can be improved. In addition, since these methods are excellent in dimensional accuracy, they are suitable for manufacturing an extrusion die for forming a precise and small extruded material such as a flat porous tube for a heat exchanger. Above all, the second method is particularly excellent in the surface roughness and dimensional accuracy of the cut surface, so that a higher quality extruded material can be formed by using a die manufactured by this method.

[Brief description of the drawings]

FIG. 1 is a perspective view of a flat perforated tube.

FIG. 2 is a cross-sectional view of a combination die for extruding a hollow material.

FIG. 3 is a perspective view of a core incorporated in the male die of the combination die of FIG. 2;

[Description of Signs] 1 ... Flat perforated tube 2 ... Combination die 3 ... Female type 4 ... Male type 21 ... Core

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23P 15/24 B23P 15/24 23/04 23/04

Claims (2)

[Claims] 1. A method of manufacturing an extrusion die, comprising cutting a die master into a required shape by water jet processing. 2. A method for manufacturing an extrusion die, wherein a jet master is cut into a required shape by laser processing, and jet water is supplied to the cut portion.