JP2780824B2 - Extrusion tool - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion tool used for manufacturing a metal mold such as aluminum.

2. Description of the Related Art During extrusion, the bearing surface of a die becomes hot with the lapse of time due to friction with the metal for extrusion, which causes deterioration of the surface quality of the die material, generation of speed cracks, reduction of dimensional accuracy, etc. It is well known to cause problems.

Conventionally, in order to cope with such a problem, a method has been adopted in which a cooling means for circulating a coolant is provided around the die forming hole to suppress the temperature around the die forming hole from increasing with time.

However, the above-mentioned die cooling means is intended to uniformly cool the periphery of the molding hole over the entire circumference, and is effective for improving the surface quality of the extruded material, preventing the occurrence of speed cracks, and the like. However, in order to stabilize and improve the dimensional accuracy of the mold material, it was not always possible to achieve perfect effectiveness.

That is, the stability of the dimensional accuracy of the mold material can be achieved by making the metal flow rate of the extruded material metal passing through the die hole uniform over the entire molding hole, for example, particularly in a cross section, in particular, partially. When trying to produce a mold material with a different wall thickness or a deformed cross-sectional shape having a complicated shape, the tendency to cause partial non-uniformity in the metal flow speed appears remarkably, and the straightness and the cross-sectional shape accuracy are reduced. In many cases, it was difficult to extrude excellent mold materials.

Therefore, conventionally, especially in the case of extruding such a shaped member, the bearing length of the die is shortened in the portion where the metal flow tends to be slow, and in the portion where the metal flow tends to be fast, corresponding to the cross-sectional shape of the die material. A technique has been adopted in which the metal flow speed passing through the forming hole is made uniform overall by setting the length to be long.

However, the adjustment by setting the length of the bearing length is very difficult in practice. In other words, since the extrusion characteristics are individually different depending on the type of the metal for extrusion and the change in the cross-sectional shape of the mold, etc., it is a considerable skill to achieve uniform extrusion by changing the bearing length in advance to each part. Is also very difficult.

The present invention has been made in view of the above-described problems, and has been considered to be able to extrude a high-precision mold material by making the overall metal flow speed of a metal passing through a forming hole of a die uniform.
In addition, it is an object of the present invention to easily achieve the uniformity.

SUMMARY OF THE INVENTION For the above objects, the present invention comprises a plurality of individually controllable cooling and / or heating temperature control means, each of which is independent of the die. In a position around one of the molding holes, the effective action site close to the molding hole is provided so as to be distributed and arranged in the circumferential direction so as to share predetermined sections in the direction around the molding hole. The extruder is a gist.

In the above-described extrusion tool, the temperature of the bearing surface can be variously changed in the circumferential direction by locally cooling and / or heating the bearing surface in the circumferential direction by the temperature adjusting means. Therefore, during extrusion, while confirming the parts where the metal flow tends to be slower and the parts where the metal flow tends to be faster, the metal flow speed is changed overall by varying the temperature of the bearing surface in the circumferential direction as described above. It can be made uniform.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the extrusion molding device (1) shown in FIG.
(2) is a container, and (3) is an extrusion tool provided at the front of the container (2). The extrusion tool (3) is configured to include a die (4), a backer (5), and a die ring (6) for storing these.

The die (4) is a rear first die (4a) having a bearing portion (9) surrounding a substantially U-shaped forming hole (8).
And a second die (4b) having a relief portion (10), and as shown in FIG.
By forming a groove in the front end face of the die (4a),
First to sixth independent heat exchange medium passages (7a) to (7f) for allowing a cooling medium to flow between the die and the die (4b).
Is provided as a component of the temperature control means. These heat exchange medium passages (7a) to (7f) have openings at both ends thereof open to the outer peripheral surface of the extrusion tool (3), and the middle portion is close to the periphery of the forming hole (8) of the die (4). And the flow of the cooling medium can be individually controlled. Moreover, the heat exchange medium passage (7a)-
(7f) is arranged so that the effective action site close to the forming hole (8) shares predetermined sections in the direction around the forming hole (8). That is, the first passage (7a) is near the upper half outside the central side of the U-shaped forming hole (8), the second passage (7b) is near the lower half, and the third passage (7c) is the same. The fourth passageway (7d) is arranged near the lower half, the fifth passageway (7e) is arranged near the outer side of the upper side, and the sixth passageway (7f) is arranged near the lower side near the inner upper half. I have. Therefore, for example, the first
By passing a cooling medium through the passage (7a), the upper part of the central side of the molding hole (7) is locally cooled from the outside,
By allowing the cooling medium to flow through the sixth passage (7f), the lower side of the forming hole (8) is locally cooled from the outside, and by allowing the cooling medium to flow through the fifth passage (7e),
The temperature distribution in the circumferential direction of the forming hole (8) can be variously changed, for example, by locally cooling the upper side of the forming hole (8) from the outside.

In addition, as a cooling medium, for example, water, air, liquid nitrogen, or the like is used.

Next, a description will be given of an experiment performed for confirming how changing the temperature around the forming hole of the die locally in the circumferential direction can affect the shape of the mold material.

The die having the configuration shown in FIG. 1 was used. As shown in FIG. 3, the dimensions of the forming hole (8) are as follows: the length a of the central side portion is 45.45 mm, the length b of both side portions is 15.15 mm, and The length c was 3 mm, the width d of the central arc-shaped concave portion was 4 mm, the depth e was 5 mm, and the width t was 1 mm. The bearing length of the forming hole (8) was set to 3 mm only at the lower side of the forming hole and to 10 mm for all other portions in order to easily confirm the local cooling effect.

The die (4) was set at an initial temperature of 390 ° C. and assembled into an extrusion molding apparatus. Using an aluminum billet of A6063 alloy having a diameter of 3 inches, a billet temperature of 500 ° C. and a ram speed of 3 mm / sec were used for 180 seconds. Was extruded.

In the first experiment, extruding was performed without allowing the cooling medium to flow through any of the heat exchange medium passages (7a) to (7f), and thus without locally cooling the die.

However, since the obtained mold material (a) has a metal flow speed extremely higher at the lower side of the forming hole (8), that is, at the portion where the bearing length is set to 3 mm than at the other portions, the fifth material has the fifth shape. As shown in the figure, one side (8a) corresponding to the lower side had significant waving deformation.

Then, next, as a second experiment, of the heat exchange medium passages (7a) to (7f), the sixth passage (7f) located on the outer side of the lower side of the forming hole (8) was supplied with air at about 20 ° C. Was extruded under the same extrusion conditions as described above, while flowing as a cooling medium.

As a result, it was possible to eliminate the waving deformation of one side of the mold material (a) and obtain a mold material having high dimensional accuracy in the cross-sectional shape shown in FIG.

Therefore, in the case of the second experiment, the temperature distribution around the forming hole (8) was changed to the position A near the lower side, the position B near the center of the central side, and the position C near the upper side shown in FIG. Was measured over time throughout the extrusion, and the results shown in the graph of FIG. 4 were obtained.
Cooling was started 25 seconds after the start of extrusion. From this experimental result, it was confirmed that locally changing the temperature of the bearing surface of the die in the circumferential direction can considerably affect the shape of the die.

In the above embodiment, the die (4) is divided into two parts, and the passage is formed between them. The point is that the passage can be provided near the bearing of the die. Well, therefore, a passage may be formed between the one-piece die and a baffle plate that may be located at the rear of the die. Further, in the above embodiment, from the viewpoint of easiness of process management, the temperature adjusting means by cooling that allows the cooling medium to flow through the passage is employed, but a temperature adjusting means by heating using a heater or induction may be employed. ,
Further, a combination of the temperature adjusting means by cooling and the temperature adjusting means by heating may be used.

Advantageous Effects of the Invention As mentioned above, the extrusion tool of the present invention has a plurality of independently controllable cooling and / or heating temperature control means, each of which comprises one of the dies.
At a position around one of the molding holes, the effective action site close to the molding hole is distributed and arranged in the circumferential direction so as to share predetermined sections in the direction around the molding hole. By cooling and / or heating locally around the forming hole in the circumferential direction by the adjusting means, the temperature distribution in the circumferential direction of the bearing portion can be individually adjusted in each portion. Therefore, during extrusion, the temperature of the bearing portion is adjusted in the circumferential direction as described above, while confirming the parts where the metal flow tends to be slow and the parts where the metal flow tends to be fast, so that the metal flow speed can be made uniform throughout. It is possible to extrude a high-precision mold material with stable dimensional accuracy. In addition, since it is only necessary to perform the control by the temperature adjusting means, the metal flow speed can be made uniform very easily.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an extrusion tool of the present invention, FIG. 2 is a front end view of a first die constituting the extrusion tool, FIG. 3 is a front view of a molding hole of the die, and FIG. FIG. 5 is a graph showing the relationship between the extrusion time and the temperature in the die when the test was performed. FIG. 5 is a perspective view of a mold material having a dimensional accuracy defect in the first experiment. (3) ... extrusion tool, (4) ... die, (7a) to (7)
f)… heat exchange medium passage (temperature control means), (8)…
Molded holes.

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Claims (1)

(57) [Claims] 1. A plurality of individually controllable cooling and / or heating temperature control means, each of which is located at a position around one forming hole of a die. An extrusion tool, characterized in that an effective action portion close to the hole is provided so as to be distributed and arranged in the circumferential direction so as to share predetermined sections in the direction around the forming hole.