JPH04200929A - Bending method for aluminum material - Google Patents

Abstract

PURPOSE:To prevent a die from being seized and gnawed by adjusting the surface roughness, the surface oxide layer of a work made of Al below a fixed value to execute bending. CONSTITUTION:When bending is executed to the work made of a long sized Al material, the surface of the work 10 is adjusted to a <=20mum surface roughness, Ra and the thickness of the surface oxide layer is adjusted below 30Angstrom . The work 10 is bent when the work 10 is advanced under the supply of lubricant as it is forced into a work communicating hole 9 of a movable gyro die 3 through a work communicating hole 4 of a fixed die 2, and a two-dimensional or three-dimensional bend is given by changing the direction and position of a gyro die 3. The surface roughness of the work 10 affects lubricating action by reducing the frictional force and also the thickness of the oxide film improves the lubricating function by improved retention of working oil to prevent the lubricant from being short.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a method for bending aluminum material, and in particular, to a method for bending aluminum material, in particular, using an aluminum extrusion die +4 as a workpiece, a fixed die and a movable gyro die correspondingly arranged in front of the die. The present invention relates to a bending method when bending is performed using a bending machine having a bending machine.

Conventional technology: Long aluminum materials used for mechanical parts, automobile parts, etc., especially aluminum extruded materials, can be processed in two dimensions.
Alternatively, in the case of three-dimensional bending, a bending machine equipped with a fixed mold and a movable gyro mold, generally called a multi-bender, has recently been used. When processing using such a bending machine, the bending process is performed by predominantly utilizing the principle of compressive bending, which bends the workpiece while pushing it, so local elongation or compression of the material is relatively small. There is an advantage in that bent products with fewer material defects and surface defects can be obtained.

Problems to be Solved by the Invention However, when bending an aluminum material using the above-mentioned multi-bender, especially when performing continuous bending for a long time or bending into a shape close to local bending with an irregular cross-sectional shape, Despite the supply of lubricants such as processing oil to the workpiece, the phenomenon of seizure and galling of the workpiece against the mold occurs, resulting in scratches on the workpiece and often impeding smooth bending. I had to put it away.

Conventionally, attempts have been made to improve this by subjecting the mold to surface treatment such as chrome plating to improve slipperiness, but when the workpiece is made of aluminum, the galling and seizure described above occur. The phenomenon was still not preventable.

An object of the present invention is to provide a bending method that can solve the above-mentioned problems.

Means for Solving the Problems As a result of various experiments and research aimed at solving the above problems, the inventors have found that the unevenness of the surface of aluminum material and the thickness of the surface oxide film are It was discovered that this is involved in the occurrence of galling and seizure, and this invention was completed.

That is, the present invention uses a bending machine having a movable gyro mold that can be turned and displaced in three dimensions in front of a fixed mold having a workpiece conduction hole, and both molds are sequentially moved by the operation of the gyro mold. When supplying a lubricant to a workpiece that is forced into electrical conduction and performing a prescribed bending process, the workpiece made of aluminum is adjusted to have a surface roughness of 20 μm or less and a surface oxide film thickness of 30 Å or less. The gist of the present invention is a method for bending an aluminum grinder, which is characterized in that it is subjected to processing.

The aluminum material of the workpiece is mainly an aluminum extrusion mold material, and various aluminum materials or aluminum alloy materials ranging from A100O series to 7000 series, such as 60
63.606], 6N01.3003.7N01, DT
Materials made of various alloy materials such as 80.7003.5052.5N01 are applicable.

By specifying the surface roughness of the aluminum grinder, which is the workpiece, to 20 μm or less, the frictional force generated between the aluminum grinder and the mold is reduced.

Furthermore, by setting the oxide film on the surface of the aluminum material to be 30 Å or less, the lubricant retention property of the surface of the aluminum material is improved, and the frictional force is further reduced by the action of the lubricant. By reducing this frictional force, the workpiece is prevented from adhering to the bending die, and seizing and galling are prevented.

Embodiment In the illustrated embodiment, (1) is a bending machine of a type generally called a multi-venter, which includes a fixed mold (2),
It has a movable gyro mold (3) correspondingly arranged in front of it.

There are various types of fixed molds (2), but in the illustrated embodiment, the fixed mold (2) is made of a large number of molds arranged so that a central workpiece conduction hole (4) surrounds the workpiece (10). It is composed of a group of guide rollers (5), and a mouthpiece (6) made of hot work tool steel such as SKD steel, carbon, or ceramics is attached to the tip on the exit side.

On the other hand, the movable gyro mold (3) is mounted on a gyro mold mounting frame (8) that is movable up and down and left and right, and is disposed in front of the fixed mold (2). This gyro mold (3) is three-dimensionally turned and displaced using the gyro principle, and by operating it three-dimensionally, both molds (2) and (3) are operated. The workpiece (10), which is forcibly pressed and moved in the direction of the arrow in Fig. 1 through the workpiece conduction holes (4) and (9) of the This gives a bending effect. Then, by moving the gyro mold (3) in the front-back direction and changing the distance between it and the fixed mold (2), the workpiece (10
) can adjust the magnitude of the bending moment applied to the

When performing a prescribed bending process on a workpiece (10) made of a long aluminum material using the above-mentioned bending machine, the surface of the workpiece is preliminarily polished to a surface roughness (Ra) of 20 μm or less.
), and the surface oxide film is adjusted to a thickness of 30 Å or less. One such adjustment method is
Examples include a method of polishing the surface of the aluminum material with nylon para l-, sandpaper, Scotchbrite, etc. along the extrusion direction and the bending direction.

In this way, the reason why the surface roughness of the aluminum material is specified to be 20 μm or less is to make the surface of the aluminum material as smooth as possible and reduce the frictional force generated between it and the mold.
This is because if the surface roughness exceeds 20 .mu.m, the frictional force will be large, and it will be easy to cause seizure or galling to the mold. on the other hand,
The reason for specifying the oxide film thickness to be 30 Å or less is that the thinner the oxide film is, the better the lubricant retention property is, and if the oxide film thickness exceeds 30 Å, the lubricant retention property is poor, resulting in poor bonding with the mold. This is because as a result of the increased frictional force between the parts, the risk of scorching or galling increases.

Workpieces with surface roughness and oxide film thickness defined as above (
10) The bending process is performed by supplying lubricant such as processing oil and passing it through the workpiece conduction hole (9) of the movable gyro mold (3) via the workpiece conduction hole (4) of the fixed mold (2). By moving forward while forcibly pushing the gyro mold (3)
This is done by imparting a two-dimensional or three-dimensional bend by the turning displacement operation of the At this time, the workpiece (1
The surface roughness of 0) of 20 μm or less exerts a lubricating effect by reducing frictional force, and the oxide film thickness of 30 Å or less promotes a lubricating effect by improving the retention of machining oil, thereby preventing the lubricating oil from running out.

Therefore, even if the mold temperature increases somewhat due to continuous bending, the workpiece (10) is prevented from seizing or galling against the molds (2) and (3).

Next, the following tests were conducted to confirm the effects of this invention.

That is, a plurality of rectangular cylindrical extruded materials made of A606B aluminum alloy were polished with a nylon bat, sandpaper, Scotchbrite, etc. to adjust the surface roughness and oxide film thickness to various values shown in Table 1. Note that the oxide film thickness was measured by the Hunter-Hall method.

Next, each of the above aluminum materials was bent under the same conditions using the bending machine shown in FIG. 1, and the occurrence of surface defects such as seizure and galling was investigated. The results are also shown in Table 1.

[Margins below] -Q = Table 1 (Note) ○: No seizure or galling was observed.

△... Occurrence of seizure or galling was partially observed.

×... Occurrence of seizure or galling was observed over a wide area.

From the above results, it was confirmed that the present invention suppresses the occurrence of seizure and galling.

Effects of the Invention According to the present invention, as described above, by bending a workpiece made of aluminum material with the surface roughness and surface oxide film of the workpiece adjusted to below a certain value, the workpiece and mold can be bent. It is possible to reduce the frictional force generated between the bending process and the bending process, and the bending process can be carried out smoothly without causing sticking or galling to the mold, and it is possible to obtain a high-quality bent product with no surface flaws.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the invention. (1)...Bending machine, (2)...Fixed mold, (3)
... Gyro mold, (10) ... Workpiece. that's all

Claims (1)

[Claims] A bending machine has a movable gyro mold that can be turned and displaced in three dimensions in front of a fixed mold having a workpiece conduction hole, and both molds are sequentially forced to conduct by the operation of the gyro mold. When supplying a lubricant to a workpiece to perform a prescribed bending process, it is recommended that the workpiece made of an aluminum material be adjusted to a surface roughness of 20 μm or less and a surface oxide film thickness of 30 Å or less before being subjected to the bending process. A distinctive method for bending aluminum materials.