JPH07144236A - Production of aluminum thin walled tube - Google Patents

Abstract

PURPOSE:To produce an aluminum thin walled tube by a method for surely obtaining a required roundness in the aluminum thin walled tube subjected to ironing for an aluminum blank tube and then cutting. CONSTITUTION:At the time of obtaining an aluminum thin walled tube of a required thickness by ironing an aluminum blank tube while passing it through inside at least one of dies and then cutting it, ironing is executed at less than 70% draft, especially in the case that the thickness of the aluminum thin walled tube is <=1.5mm, it is executed at 45% to 70% draft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an aluminum thin-walled tube suitable for manufacturing an aluminum thin-walled tube for a photosensitive drum, for example.

[0002]

2. Description of the Related Art Generally, when manufacturing a thin aluminum tube such as an aluminum photosensitive drum, an ironing method using an ironing machine as shown in FIGS. 3 and 4 is adopted. ing. That is, first, a curling 2 having a diameter gradually reduced toward one end of the aluminum tube 1 is machined, and then the punch 3 is inserted into the aluminum tube 1 as shown in FIG. 3 is advanced to insert the aluminum tube 1 into a plurality of stages (4 stages in the figure) of dies 4 as shown in FIG. 4 for ironing, and then a stopper 5 is advanced to perform ironing. The aluminum pipe 6 is separated from the punch 3 by pulling out (stripping) the punch 3 with the base end portion of the pipe 6 being locked, and the obtained aluminum pipe 6 is cut around the outer circumference by a cutting machine such as a lathe. The aluminum thin-walled tube having a desired wall thickness was manufactured by cutting.

[0003]

By the way, in the production of an aluminum thin-walled tube by such ironing, it is important to obtain the dimensional accuracy of the obtained aluminum thin-walled tube, particularly the desired roundness. Therefore, conventionally, various ironing conditions such as processing speed, viscosity of lubricating oil, processing temperature, shape or material of die or punch, material of work material, etc., are set according to the thickness and diameter of the thin aluminum pipe to be processed. Therefore, it is necessary to find the conditions for ironing to obtain the desired roundness by trial and error, and then to manufacture the above-mentioned thin-walled aluminum tube, which requires a great deal of effort. There was a point.

In addition, in the above-described conventional method for manufacturing an aluminum thin-walled pipe, when ironing is performed a plurality of times, misalignment occurs during setup change,
It is necessary to insert a plurality of dies 4 ... At a time into an aluminum tube having a predetermined wall thickness to form an aluminum tube 6 having a predetermined wall thickness before cutting. For this reason, there is a problem that it is difficult to surely obtain excellent roundness even if the above-mentioned various ironing conditions are adjusted.

Therefore, the inventors of the present invention, when manufacturing the above-mentioned thin aluminum tube, paid attention to the influence of the reduction ratio during the ironing process on the obtained aluminum tube, and conducted diligent research. When the total reduction ratio when inserting 4 ... is 70% or less, especially when the thickness of the aluminum thin-walled tube which is the final product after cutting is 1.5 mm or less, in the range of 45% to 70% Therefore, we have come to the knowledge that the desired roundness can be surely obtained in the final product.

The present invention has been made on the basis of such findings, and provides a method for manufacturing an aluminum thin-walled pipe after cutting, which can surely obtain a desired roundness. The purpose is to do.

[0007]

A method for manufacturing an aluminum thin-walled tube according to the present invention is a method in which an aluminum tube is inserted into at least one die and ironed.
When cutting is performed to obtain an aluminum thin-walled tube having a desired wall thickness, the ironing is performed at a rolling reduction of 70% or less.

Here, when the thickness of the thin aluminum tube is 1.5 mm or less, the ironing process is performed 45 times.
It is necessary to carry out the reduction rate of 70% to 70%.

[0009]

First, the reason why the reduction rate of the ironing process is set to 70% or less will be described. FIG. 1 shows the effect of the reduction ratio during ironing on the roundness of a thin-walled pipe after cutting for an aluminum thin-walled pipe having an outer diameter of 80 mm and a final wall thickness of 1.0 mm. That is, if the total reduction ratio of one or more dies exceeds 70% when ironing the aluminum tube, excessive internal stress acts on the aluminum tube due to the ironing. Since this internal stress is released by the subsequent cutting process, the shape of the thin aluminum tube changes after the cutting process, and as a result, the roundness sharply deteriorates. Therefore, the reduction rate of the ironing process is limited to 70% or less.

Next, the thickness of the thin aluminum tube is 1.5.
The reason why the lower limit of the rolling reduction is set to 45% when it is less than or equal to mm will be described. If the thickness of the thin aluminum tube after cutting is 1.5 mm or less and the reduction ratio is excessively reduced, it is necessary to reduce the thickness of the aluminum base tube in advance. However, generally, when the aluminum raw pipe is processed by extrusion and the wall thickness of the aluminum raw pipe is 1.7 mm or less, the uneven thickness of the raw pipe becomes large, and the final thin aluminum pipe after processing is processed. The fluctuation of the shake becomes large. For this reason, it is considered that the aluminum raw pipe is cut before the ironing process so as to have a uniform wall thickness (an uneven thickness is taken), but the number of processing steps increases and the manufacturing cost rises. Therefore, the wall thickness of the aluminum tube is 1.7 m.
It is necessary to use the thing of m or more. To explain this concretely, FIG. 2 shows a reduction ratio in ironing when an aluminum thin-walled tube having an outer diameter of 60 mm and a thinnest wall thickness of 0.75 mm used for a photosensitive drum is manufactured, It shows the relationship with the wall thickness of the aluminum base pipe corresponding to each rolling reduction. As is clear from the figure,
If the reduction ratio during ironing is less than 45% in order to process an aluminum thin-walled tube having a wall thickness of 0.75 mm, the wall thickness of the aluminum raw tube before processing will be 1.7 mm or less, which is described above. As described above, the fluctuation of the runout becomes excessively large in the final thin aluminum tube after processing. From the above, the thickness of the thin aluminum tube is 1.
When it was 5 mm, the lower limit of the rolling reduction was set to 45%.

As described above, when manufacturing an aluminum thin-walled tube, the reduction rate during ironing is 70% or less,
Especially when the thickness of the aluminum thin-walled tube is 1.5 mm or less, by setting it to 70% to 45%, it is possible to surely obtain an aluminum thin-walled tube with excellent roundness even after cutting. You can

Therefore, according to the method for manufacturing an aluminum thin-walled tube of the present invention, the thin-walled aluminum tube for a photosensitive drum is required to have a particularly thin wall thickness of 0.75 to 1.5 mm and a high roundness of 50 μm or less. It is suitable for use in the production of.

[0013]

Example 1 First, as shown in FIG. 5, the wall thickness is 6.6 m.
m, 4.7 mm and 2.4 mm of three types of aluminum base pipes were prepared, and 75%, 65
After ironing at a reduction ratio of 30% and 30%, the outer periphery was further cut by 0.1 mm to produce an aluminum thin-walled tube having an outer diameter of 80 mm and a wall thickness of 1.6 mm. At the time of the above processing, the roundness of the aluminum tube obtained after the ironing processing and after the cutting processing was measured. As a result,
When the rolling reduction was 75%, the residual internal stress during the ironing process was released by the cutting process, and the roundness after the cutting process deteriorated, which was unsuitable. On the other hand, when the rolling reduction was 65%, the aluminum tube was not deformed due to the residual internal stress even by cutting, and the desired roundness could be obtained in the final thin aluminum tube. Further, even when the rolling reduction is 30%, the wall thickness of the final thin aluminum tube is 1.5 mm or more, and thus the wall thickness of the aluminum raw tube is 2.4 mm.
Since it was 1.7 mm or more, there was no inconvenience such as excessive runout in the final thin aluminum tube.

[0014]

[Embodiment 2] Next, as shown in the figure, the wall thickness is 3.8 mm, 2.7 mm, 1.9 mm, 1.7 mm, respectively.
Six types of 1.6 mm and 1.5 mm aluminum base pipes are prepared, and 75%, 65%, and
After ironing at a reduction rate of 50%, 45%, 40% and 30%, further cutting the outer periphery by 0.2 mm,
An aluminum thin-walled tube having an outer diameter of 60 mm and a wall thickness of 1.0 mm was manufactured. In this processing as well, the roundness of the aluminum tube obtained after the ironing and the cutting was similarly measured.

As a result, when the rolling reduction is 75%, the residual internal stress during the ironing process is released by the cutting process as in the case of Example 1, so that the roundness after the cutting process is improved. It became worse and was unsuitable. In addition, even when the rolling reductions are 40% and 30%, the final thin-walled aluminum tube has a wall thickness of 1.5 mm or less, and thus the aluminum tube has a wall thickness of 1.6 mm and 1.5 mm, respectively. Since it was less than 1.7 mm,
The final aluminum thin-walled tube was unsuitable as a product due to excessive runout. On the other hand, the reduction rate is 65
%, 50% and 45%, the thickness of the aluminum tube is 1.7 mm or more, and no large internal stress remains during ironing,
In each final thin-walled aluminum tube, excellent roundness of 50 μm or less could be obtained.

[0016]

As described above, in the method for manufacturing an aluminum thin-walled pipe according to the present invention, the aluminum base pipe is inserted through at least one die to be ironed and then cut to be desired. When obtaining a thin aluminum tube having a wall thickness of 70% or less, particularly, when the wall thickness of the thin aluminum tube is 1.5 mm or less, a reduction rate of 45% to 70% is applied to the ironing process. Since it is characterized in that it is performed in step 1, even if the cutting process is performed in the subsequent step, it is possible to surely obtain an aluminum thin-walled tube having excellent roundness. Therefore, especially the wall thickness is 0.75
It is suitable for use when manufacturing an aluminum thin-walled tube for a photosensitive drum, which requires a thinness of about 1.5 mm and a high roundness.

[Brief description of drawings]

FIG. 1 is a graph showing the effect of the rolling reduction during ironing on the roundness of thin aluminum tubes.

FIG. 2 is a graph showing the relationship between the rolling reduction during ironing and the wall thickness of the aluminum base pipe.

FIG. 3 is a conceptual diagram for explaining a general state before ironing.

FIG. 4 is a conceptual diagram for explaining a state after ironing of FIG.

FIG. 5 is a table showing experimental results for confirming the effect of the method for producing an aluminum thin-walled tube of the present invention.

[Explanation of symbols]

 1 Aluminum tube 4 Dice

Claims (3)

[Claims] 1. A method for producing an aluminum thin-walled pipe, wherein the aluminum raw pipe is inserted through at least one die to perform ironing, and then cutting is performed to obtain an aluminum thin-walled pipe having a desired wall thickness. Ironing process 7
A method for producing an aluminum thin-walled tube, which is performed at a rolling reduction of 0% or less. 2. The thin-walled aluminum tube has a wall thickness of 1.5.
mm or less and 45% to 70% of the above ironing
The method for producing an aluminum thin-walled tube according to claim 1, wherein the reduction is performed at 3. The thin aluminum tube is a thin aluminum tube for a photosensitive drum.
The method for producing an aluminum thin-walled tube according to.