JPS603924A - Method for forming can - Google Patents

Abstract

PURPOSE:To prevent the phenomena of a hair crack due to a chip of broken earing caused at the time of ironing and a breakage of bottom by performing a doming before the ironing of a final process, in forming a DI can. CONSTITUTION:In forming an Al can (DI can) used for a vessel of carbonated beverage and beer, etc., a blank sheet 1 cut into a prescribed size from a coiled blank material is formed into a primary work piece 2 having a cylindrical shape and a bottom through a cupping process. Next the work piece 2 is redrawn through a redrawing and the 1st ironing processes as well as is worked to form a reinforcing domed-part 5 at its bottom, to obtain a secondary work piece 3. The work piece 3 is finally worked through the 2nd ironing process to obtain a tertiary work piece 4, which is carried to a finishing process. In this way, the object is achieved, because the doming is performed when the wall thickness of work piece is thick, and the quality of a can-product is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming aluminum cans (hereinafter referred to as DI cans), which are widely used as containers for carbonated drinks or beer, and aims to improve the quality of can products. This is the purpose.

In the conventional molding of this type of DI can, in the case of a small can, as shown in FIGS.
After performing camping to process the primary processed product 2 into a short cylindrical shape with a bottom, the primary processed product 2 is sent to the redrawing and ironing process for redrawing and ironing, and the can bottom shape is formed in two steps. was. On the other hand, in the case of large DI cans, due to the stroke length of the forming equipment, the blank plate 1 is processed into a primary processed product 2 in the shape of a short cylinder with a bottom, as shown in Fig. 2 (at to d). The comping process and the short cylindrical primary processed product 2' with a bottom processed in this comping process ! : It is generally carried out in three steps: a re-drawing process for re-drawing, and an ironing process for ironing the body of the secondary processed product 3 processed in the re-drawing process. In any of these forming methods, after ironing is completed, doming processing is performed to process the dome portion 5 in order to provide the bottom of the secondary processed product 3, etc. with full internal pressure resistance (see Fig. 1).
l and Figure 2 (see di).

However, during the ironing process in this type of DI can molding method, because the wall thickness becomes thinner, ears are formed at the opening of the processed product, and these ears are cut and the chips are attached to the bottom of the processed product. Sometimes I jump in. Therefore, if the entire doming process is performed in this state, it may lead to defects such as bottom cracks in the processed product. Furthermore, in some cases, they may appear as minute cranks, which may significantly reduce the quality of the can.

This invention has been made with the full intention of solving the above-mentioned problem, and its gist is that after the comping process of processing a blank material to be machined into a short cylinder shape with a bottom, This method is characterized in that the next processed product is re-drawn, a reinforcing dome is formed on the bottom of the product, and then ironed. The ironing process is performed before the ironing process. Ear. circle. It is an object of the present invention to provide a method for shaping the bottom of a can, which is characterized in that it prevents the bottom cracking phenomenon and improves the quality of can products.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the accompanying drawings, FIG. 3 is a schematic side view showing the main part of the can bottom-shaped device, that is, the second processing step, and in the figure, 11 is the side wall of the primary processed product 2 that has been previously processed into a short cylinder shape with a bottom. This is a press means for redrawing or ironing, and the press means 11 is provided with a recalibration goose 6, an ironing die 12, and a stripper device 7.
Regarding this, a bunch 8 that performs redrawing and ironing in cooperation with the redrawing die 6 and a receiving die 9 that performs doming on the bottom of the workpiece are disposed facing each other. 11 and the receiving mold 9 is a conveying base 1.
0 is deployed. In this case, Ailki Punch 8
is connected to a drive source via a crank mechanism (not shown) so that it can reciprocate and hang in order to enter the redrawing die 6.

The can bottom shaping method of the present invention for molding cans using the molding apparatus configured as described above is similar to the conventional can bottom shaping method as shown in FIG. 4 (at to d). The raw plate L cut into a predetermined size is processed into a primary processed product 2 in the shape of a short cylinder with a bottom in a comping process, and then a redrawing and first firing process (see Fig. 4 1c) ) to re-draw the primary processed product 2, and
5 reinforcing dome parts are machined on the bottom part 2a, and in the next step, the second eye-opening process, the secondary processed product 3 processed in step Aj1 redraw and step 11 Iani/g is ironed. This is a characteristic feature. Note that the tertiary processed product 4 processed in the second ironing process is transferred to the transport base 1.
0, and the finishing process (
(not shown).

As explained above, according to the can bottom shape method of the present invention, the balance of the stroke length and processing speed during redraw processing and ironing processing is performed on the short cylindrical primary processed product after the canning process. The ironing process is carried out several times in consideration of this, and the first ironing process is performed at the same time as the redraw process, and a reinforcing dome part is added to the bottom of the secondary processed product, which has a side wall thickness that does not yet cause edge cuts. After that, the secondary processed product is ironed through the second firing process, which eliminates the occurrence of minute cranks caused by chips caused by edge breakage and bottom cracking, which improves the quality of can products and improves product quality. Excellent effects such as improved retention can be obtained.

Note that the depth of the reinforcing dome processed in the redraw and first ironing process becomes slightly shallower due to the second ironing process, but as a result of experiments, the amount is small and there is little variation, so it is better than the conventional one. There was no difference in comparison. If it is necessary to increase the depth of the dome portion from the conventional depth, the height of the dome portion may be deepened in advance by the amount of reduction.

[BRIEF DESCRIPTION OF THE DRAWINGS] In the accompanying drawings, FIG. 1 1al to lcl and FIG. 2 1a
) to ldl are schematic side sectional views showing the processing procedure of the conventional can bottom shaping method, FIG. 3 is a schematic side view showing the main parts of the can bottom shaping device in the present invention, and FIG. FIG. 2 is a schematic side sectional view showing the processing procedure of the can bottom shape method of the present invention. In the figure, 1 raw plate 2 short cylindrical primary processed product with a bottom 3 secondary processed product 4 reinforcing dome portion 5 tertiary processed product 6 drawing die 7 stripper device 8 bunch 9 receiving mold 1O conveying base 11 by the breath means be. Patent applicant Nippon Light Metal Co., Ltd. Figure 1 (a) ■ (b) Figure 3

Claims (1)

[Claims] A camping process in which the raw plate for processing is processed into a short cylindrical shape with a raised bottom, and the primary processed product in the shape of a short cylinder with a bottom that has been processed in this camping process is redrawn, and a reinforcing dome is added to the bottom of the primary processed product. A method for shaping a can bottom, comprising: a redrawing and first ironing step, and a second ironing step, which irons the secondary product processed in the redrawing and first ironing step. .