JPH038527A - Manufacture of necking can with impact extrusion - Google Patents

Abstract

PURPOSE:To form the smooth bead part and to surely obtain sealing property by forming the thickness of the shoulder part of the necking can and the part corresponding to the bead part thicker than that of the drum part and making this thickness part thin with the squeezing effect. CONSTITUTION:Soft Al slag is subjected to impact extrusion to form a cylindrical preform can 1'' nearly the same form as in the conventional manner having a 1st thickness part 1''a, a taper part 1''c, and a drum mainly part 1''b. At this time, the thickness part 1''a1 is formed slightly thicker than the neighborhood of mouth part of the conventional preform can. And then the specular finished punch 17 having substantially the same diameter as the internal diameter of the preform can 1'' is inserted and is moved to the arrow mark direction and the part 1''a2 is subjected to working to form the 2nd thickness part 1''a2 where the thickness is a slightly thinner than that of the part 1''a1 and a slightly thicker than that of the drum main part 1''b with the die ring 16. The open mouth end part 1''d2 of this preform can 1'' is trimmed to the prescribed height and simultaneously subjected to correction of form, washing, coating, necking and the bead part is formed. In such a way, the necking can 11 having the cylindrical drum part 11, the shoulder part 13, and the smooth bead part 14 is obtained and the machining for the upper end of the bead part is unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing an impact extrusion mouth squeeze can used for pressure-resistant cans such as aerosol cans.

(Prior Art) An impact extrusion mouth squeeze can 1 used for an aerosol can or the like usually has a cylindrical body 2. Shoulder portion 3 and mounting cup 5 extending diagonally upward on the inside
(See FIG. 4) is provided with a bead portion 4 for clinching and sealing.

As shown in FIG. 3(a), the conventional mouth-squeezing can 1 has the following features:
After impact-extruding a soft aluminum slab, the open end is trimmed to form a cylindrical preform can 1', which is washed and painted (including baking treatment) on the inside and outside surfaces, followed by doming the bottom 1f. It is formed into a dome shape that is concave inward, and then the part 1'a near the opening is drawn.
The shoulder portion 3 and the short cylindrical mouth constriction portion 6 are formed in Fig. 3 (
b) ), manufactured by forming a rear aperture 6 in the bead 4;

Portion 1 near the opening that should normally become the shoulder portion 3 and bead portion 4
/a is the lower body part 2 as shown in FIG. 3(a).
It is formed to be slightly thicker and convex outward than the portion 1'b that should be formed. The opening vicinity portion 1'a and the portion 1'b are connected via the chip i4 portion 1'c. Forming the thick wall portion in this way strengthens the shoulder portion 3 and prevents troubles such as the shoulder portion 3 caving in due to the axial load applied when forming the bead portion 4 or when clinching the mounting cup 5. This is to prevent it from happening. Also mounting cutter 7
This is to form a bead portion 4 that is strong enough not to be soaked when clinching the ``5''.

The conventional mouth-drawn can 1 manufactured as described above has a bead portion 4 shown in FIG.
A vertical wrinkle-like uneven pattern 7 as shown in c) is likely to occur. This uneven pattern 7 causes a problem in that after the mounting cup 5 is clinched, a narrow tube-shaped gap extending in the radial direction is formed between the sealing cone sound 8 and the bead portion 4, impairing the sealing performance (Fig. 4). ).

In order to solve this problem, conventionally, the upper surface part 4 of the bead part 4
A (FIG. 4) is cut in the circumferential direction to form a relatively smooth cut upper surface 4b, which has vertical wrinkle-like concavities.

Sealing performance was ensured by removing the convex pattern 7.

This kind of cutting work requires maintenance of the cutting tool (cutter) and quality control of the cut surface, and also involves applying paint manually to the cut top surface 4b after finishing the process, and then performing a baking process, which is extremely time-consuming. A problem occurred that required such repair work.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for producing an impact-extruded mouth-drawn can in which sealing performance is ensured without cutting the upper surface of the bead portion.

(Means for Solving the Problems) A method for manufacturing an impact extrusion mouth draw can of the present invention is a method for manufacturing an impact extrusion mouth draw can having a cylindrical body, a shoulder, and a bead, the method comprising: impact extrusion. , a cylindrical plastic can is formed in which a portion approximately corresponding to the shoulder portion and the bead portion is a first thick portion that is thicker than the body portion, and then by ironing, The first thick part is formed into a second thick part which is thinner, and the opening end is trimmed, and then the second thick part is formed in the shoulder part and the bead part. .

(Function) During can manufacturing by impact extrusion, a fibrous structure extending in the axial direction develops in the body, and as a result, very fine streak-like longitudinal grooves are generated on the inner and outer surfaces of the body. During the mouth drawing and bead formation, it is thought that the vertical grooves on the inner surface become starting points and develop into a vertical wrinkle-like uneven pattern 7 that is visible to the naked eye.

Ironing is usually carried out between a punch with a mirror-finished cemented carbide surface and a gilling also made of cemented carbide. In the present invention, the first thick part of the cylindrical preform can formed by impact extrusion is ironed into the thick part of the nest 2 which is thinner than the first thick part.

During this ironing process, the inner surface of the thick part is smoothed by sliding under pressure along the mirror-finished punch surface, and the longitudinal grooves are substantially eliminated. This thick wall portion is the portion that should become the shoulder portion and bead portion of the mouth-drawn can, and since the vertical grooves have substantially disappeared, the vertical wrinkle-like uneven pattern 7 is not generated in the bead portion.

In addition, the portions that should become the shoulders and beads remain the second thicker portions than the body even after ironing, making it possible to form shoulders and beads with relatively high strength. can.

(Example) First thick portion 1〃a7. shown in FIG. 1 that protrudes outward.
A cylindrical preform can 1 having a chi-9 part 1"C and a body main part 1//b, the soft aluminum body inner surface 1"e is generally cylindrical. Preform can 1"
has almost the same shape as the conventional preform can 1/ (Fig. 3 (a)), but the second thick part 1 is formed by ironing.
After forming a2 and then trimming the open end, it has the same dimensions as the preform can 1'.

Therefore, the thickness of the first thick portion 1''al is slightly thicker than that of the portion 1/a near the opening of the preform can 1' since then.

Next, a mirror finish punch 17 having a diameter substantially equal to the inner diameter of the preform can 1 is inserted into the preform can 1, and the punch 17 is moved in the direction of the arrow until it is fixed by the holder 15. In cooperation with the guiling ring 16, the first thick part 1〃a1 is made slightly thinner than the first thick part 1〃a1, and the body main part 1//
A second thick portion 1〃a2 (indicated by a dashed line) is formed slightly thicker than b. At this time, cooling lubricant is sprayed onto the upstream side of the guiling ring 16. 111d2 is the opening end after forming the second thick part 1''a2, and has an irregular shape.The ironing rate is preferably 5 to 30 inches;
10 to 20% is more preferable.

Next, the opening end of the Glyform can 1 with the second thick wall portion 1''a2 formed thereon is trimmed to a specified height, and at the same time the opening end surface is shaped, followed by cleaning and painting (including a baking process). After that, the mouth is drawn, the bead part is formed, and the second
A squeezable can 11 having a cylindrical body, a shoulder 13 and a smooth bead 14 as shown in the figure is formed.

Next, a specific example will be explained.

A circular slurry of soft aluminum (purity 99.7%) with a diameter of 49.8 van and a thickness of 7.5 + ms was formed into a preform can 1" by a conventional impact extrusion process. Preform can 1 The height is approximately 170 m
, the inner diameter is 49.5 ran, the length of the first thick part 1〃a1 is about 28 gourds, the thickness is 0.45 ras, the length of the body main part 1〃b is 100 ran, the thickness is It was 0.35 mm. The roughness (Ra) of the inner surface of the body was 0.5 to 0.6 μm.

A punch 17 having a mirror-finished cemented carbide sleeve with a diameter of 49.3 mm is inserted into the preform can 1, and in cooperation with a cemented carbide guiling ring 16 with an inner diameter of 50.1 ran, the first can is ironed. 1 was formed on the second thick portion 1〃a2 of the second thick portion 1'a2. Second thick part l'a2
The thickness was 0.4 mm (L processing rate 11%). The roughness (Ra) of the inner surface of the body 1"e after ironing is 0.
．． It was 2 to 0.3 μm.

After ironing, the preform can 1" is trimmed to a height of 160mm, washed and dried, and an epoxyphenol baked coating is formed on the circular side, and a polyester coating is applied to the outside and side. A film was formed.

Next, the bottom part is domed and a second thick part 1"
Al was subjected to a neck drawing process to form a shoulder part and a neck neck part (6) as shown in FIG. . The outer diameter of the bead portion 14 is 31 mm, and the bead width d of the bead portion 14 is
was 3M. The surface roughness (Ra) of the bead portion 14 is 0
．． It was 5 μm.

For 50 cans of the mouth-squeezing can 11 above, after filling with hair spray, the mounting cut f5 was clinched to produce sealed cans, and the weight loss after storage in a constant temperature room for 3 months was measured. The average value of the weight loss was was 0.005 to 0.10 gr.

For comparison, the preform can 1 after ironing was produced by impact extrusion without ironing.
A preformed can with the same dimensions (height differs slightly) was formed, and the can 1 was produced in the same manner as described above, except that this can was immediately trimmed. Bead portion 4 of the crimped can 1
The surface roughness (Ra) was 2.5 to 3 μm, and a prominent vertical wrinkle-like uneven pattern 7 was observed. When the weight loss of 50 sealed cans produced by clinching the mounting cup 5 without cutting the upper surface 4a of the bead portion 4 of the can was measured in the same manner as described above, the average value of the weight loss was 0.2
~0.3gr.

(Effects of the Invention) Since the impact extrusion mouth-drawn can manufactured by the method of the present invention has a smooth bead portion, it has the effect of ensuring sealing performance without cutting the upper surface of the bead portion.

Therefore, there is an advantage that there is no need to repair the cut surface of the bead portion with paint, and there is no need for maintenance of the cutting tool or quality control of the cut surface.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a main part showing the ironing process in the method of the present invention, Fig. 2 is a partially cutaway front view of a mouth-drawn can manufactured by the method of the present invention, and Fig. 3 is a conventional impact FIG. 3(a) is a drawing showing the manufacturing process of the extrusion mouth squeeze can.
is a longitudinal cross-sectional view of the preform can after impact extrusion and trimming,
FIG. 3(b) is a vertical cross-sectional view showing the state of the glyphome can of FIG. 3(a) after being squeezed, and FIG. 3(c) is a vertical cross-sectional view of the can of FIG.
Fig. 4 is a vertical cross-sectional view of a can with a bead formed on the glyph form can shown in b), and Fig. 4 is a vertical cross-sectional view of the can with a bead formed on the glyph form can shown in Fig. 3(C), after cutting the bead part of the can with a bead. FIG. 3 is a longitudinal cross-sectional view of a main part showing a state in which the cap is clinched. 1〃...Cylindrical preform can, 1"al...1st
Thick part, 1 a2... Second thick part, 11... Mouth squeeze can, 12... Body part, 13... Shoulder part, 14...
Bead part. No.

Claims (1)

[Claims] (1) In a method for manufacturing an impact extrusion mouth drawer can having a cylindrical body, a shoulder, and a bead, impact extrusion results in a portion that approximately corresponds to the shoulder and bead being thicker than the body. A cylindrical preform can with a first thick wall part was formed, and then the first thick part was formed into a thinner second wall part by ironing, and the open end was trimmed. A method for manufacturing an impact extrusion mouth drawer can, comprising: forming a second thick portion on the shoulder portion and the bead portion.