JPH0146205B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a ladder processing punch, more specifically, a ladder processing punch that allows easy extraction of a formed metal can body.
Regarding ironing punches. (Prior art) One-piece metal can bodies used for beer cans, youth cans, etc. are made by drawing and forming a cup body from a metal plate blank such as a tinned steel plate or an aluminum alloy thin plate using a punch and a die. By working,
Manufactured by ironing while spraying cooling lubricant. After the ironing process, the metal can body is prepared as described in, for example, Japanese Patent Publication No. 19679 (1967), Japanese Publication No. 1967 (1967),
As proposed in Japanese Patent No. 26352 or Japanese Patent Application Laid-Open No. 56-89335, the punch is removed by engaging the claw of the extraction device with the opening edge of the can body and returning the punch. extracted from. (Problems to be Solved by the Invention) Conventionally, punches with smooth sidewall surfaces have been mainly used as ironing punches, but even in this case, especially at the start of operation, the frictional resistance between the sidewall surface and the inner surface of the can body is This may make extraction difficult or impossible, resulting in rollback (bending outward) of the opening edge, premature wear of the pawl, or damage to the die.
It is easy to cause problems such as destruction. Japanese Patent Application Publication 1973-
When using a punch whose side wall surface has been roughened by grinding or mechanical finishing in order to improve ironing workability, as proposed in Publication No. 90668, the above-mentioned frictional resistance increases. , the above troubles are more likely to occur. (Object of the Invention) An object of the present invention is to provide an ironing punch that improves the ability of a extraction device to extract a one-piece metal can body formed by ironing. (Structure of the Invention) In the present invention, a large number of point-like recesses are formed in the smooth portion over the entire side wall surface, and each dot-like recess has an area of 0.03 to 0.8 mm ² and a depth of 0.1 to 0.8 mm 2 . 0.8 μm, and an ironing process for forming a one-piece metal can body, characterized in that the area occupied by the point-like recesses along the side wall surface is 10 to 40% per unit area of the side wall surface. It provides punch. (Example) The present invention will be described below with reference to drawings which are examples. In Fig. 1, 1 is a barbed punch, 2 is a punch immediately after being formed by barging, 1
3 is a piece metal can body, and 3 is an opening edge 2a of the can body 2 when the punch 1 returns in the direction of arrow A.
This is a claw portion of an extraction device (not shown) for engaging with the can body 2 and extracting the can body 2 from the punch 1. (Structure) At least the portion of the side wall surface made of cemented carbide of the punch 1 that should come into contact with the inner surface of the formed can body 2 (this portion is referred to as the side wall surface 1a in this specification) has a large number of The dotted recesses 4 are formed in a substantially uniform distribution. Point-like recesses 4 on the side wall surface 1a
The remaining unformed portion of is preferably
The smooth portion 5 has an average roughness of about 0.1 μm or less. As shown in FIGS. 2, 3, and 4, the surface shape of the dotted recess 4 along the side wall surface 1a is usually substantially a perfect circle or an ellipse (the ratio of major axis to short axis is preferably about 2). It has a circular shape with no sharp corners such as () below. As will be described later, the recess 4 is preferably formed by ultrasonic machining, but in that case, even if a horn with a cross-sectional shape having a sharp corner is used, the corner of the recess to be formed is This is because the corresponding parts are rounded, and the corners of the horn also become rounded due to wear and chipping during machining. The area of the dotted recess 4 along the side wall surface 1a is 0.03~
Preferably ^0.8mm2 . That is, when the recess 4 is substantially circular as shown in FIG.
The diameter d is preferably about 0.2 to 1.0 mm. In addition, it is desirable that the area occupied by the dotted recesses 4 along the side wall surface 1a is 10 to 40% per unit area. The cross-sectional shape of the recess 4 is preferably an arc shape as shown in FIG. 5, or a pot bottom shape as shown in FIG. In either case, it is preferable that the boundary portion 4a with the smooth portion 5 has a roundness. In the case of a pot bottom shape as shown in FIG. 6, the side surface 4b and the bottom surface 4
It is preferable that the boundary portion 4d with c is also rounded. In addition, in the case of a pot bottom shape, as described later, the convex part 8
Since the contact area increases when the groove slides along the smooth portion 5, an arc shape is more preferable, especially when the area or diameter of the recess 4 is large. The depth h of the recess 4 (Figures 5 and 6) is 0.1~
It is desirable that the thickness be 0.8 μm, more preferably 0.3 to 0.6 μm. When the depth h is smaller than 0.1 μm, there is no difference in roughness from the smooth part 5, and the extraction performance is the same as that of a conventional smooth finishing punch.
The ease of extraction is not improved. (Function) During the ironing process, as shown in Fig. 7, move the punch 1 along with the drawn cup body in the direction of arrow B.
By moving in the direction, the punch 1 and the first ring die 6 work together to squeeze the body wall 2'b of the cup body, thereby forming a body thinner than the body wall 2'b. A wall portion 2b is formed. The thinned body wall portion 2b is usually further squeezed through a second die and, if necessary, a third die, to become even thinner as shown in FIG.
The thickness will be approximately 0.22mm. By the above-mentioned ironing process, a convex portion 8 having a cross-sectional shape substantially corresponding to the cross-sectional shape of the recessed portion 4 is formed on the inner surface of the trunk wall portion 2b. In the recess 4x (Fig. 7) of the punch before entering the first die 6,
Since the cooling lubricant 7 (usually made of water emulsion oil) is contained, the recess 4 remains even after ironing.
The cooling lubricant 7 remains in the slight gap 9 between the convex portion 8 and the convex portion 8, and when the convex portion 8 is formed, the cooling lubricant 7 pushed out from the concave portion 4 is transferred to the smooth portion 5 of the punch.
It is presumed that a lubricating film 7a (see FIG. 8) is formed between the inner surface of the trunk wall portion 2b. To extract the punch 1 from the can body molded body 2, the opening edge 2a (FIG. 1) of the can body molded body is engaged with the claw part 3, and the can body molded body 2 is fixed. As shown in the figure, this is done by moving the punch 1 in the direction of arrow A. At that time, for example, the convex part 8x that was engaged with the concave part 4y slides up along the concave part 4y, and moves away from the concave part 4y to the smooth part 5.
Extraction is performed by repeating the process of sliding along x and then engaging with the next recess 4z. In this case, the recess 4 functions as an oil reservoir to lubricate the lower end surface 8a that contacts the convex part 8, especially the smooth part 5, and as mentioned above, the lubricating film 7a is formed on the smooth part 5. The convex portion 8 slides smoothly along the smooth portion 5. The rounded boundary portions 4a and 4d facilitate the smooth sliding up of the aforementioned convex portion 8. However, if the area of the recess 4 is smaller than 0.03 mm ² or the proportion of the area occupied by the recess 4 along the side wall surface 1a is over the entire side wall surface 1a,
If it is less than 10% per unit area (usually 1 cm ² ) of the side wall surface, the function of the recess 4 as an oil reservoir will not be sufficient and the lubricating film 7a will be formed too little, making it difficult for the above-mentioned sliding to occur smoothly. When the depth h of the concave portion 4 becomes larger than 0.8 μm, the height of the convex portion 8 that is formed also increases accordingly.
increases to a value close to . As described above, the body wall portion 2b after ironing is relatively thin and therefore easily bends due to elastic deformation. However, as the height of the convex portion 8 increases, the amount of elastic elongation of the body wall portion 2b when the convex portion 8 slides up to the smooth portion 5 also increases in proportion to the height. The radially inward elastic force applied to the punch 1 via the punch 1 also increases. Therefore, the depth h of the recess 4 is 0.8 μm.
If the convex portion 8 slides up to the smooth portion 5 and along the smooth portion 5, the frictional force becomes large despite the presence of the lubricating film 7a, etc., making it difficult to extract the lubricant. , the depth h is preferably 0.8 μm or less. Since the recess 4 is quite shallow in this way, if its area becomes larger than 0.8 mm ² , the distance required for the recess 8 to slide up to the smooth part 5 increases, which increases the frictional resistance. Even when the cross-sectional shape is arcuate, the bottom surface of the convex portion 8 that is formed tends to be flat, which increases the frictional resistance when the convex portion 8 slides along the smooth portion 5, which reduces the ease of extraction. Therefore, it is desirable that the area is 0.8 mm ² or less. When the area occupied by the recess 4 along the side wall surface exceeds 40% per unit area of the side wall surface, the frequency at which the protrusion 8 slides up the smooth surface 5 along the recess 4 increases.
The frictional resistance required for this sliding up is greater than the frictional resistance when the convex portion 8 slides along the smooth portion 5.
Therefore, the above area is reduced to 40% because the ease of extraction deteriorates.
The following is desirable. For the same reason, the recesses 4 are aligned in the direction of arrow A, which is the extraction direction, that is, in the axial direction of the punch 1 (for example, the axial pitch p is 0.5 to 1.5 mm), and the adjacent row is
It is preferable that it is formed so that it does not enter the column. In addition, the proportion of the area occupied by the recess 4 is
Even within the scope of the present invention, if the ratio is relatively small, the recesses 4 should be placed on the side wall surface 1 to prevent the area without recesses 4 from increasing locally.
It is particularly preferable that the particles be formed so as to be relatively uniformly distributed over the entire surface of a. (Method for forming recesses) FIG. 9 shows an example of a method for forming recesses 4 in the punch 1. Punch 1 is chuck 11
(e.g. on a lathe) and rotated in the direction of arrow C, preferably at a constant speed (e.g. 25 rpm). Reference numeral 12 denotes an ultrasonic vibrator, which is excited by an ultrasonic oscillator (not shown). Its tip 1
2a is made of cemented carbide and has a shape that roughly corresponds to the recess 4 to be formed. The vibrator 12 is fed by a feeding mechanism (not shown) in the axial direction of the punch 1, that is, in the direction of arrow D, preferably at a constant speed (for example, 1 mm per punch rotation). Furthermore, the vibrator 12 is a low frequency oscillator 1
3 (for example, a frequency of 130 Hz) via the amplifier 14, the punch vibrates in the radial direction of the punch, that is, in the direction of arrow E, while repeatedly coming into contact with and separating from the side wall surface 1a of the punch. It is configured as follows. During this contact, a recess 4 having a shape approximately corresponding to the shape of the tip 12a of the vibrator is formed in the side wall surface 1a. The side wall surface 1a is finished to a smooth surface with an average roughness of 0.02 .mu.m by lap finishing, for example, after finishing to a thickness of 0.4 .mu.m before forming the recess. The area of the recess 4 mainly depends on the shape of the tip 12a,
Depending on the above contact time, the depth h of the recess 4
is mainly determined by the above-mentioned contact time. Furthermore, the pitch p in the axial direction depends on the rotational speed of the punch 1 and the feed rate of the vibrator 12, and the pitch q in the recess forming direction (Fig. 2) mainly depends on the oscillator 13.
is determined by the frequency of the punch 1 and the rotation speed of the punch 1. From these pitches p and q and the area of each recess 4, the ratio of the area to the unit area of the side wall surface 1a of the recess 4 is determined. (Effects of the Invention) The ironing punch of the present invention has an effect that the can body can be easily pulled out after ironing. (Specific Example) Next, a specific example will be explained. Diameter of large diameter part 1a ₁ : 52.6mm, diameter of small diameter part 1a ₂
Average roughness of a punch made of 52.5 mm cemented carbide
The side wall surface 1a has a wrapping finish of 0.02μm,
Over the range of 145 mm in height from the bottom end 1b, by the method shown in Fig. 9, as shown in Table 1, the second
Punches 1 having various dot-like recesses 4 were produced by forming dot-like recesses 4 of the type shown in FIGS. Using these punches, a smooth punch with only a smooth part 5 without a recess 4, and a rough punch with a side wall surface treated with shot brass,
Made from 0.3mm thick tin-plated steel plate, outer diameter
A drawing cup (not shown) with a diameter of 71 mm and an average height of 37 mm was heated using a known re-drawing-three-stage ironing machine under the same conditions using water emulsion oil as the cooling lubricant 7 (spray amount 60 to 120 liters/min). After ironing, the can has an average wall thickness of 0.10 mm in the part of the body wall 2b that contacts the large diameter part 1a ₁ , a wall thickness of 0.15 mm in the part that contacts the small diameter part 1a ₂ , and an average height of 142 mm. The fuselage 2 was formed. After the formation of the above, the special public interest was established in 1986-133.
The opening edge 2a was engaged with the claw 3 of the extraction device of the type described in the publication, and the punch 1 was extracted. Table 1 shows the extraction results at the start of operation.

[Table] This occurs relatively frequently, but it is unlikely to occur during stable continuous operation.

[Brief explanation of drawings]

FIG. 1 is a plan view of a punch that is an embodiment of the present invention, and FIGS. 2, 3, and 4 are A of FIG. 1.
2 is a perfect circle, FIG. 3 is an ellipse with the short axis extending in the axial direction, and FIG. 4 is an enlarged view of the dotted recess along the side wall surface. Drawings in the case of an ellipse extending in the axial direction, FIGS. 5 and 6 are drawings for showing examples of the cross-sectional shape of the dotted recess, and FIG. 5 is a longitudinal sectional view taken along the - line in FIG. 2. ,
Figure 6 is a longitudinal sectional view taken along the - line in Figure 3;
The figure is an explanatory longitudinal cross-sectional view of the main part showing the can body being pressed and formed using the punch in Figure 1, and Figure 8 shows the punch in Figure 7 being pulled out from the formed can body. FIG. 9 is an explanatory plan view showing an example of the punch shown in FIG. 1 in a state in which point-like recesses are formed. 1... Ironing punch, 1a... Side wall surface, 2
...1 piece metal can body, 4... dotted recesses, 5...
...Smooth part, 12...Ultrasonic transducer.

Claims (1)

[Claims] 1. A large number of dot-like recesses are formed in the smooth portion over the entire side wall surface, and each dot-like recess has an area of 0.03 to 0.8 mm ² and a depth of 0.1 to 0.8 μm. An ironing punch for forming a one-piece metal can body, characterized in that the proportion of the area of the dotted recesses along the side wall surface is 10 to 40% per unit area of the side wall surface. 2. The ironing punch according to claim 1, wherein the dotted recesses are formed by ultrasonic machining.