JPH11309517A - Punching die and punch of blank for cup drawing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching die and a punch capable of reducing unnecessary parts except a blank part to be punched when a metallic plate is cup- drawn, and reducing the generation of ear when the blank is formed into a cylinder. SOLUTION: The punching section of a die and a punch is basically, a hexagon two side of which facing each other are substantially parallel to each other. Each corner part on the periphery of the hexagon is formed in an arc shape, and the ratio (R/2r) of the radius (R) of curvature of the arc to the diagonal length of the shape in which each corner part on the periphery of the hexagon is formed in the arc shape (the distance of between the corner parts after the corners are rounded: 2r) is set to 0.15-0.45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a die and a punch for blanking a blank for cylindrical drawing from a metal plate. More specifically, the present invention relates to a die and a punch used for blanking a blank used for cylindrical drawing with a good yield and a small ear ratio (variation in the height of the cylindrical can) of a cylindrical can formed from the blank. .

[0002]

2. Description of the Related Art Conventionally, when a metal plate is drawn into a cylinder, a blank punched into a disk has been used. However, when blanks such as discs are punched from a long metal rolled plate, the blanks to be punched are arranged in a staggered manner, and the blanks are arranged so that unnecessary portions that become gaps between adjacent blanks are minimized. However, an unnecessary portion of a substantially triangular shape necessarily occurs as a scrap portion. In order to reduce the generation of the scrap portion and the ear portion, punching the blank in a non-circular shape is disclosed in Japanese Patent Publication No. 7-1
It is disclosed in 1257503. Tokuhei 7-11
In the 257505 gazette, it is assumed that a material in which ears appear in a direction parallel or perpendicular to the rolling direction is presumed to be punched out in a dodecagonal shape at the time of drawing.

It is also disclosed that an arc portion is formed at the corner of the dodecagon, and the ear ratio is minimized when the curvature is 25 to 40% with respect to the aperture diameter.

[0004] The inventors of the present invention conducted various experiments to change the anisotropy and the number of blanks punched in the width direction of the sheet in order to reduce the occurrence of unnecessary portions in blanking. It has been found that blanking is most effective using a dice having a shape based on a square shape and a rounded corner with a certain radius of curvature.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to reduce unnecessary portions other than blank portions to be punched when a metal plate is drawn into a cylinder. Another object of the present invention is to provide a punching die and a punch for suppressing generation of ears when a blank is formed into a cylinder.

[0006]

According to the present invention, there is provided a punching machine in which a hexagon whose two sides facing each other are substantially parallel has a basic shape, and each corner around the hexagon is formed in an arc shape. A blanking die and a punch of a cylindrical drawing blank having a cross section, wherein in the above punched cross section,
The ratio of the radius of curvature (R) of the arc to the diagonal length (distance between opposite corners after rounding the corner, hereinafter 2r) of a shape in which each corner around the hexagon is formed in an arc shape (R / 2r) is 0.15 to 0.45, and the hexagon is a regular hexagon.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is intended to reduce unnecessary portions other than blank portions to be punched when a metal plate is drawn into a cylinder, and to reduce the occurrence of ears when the blank is formed into a cylinder. The results of a wide range of studies aimed at providing dies for use in blanking methods that reduce the extent to which the ears are generated when drawing a slab, have shown that the two sides facing each other are essentially hexagonal It was punched out using a die and a punch that punches a blank having a shape in which each corner around the hexagon is rounded in an arc shape (hereinafter, a die and a punch are collectively referred to as a die in order to simplify the description). Unnecessary parts other than the blank part to be punched are reduced by cylindrical blanking of the blank, and ears are generated when the blank is formed into a cylinder Was low, it was found that efficiently can be a blank cutout.

(Embodiments) The present invention will be described in detail below with reference to embodiments. First, a circle (diameter: 2r = 150m)
m), a regular dodecagon and a regular hexagon (each diagonal length: 2r = 150 mm) as a basic shape, and each corner is rounded in an arc shape (curvature radius: R = 0 to 50 m)
The dies for punching out the three types of blanks of m) were prepared, and an experiment was performed on the yield (unnecessary portion generation rate) when punching from a long cold-rolled steel sheet using these dies. A long die rolled steel sheet having a constant thickness of 0.18 mm is pierced into a die having a cross section of each of the above figures so that the spacing between adjacent blanks and the margins at both ends in the sheet width direction are the same. Are arranged in a punching press so as to be arranged in two rows in a staggered manner in the longitudinal direction in the same number (n = 2, 3, 5, 7) in the plate width direction, and a long rolled steel plate is continuously connected to the punching press. It was punched out while supplying it. Table 1 shows the results.

[0009]

[Table 1]

As shown in Table 1, when a punching die for punching a circular blank is used, the yield increases as the plate width is increased and the punching dies are arranged in a zigzag manner in the plate width direction. When a punching die for punching a dodecagonal blank is used, the yield is improved as compared with the case of a circle. However, the number n of the dice arranged in the plate width direction,
And slightly different depending on the radius of curvature R in which the dodecagonal corner of the punched section is rounded in an arc shape, but 2%
Only a small increase in yield can be achieved. On the other hand, when using a punching die for punching a hexagonal blank, regardless of the number n of the dies arranged in the plate width direction and the radius of curvature R for rounding the hexagonal corner of the punched cross section into an arc shape, , Circles and dodecagons, higher yields are obtained. When punching with a blank having this hexagon as a basic shape, the yield varies depending on the radius of curvature R that rounds the corner of the punched cross section into an arc shape, and the yield decreases as the radius of curvature R increases. That is, there is an upper limit of the radius of curvature R for achieving the target yield. On the other hand, if the radius of curvature R is reduced, the yield is improved, but even if the anisotropy of the metal material or the drawing method is changed, a drawn can with a low ear ratio in the intended drawing cannot be obtained. That is, there is a lower limit of the radius of curvature R in terms of ear ratio. In addition,
As shown in Table 1, when the number n of the punching dies arranged in the plate width direction is 2 or less, the yield is low in any of the blanks of the circle, dodecagon, and hexagon, and the blanks are arranged in the plate width direction. The number n of the punching dies is preferably at least three or more.

Next, a punching experiment was conducted on the number of blanks obtained from a fixed amount of cold-rolled steel sheets. Punching dies having the above-described punching cross-sections for blanking blanks using a long cold-rolled steel sheet, and blanks having a rounded corner based on a regular dodecagon and a regular hexagon. Were carried out by arranging seven in the plate width direction. As for the circular blank, seven sets of dies having a circular cross section are prepared, and three sets are arranged in the front row so as to be on the same line in the direction perpendicular to the rolling direction of the cold-rolled steel sheet (the sheet width direction). The pair is set in the back row, the centers of the dies in the front and rear rows are arranged so as to be staggered in the direction (longitudinal direction) parallel to the rolling direction, and the dies are punched at equal intervals between the punching cross sections. Placed and attached to a punching press. The margins (side bridges) in the plate width direction were made equal at both ends. Continuous blank punching of 1 ton of cold-rolled steel sheet
33,000 blanks were obtained.

With regard to a blank having a regular dodecagon shape and a rounded corner, seven sets of dies for punching a blank having the same area as a circle are prepared, and three sets of dies are arranged in the front row, in a direction perpendicular to the rolling direction of the cold-rolled steel sheet ( (The width direction of the plate) and the other four sets are arranged in the back row, and the centers of the dies in the front and rear rows are arranged in a staggered manner in the direction (longitudinal direction) parallel to the rolling direction, The dies were mounted on a punching press so that the intervals between the pseudo dodecagonal blanks were equal to those of a circular blank and were punched at equal intervals. The cold-rolled steel sheet was the same steel type as that used for punching a circular blank, had the same plate thickness, and was adjusted so that the margin (side bridge) in the plate width direction was the same as in the case of punching a circular blank. One having a plate width was used. When one ton of the cold-rolled steel sheet was continuously punched out in this manner, about 33900 blanks were obtained.

With respect to a blank having a regular hexagon and a rounded corner, two sets of punching dies having different blank shapes to be punched were prepared, and two types of punching were performed.
First, so that the blank area is the same as the circle blank,
Radius of curvature / diagonal length after rounding corners: R / 2r = 0.0
6. Prepare seven sets of dies for punching blanks with rounded corners in step 6, and arrange three sets of front rows so that they are on the same line in the direction perpendicular to the rolling direction of the cold-rolled steel sheet (the sheet width direction).
The pairs are arranged in the back row, and the dies in the front and rear rows are arranged in a zigzag pattern in the direction (longitudinal direction) parallel to the rolling direction, and the intervals between the pseudo hexagonal blanks are the same as those of the circular blanks. It was attached to a punching press so as to be punched at intervals. The cold-rolled steel sheet has the same steel type and thickness as the one used for punching circular blanks, and the margin in the width direction (side bridge) is adjusted to be the same as for blank blanks. The one having the plate width set as described above was used. When one ton of the cold-rolled steel sheet was continuously punched in this manner, about 35700 blanks were obtained.

Next, it is considered that the blank can be formed at a low ear ratio when drawing a blank into a cylinder. The blank has a punched cross section of a regular hexagon with a large radius of curvature of the corner and a rounded corner. Punching was performed using a die.
That is, the radius of curvature / diagonal length after rounding the corners: R / 2r = so that the blank area is the same as the circular blank.
Seven sets of dies for punching blanks with rounded corners at 0.32 are prepared, and three sets are arranged in the front row so as to be on the same line in the direction perpendicular to the rolling direction of the cold-rolled steel sheet (the sheet width direction). Are arranged in the back row, and the centers of the dies in the front and rear rows are arranged in a staggered manner in the direction (longitudinal direction) parallel to the rolling direction, and the interval between the pseudo hexagonal blanks is the same as that of a circular blank. And attached to a punching press so as to be punched at equal intervals. The cold-rolled steel sheet has the same steel type and thickness as the one used for punching circular blanks, and the margin in the width direction (side bridge) is adjusted to be the same as for blank blanks. The one having the plate width set as described above was used. When one ton of the cold-rolled steel sheet was continuously punched in this way, about 34,700 blanks were obtained. As described above, when blanks having the same thickness and the same area are punched from the same amount of steel sheet, the blanks to be punched are formed into a basic shape of a circle or a regular dodecagon, and a basic hexagonal shape rather than a rounded corner is used. It was confirmed that by making the shape round, it was possible to greatly improve the yield of blanking.

As described above, the blanking section of the blank is a hexagon whose corners are rounded with a certain radius of curvature, and the number of punching dies arranged in the width direction of the blank is adjusted so that the highest yield can be obtained. By choosing
It turned out that it was possible to blank with the best yield. Further, in consideration of the production of a die for punching a blank, a die having a hexagonal punching cross section can be manufactured much more easily than a die having a hexagonal punching cross section.

Next, based on the above results, it has been confirmed that blanking using a punching die having a punching cross section of a regular hexagonal basic shape and a rounded corner is excellent in yield. Therefore, two types of long steel sheets of A and B shown in Table 2 were subjected to electrolytic chromic acid treatment, and a resin-coated steel sheet coated on both sides with a polyester resin was used as a test material, and a punching die having a circular cross section, and A circular blank and a regular hexagon shown below were used as a basic shape, and a circular blank and a regular hexagon were used as a basic shape using a punching die having a cross section in which the corners were rounded into an arc shape with various radii of curvature. As shown in FIGS. 1 and 2, a blank having a shape in which the corners are rounded into an arc with various radii of curvature is blanked from a long resin-coated steel sheet, and drawn. , It was molded into a cylindrical cans. [1] Circle (Fig. 1 (a)) Diameter (2r): 98mm [2] Regular hexagon (Fig. 1 (b)) Diagonal length (2r): 98mm (Diagonal length: after rounded corners) Rolling direction deviation angle (θ): 90 ° (angle formed by one side of a hexagon with respect to the rolling direction of the steel sheet, the same applies hereinafter) Radius of curvature of arc portion (R): 15 mm, 22 mm, 25
mm, 29 mm, 34 mm, 44 mm [3] Regular hexagon (FIG. 2 (c)) Diagonal length (2r): 98 mm Rolling direction deviation (θ): 75 °, 80 °, 85 °, 95
{, 100}, 105} The radius of curvature of the arc portion: 34 mm Conditions for blanking of 20 types selected from the above conditions,
Tables 3 and 4 show the ear ratios of the obtained cylindrical cans. Ear ratio is defined by the following equation. That is, the height to the bottom of the can was measured at the valley and the crest generated at the upper end of the created cylindrical can, and the average value was taken as the average height (H). When the height difference (ΔH) is used as an ear, the ear ratio is defined as follows: ear ratio = (ΔH / H) × 100 (%).

[0017]

[Table 3]

[0018]

[Table 4]

As shown in Table 3 and FIG. 1 (b), a punched cross section in which a regular hexagon is used as a basic shape, the above-mentioned deflection angle in the rolling direction is 90 °, and the corner is rounded in an arc shape. When blanking is performed using a die having the same, when blanking is performed using a punching die having a radius of curvature / diagonal length (R / 2r) of 0.25 or more, the blank is equivalent to a circular blank or a circular blank. It has been found that it is possible to draw a cylindrical can with anisotropy lower than the ear rate.

Also, as shown in Table 4 and FIG.
In the case where blanks are formed by arranging the two parallel sides of a regular hexagon of the punching cross section of the punching die in the rolling direction so that the declination in the rolling direction is slightly deviated from 90 °, rounding the corners into an arc shape, and blanking. If the deviation of the arrangement with respect to the vertical direction is within ± 10 °, the yield is not reduced, and the ear ratio is not so high. If it is within ± 5 °, a low ear ratio can be obtained with almost good yield. There was found.

Further, as shown in FIG. 3 (d), the corners are rounded in an arc shape such that a pair of opposite sides of a hexagon of a punching section of a punching die are not parallel to each other, and the blank is blanked. When taken, the degree of departure from parallel is small, and as long as they are substantially parallel, the ear ratio does not increase so much, and almost good ear ratio can be obtained.

Further, as shown in FIG. 3 (e), the length of each side of the hexagon of the punching section of the punching die is equal, the angle of a pair of opposite corners is equal, and the adjacent corners are equal. When the blank is obtained by rounding the corners into an arc shape so that the angles are different from each other, the ear ratio does not increase so much as long as the deviation of the arrangement from 120 ° where the adjacent corners are equiangular with each other is small, and almost good. Ear rate is obtained.

Further, as shown in FIG. 4 (f), the angles of the six corners of the punching section of the punching die are equal, and of the six sides, the length of two sides perpendicular to the rolling direction is set. Is arranged so as to be different from the length of the other four sides, and the corners are rounded in an arc shape and blanked, the ear ratio does not increase so much as long as the ratio of the different lengths is low, and the ear ratio is almost good. Is obtained.

Next, the test material A shown in Table 1 was formed by punching a die having a circular cross section (diameter: 160 mm) and a shape obtained by rounding the corners of a regular hexagon (diagonal length: 160 m).
m, R / 2r: 0.34), and blanking was performed using a die for punching. Next, a redrawing can having a can diameter of 80 mm was obtained by redrawing. The redrawn can was ironed at the same time as the redrawing to obtain a cylindrical drawn ironed can having a can diameter of 66 mm. Among the obtained drawn and ironed cans, cans formed from circular blanks have an ear ratio of 12.5% and a rounded R-shaped hexagon.
The ear ratio of the can molded from the / 2r blank was 14.0%, which was almost the same as the can molded from the circular blank.

[0025]

According to the present invention, there is provided a blank having a hexagonal shape whose two opposite sides are substantially parallel to each other from a metal plate, and each corner around the hexagon is formed in an arc shape. It is a blanking die of a blank for cylindrical drawing, characterized by punching out, by blanking the blank punched using the blanking die of the present invention,
Unnecessary portions other than blank portions to be punched are reduced, and the occurrence of ears when the blank is formed into a cylinder is reduced, so that material can be efficiently removed.

[0026]

[Brief description of the drawings]

FIG. 1A is a schematic diagram of a case where a circular blank is punched from a long metal rolled plate. (b) is a schematic diagram in the case where a blank having a regular hexagonal basic shape is punched from a long metal rolled plate so that an angle formed by one side of the hexagon with respect to the rolling direction of the steel plate is 90 °.

FIG. 2 (c) shows a blank having a regular hexagonal shape as a basic shape punched from a long metal rolled plate such that the angle formed by one side of the hexagon with respect to the rolling direction of the steel plate is shifted from 90 °. It is a schematic diagram in the case.

FIG. 3 (d) shows an angle formed by one side of a hexagon with respect to the rolling direction of a steel sheet from a long metal rolled sheet to a blank having a pair of opposite sides having a hexagonal shape that is not parallel to each other as a basic shape. Is a schematic diagram in the case of punching out to make 90 °. (e)
Rolling a steel plate from a long metal rolled plate, using a hexagonal basic shape with the same length on each side, a set of opposite corners at equal angles, and adjacent angles at different angles. It is a schematic diagram at the time of punching out so that the angle which one side of a hexagon with respect to a direction may become 90 degrees.

FIG. 4 (f) is a view from a long metal rolled plate in which the angles of six corners are equal, and of the six sides, the length of two sides perpendicular to the rolling direction is the length of the other four sides. FIG. 7 is a schematic diagram in a case where a blank having a hexagon different from the basic shape is punched so that an angle formed by one side of the hexagon with respect to the rolling direction of the steel sheet is 90 °.

[0027]

[Explanation of symbols]

2r: diameter or diagonal length θ: angle formed by one side of the hexagon with respect to the rolling direction of the steel sheet α: angle of one corner of hexagon in which adjacent angles are different β: angle of adjacent corners is different Other one of the hexagons
Angle of two corners a: Length of two sides perpendicular to the rolling direction of a hexagon in which six angles are equal b: Except for two sides perpendicular to the rolling direction of a hexagon in which six angles are equal Length of four sides

[Table 2]

Claims (3)

[Claims] 1. A cylindrical drawing blank having a hexagonal shape whose two opposite sides are substantially parallel to each other and having a punched cross section in which each corner around the hexagon is formed in an arc shape. Punching dies and punches. 2. In the punched cross section, a radius of curvature (R) of the circular arc and a diagonal length of a shape in which each corner around the hexagon is formed in an arc shape (relative distance after rounded corners) (R / 2r) ratio (R / 2r) of 0.15 to 0.4
5. The blanking die and punch for a blank for cylindrical drawing according to claim 1, wherein the punch is a die. 3. The punching die and punch for a cylindrical drawing blank according to claim 1, wherein the hexagon is a regular hexagon.