JP2014188550A - Cutting method of metal thin plate - Google Patents

Abstract

A metal sheet having a thickness of about 5 to 100 μm is cut with a cutting die to obtain a good cut surface quality. At the same time, it does not require strict clearance for the mold.
A curved surface chamfering portion having a curvature of 2.5 times or more the plate thickness is provided on one of a punch and a die of a die, and cutting is performed in a state in which the vicinity of the cutting portion is made to follow the chamfering portion. Solved the problem. The cross-sectional quality is substantially perpendicular to the wide surface of the thin metal plate, and almost no burrs are generated. In addition, the mold clearance is about 5 to 10 μm and does not require a narrow clearance that is particularly difficult to manufacture.
[Selection] Figure 2

Description

The present invention generally relates to a method for cutting a thin metal plate having a thickness of about 2 to 100 μm.

  As a method of forming a product from a thin plate, a method of punching a thin plate with a mold (punch and die) is generally used. Further, a method of punching by a rotary cutter method that rotates in opposite directions and has irregularities on the surface may be used.

  Various techniques for punching with a mold have been disclosed so far.

  For example, Non-Patent Document 1 shows an appropriate relationship between the thickness of a metal plate of a plate to be processed and the clearance between a punch for punching it and a die (punching hole), that is, a clearance. According to this document, about 5 to 10% of the plate thickness of the processed plate material is considered to be an appropriate clearance, and most of the metal plate cutting molds currently in use have this clearance ratio. Used.

  When this range is applied to a thin metal plate used for a lithium ion battery electrode material for which demand is currently increasing, an appropriate clearance is 1 μm to 2 μm with respect to a typical electrode material plate thickness of 20 μm. On the other hand, when manufacturing the mold, the clearance between the punch and the die is determined by the relative dimensions of the punch and the die, and managing the clearance is equivalent to managing the machining dimensions, and strictly controlling the machining dimensions of the punch and the die. It is important to manage. However, it is very difficult to manage the processing dimensions with an appropriate clearance (1 to 2 μm or less). Therefore, although this level of clearance is not feasible, manufacturing and management costs are significantly increased. Even if the processing dimension can be processed with this clearance, it is very difficult to maintain this clearance by using it continuously or intermittently.

FIGS. 5-1 and 5-2 show cutting forms using a general mold in which both the punch and the die have sharp edges (not chamfered). The clearance between the punch and the die was 1 μm, which is close to the lower limit at which the width C ₀ can be produced. This mold is extremely expensive to manufacture and maintain. The thin metal plate to be cut was a copper plate having a thickness of 20 μm. The punch P descended from above in FIG. 5-1, contacted the thin metal plate M, then fitted with the die D, and cut back and forth in the state of FIG. The cut surface is separated into the side that remains on the die and the side that falls out of the die hole. Both the side that remains on the die and the side that falls out of the die hole are close to a right angle to the wide surface of the thin metal plate, The occurrence was small. However, reducing the clearance in this way has difficulty in manufacturing and management as described above. Further, these costs depend on the shape and the like, but require several to several tens of times the cost of a mold having a clearance of 10 μm, which is easy to manufacture and manage.

Generally, the clearance of a mold that is easy to manufacture is about 5 to 10 μm. If a thin metal plate is cut with a mold having such clearance, the cutting itself can be performed, but the cutting of a thin metal plate with very low cutting surface quality is possible. Only the body cross section can be obtained. Although the schematic diagram of the state of a cut surface is shown in FIG.
1. 1. The cut surface is not perpendicular to the surface direction (= the wide surface direction of the thin metal plate). 2. A step is formed on the cut surface. One wide surface side is stretched by plastic deformation due to tension.

In order to improve the quality of the cut surface by cutting using a mold, the punch and die clearance can be reduced to, for example, about 1 μm or less. However, by reducing the clearance, the mold can be manufactured. Time, costs, management costs, etc. will rise significantly.

In other words, the problem of cutting thin metal sheets using the current mold is
(1) The appropriate width of the die / punch clearance decreases as the metal thin plate becomes thinner. For example, if the metal thin plate is 20 μm thick, the appropriate clearance is 1 to 2 μm, and if the metal thin plate is 10 μm thick, the appropriate clearance is 0.5 to 1 μm. (2) As described in (1) Manufacturing a mold with a clearance width, if not impossible, requires enormous manufacturing time, manufacturing costs, and maintenance costs.

Therefore, although cutting with a metal mold is not impossible at present, it is not a practical solution for cutting a thin metal plate.

  As another document, Patent Document 1 shows that a punch is chamfered for the purpose of preventing exposure of a non-plated layer by punching with a die for a workpiece whose surface is plated. Yes. The purpose of this document is to plastically deform the plated layer and cover the punched side surface. In this document, there is a description of the relationship between the plate thickness and the clearance (0008 clearance is about 20% of the lead thickness) and the chamfer size (0012, 0013), but there is no description about the plate thickness. As can be seen from FIGS. 1 and 5, the plate thickness is about 2 to 5 times the chamfer dimension.

Patent Document 2 discloses that when a lead is cut, the solder layer above the lead is plastically deformed, and the solder layer is plated from the upper edge to the lower edge of the cut surface. The punched portion 23 is chamfered for the purpose of covering a part of the solder layer 11 in the lead 10 direction. This document does not describe the values of the thickness, chamfer dimension, clearance, etc. of the cut product, but only describes that the clearance is about 10% of the thickness of the cut product.

Japanese Patent Laid-Open No. 11-031774 Japanese Patent Laid-Open No. 08-037262

Akira Hashimoto, “New work of press work and mold work”, 7th edition, Nikkan Kogyo Shimbun, April 30, 1975, p35

The present invention can be realized even in a die having a clearance of, for example, about 5 to 10 μm, which is easy to manufacture, while maintaining a high quality cut surface after cutting (1) in the cutting of a thin metal plate with a die. It was intended to be. This “high quality” means that no burrs are generated on the cut surface, and the cut surface is nearly perpendicular to the surface of the thin metal plate. A high-quality cut surface is generally required only on one side (product side) that has been cut, and the trim (uncut) side is not limited to this.

  In the present invention, when cutting a metal thin plate with a die having a punch and a die, one of the punch and the die is a sharp edge and the other is a die having a chamfered portion, and is sandwiched between the sharp edge and the chamfered portion. A thin metal plate is cut. At this time, the structure in the surface direction of the metal thin plate is maintained almost as it is as shown in FIG. 6 (right figure after cutting). The lines shown in the cross-sectional direction in FIGS. 6 and 7 do not actually exist, but are virtual lines for explaining the state of connection before and after cutting.

  The metal thin plate is particularly suitable for use on a plate that is homogeneous in the thickness direction, for example, a single material and does not have a special plating layer on the surface.

  The sharp edge refers to an edge that has not been chamfered and is processed by grinding or the like. Normally, the edge of the cutting die is a sharp edge for both the punch and die.

  In the present invention, attention is paid to the shearing direction and the direction of the metal sheet at the moment of cutting by shearing, and the shearing direction (cutting surface direction) and the center line of the surface direction of the metal sheet are cut at a right angle or near a right angle. The quality of the cut surface can be improved.

In order to make the cut surface perpendicular or close to right angle to the wide surface direction of the sheet metal (also referred to as the surface direction), the die or punch is provided with a curved surface with an appropriate size (especially R chamfering) to cut the sheet metal. It may be cut by generating a shear stress between the curved surface-carrying portion and the die or punch edge portion on the opposite surface with the thin metal plate sandwiched between the curved surface portion and the curved surface portion. In the present invention, this chamfer is provided at the edge of one side of the punch or die, and when cutting, the metal thin plate follows the elastic deformation, and the direction of the cut portion of the metal thin plate is substantially perpendicular to the cutting direction. Do. The cutting direction is a direction connecting one sharp edge of the die or punch and the vicinity of the point closest to the sharp edge at the other chamfer. At this time, the surface quality of the cut surface portion can be maintained by concentrating the plastic deformation occurring before cutting on the remaining cut portion (trim side).

In order to realize these, arc-shaped chamfering may be performed on one of the punch and the die. Alternatively, gentle chamfering including R chamfering may be performed. This “arc shape” does not necessarily mean a part of a circle, but may be a rounded smooth curve. Moreover, it is not necessary to provide similarly on the front end surface and the side surface of the punch. For example, as shown in FIGS. 8-1 to 8-3, the chamfer sizes of the front end surface and the side surface may be different. Different surfaces may be continuous. Further, there may be a straight (planar) portion in part. In any case, it is preferable that there is no sharp part so that a pressing mark does not remain by being pressed against the metal thin plate before and after cutting, and a smooth state is preferred.

The present invention has both of the following effects.
(1) The metal sheet can be cut after setting the clearance between the punch and the die relatively large, and the mold can be manufactured easily and inexpensively.
(2) The cut surface of the thin metal plate to be cut can be of high quality.

An example of the apparatus which performs the cutting method of the present invention is shown. 1 is an enlarged view of the main part. It is a schematic diagram of the form of cutting of the present invention It is a schematic diagram of the form of cutting of the present invention It is a schematic diagram of the form of cutting of the present invention It is a schematic diagram of the form of cutting of the present invention It is a schematic diagram of the form of cutting of the present invention It is a schematic diagram of the cutting | disconnection performed by the conventional method. It is a schematic diagram of the cutting | disconnection performed by the conventional method. It is a schematic diagram of the cutting | disconnection performed by the conventional method. Schematic diagram of cutting with a die with extremely narrow clearance Schematic diagram of cutting with a die with extremely narrow clearance State of thin metal plate after cutting performed by the method of the present invention State of the thin metal plate after cutting performed by the conventional method It is a schematic diagram which shows the some form of a chamfering part. It is a schematic diagram which shows the some form of a chamfering part. It is a schematic diagram which shows the some form of a chamfering part. It is a schematic diagram of a die and a punch used in Example 2.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic view of a mold, and main components are a punch P, a die D, and a thin metal plate M to be cut. The punch is movable in the direction perpendicular to the drawing, and the die is stationary and does not move. For cutting, a thin metal plate is installed on the upper side of the die drawing, and the punch is moved in the die (downward) direction so that the punch is inserted downward from above the position where the bottom surface of the punch and the upper surface of the thin metal plate are aligned horizontally.

  The apparatus used for the cutting method of the metal thin plate of this invention is demonstrated.

  This will be described with reference to FIGS. The punch P (hereinafter also referred to as “P” in the specification) has a convex portion toward the bottom of the drawing, and the die D (hereinafter also referred to as “D” in the specification). ) Has a die hole, and by fitting P and D, a thin metal plate M sandwiched between P and D (hereinafter also referred to as “M” in the specification) P and D This is a die that is punched and cut into a product shape similar to the outline of the product.

  This apparatus has a chamfered portion having a curvature of R (μm) in the chamfered portion r (hereinafter also referred to as “r” in the specification) at the edge portion corresponding to the product shape portion of P. doing.

  On the other hand, as for D, the edge part corresponding to a product shape has a sharp edge.

Also, P and D are the clearance CR between the die and the punch (the die and the punch are matched) with respect to the thickness t of the thin metal plate M to be cut (hereinafter also referred to as “t” in the specification) μm. The width of one side gap (which may be referred to as “CR” in the following description) is set to C ₁ (μm).

The chamfering curvature R (μm) of the chamfered portion r and the clearance width C ₁ (μm) between the die and the punch depend on the thickness t (μm) of the metal thin plate. It is desirable to satisfy one or both of the two relationships.

Formula 1 1 ≦ C ₁ ≦ 0.75 t (μm)

It is appropriate that the range of C ₁ particularly satisfies 1 ≦ C ₁ ≦ 0.75 t (μm). If C ₁ is less than 1 [mu] m, the die manufacturing and maintenance is is extremely difficult cost becomes high. Moreover, if it is larger than 0.75 times with respect to the thickness of the metal thin plate, there is a possibility that the shear stress at the time of cutting the metal thin plate is not sufficiently generated. If C ₁ is the range, while retaining a sufficient shearing stress, mold manufacturing and maintenance can be a clearance width is realistic.

Formula 2 2.5t ≦ R ≦ 50t (μm)

It is more suitable to set R to 2.5 t or more because if the curvature becomes smaller than this, many metal thin plates cause not only elastic deformation but also plastic deformation when following r. In the method of the present invention, it is better not to cause plastic deformation as much as possible in the product shape of the thin metal plate. On the other hand, if the upper limit value of R becomes too large, the fitting amount between the punch and the die becomes large, and it is difficult to adapt to an actual product, and the upper limit is about 50 t. If the size of R is 2.5t to 50t, the size of each mold member having an appropriate size can be obtained without causing plastic deformation to the product shape of the thin metal plate as much as possible.

  Next, the mode of cutting the thin metal plate M will be described with reference to FIGS.

  M is inserted with the punch P and the die D sufficiently separated. In this state, the punch advances downward toward the die side (FIG. 3-1).

During the progress, the thin metal plate M undergoes elastic deformation in the vicinity of the closest portion (Z ₁ ) between P and D along the chamfered portion r of the punch (FIG. 3-2). This elastic deformation is applied when t is sufficiently small as 100 μm or less, that is, a thin metal plate.

Further, an edge portion E1 of the to P descends D, the distance of the closest portion E2 of the E1 and P becomes smaller than t (the thickness of the sheet metal), at which point _{t x,} between E1-E2 Cracks occur and cuts the metal sheet. Although t _x varies depending on the material, there are many materials 0.5 to 0.95 times as large as t (note that E2 is present in the r portion of the punch). In other words, the fracture occurs when t is compressed by 5% to 50%. At this time, the metal thin plate M is elastically deformed along r, and the center line of the metal thin plate described by dotted lines in FIGS. 3-3 to 3-5 is the line connecting the E1-E2 It becomes almost right angle. Then, cracks are introduced and cut in a state connecting E1 and E2. (FIG. 3-3).

Thereafter, the punched and cut metal sheet is released from elastic deformation and returns to a flat state (FIGS. 3-4 and 3-5).
The cut surface is substantially perpendicular to the surface direction of the thin metal plate. On the other hand, the trim part T which is not a product shape is greatly plastically deformed, and the cross-sectional state is a state in which the central part in the cross-section protrudes (FIG. 6).

The thickness of the metal sheet to be cut and connected according to the present invention is a metal sheet having a thickness of about 2 to 100 μm. In general, the thickness of a thin metal plate that can be easily manufactured is about 2 μm at least. Further, when the metal thin plate is 100 μm or more, both P and D can be manufactured with a die having a sharp edge at the edge corresponding to the product shape portion, and the clearance width C ₁ is 5 to ₁₀ μm. The need to use is not high. In addition, when the thickness of the plate to be cut exceeds 100 μm, many metal plates are less likely to be elastically deformed along the chamfered portion r. Therefore, the chamfering of P as shown in FIGS. 3-2 and 3-3 is performed. It becomes difficult to make the metal thin plate follow the elastic region.

  In the present invention, attention is paid to the shearing direction and the direction of the thin metal sheet at the moment of cutting by shearing, and the cutting is performed so that the shearing direction (cutting surface direction) and the center line of the surface direction of the thin metal sheet are perpendicular or close to a right angle. By doing so, the quality of the cut surface could be improved.

To make the cut surface and the surface direction of the metal sheet perpendicular or close to right angle, the die or punch should be provided with a curved surface with an appropriate size (R chamfering), and the metal sheet should be imitated with this curved surface before cutting. What is necessary is just to cut | disconnect by elastically deforming and generating a shear stress between the curved-surface-carrying part and the edge part of die | dye or punch in an opposing surface on both sides of a metal thin plate.

In the above description, the die is fixed and the punch is movable up and down for the sake of explanation. However, as is apparent from the embodiment of the present invention, the die and the punch can be moved in the same manner, or both can be moved. Similarly, the punch has been chamfered and the die has been described as having a sharp edge, but the die can be chamfered and the punch can be similarly sharpened. Further, although an example has been given in which the punch is positioned upward and the die is positioned downward, the positional relationship is not limited to the illustrated direction, and any method can be used.

(Conventional cutting method)
For comparison with the present invention described above, FIG. 4-1 shows a conventional cutting method using a die having a sharp edge in both the die and punch and having a clearance of about 10 μm. This will be described with reference to -4-3.

FIGS. 4-1 to 4-3 are schematic diagrams when C ₁ is the same as FIG. 3 and t is the same.

When the edge portion corresponding to the product shape portion of P is a sharp edge, the metal thin plate M is in contact with P and M in the vicinity of the closest portion (Z ₂ ) of P and D when compared with the method of the present invention. The sharp edge E3 of the punch and the sharp edge E4 of the die are close to each other without being elastically deformed (FIG. 4-2) and cut after plastic deformation. Therefore, the cutting direction is not perpendicular to the line connecting E3 and E4 and the dotted line which is the center line in the thickness direction of the thin metal plate, and is cut with an angle α. Further, in the process where the metal thin plate is crushed between E3 and E4 before cutting, the front and back surfaces near the cutting portion are drawn into the cutting portion and plastically deformed (two S portions in FIG. 4-3).

As a result, as shown in FIG. 4-3, the cut surface of the cut metal sheet is plastically deformed on one side of the surface of the metal sheet, and is not perpendicular to the direction of the metal sheet. Further, in the cut metal sheet, one of the metal sheet surfaces is plastically deformed, and the cut surface is inclined with respect to the metal sheet surface direction.

Example 1
The first embodiment of the present invention will be described below.

The cutting method of the present invention was carried out with the apparatus shown in FIG. The thickness of the metal sheet M is 20 [mu] m, R dimension of the chamfered portion r of the edge portion of the punch P is 100 [mu] m, the width _{C 1} of the clearance CR punch and the die is 10 [mu] m. The die has a product-shaped sharp edge. It is easy on the mold manufacturing for the C ₁ and 10 [mu] m.

  The metal thin plate to be cut was tested using aluminum, copper, and titanium.

As test conditions, 3000 shots were punched and cut 18 shots per minute. When the cut surface of the product shape (the punched portion) of the thin metal plate after cutting was observed, the product shape side was substantially perpendicular to the metal thin plate surface direction as shown in FIG. Moreover, there was no unevenness in the cross section and thickness, and it was cut while maintaining the cross-sectional properties. Furthermore, even when the metal thin plates cut at the first shot and the 3000th shot were compared, the cut surfaces did not change. After the test was completed, even if the metal molds from which any of the metal thin plates were removed were observed, no breakage or adhesion of the metal thin plates occurred, and it was normal.

(Example 2)
FIG. 9 is a diagram showing a cutting method of the present embodiment, in which the thickness of the metal thin plate M is 100 μm, the R dimension of the chamfered portion r provided on the die D of the mold is 300 μm, and the punch has a sharp edge. clearance _{C 1} punch and the die is 40 [mu] m. The metal thin plate M is an aluminum electrode foil for a lithium ion electrode.

As test conditions, punching and cutting of 30 shots per minute were performed 5000 shots. When the cut surface of the product shape (the punched portion) of the metal sheet after cutting was observed, it was almost perpendicular to the direction of the metal sheet surface. Further, even when the metal thin plates cut at the first shot and the 5000th shot were compared, the cut surface did not change. After the test was completed, the used mold was observed, and no damage or adhesion of the metal thin plate occurred and it was normal.

(Example 3)
The other conditions are the same as in Example 1 except that the thin metal plate M is a foil for lithium ion electrodes and the thickness is 8 μm, the R dimension of the chamfered portion r provided on the punch is 30 μm, and the clearance CR between the die and the punch is CR the width _{C 1} was 5 [mu] m.

  For reference, when a die having both sharp punches and dies having a sharp edge is used for cutting the thin metal plate, the required clearance is about 0.4 to 0.8 μm, and the die manufacture becomes extremely difficult. .

Under the test conditions of this example, 1000 shots were punched and cut for 10 shots per minute. When the cut surface of the product shape (the punched portion) of the thin metal plate after cutting was observed, the cut surface of the copper foil was substantially perpendicular to the surface of the thin metal plate. Even when the first shot and the 1000th shot were compared, the cut surface did not change. After the test was completed, the used mold was observed, and no damage or adhesion of the metal thin plate occurred and it was normal.

P Punch D Die CR Clearance C ₁ Clearance width r Chamfered part R Chamfered part curvature M Metal sheet (material to be cut)
t Thickness of the thin metal sheet t _x Thickness of the thin metal sheet T at the time of cutting Near the closest part of the punched and trimmed Z ₁ , Z ₂ P and D α Angle between the cutting direction and the center line of the thickness of the thin metal sheet

Claims (7)

It is a method of cutting a thin metal plate with a mold having a pair of punches and dies corresponding to the cutting shape,
One of the punch and die has a chamfer, the other has a sharp edge,
A method for cutting a metal thin plate, in which a metal thin plate sandwiched between the chamfered portion and the edge is cut while maintaining a state in a thickness direction of the metal thin plate before cutting by fitting a punch and a die.   The method of cutting a thin metal plate according to claim 1, wherein a cut portion of the thin metal plate at the time of cutting is in an elastically deformed state along the chamfered portion of the punch and die.   The angle of the center line with respect to the thickness of the thin metal plate at the cut portion that is in an elastically deformed state at the time of cutting is perpendicular to or close to a right angle with respect to the crack generation angle connecting the sharp edge and the chamfered portion. The method for cutting a thin metal sheet according to the description. The thickness t (μm) of the metal thin plate is
2 ≦ t ≦ 100 (μm)
The method for cutting a thin metal plate according to any one of claims 1 to 3.   The method for cutting a thin metal plate according to any one of claims 1 to 4, wherein the thin metal plate is homogeneous in a thickness direction. The chamfered portion is an R chamfer, and the R dimension (μm) representing the curvature is 2.5 t ≦ R ≦ 50 t (μm) with respect to the metal thin plate t (μm).
The method for cutting a thin metal plate according to any one of claims 1 to 5, which satisfies the relationship: The clearance width C ₁ between the punch and the die is 1 ≦ C ₁ ≦ 0.75 t (μm) with respect to the thickness t (μm) of the metal thin plate.
The method for cutting a thin metal plate according to any one of claims 1 to 6, which satisfies the relationship:

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