JP2015188966A - Mold for punching thin plate, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching mold with extremely small clearance, capable of punching a plate which is a cut object with extreme thinness of a few or few tens of micrometers, with an extremely small amount of burrs and flashes on a cut surface, and provide a method of manufacturing the mold at a low cost and a punch tip at an extremely low cost.SOLUTION: First, a tip thin plate 6 connected to a punch base material P1 is punched with the use of a punch base material P1 of a punch P and a die hole D1 of a die D. The tip thin plate 6 becomes a punch thin plate P2 provided on the punch base material 1, and constitutes a punch P with extremely small clearance from the die hole D1, in coordination with the punch base material P1. Then an extremely thin plate with thickness of a few or few tens of micrometers, which is a cut objects, is punched with the use of the obtained punch P and die D.

Description

The present invention relates to a thin plate punching die for punching a sheet-like workpiece by a reciprocating motion on a relative axis of a punch and a die.

For example, in the process of punching a large number of identical shapes from an object to be cut as thin as 5 to 100 μm (hereinafter sometimes simply referred to as “work”), punching die is punched by linear reciprocating motion of the punch and die. In many cases, a method (hereinafter simply referred to as “mold”) is used. There are various materials for the workpiece, and examples thereof include a metal foil, an extremely thin resin material, a thin film, or a material in which an inorganic material is laminated thereon.

Punching dies are often inferior in the maximum speed of operation compared to the rotary cutter type punching device, but it does not cost to manufacture and does not require large-scale equipment. It is possible and effective.

  One of the main points in manufacturing a punching die is the size of “clearance”.

  Clearance refers to the width of the gap when the punch and die are in a fitted state. The allowable range for the width setting varies greatly depending on what kind of work is used. Although it is one standard, Non-Patent Document 1 has a description that “5 to 10% is an allowable range with respect to the thickness of the workpiece (workpiece)”. If it is within this range, good cutting can be performed. However, if a clearance is provided beyond this range, the workpiece is deformed by being caught between the punch and the die, or large burrs or burrs are formed at the end of the cut surface. And the quality is significantly reduced.

  When designing and manufacturing a punching die, the size of the clearance greatly affects the manufacturing cost. Naturally, as the workpiece becomes thinner and the required accuracy increases, the manufacturing cost increases because precise processing and alignment are required. In general, the manufacturing is easy if the clearance is 20 μm or more, the manufacturing cost is slightly increased if the clearance is about 10 to 20 μm, the cost is very high if the clearance is 10 μm or less, and the manufacturing itself is difficult if the clearance is 5 μm or less.

On the other hand, when the thickness of the workpiece is 5 to 100 μm, for example, if the numerical value of Non-Patent Document 1 is used, the appropriate clearance is 0.5 to 10 μm at the maximum. This is a value that requires a special cost or makes it difficult to manufacture.

Patent Document 1 discloses a method of punching without fitting a punch and a die when an intermediate such as a resin overlapped with a workpiece is used or when the workpiece itself has a non-metal layer. This method does not necessarily fit, so it is not necessary to strictly control the clearance between the die and the punch, but it is necessary to prepare an intermediate for cutting when the workpiece has a laminated structure with a non-metal layer. There is a problem that it cannot be applied or the cost required for punching increases.

International Publication No. WO2010 / 013818

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

  If the workpiece is an extremely thin metal foil, resin, film, or a laminate of inorganic materials, it is difficult to punch it well with a general mold with burrs and burrs suppressed. is there. This is a problem of allowable clearance, and as the clearance becomes narrower, it becomes difficult to manufacture the mold and the manufacturing cost increases.

In order to solve this problem, a method using an intermediate has been proposed. However, as described above, the punching cost is inevitably increased.

The present invention can obtain a die for punching a thin workpiece satisfactorily without increasing or lowering the manufacturing cost of the die itself, the punching cost of the workpiece, and the punch tip of the die. The purpose is to do.

The punching die according to the present invention is
A punching die for punching a thin workpiece by relative movement on one axis of a punch and a die,
A punch base material portion in which the punch is not in direct contact with at least the workpiece;
A punch tip joined to the punch base material and in contact with the workpiece;
The above-mentioned problem has been solved by making the punch tip part a punching die obtained by punching a thin plate with the punch base and the die.

The present invention also proposes a method for manufacturing the mold at a low cost.

  According to the mold of the present invention, the clearance between the punch and the die can be reduced to about 0 to 10 μm, more preferably 5 μm or less at an extremely low cost, and a thin work such as a metal can be cut into burrs and burrs extremely small. It becomes possible.

In addition, according to the mold manufacturing method of the present invention, a mold having a very small clearance between the punch and the die can be manufactured at low cost. Furthermore, the replacement cost when the punch is worn is extremely low, and the replacement can be performed in a short time.

Schematic diagram of the entire mold of the present invention Detailed schematic diagram of die punch of the present invention Schematic diagram of thin plate joined to punch substrate Schematic diagram of the method for forming punch thin plates Schematic diagram of punching of the present invention Allowable size of punch dimensions of the prior art and the present invention Schematic diagram of punch plate formation with different clearances Example of desired workpiece punching shape Schematic diagram of workpiece punching with the mold of the present invention Photograph of the punch tip (P1, P2) of the present invention Cut surface photograph of aluminum foil punched with the punching die of the present invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of the entire punching die 100 of the present invention. The punch or die moves relatively in the uniaxial direction (vertical direction in the figure), and when the two approach each other, the workpiece W sandwiched therebetween is punched and cut.

  P is a punch and D is a die. The outer shape of the punch P and the inner shape (die hole) of the die D have substantially the same shape as the shape to be punched.

  As shown in FIG. 2 near the tip, the punch P has a punch base P1 and a punch thin plate P2 at the tip.

  The punch base material portion P1 has a cross section having a shape similar to the shape in which the workpiece W is desired to be punched, and the end surface is desirably in a state where an edge stands, that is, a so-called “pin angle” state. This is because if there is chamfering, the workpiece being cut follows it, and the cut surface may be disturbed by plastic deformation.

  Details of the punch thin plate P2 at the punch tip will be described later.

  The die D has a concave die hole D1 in a shape in which the workpiece W is to be punched. The die hole D1 is a portion recessed from the flat surface 2 (indicated by a dotted line) of the die shown in FIG. The edge of the die hole D1 is also not chamfered, and a so-called “pin angle” state is desirable. If there is chamfering, the workpiece being cut follows it, and the cut surface may be deformed. Similarly to the punch, the edge of the die hole D1 has a shape similar to the shape in which the workpiece W is to be punched.

  The punch and die punch and cut the workpiece W sandwiched between them by fitting the punch P and the die hole D1.

  Next, the punch thin plate P2 at the punch tip will be described.

  The thin plate 6 is fixed to the tip of the punch base material P1. As an example, FIG. 3 shows a schematic diagram in which a rectangular thin plate 6 is fixed to the surface of the punch base P1. The fixing means may be a known means such as adhesion or brazing (the fixing portion is 3 in FIG. 3). However, since it will be peeled off later, a method that is easy to attach and detach is desirable.

  The thickness of the thin plate 6 is not particularly limited, but needs to be a thickness that can be punched by the punch base P1 and the die D. Therefore, in reality, the thickness is about 5 to 500 μm. Further, the punch base P1 and the die are punched out in a state where the punch base P1 does not fit into the die hole D1 and the thin plate 6 fits into the die hole D1. Therefore, if it says from this surface, the conditions that the thickness of the thin plate 6 is thicker than the shortest distance in operation of the punch base material P1 and the die hole D1 are added.

  As shown in FIGS. 4 (1) to (4), in a state where the thin plate 6 is fixed to the tip of the punch base P1, the thin plate 6 is first punched out with the punch base P1 and a die. In this case, a thin intermediate such as resin may be used between the thin plate 6 and the die hole D1. By punching, the thin plate 6 at the tip of the punch base P1 remains, and the other part of the metal plate (the punched residue 5) is separated, so that it is removed as it is. At this time, the punch base P1 is not fitted into the die hole D, and only the thin plate 6 is fitted and punched. The amount of fitting is greater than 0 and less than or equal to the thickness of the thin plate 6.

In this way, the tip thin plate 6 is provided at the tip of the punch base P1. Since the thin plate 6 is already fitted in the die hole D1, the thin plate 6 and the die hole are in a fitted state as shown in FIG. This thin plate 6 becomes the punch thin plate P2. Further, this “base material P1 + punch thin plate P2” becomes the punch P.

  A detailed schematic diagram of the punch is shown in FIG.

  First, the punch base material P1 needs to have the same contour shape and edge contour shape as the die hole D1. However, since the punch base P1 and the die hole D1 are not fitted and in contact with each other, it is not necessary to strictly match the shapes, for example, within a few μm. It is only necessary to have the same edge shape as that of the die hole D1 within 30 μm. With this accuracy, it can be sufficiently shaped and processed at low cost with a general industrial processing machine without requiring special processing.

  Next, the tip thin plate P2 of the punch (or expressed as “punch thin plate P2”) will be described.

As described above, the punch thin plate P2 is provided at the tip of the punch base P1. The punch base P1 and the punch thin plate P2 are integrated by means such as bonding or brazing as shown in FIG. 3 before punching and forming the punch thin plate P2. In this state, it is formed by punching the thin plate 6 for the punch thin plate P2. As described above, the thickness of the thin plate 6 is larger than the shortest distance between the punch base P1 and the die hole D1. Therefore, when the thin plate 6 is punched, the thin plate 6 enters the inside of the edge of the die hole D1, and the thin plate 6 and the die hole D1 are in a fitted state. At this time, the thin plate 6 is accurately punched by the dimensional shape of the die hole D1 in order to fit with the die. The schematic diagram at the time of punching is shown in FIGS. In this way, the punch thin plate P2 fitted into the die hole D1 can be obtained very easily by punching the thin plate 6 to form the punch thin plate P2. Further, since the punch thin plate D2 is once fitted to the die, it is punched into a shape very close to the die hole. In the first place, in the punching die, when the outer shape of the punch is different from the inner shape of the die, the workpiece to be punched is punched according to the shape of the die. Therefore, according to this method, the punch thin plate P2 does not come into contact with the die, or strictly speaking, even if it comes into contact with the die, the interference can no longer be extended, and the ideal shape can be obtained with the clearance reduced to the limit.

  The ease of formation of the punch thin plate P2 will be compared with the prior art.

  In the prior art, since the punch and die are each machined and manufactured, it takes a lot of time to manufacture, assemble and position the mold in order to reduce the clearance. Specifically, grinding the mold, actually assembling the punch and die, disassembling after seeing the fitting condition, and further grinding the mold for clearance adjustment Must be repeated. Only when this is repeated, a mold having a clearance of, for example, 5 μm or less can be obtained.

  In addition, once the punch or die is worn or chipped, the mold becomes unusable, and it is necessary to start over from grinding. During such repairs and adjustments, the die cannot be used, and therefore the workpiece punching line must be stopped for a long time, which is problematic in use.

  On the other hand, according to the mold of the present invention and the manufacturing method thereof, it is not necessary to perform any special work in order to narrow the clearance. As described above, in the prior art, the clearance setting of the mold is accompanied by a large manufacturing cost as the clearance becomes narrower. In the first place, the mold of the present invention does not need to narrow the clearance between the punch of the mold and the die. It is sufficient if the punch thin plate is punched out when the punch base material and the die are not fitted. Further, since the punch base portion and the die do not fit in the first place, it is not necessary to make the inner diameter of the die larger than that of the punch, and the outer diameter of the punch may be larger. The allowable clearance between the punch base and the die is about ± 30 μm. If it is this range, the thin plate used as a front-end | tip thin plate can be punched according to the shape of die | dye. Since the punched-out tip thin plate is fitted with the die when punched, it has a shape with a very small clearance from the die.

  FIG. 6 shows a conventional technique in which a punch thin plate is not used and a die base material of the present invention using a punch tip thin plate is allowed with a die as a reference (origin 0 μm). An example in which the thickness of the workpiece is 20 μm is shown. FIG. 7 is a schematic diagram of the punch tip formed when the clearance is positive (1), zero (2), and negative (3). From the comparison between the two, it can be confirmed that the manufacturing ease of the mold of the present invention is excellent.

  Also, with a conventional mold, it is very difficult to replace the punch. Since the die and the punch are manufactured while making corrections to reduce the clearance between the die and the punch, the punch and the die cannot maintain a clearance with other individuals, and become a so-called “one-point object”. Therefore, replacement is not easy, and as a result, a hard material such as a cemented carbide having high wear resistance is used for both the punch and the die. However, a hard material used for a mold generally has a trade-off relationship that chipping resistance is reduced when the hardness is increased. If a material with high hardness is used to reduce the replacement frequency, the risk of chipping increases, and if a material with low hardness is used, replacement is necessary due to wear. There is a need to choose one of these.

  On the other hand, with the metal mold of the present invention, the replacement of the punch tip is very simple and can be performed in a short time. Further, since the punch can be easily replaced, the punch material and the die material can be combined with each other such as a soft punch and a hard die. By doing so, it is possible to operate on the premise that the punch (tip member) is replaced, and the tip of the punch can be changed in one day, changed in 300 shots, or the like. Unlike conventional molds, it can respond to punch wear and breakage very quickly, and the operating rate as a workpiece punching device can be remarkably increased.

  Although the material of the thin plate 6 depends on the material of the workpiece W, it is more suitable to use a hard metal such as stainless steel, copper, tool steel or plastic. Since the punch thin plate P2 is in direct contact with the workpiece W and applies a shearing force, wear occurs in the vicinity of the edge portion by repeated use. Therefore, these materials that are resistant to wear are suitable. In addition, a material whose edge shape collapses during punching or a material that is difficult to punch is also not preferable. Therefore, a material that is harder than the material of the workpiece W and softer than the material around the die hole D1 is most preferable for the reason described later.

  When the punch thin plate P2 is worn and the cross-sectional quality of the punched workpiece W cannot be maintained, the punch thin plate P2 may be peeled off from the punch base P1, and a new thin plate 6 may be joined and punched. That is, the replacement of the punch P is not only costly but can be performed in a very short time as compared with the case of manufacturing a punch with a newly adjusted die D and clearance.

  The material of the punch base P1 may be any material that is less deformed when stress is applied and can penetrate the thin plate 6. For this reason, for example, an iron material that is not expensive to manufacture is sufficient, and if a long-term specification is considered, a harder cemented carbide can be used.

The material around the die hole D1 is preferably a material that is not easily deformed in order to maintain a sharp edge necessary for punching the workpiece W. Further, unlike the punch base material P1, when a shearing force is applied to the workpiece W, it is a part that is always subjected to stress, so that the wear environment is likely to be worn. Further, since the replacement is not as easy as the punch thin plate P2, it is preferable to use a material with as little wear as possible. Therefore, it is desirable to manufacture the periphery of the edge of the die hole D1, at least several millimeters from the edge, with cemented carbide, tool steel, ceramics, etc., and further with a ceramic coating such as DLC (diamond-like carbon) or TiN. Also good. As for wear, since it is used in a state in which it is most likely to proceed among the punch base P1, the punch thin plate P2, and the die hole D1, a material having higher hardness than the punch base P1 and the punch thin plate P2 should be used. Is suitable.

Summarizing the hardness of each member described above, when the hardness is expressed by Rockwell hardness A scale (HRA), it is suitable to make the material constituting the die hole D1 the hardest. Since the punch thin plate P2 is subjected to the same stress as the material constituting the die hole, a material that is hard to some extent is desirable.
1. 1. It is necessary to punch through the punch base P1 and the die hole D1. The punch thin plate P2 does not need to be as hard as the material constituting the die hole D1 because it can be easily replaced.

Further, the punch base material P1 is not directly used for punching the workpiece W, and it is sufficient if the thin plate 6 can be punched when the punch tip is replaced. Therefore, a material that is equal to or less rigid than the punch thin plate P2 can be selected. Therefore, the value of the material constituting the die hole D1 on the Rockwell hardness A scale is H _D (HR _A ), the punch base P1 is HP ₁ (HR _A ), and the punch thin plate P2 is _{HP 2} (HR _A )
H _D > H _P2 ≧ H _P1
It is most desirable from the viewpoint of manufacturing cost and parts replacement.

In addition to the combinations described above,
H _D ≧ H _P1 > H _P2
There are cases where a combination satisfying the above is effective.

This combination is characterized in that the hardness of the punch base P1 is equal to or less than that of the die D and higher than that of the punch thin plate P2. Die D has the highest hardness for the same reason as above,
By increasing the hardness of the punch base P1, the punching die can be used without processing the punch base P1 itself for a longer period of time. In addition, when a hard material or a thick material is selected as the punch tip P2, it is necessary to make the punch base material P1 a hard material to some extent. This combination is particularly effective when the workpiece is made of a material that is relatively difficult to punch, such as copper or stainless steel, or a lead frame material.

As for the workpiece W to be punched out, a good cutting quality can be obtained even if it is a metal thin plate of about 5 to 100 μm, a thin resin, an inorganic sheet, or a workpiece W on which a coating agent is applied.

(Example 1)
(Formation of punch tip (punch thin plate))
An iron plate having a thickness of 20 μm was prepared as a workpiece, and a die and a punch were prepared in order to punch out an L-shaped part W1 as shown in FIG.

  The punch and die were made of hardened steel (SKD-11) at the punch base material. The outer diameter of the L-shaped punch part P1 is set to a shape whose outer periphery is about 15 μm larger than the shape in which the workpiece W is desired to be punched.

  A punch base material, a die, and a vertically movable mold unit were mounted, and the shapes of both were adjusted so as to coincide on the axis. This mold unit has a structure in which only the punch side moves up and down without moving the die side.

  Next, the bottom dead center of the punch base was adjusted to a height of 15 μm from the flat surface of the die.

  In this state, as shown in FIG. 3, a uniform iron plate 6 having a thickness of 25 μm cut out in a square shape was attached to the tip of the punch base material with an adhesive. Iron plate and hardened steel (SKD-11) are harder in the latter.

  The punch was lowered to the bottom dead center while the iron plate 6 was stuck to the end face of the punch base D1. As a result, the plastic plate 6 was punched, and the bonded portion remained attached to the end surface of the punch base D1.

  A part of this punch portion was photographed with a CCD camera. A photograph is shown in FIG.

The plastic plate 6 was stuck to the end surface of the punch base material P1, and the iron plate 6 was punched into the same outer shape as the inner surface of the die and had a sharp edge.

(Work punching)
An aluminum foil W having a thickness of 20 μm was inserted as a workpiece W on the edge surface of the die, and the punch located above was lowered to the bottom dead center as shown in FIG.

  After the punch was lowered to the bottom dead center and raised again, the punched workpiece was taken out. The aluminum foil W was punched into an L shape, and the size thereof substantially coincided with the shape of the die hole D1. Further, as shown in the photograph (FIG. 11), the cut surface was in a good state with no noticeable burrs and burrs.

  Up and down movement of the punch and accompanying insertion and removal of the workpiece W for one up and down movement were repeated continuously, and 500 shots were punched. At that time, the vertical movement of the mold was interrupted, and the punch portion P was observed.

  Since the iron punch thin plate was worn by several μm, it was peeled off from the bonded portion. Subsequently, an unused plastic plate 6 having the same thickness was attached to the punch base material portion as before, and punched out as it was to obtain a new punch thin plate P2. Similarly to the first punch tip member, the replaced punch thin plate P2 was able to cut the workpiece with an excellent cutting surface.

Similarly, the periphery of the die hole D1 was also observed. However, since the hardness is larger than any of the aluminum foil W, the punch base material P1, and the punch thin plate P2, the wear amount is small, and replacement is necessary. There was no need.

(Example 2)
The other conditions were the same as in Example 1, and only the matters described below were changed.
(1) Change the material of the punch base material from hardened steel SKD11 to carbon steel S45C. (2) Change the material of the thin plate at the punch tip from stainless steel to hardened steel SK material, and change the thickness of the thin plate from 25 μm to 50 μm. (3) The material of the workpiece is changed from aluminum foil to a resin sheet (polypropylene material), and the thickness is changed from 20 μm to 10 μm. The material of the die is not changed with cemented carbide, and the hardened steel SK is carbon steel S45C. Harder than.

When the workpiece was punched under these conditions, it was possible to obtain a cut cross section having almost no burrs and burrs and having no collapsed structure. Regarding the life, since a slight amount of wear was observed at the tip of the punch when punching out 1 million shots satisfactorily, it was peeled off from the bonded portion and removed. Subsequently, an unused SK plate with the same thickness was pasted on the punch base as before, and the SK plate was punched out with the bottom dead center and other settings intact, to obtain a new punch tip thin plate P2. . The time required for the exchange was about 10 minutes, and the punch tip P2 after the exchange was able to cut the resin material with an excellent cut surface, like the first punch tip. The replacement time was extremely short, and the replacement was possible without incurring costs.

P Punch P1 Punch base material part P2 Punch tip part D Die D1 Die hole D2
W Workpiece (material to be cut)
W1 Workpiece punching shape 1 Mold frame 2 Die flat surface 3 Punch base part P1 and thin plate joint 4 Punch moving direction 5 Workpiece punch 6 Thin plate 7 Punched work 100 Mold of the present invention

Claims (10)

A punching die for punching a thin workpiece by relative movement on one axis of a punch and a die,
A punch base material portion in which the punch is not in direct contact with at least the workpiece;
A punch tip joined to the punch base material and in contact with the workpiece;
The punch tip is a punching die obtained by punching a thin plate with the punch base and the die.   The punching die according to claim 1, wherein a clearance between the punch tip portion and the die is more than 0 µm and 10 µm or less.   The punching die according to any one of claims 1 and 2, wherein the punch tip portion and the punch base material are bonded by an adhesive.   The punching die according to any one of claims 1 to 3, wherein the punch tip is one of iron, stainless steel, copper, and hard plastic.   The punching die according to any one of claims 1 to 4, wherein a thickness of the tip of the punch is in a range of 5 to 500 µm. The thickness of the punch tip is
The punching die according to claim 5, wherein the punching die is larger than the shortest distance between the punch base material and the die during punching motion.   The punching die according to any one of claims 1 to 6, wherein a clearance between the punch base and the die is in a range of -30 m to 30 m. Rockwell hardness A scale of the punch base portion _H P1 _(HR A),
Rockwell hardness A scale of the punch tip is _{HP 2} (HR _A ),
When the Rockwell hardness A scale of the material constituting the die is expressed as H _D (HR _A ),
H _D > H _P2 ≧ H _P1
The punching die according to any one of claims 1 to 7, which satisfies the relationship: Rockwell hardness A scale of the punch base portion _H P1 _(HR A),
Rockwell hardness A scale of the punch tip is _{HP 2} (HR _A ),
When the Rockwell hardness A scale of the material constituting the die is expressed as H _D (HR _A ),
H _D ≧ H _P1 > H _P2
The punching die according to any one of claims 1 to 7, which satisfies the relationship: Using a punch substrate and a die having a clearance of −30 μm to 30 μm, at least the following 1. To 3. The manufacturing method of the punching die which has these processes.
1. 1. a step of setting the distance between the punch base and the die closest to 0 to 100 μm or less A thickness of 5 to 100 μm on the tip surface of the punch substrate; 2. Joining thin plates that are thicker than the closest distance at A process in which a punch base member and a die are relatively approached on one axis, and all or a part of the thickness of the thin plate portion is fitted to the die, punched, and punched chips are removed to obtain a punch tip member.

Images