JP2019177417A - Punch hole formation method and punch hole formation device - Google Patents

Abstract

To provide a punch hole formation method and a punch hole formation device capable of preventing temperature of a workpiece from decreasing by a processing tool when the workpiece is die-cut by the processing tool to form a hole.SOLUTION: In a punch hole formation method, a workpiece O that is a plate-like member having a thickness of 0.01 mm or larger and 1 mm or smaller is placed on a die 10, when the workpiece O is die-cut by a punch 20 in a thickness direction to form a hole, the temperature of the workpiece O at least during the hole is being formed is maintained to a temperature TO at which the workpiece O can be die-cut.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a punch hole forming method and a punch hole forming apparatus for punching holes in a substrate.

  When a hole is provided in a workpiece to be punched, generally, the workpiece is placed on a die and the hole is provided in the workpiece by punching. Patent Document 1 discloses a hot forging technique in which a workpiece is heated to reduce the deformation resistance of the workpiece, that is, the hole is punched by increasing the deformability. When the workpiece is heated in this manner, the wear of the punch, burnout, and the like occur due to the temperature of the heated workpiece itself, friction when punching holes, and the like, and the life of the punch is reduced. Therefore, in Patent Document 1, a cooling medium is constantly flowed inside the punch, and the cooling medium is intensively injected onto the punch tip to cool the punch tip.

JP-A-8-309473

  In the case of a relatively thin workpiece, when punching is placed on a die, the temperature of the workpiece is lowered by the die and the punch, and the deformability is lowered, so that a hole may be punched into the workpiece. Have difficulty. In Patent Document 1, as described above, the punch is cooled with the subject that the punch is heated and burnt out by the workpiece having a large heat. That is, Patent Document 1 does not disclose a method for punching holes in a work piece so that a die, a punch, or the like does not take heat from the work piece.

  Therefore, the present invention has been made in view of the above-mentioned problems, and when punching a workpiece with a processing tool to form a hole, the punch hole can suppress the temperature of the workpiece from being lowered by the processing tool. An object is to provide a forming method and a punch hole forming apparatus.

The characteristic configuration of the punch hole forming method according to the present invention is:
When a workpiece, which is a plate-like member having a thickness of 0.01 mm or more and 1 mm or less, is placed on a die, and the workpiece is punched out in the thickness direction by a punch, holes are formed at least. The temperature of the workpiece in the meantime is maintained at a temperature TO at which the workpiece can be punched.

  When a relatively thin workpiece having a thickness of 0.01 mm or more and 1 mm or less is placed on a die, the temperature of the workpiece may be lowered by contact with the die. On the other hand, since the workpiece is a relatively thin plate, if the workpiece is heated too much, the workpiece may not be able to maintain a plate shape and may be deformed.

In consideration of these points, according to this characteristic configuration, the temperature of the workpiece is maintained at a temperature TO at which punching can be performed while the workpiece, which is a relatively thin plate, is placed on the die. Therefore, a decrease in the temperature of the workpiece can be suppressed, and the deformation resistance (tensile strength) can be kept small. That is, it is possible to easily punch a workpiece by a punch and form a hole while keeping the deformation resistance of the workpiece small and improving the deformability. In addition, since the resistance when forming the hole is small, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the relatively thin workpiece. Furthermore, since the temperature TO is a temperature at which the workpiece can be punched and is not a temperature at which the shape of the workpiece itself is deformed, deformation of the shape of the workpiece itself can be suppressed.
Further, since the deformation resistance of the workpiece is small, the possibility of punch buckling can be avoided.

  A further characteristic configuration of the punch hole forming method according to the present invention is that a load applied to the workpiece when the punch punches the workpiece at the temperature TO is not more than a predetermined value.

  According to this feature, the deformation resistance of the workpiece is reduced by maintaining the workpiece at a temperature TO at which punching can be performed. Then, the deformation resistance of the workpiece decreases, so that the load when the workpiece is punched by the punch (compressive stress acting on the punching blade of the punch) becomes a predetermined value or less. Here, if a workpiece is punched by applying a large load, the workpiece may be pulled in the punching direction, including the position where the hole is formed and its surroundings, and the workpiece may be deformed. is there. By maintaining the workpiece at the temperature TO and forming a hole (compressive stress) at a predetermined value or less, a hole having a desired hole diameter can be suppressed while suppressing deformation of the thin workpiece itself. Can be formed with high accuracy.

  When the punch forms a hole in the workpiece, the load applied to the workpiece maintained at the temperature TO is 10% or more of the load required when the punch forms a hole in the workpiece at room temperature. It is in the point which is 30% or less.

  According to this characteristic configuration, the load required when forming the hole while the workpiece is maintained at the temperature TO is sufficiently smaller than the load required when forming the hole in the workpiece at room temperature. it can. Therefore, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the relatively thin workpiece itself.

  A further characteristic configuration of the punch hole forming method according to the present invention is that the temperature TO is 300 ° C. or higher and 950 ° C. or lower.

  According to this characteristic configuration, by maintaining the temperature TO of the workpiece at 300 ° C. or more and 950 ° C. or less, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the thin plate workpiece itself.

  A further characteristic configuration of the punch hole forming method according to the present invention resides in that the workpiece is maintained at the temperature TO by placing the workpiece on a die heated to a temperature TD.

  Conventionally, dies and punches have been cited as a problem that they are burned by heating and have a reduced life. For this reason, the idea itself of punching a workpiece after heating a die or the like has not been cited. According to this feature configuration, the thickness of the workpiece is relatively thin, so paying attention to the fact that the temperature immediately drops when the workpiece is placed on a die that has not been preheated. As a completely different method, the die is heated to a temperature TD. Then, by placing the workpiece on the heated die, the workpiece is maintained at the temperature TO by heat transfer from the heated die by heat conduction, radiation, or the like.

  A further characteristic configuration of the punch hole forming method according to the present invention is that the workpiece is maintained at the temperature TO by being punched by the punch heated to the temperature TP.

  Conventionally, the punch is not heated in consideration of the life of the punch. However, according to this characteristic configuration, the punch is heated to the temperature TP by paying attention to the fact that the workpiece is relatively thin. Then, the workpiece placed on the die is punched by the heated punch. The work piece is maintained at the temperature TO not only by heat transfer from the die but also by heat transfer by heat conduction and radiation from the heated punch when it is punched to form a hole. The

  A further characteristic configuration of the punch hole forming method according to the present invention is that the aspect ratio, which is the ratio of the thickness of the workpiece to the hole diameter (thickness / hole diameter), is larger than the limit value of the conventional punch hole forming method. is there. Increasing the aspect ratio means that when the work piece is used for a filter, for example, the strength is increased and the range of use is widened, which is advantageous. Therefore, the aspect ratio is preferably 2 or more, more preferably 3 or more, and more preferably 5 or more. Further preferred. If the aspect ratio is too large, there will be problems with the strength and durability of the punch or die, so it is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less.

  A relatively thin workpiece is maintained at a temperature TO at which punching can be easily performed by punching, and the deformation resistance is kept small. Therefore, the workpiece can be easily punched out by the punch while keeping the deformation resistance of the workpiece small and improving the deformability and suppressing the deformation of the shape of the workpiece itself. Therefore, holes having an aspect ratio of 2 to 30 can be formed by punching a relatively thin workpiece as in this feature configuration. The thickness range of the thin plate is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more for the lower limit, depending on the economics of processing. In addition, about an upper limit, 1 mm or less is preferable, 0.75 mm or less is more preferable, and 0.5 mm or less is still more preferable.

  A further characteristic configuration of the punch hole forming method according to the present invention is that the upper limit of the hole diameter is 1 mm or less, which is difficult with the conventional punch forming method. In addition, from the viewpoint of difficulty and cost in manufacturing punches and dies, the lower limit is preferably 0.005 mm or more, more preferably 0.01 mm or more, and further preferably 0.02 mm or more.

  A further characteristic configuration of the punch hole forming method according to the present invention is that a plurality of the holes are formed in the workpiece. When the workpiece is used for the purpose of filtration such as a filter, the more the holes, the more advantageous the pressure loss of the filter. On the other hand, the principle of punch hole formation is that the hole is formed in the workpiece by the shearing force of the punch, so that if the interval between adjacent holes is too narrow, significant deformation or cracking between the holes of the workpiece May occur. From this, the interval between the adjacent holes is preferably 2 times or more of the punch hole diameter, more preferably 3 times or more, and further preferably 4 times or more.

  A further characteristic configuration of the punch hole forming method according to the present invention is that the workpiece is formed of any material selected from heat-resistant metal materials such as ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, and the like. On the other hand, the processing material for punches and dies is formed of a material having a strength 10 times or more that of the material to be processed at the processing temperature.

  Since the workpiece is formed of a material having this characteristic configuration, for example, desired holes can be easily formed in the workpiece satisfying at least one of heat resistance, oxidation resistance, and low cost. Therefore, such a workpiece can be suitably used for, for example, a substrate for stacking various electrodes and electrolytes of a fuel battery cell, a filter having a plurality of pores, and the like.

  A further characteristic configuration of the punch hole forming method according to the present invention is that at least one of the punch and the die is formed of a super hard material containing at least one of ceramics and tungsten.

  According to this characteristic configuration, at least one of the punch and the die is formed of a predetermined material having a relatively high hardness. Therefore, it is preferable that when the hole is formed by punching the workpiece, even if the punch and the die are heated, they are not deformed by heating and are not deformed by the load at the time of punching.

  A further characteristic configuration of the punch hole forming method according to the present invention is that a cooling gas is blown onto the punch after the workpiece is punched out by the punch.

  When a workpiece is punched out by a punch, the temperature of the punch rises due to friction. According to this characteristic configuration, an excessive temperature rise of the punch is suppressed by blowing the cooling gas onto the punch. As a result, the life of the punch due to burnout or oxidation is suppressed.

  A further characteristic configuration of the punch hole forming method according to the present invention is that the cooling gas is at least one of carbon dioxide, oxygen and nitrogen not containing oxygen.

  According to this feature configuration, since the cooling gas is at least one of carbon dioxide, nitrogen, and argon, corrosion of the punch can be suppressed.

A further characteristic configuration of the punch hole forming method according to the present invention is:
The punch is
A plate-like punch body having a predetermined thickness;
A punching blade that protrudes and extends from an opposing surface of the punch body that faces the workpiece, and that forms a hole in the workpiece;
Of the two opposing surfaces of the punch body, a base located on a surface opposite to the projecting direction of the punching blade, and the punch body penetrates the punch body from the base in the projecting direction of the punching blade. A stripper member having a stripper pin extending longer than the thickness of the main body,
When punching out the workpiece by the punch, the stripper pin is retracted so as not to protrude from the facing surface,
After punching out the workpiece by the punch, the tip of the stripper pin protrudes from the facing surface and presses the workpiece, whereby the punching blade together with the punch body is pulled out from the workpiece. In the point.

  According to this characteristic configuration, when a thin workpiece is punched, the punching blade can be easily pulled out of the workpiece by pressing the workpiece with the stripper pin.

The characteristic configuration of the punch hole forming apparatus according to the present invention is:
A punch hole forming apparatus for forming a hole in the workpiece using the punch hole forming method described above,
A die on which the workpiece is placed;
A punch that forms a hole by punching the workpiece placed on the die in the thickness direction;
And a control unit that performs control to maintain the temperature of the workpiece while the hole is formed at a temperature TO at which the workpiece can be punched.

According to this characteristic configuration, the temperature of the workpiece is maintained at a temperature TO at which punching can be performed while the workpiece, which is a relatively thin plate, is placed on the die. Therefore, a decrease in the temperature of the workpiece can be suppressed, and the deformation resistance (tensile strength) can be kept small. That is, it is possible to easily punch a workpiece by a punch and form a hole while keeping the deformation resistance of the workpiece small and improving the deformability. In addition, since the resistance when forming the hole is small, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the relatively thin workpiece. Furthermore, since the temperature TO is a temperature at which the workpiece can be punched and is not a temperature at which the shape of the workpiece itself is deformed, deformation of the shape of the workpiece itself can be suppressed.
Further, since the deformation resistance of the workpiece is small, the possibility of punch buckling can be avoided.

It is a perspective view which shows the whole punch hole formation apparatus structure. It is a schematic diagram which shows a mode that the punch is applied to the workpiece mounted on the die | dye. It is a partial enlarged schematic diagram which shows a mode that a hole is formed in a workpiece by a punch hole forming apparatus.

Embodiment
Hereinafter, a punch hole forming apparatus and a punch hole forming method according to the present embodiment will be described with reference to FIGS.
(1) Punch hole forming apparatus First, the punch hole forming apparatus 100 will be described below.
The punch hole forming apparatus 100 includes a die 10 on which a workpiece O that is a target for forming a hole is placed, a punch 20 that punches the workpiece O placed on the die 10 to form a hole, A stripper member 50 for facilitating extraction of the punching blade 23 from the workpiece O, a cooling device 60 for cooling the punching blade 23 of the punch 20, and a hole is formed by punching the workpiece O. And a control unit 30 that performs various types of control.

The workpiece O of this embodiment is a relatively thin plate-like member having a thickness of 0.01 mm or more and about 1 mm or less. Then, as shown in FIG. 2, the workpiece O is set in a punch hole forming apparatus 100 and punched, whereby a plurality of holes penetrating the workpiece O are formed at a time. The plurality of holes have a large aspect ratio of 2 or more in the present embodiment.
The aspect ratio is the ratio of the thickness of the workpiece O to the hole diameter (thickness / hole diameter). In this embodiment, the hole diameter is, for example, 0.005 mm or more and 0.5 mm or less, and the hole pitch is four times or more the punch hole diameter.

  Further, the workpiece O is not limited to this, but is formed of any material selected from heat-resistant metal materials such as ferritic stainless steel, austenitic stainless steel, and martensitic stainless steel. By forming the workpiece O from such a material, for example, desired holes can be formed in the workpiece O satisfying at least one of heat resistance, oxidation resistance, and low cost. Therefore, such a workpiece O can be suitably used for, for example, a substrate for laminating various electrodes and electrolytes of a fuel cell and a filter having a plurality of pores.

  As described above, in order to form a plurality of holes having a large aspect ratio of 2 or more in the workpiece O at a time, in the present embodiment, the control unit 30 maintains the workpiece O at the temperature TO, Control is performed so that the workpiece O placed on the die 10 is punched out by the punch 20 to form a hole. In this case, the control unit 30 controls the workpiece O to be maintained at the temperature TO by heating the die 10 and the punch 20.

  The die 10 is fixed at a predetermined position, and the movable punch 20 is moved downward toward the workpiece O placed on the die 10 so that the workpiece on the die 10 is processed by the punch 20. A hole is formed in the object O.

  The punch 20 includes a punch body 21 that is generally plate-shaped, and a plurality of punching blades 23 that protrude from the punch body 21. The punch main body 21 has a punch lower surface (opposing surface) 21 a that is a plate-like surface on the side facing the die 10, and a punch upper surface 21 b on the opposite side. The plurality of punching blades 23 are formed so as to protrude downward from the punch lower surface 21a on the die 10 side.

  As shown in FIG. 3, the punching blade 23 has, for example, a cylindrical main body portion 23a and a front end portion 23b that narrows from the main body portion 23a toward the front end. The diameter of the main body portion 23a of the punching blade 23 is approximately the same as the hole diameter corresponding to the hole diameter of the workpiece O of 0.005 mm or more and 0.5 mm or less. Further, the pitch of the plurality of punching blades 23 formed on the punch body 21 is four times or more the punch hole diameter which is the hole pitch. A plurality of punching blades 23 having such hole diameters and pitches are arranged at lattice points of a square lattice along, for example, rows and columns.

  When the punch 20 is brought closer to the die 10, the plurality of punching blades 23 are inserted into the insertion holes 13 provided in the die 10 as shown in FIGS.

The punch 20 includes a punch heater 25 that heats the punch body 21 to a predetermined temperature TP. The punch heater 25 is provided, for example, inside the punch body 21 and heats the punch body 21 and the punching blade 23 to a temperature TP. In this case, the punch heater 25 may heat the punch lower surface 21 a that contacts the workpiece O and the punching blade 23. Alternatively, the punch heater 25 may heat at least the punching blade 23 that contacts when the workpiece O is punched to the temperature TP.
Hereinafter, in the punch 20, heating of the entire punch body 21, at least one of the punch lower surface 21 a of the punch body 21 and the punching blade 23 is referred to as heating of the punch 20.

  The die 10 includes a die body 11 that is generally plate-shaped on which the workpiece O is placed. The die body 11 has a die upper surface 11a which is a plate-like surface on the side facing the die 10 and a die lower surface 11b on the opposite side. The die body 11 is formed with a plurality of insertion holes 13 penetrating from the die upper surface 11a to the die lower surface 11b. Each of the plurality of insertion holes 13 is formed at a position corresponding to the plurality of punching blades 23, and the plurality of punching blades 23 are inserted therein.

Further, the die 10 includes a die heater 15 that heats the die body 11 to a predetermined temperature TD. The die heater 15 is provided, for example, inside the die body 11 and heats the die body 11 to a temperature TD. In this case, the inner surface of the insertion hole 13 is also heated to the temperature TD by heating the die body 11. Alternatively, the die heater 15 may heat at least one of the die upper surface 11 a on which the workpiece O is placed and the inner surface of the insertion hole 13.
Hereinafter, in the die 10, heating of at least one of the entire die body 11, the die upper surface 11 a of the die body 11, and the inner surface of the insertion hole 13 is referred to as heating of the die 10.

  A small protrusion 17 (FIG. 3) is formed on the die upper surface 11a. The small protrusions 17 are formed so as to protrude upward from the die upper surface 11a. The degree of the protrusion is high enough to prevent the workpiece O placed on the die upper surface 11a from being displaced from a predetermined position and not to damage the workpiece O. The shape of the small protrusion 17 is preferably a shape that does not damage the workpiece O. The position where the small protrusion 17 is formed is, for example, a portion adjacent to the insertion hole 13 as shown in FIG. The small protrusions 17 need only be provided to such an extent that the workpiece O does not deviate from a predetermined position on the die upper surface 11 a, and need not be provided corresponding to all the insertion holes 13.

At least one of the die 10 and the punch 20 is not limited to this, but is formed of a super hard material containing at least one of ceramics and tungsten. At least one of the punch 20 and the die 10 is formed of a predetermined material having a relatively high hardness. Therefore, when the hole is formed by punching the workpiece O, it is preferable that even if the punch 20 and the die 10 are heated, they are not deformed by heating and are not deformed by a load at the time of punching.
Further, even when a heat resistant metal material such as ferritic stainless steel, austenitic stainless steel, martensitic stainless steel or the like is selected as the material of the workpiece O, the die 10 and the punch 20 are formed of the above-described materials. Accordingly, there is a strength capable of applying an appropriate load for punching the workpiece O.

The control unit 30 controls the temperature of the workpiece O to be maintained at a temperature TO at which a hole having an aspect ratio of 2 to 30 can be punched. More specifically, when the control unit 30 punches the workpiece O with the punch 20 in the thickness direction of the plate member to form the hole, the control unit 30 removes the workpiece O at least while the hole is formed. Maintain at temperature TO.
In this case, the control unit 30 turns on the die heater 15 and heats the die 10 to the temperature TD before punching out the workpiece O. Here, the temperature TD is a temperature at which the workpiece O can be maintained at the temperature TO when the workpiece O is placed on the die 10. When the relationship of temperature TO <temperature TD is satisfied, it is preferable that the workpiece is easily maintained at the temperature TO by the higher-temperature die 10.

  Further, before punching out the workpiece O, the control unit 30 turns on the punch heater 25 and heats the punch 20 to the temperature TP. Here, the temperature TP is a temperature at which the workpiece O can be maintained at the temperature TO when the workpiece O placed on the die 10 is punched out by the punch 20. The relationship of temperature TO <temperature TP is preferable because the workpiece O can be easily maintained at the temperature TO by the higher temperature punch 20.

  Note that the temperature TD of the die 10, the temperature TP of the punch 20, and the temperature TO of the workpiece O may be a certain point temperature or may have a width. Moreover, although temperature TD, temperature TP, and temperature TO depend on these materials, when the workpiece O is a substrate used when forming a fuel cell, for example, it is in the range of 300 ° C. or higher and 950 ° C. or lower. By setting various temperatures within this range, it is possible to accurately form a hole with a desired hole diameter while suppressing deformation of the thin workpiece O itself.

  As described above, the temperature of the workpiece O is maintained at the temperature TO by heating the die 10 and the punch 20. Thereby, when the punch 20 punches the workpiece O, the load applied to the workpiece O at the temperature TO by the punch 20 becomes a predetermined value or less. The load necessary for the punch 20 to punch the workpiece O at the temperature TO is, for example, 10% to 30% of the load necessary for the punch 20 to punch the workpiece O at the room temperature.

  When the workpiece O placed on the die 10 is punched by the punching blade 23 to form a hole and then the punching blade 23 is pulled out of the workpiece O, the cooling device 60 cuts the punching blade 23. Spray cooling gas on Although the gas for cooling is not limited to this, For example, a carbon dioxide gas, nitrogen, argon, etc. are mentioned.

  As shown in FIG. 3, the stripper member 50 has a base 51 located on the punch upper surface 21 b side of the punch body 21, and extends from the base 51 in the protruding direction of the punching blade 23 to penetrate the punch body 21. A stripper pin 53 extending longer than the thickness of the main body 21. The length of the stripper pin 53 is preferably about the length obtained by adding the thickness of the punch body 21 and the length of the punching blade 23 in the protruding direction. Moreover, the stripper pin 53 has a pair of stripper pins 53a and stripper pins 53b with the punching blade 23 sandwiched substantially in the center. The stripper pin 53 is slidable in the punch body 21 along the direction in which the stripper pin 53 extends. An example of use of the stripper member 50 will be described later.

(2) Punch Hole Forming Method Next, a punch hole forming method using the punch hole forming apparatus 100 will be described mainly with reference to FIG.
First, a workpiece O that is a relatively thin plate-like member having a thickness of 0.01 mm to 1 mm is prepared. The holes formed in the workpiece O have a hole diameter of 0.005 mm or more and 0.5 mm or less, and a pitch that is four times or more the punch hole diameter. And the aspect ratio of a hole is 2-30.

(2-1) (i) in FIG.
In forming the hole by punching the workpiece O, the control unit 30 turns on the die heater 15 and heats the die 10 to the temperature TD and punches the punch heater 25 before punching the workpiece O. The punch 20 is heated to the temperature TP.

  For example, the control unit 30 may heat the die 10 and the punch 20 when receiving an instruction to start punching a hole in the workpiece O from an operator and another device.

Then, when the die 10 and the punch 20 reach a predetermined temperature, the control unit 30 notifies the operator that the workpiece O is ready to be placed on the die 10 by, for example, sound or video. Upon receiving the notification, the operator places the workpiece O on the die 10.
Alternatively, when the die 10 and the punch 20 reach a predetermined temperature, the control unit 30 may place the workpiece O prepared at a predetermined position on the die 10 with a robot arm or the like.

  In (i) of FIG. 3, the workpiece O is placed on the die upper surface 11a of the die 10 fixed at a predetermined position in accordance with a predetermined hole formation position. And the punch 20 is arrange | positioned so as to oppose the to-be-processed object O mounted in the die | dye upper surface 11a so that the punch lower surface 21a may oppose. In this case, the punching blade 23 protruding from the punch lower surface 21a and the insertion hole 13 of the die 10 are arranged to face each other.

  The stripper member 50 is shown in FIG. 3 (i) before the punch 20 starts punching the workpiece O and in FIG. 3 (ii) after the punch 20 punches the workpiece O. Is positioned in the retracted position. That is, when the stripper member 50 punches out the workpiece O by the punch 20, the pair of stripper pins 53a and the stripper pins 53b are formed so that the base 51 is pulled up above the punch upper surface 21b and the punch lower surface 21a. So as not to protrude from the punch body 21. Therefore, only the punching blade 23 protrudes from the punch lower surface 21a.

(2-2) (i) to (ii) in FIG.
In the state of (i) of FIG. 3, the punch 20 is brought close to the workpiece O placed on the die 10 at the fixed position, and the workpiece is machined by the punching blade 23 as shown in (ii) of FIG. The object O is punched to form a hole. As shown in FIGS. 1 and 2, a plurality of holes are simultaneously formed in the workpiece O by the plurality of punching blades 23. The punching waste Oa generated by punching the hole is pushed out by the punch 20 and separated from the workpiece O.

  Since the die 10 is heated to the temperature TD and the punch 20 is heated to the temperature TP from the start of punching of the workpiece O to the end of punching, the workpiece O is maintained at the temperature TO. ing. The temperature TO is a temperature at which the workpiece O can be punched or is easy.

  Here, when a relatively thin workpiece O having a thickness of 0.01 mm or more and 1 mm or less is placed on the die 10, the temperature of the workpiece O may be lowered by contact with the die 10. On the other hand, since the workpiece O is a relatively thin plate, the workpiece O may not be maintained in a plate shape and may be deformed if the degree of heating is too large.

Considering these points, as described above, the temperature of the workpiece O is maintained at the temperature TO at which punching can be performed while the workpiece O that is a relatively thin plate is placed on the die 10. Therefore, the temperature drop of the workpiece O can be suppressed and the deformation resistance (tensile strength) can be kept small. That is, it is possible to easily punch the workpiece O by the punch 20 and form a hole while keeping the deformation resistance of the workpiece O small and improving the deformability. Further, since the resistance when forming the hole is small, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the workpiece O itself which is a relatively thin plate. Furthermore, since the temperature TO is a temperature at which the workpiece O can be punched and is not a temperature at which the shape of the workpiece O itself is deformed, the deformation of the shape of the workpiece O itself can be suppressed.
Further, since the deformation resistance of the workpiece O is small, the possibility of buckling of the punch 20 can be avoided.

  Conventionally, it has been cited as a problem that the die 10 and the punch 20 are burned by heating and have a reduced life. For this reason, the idea of punching the workpiece O after heating the die 10 or the like has not been cited. According to the above configuration, since the thickness of the workpiece O is relatively thin, attention is paid to the fact that the temperature immediately decreases when the workpiece O is placed on the unheated die 10. As a completely different method, the die 10 is heated to the temperature TD. Then, by placing the workpiece O on the heated die 10, the workpiece O is maintained at the temperature TO by heat transfer from the heated die 10 by heat conduction, radiation, or the like.

  As described above, conventionally, the punch 20 has not been heated in consideration of the life of the punch 20. However, according to the above-described configuration, the punch 20 is formed by paying attention to the fact that the workpiece O is relatively thin. Heat to temperature TP. The workpiece 20 placed on the die 10 is punched out by the heated punch 20. The workpiece O has a temperature not only due to heat transfer from the die 10 but also due to heat transfer from the heated punch 20 due to heat conduction, radiation, etc. when it is punched to form a hole. Maintained at TO.

  In addition, in the drilling method using a rotary blade such as a drill and the method of forming holes in the workpiece O by melt penetration by laser irradiation, holes are formed one by one. Therefore, if a plurality of holes are formed, the processing time becomes long, which is an adverse effect of mass production. However, according to the above configuration, since the temperature of the workpiece O is maintained at the temperature TO at which punching is possible, that is, the entire workpiece O is maintained in an easily punched state. A plurality of holes can be formed simultaneously in a predetermined range of the processing region of the object O. Therefore, a plurality of holes can be formed in the workpiece O in a short time. For example, a plurality of holes can be simultaneously punched into the workpiece O placed on the die 10 by a plurality of punches 20. Therefore, the workpiece O having a plurality of holes can be mass-produced in a short time, and the cost of the workpiece O after processing can be reduced.

  In addition, in the method of forming a hole in the workpiece O by melting penetration by laser irradiation or the like, since it is necessary to melt a part of the workpiece O, dross such as oxide generated by melting adheres in the hole. The problem which obstruct | occludes and a separate process, such as removal of adhering dross, etc. arises. However, according to the above configuration, since the workpiece O is punched by the punch 20 to form a hole, the punching waste Oa generated by punching the hole is pushed out by the punch 20 and separated from the workpiece O. Thus, problems such as hole blockage due to laser irradiation and the like are unlikely to occur.

In addition, by maintaining the workpiece O at the temperature TO, a load necessary for the punch 20 to punch the workpiece O at the temperature TO (compressive stress acting on the punching blade 23 of the punch 20) is The load required for the punch 20 to punch the workpiece O at room temperature is, for example, not less than 10% and not more than 30%.
Here, when the workpiece O is punched by applying a large load, the workpiece O is pulled in the punching direction including the position where the hole is formed and its periphery at the time of punching, and the workpiece O is deformed. there is a possibility. By maintaining the workpiece O at the temperature TO and reducing the load when forming the hole to a predetermined value or less, it is possible to accurately control the hole having a desired hole diameter while suppressing deformation of the workpiece O itself which is a relatively thin plate. Can be well formed.

  The aspect ratio of the hole formed by punching the workpiece O is 2 or more and 30 or less. As described above, the workpiece O is maintained at the temperature TO at which the workpiece O can be easily punched by the punch 20 during punching, and the deformation resistance (tensile strength) is kept small. Yes. Therefore, it is possible to easily punch the workpiece O with the punch 20 while keeping the deformation resistance of the workpiece O small and improving the deformability and suppressing the deformation of the shape of the workpiece O itself. it can. Therefore, a hole having an aspect ratio as large as 2 or more and 30 or less can be formed by punching a workpiece O that is a relatively thin plate. For the same reason, holes having a large aspect ratio of 2 to 30 and a hole diameter of 0.005 mm to 0.5 mm and a pitch of four times the punch hole diameter are processed to a relatively thin plate. It can be formed by punching the object O.

Here, in the cold forging performed at room temperature or the like without heating the workpiece O, when a hole having an aspect ratio of 2 or more is formed in the workpiece O by the punch 20, the load applied to the punch 20 during punching ( The compressive stress acting on the punching blade 23 of the punch 20 is large. Further, when a relatively thin workpiece O is punched out, even if the workpiece O is heated and placed on the die 10, the workpiece O is cooled because of its thin thickness. As a result, when the hole having an aspect ratio of 2 or more is formed in the workpiece O by the punch 20, the compressive stress applied to the punch 20 is large. In this case, the compressive stress and the buckling stress applied to the punch 20 exceed the limit values, and it is difficult to form a hole having an aspect ratio of 2 or more.
However, according to the above configuration, the workpiece O is maintained at the temperature TO at which punching can be performed by heating the die 10 and the punch 20. Therefore, the compressive stress applied to the punch 20 becomes relatively small, and a hole having an aspect ratio of 2 or more can be easily formed.

(2-3) (ii) to (iii) in FIG.
When the workpiece O is punched by the punching blade 23 to form a hole as shown in (ii) of FIG. 3, the punching blade is cut from the workpiece O as shown in (iii) of FIG. 23 is pulled out.
When the punching blade 23 is pulled out, the stripper member 50 is pushed so as to move toward the workpiece O, and the punch 20 is moved upward away from the die 10. As a result, the tips of the pair of stripper pins 53a and stripper pins 53b protrude from the punch lower surface 21a and press the upper surface of the workpiece O. Therefore, the punching blade 23 is easily pulled out from the workpiece O together with the punch body 21.

  The stripper member 50 may be moved manually by the operator. Alternatively, the control unit 30 controls the stripper member 50 to the retracted position until the punching of the workpiece O is completed by the punching blade 23, and moves the stripper member 50 to the workpiece O side after the punching is completed. The punching blade 23 may be pulled out after the workpiece O is pressed.

When the punching blade 23 is pulled out from the workpiece O, for example, a manual operation by an operator or the control unit 30 controls, and a cooling gas is blown from the cooling device 60 and blown to the punching blade 23. When the workpiece O is punched by the punch 20, the temperature of the punching blade 23 rises due to friction. By blowing the cooling gas onto the punching blade 23 as described above, the temperature rise of the punching blade 23 is suppressed. Thereby, the lifetime reduction by burning of the punch 20 is suppressed.
When at least one of carbon dioxide and argon is used as the cooling gas, corrosion of the punch 20 can be suppressed. Note that the cooling gas is not limited to these gases as long as the corrosion of the punch 20 can be suppressed.

(3) Simulation when forming a hole in the workpiece As described above, when forming the hole in the workpiece O, the control unit 30 heats the die 10 to the temperature TD and sets the punch 20 to the temperature TP. Heat to. As a result, the workpiece O placed on the die 10 and punched out is maintained at a temperature TO at which punching is possible.
A simulation of whether or not a hole having an aspect ratio of 2 or more and 30 or less can be formed when forming a hole using such a punch hole forming method will be described below.

  As the workpiece O, a plate-like member made of SUS430 (ferritic stainless steel) and having a thickness of 0.3 mm was used. The hole diameter formed by punching is 0.025 mm, and the aspect ratio is 12. Further, the punch and the die are maintained at 700 ° C. A cylindrical punching blade 23 is used for the punch 20.

The tensile strength σ ₇₀₀ of SUS430 at 700 ° C. is about ５ of the tensile strength σ ₂₀ at room temperature of 20 ° C., and is about 100 MPa (10.2 kgf / mm ² ). For this value, reference was made to Masao Kikuchi's paper “High-temperature properties of stainless steel”.

Next, the punching force P (kgf) necessary for punching with the punch 20 is calculated by the following equation (1).
P = LH × t × S × k (1)
Here, LH is the total circumferential length (mm) of the hole formed in the workpiece O by the punch 20. T is the thickness (mm) of the workpiece O, S is the shear stress (kgf / mm ² ), and k is the safety factor.
Since S is generally 0.8 times the tensile strength, the tensile strength σ ₇₀₀ was obtained by multiplying 0.8.
k is generally 1.2. However, in order to calculate a later-described collapse safety factor K closer to safety, k is set to 1.0 here.

In Formula (1), 0.025 mm × 3.142 as LH, 0.3 mm as t, 0.8 × 10.2 kgf / mm ² as S, and 1.0 as k were input, and the following 0.1923 (kgf) was obtained.
P = (0.025 x 3.14) x (0.3) x (0.8 x 10.2) x (1.0)
= 0.1923 (kgf) = 1.886 (N)
Therefore, the punching force P necessary for punching one hole is 0.1923 (kgf) = 1.886 (N).

The compressive stress σp acting on the cylindrical punching blade 23 of the punch 20 that punches one hole can be obtained by the following equation (2) if the cross-sectional area of the cylindrical punching blade 23 is A (mm ² ). .
σp = P ÷ A (2)
Here, if the diameter of the cylindrical punching blade 23 is the same as the hole diameter, the cross-sectional area A is obtained as follows.
A = (0.025 / 2) x (0.025 / 2) x 3.142
Therefore, by applying the equation (2), the compressive stress σp is obtained as follows.
σp = (0.1923) ÷ ((0.025 / 2) × (0.025 / 2) × 3.142)
= 391.7 (kgf / mm ² )

Here, M78 (manufactured by NJS Co., Ltd.) was used as the material of the punch 20. The compressive strength σn of M78 has 8.120 MPa (828.0 kgf / mm ² ) at 700 ° C.
Therefore, the crush safety factor K against the compressive fracture of the cylindrical punching blade 23 is K = σ _n / σ _p = 2.1. From this value, it can be seen that the punching blade 23 does not undergo compression failure at 700 ° C.

In addition, since the aspect ratio of the hole is 12 and is large, the buckling of the punching blade 23 needs to be examined. Here, the length LP of the punching blade 23 was set to 0.35 mm which is longer than the thickness 0.3 mm of the workpiece O, and the diameter of the punching blade 23 was set to 0.025 mm which is the same as the hole diameter.
In this case, the elongated ratio of the punching blade 23 is 14.0 (0.35 mm / 0.025 mm). Generally, since it is necessary to consider buckling at an elongated ratio of 15 or more, Euler's buckling load Pcr (N) and punching force P are compared. Euler's buckling load Pcr (N) is obtained from the following equation (3).
Buckling load Pcr (N) = m × ((3.142) ² × E × I) ÷ LP ² (3)
Here, m is 0.25 under the condition of one-end fixing, and LP is 0.35 mm.
E is the Young's modulus (Pa), and I is the moment of inertia of the cross section (mm ⁴ ). E × I is a bending moment, and usually corresponds to a bending force in mold processing. Transverse rupture strength of the M78 is the nominal value 1500 (MPa) (1500 (N / mm 2)).
From the above, the buckling load Pcr (N) is obtained as follows by applying a numerical value to the equation (3).
Buckling load Pcr = 0.25 × (3.142) ² × 1500 ÷ (0.35) ² = 3.022 × 10 ⁴ (N)

The punching force P (kgf) is 1.886 (N), which is smaller than the buckling load Pcr of 3.022 × 10 ⁴ (N) (Pcr >> P). Therefore, it can be understood that the punching force P is sufficiently smaller than the buckling load Pcr, and even if the punching force P is applied to the punch 20 in order to punch the workpiece O, it does not buckle.

For example, the total load PP required when one million holes are formed by one punching at a time is obtained from the following equation (4).
Total load PP = Punching force P × Number of holes (4)
Therefore, the total load PP is obtained as 0.173 (kgf) × 1000000 (pieces) = 197300 (kgf) = 198 (ton). When punching by the conventional method, since the load capacity is required 5 times, a large press machine of 1000 ton class is necessary. According to the present invention, punching is performed by using a small press machine of 200 ton class. I can see that

[Other Embodiments]
Note that the configurations disclosed in the above-described embodiments (including the other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in the other embodiments unless there is a contradiction. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

(1) In the above embodiment, a plurality of holes having a large aspect ratio of 2 or more are formed in the workpiece O. Therefore, the control unit 30 maintains the workpiece O at a temperature TO at which punching can be performed by heating the die 10 to the temperature TD and heating the punch 20 to the temperature TP.
However, in order to maintain the workpiece O at a temperature TO at which punching can be performed as in the above-described embodiment, the control of heating the die 10 and heating the punch 20 is performed so that the aspect ratio of the workpiece O is less than 2. The present invention is also applicable when forming a plurality of small holes.
Even when a plurality of small holes having an aspect ratio of less than 2 are formed, the workpiece O is maintained at the temperature TO, so that the deformation resistance of the workpiece is kept small and the deformability is maintained as in the above embodiment. The hole can be formed by punching the workpiece easily with a punch while keeping the height high. In addition, since the resistance when forming the hole is small, it is possible to accurately form a hole having a desired hole diameter while suppressing deformation of the relatively thin workpiece.

  (2) In the above embodiment, the punching blade 23 is pulled out from the workpiece O using the stripper member 50 after punching the workpiece O with the punch 20 to form a hole. However, the stripper member 50 may be omitted.

(3) In the above embodiment, when punching the workpiece O to form a hole, the workpiece O is maintained at the temperature TO. In order to maintain the temperature of the workpiece O at the temperature TO, the die 10 is heated by the die heater 15 and the punch 20 is heated by the punch heater 25. However, in order to maintain the temperature of the workpiece O at the temperature TO, the die 20 may be heated only by the die heater 15 without heating the punch 20.
Alternatively, the workpiece O may be preheated and placed on the heated die 10.
Further, the method of maintaining the workpiece O at the temperature TO when the hole is formed by punching the workpiece O is not limited to the above-described embodiment. For example, the atmosphere for punching the workpiece O is maintained at the temperature TO. By doing so, the workpiece O can also be maintained at the temperature TO. Further, the workpiece O can be maintained at the temperature TO by applying a voltage to the workpiece O, for example.

  (4) In the above-described embodiment, the punching blade 23 of the punch 20 has the cylindrical main body portion 23a and the tapered tip portion 23b. In consideration of the load pressure applied to the punch 20, the tapered shape of the tip portion can be appropriately changed. Moreover, the punching blade 23 may not be provided with the tip portion 23b but may be constituted by the main body portion 23a.

  (5) In the above embodiment, after punching the workpiece O with the punch 20, a cooling gas is blown from the cooling device 60 to the punching blade 23 in order to cool the punching blade 23 of the punch 20. However, the blowing of the cooling gas to the punching blade 23 is not essential, and the cooling device 60 may be omitted.

  (6) In the above embodiment, the workpiece O is placed on the die upper surface 11a of the die 10 from the upper part of the die 10 as shown in FIG. However, the workpiece O may be placed so as to slide on the upper surface 11a of the die along a groove-shaped guide (not shown) provided on the die 10. Alternatively, the punch hole forming apparatus 100 may be provided with a pressing member (not shown) that presses the workpiece O placed on the die upper surface 11a from above.

  (7) In the above embodiment, the die 10 is fixed at a predetermined position, and the punch 20 moves toward the die 10. However, the punch 20 may be fixed at a predetermined position, and the die 10 may move toward the punch 20.

  (8) In the above-described embodiment, the small protrusions 17 are formed in order to prevent the positional deviation of the workpiece O placed on the die 10. However, the small protrusion 17 may be omitted.

10: Die 20: Punch 23: Punching blade O: Workpiece

Claims (15)

  When a workpiece, which is a plate-like member having a thickness of 0.01 mm or more and 1 mm or less, is placed on a die, and the workpiece is punched out in the thickness direction by a punch, holes are formed at least. A punch hole forming method in which the temperature of the workpiece in between is maintained at a temperature TO at which the workpiece can be punched.   The punch hole forming method according to claim 1, wherein a load applied to the workpiece when the punch punches the workpiece at the temperature TO is equal to or less than a predetermined value.   When the punch forms a hole in the workpiece, the load applied to the workpiece maintained at the temperature TO is 10% or more of the load required when the punch forms a hole in the workpiece at room temperature. The punch hole forming method according to claim 2, which is 30% or less.   The punch hole forming method according to any one of claims 1 to 3, wherein the temperature TO is 300 ° C or higher and 950 ° C or lower.   The punch hole forming method according to any one of claims 1 to 4, wherein the workpiece is maintained at a temperature TO by placing the workpiece on a die heated to a temperature TD.   The punch hole forming method according to claim 5, wherein the workpiece is maintained at a temperature TO by being punched out by a punch heated to a temperature TP.   The punch hole forming method according to any one of claims 1 to 6, wherein an aspect ratio, which is a ratio of a thickness of the workpiece to a hole diameter (thickness / hole diameter), is 2 or more and 30 or less.   The punch hole forming method according to claim 7, wherein the hole diameter is 1 mm or less.   The punch hole forming method according to claim 1, wherein a plurality of the holes are formed in the workpiece.   The workpiece is formed of any material selected from heat-resistant metal materials such as ferritic stainless steel, austenitic stainless steel, and martensitic stainless steel. The punch hole forming method as described.   The punch hole forming method according to any one of claims 1 to 10, wherein at least one of the punch and the die is formed of a super hard material containing at least one of ceramics and tungsten.   The punch hole forming method according to claim 1, wherein after punching the workpiece by the punch, a cooling gas is blown onto the punch.   The punch hole forming method according to claim 12, wherein the cooling gas is at least one of carbon dioxide, nitrogen, and argon. The punch is
A plate-like punch body having a predetermined thickness;
A punching blade that protrudes and extends from an opposing surface of the punch body that faces the workpiece, and that forms a hole in the workpiece;
Of the two opposing surfaces of the punch body, a base located on a surface opposite to the projecting direction of the punching blade, and the punch body penetrates the punch body from the base in the projecting direction of the punching blade. A stripper member having a stripper pin extending longer than the thickness of the main body,
When punching out the workpiece by the punch, the stripper pin is retracted so as not to protrude from the facing surface,
After punching out the workpiece by the punch, the tip of the stripper pin protrudes from the facing surface and presses the workpiece, whereby the punching blade together with the punch body is pulled out from the workpiece. The punch hole forming method according to any one of claims 1 to 13. A punch hole forming apparatus that forms a hole in the workpiece using the punch hole forming method according to claim 1,
A die on which the workpiece is placed;
A punch that forms a hole by punching the workpiece placed on the die in the thickness direction;
A punch hole forming apparatus, comprising: a control unit that performs control to maintain the temperature of the workpiece while the hole is formed at a temperature TO at which the workpiece can be punched.

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