Punching method

Abstract

To provide a punching method in which an unwanted portion pulled out after punching can be surely recovered onto a belt conveyor or the like, in recovering the unwanted portion.SOLUTION: A punching method comprises: a temporarily punching step of forming a cut line B2 along an outline in a nearly circular shape on a work-piece W1 in a thin plate-shape, while leaving bridges B1 at both end parts thereof; a bending step of deforming an unwanted portion W2 inside the cut line B2 in the work-piece W1 into a folded-back shape along a radial direction in which the bridges B1 are joined to each other; a main punching step of punching the unwanted portion W2 from the work-piece W1 so that protrusions W2a protruding to outside in the radial direction are formed at both end portions of the deformed unwanted portion W2; and a recovering step of recovering the punched unwanted portion W2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a stamping method. [Background technology]

[0002] A punching process is known in which a thin plate-like workpiece is punched into a predetermined shape using a die consisting of an upper die and a lower die. Unnecessary parts (unnecessary parts) generated by the punching process are discharged as scrap pieces. An example of a punching device used for such a punching process is disclosed in Patent Document 1.

[0003] Patent Document 1 discloses a punching device having an outer diameter punch provided on a lower die, an outer diameter punching die provided on an upper die, an upper die plate holding portion, a lower die plate holding portion, a cutter cutting means for cutting the edges around a punched hole in a steel material with an upper die cutting blade and a lower die cutting blade, a scrap piece discharge portion for dropping and discharging scrap pieces on the steel material feed direction side of the cutting position where the edge is cut by the cutter cutting means, and a lifter for tilting the blank material in the discharge direction and guiding it to be discharged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-220467 A Summary of the Invention [Problem to be solved by the invention]

[0005] The punching device described in Patent Document 1 is described as being capable of improving the yield of materials while ensuring the flatness of punched products, and improving the dischargeability of punched products and scrap pieces. However, when unnecessary parts (scrap pieces) are punched out from a workpiece by press processing using a punch provided on an upper die and a die provided on a lower die, for example, and collected on a belt conveyor, the unnecessary parts formed in a substantially circular thin plate shape tend to roll randomly on the conveying surface of the belt conveyor. Therefore, there is a problem in that the punched out unnecessary parts roll on the conveying surface and fall to the side of the belt conveyor or get into the gaps in the belt conveyor, stopping the press operation of the punching device.

[0006] The present disclosure has been made to solve such problems, and aims to provide a punching method that reliably recovers the unnecessary parts that are punched out after punching and are then collected on a belt conveyor or the like. [Means for solving the problem]

[0007] A punching method according to one embodiment includes a temporary punching process in which a cut is formed in a thin plate-like workpiece along a substantially circular contour while leaving bridges at both ends; a bending process in which an unnecessary portion of the workpiece inside the cut is deformed into a shape bent in the radial direction connecting the bridges; a main punching process in which the unnecessary portion is punched out of the workpiece so that both ends of the deformed unnecessary portion have protrusions that protrude radially outward; and a recovery process in which the punched-out unnecessary portion is recovered. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a punching method that reliably collects the unnecessary parts punched out after punching on a belt conveyor or the like. [Brief description of the drawings]

[0009] [Figure 1]FIG. 2 is a diagram for explaining a punching method according to the first embodiment. [Diagram 2] 1A and 1B are diagrams for explaining problems that arise when removing an unnecessary part formed in a substantially circular thin plate shape from a workpiece and collecting it on a belt conveyor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First embodiment Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiment. In addition, in order to clarify the description, the following description and drawings are appropriately simplified. What is shown in the drawings is only a part of the whole, and in reality, many other configurations that are not shown are included. In the following description, the same or equivalent elements are given the same reference numerals, and duplicated descriptions are omitted.

[0011] Fig. 1 is a diagram for explaining a punching method according to the first embodiment. In a punching process in which a punched product is obtained by punching a thin plate-like workpiece W1, a plurality of small holes W3 used for positioning may be provided in the workpiece W1 before punching the punched product. Therefore, in this embodiment, a punching method is described in which an unnecessary portion W2 is punched out of a thin plate-like workpiece W1 using a punching device shown in Fig. 1 to form a substantially circular small hole W3 in the workpiece W1.

[0012] This punching device has an upper die and a lower die. The upper die is disposed on the top of the press and attached to a slide that reciprocates in the vertical direction. The lower die is attached to a bolster that is fixedly disposed on the bottom of the press. The press can move the upper die in the vertical direction, approaching and separating it from the lower die, by driving the slide in the vertical direction. Various configurations can be applied to drive the slide.

[0013] The punching device performs press processing on the workpiece W1, which is a strip-shaped thin plate fed between the upper and lower dies by a conveying means, while intermittently conveying the workpiece W1 along its longitudinal direction, to form a plurality of small holes W3 in the workpiece W1. The punching device has a temporary punching section 10, a bending section 20, a main punching section 30, and a belt conveyor 40. The temporary punching section 10, the bending section 20, and the main punching section 30 are arranged in this order from the upstream side to the downstream side in the conveying direction of the workpiece W1. The belt conveyor 40 is arranged below the main punching section 30. The upper side of FIG. 1 shows plan views showing parts of the workpiece W1 processed by the temporary punching section 10, the workpiece W1 processed by the bending section 20, and the workpiece W1 processed by the main punching section 30. In FIG. 1, the outline arrow indicates the conveying direction of the workpiece W1.

[0014] FIG. 1(a) shows a cross section of the temporary punching section 10 as viewed from a direction perpendicular to the conveying direction in a horizontal plane. As shown in FIG. 1(a), the temporary punching section 10 forms a cut B2 along a substantially circular contour in the thin plate-like workpiece W1, leaving bridges B1 at both ends. The temporary punching section 10 has a first upper punch 11, a first die 12, and a first lower punch 13. The first upper punch 11 is provided in the upper mold. The first die 12 and the first lower punch 13 are provided in the lower mold. The first upper punch 11 has a substantially cylindrical shape and has a cutting blade portion 11a at its lower end that corresponds to the shape of the cut B2. The first die 12 has a substantially cylindrical shape and has a first die hole 12a that penetrates in the vertical direction. The first lower punch 13 has a substantially cylindrical shape with an outer diameter smaller than the inner diameter of the cutting blade portion 11a of the first upper punch 11, and has a pressing surface 13a at its upper end surface. The first lower punch 13 is inserted into the first die hole 12a so that the pressing surface 13a is located at approximately the same height as the upper end surface 12b of the first die 12.

[0015] FIG. 1(b) shows a cross section of the bending section 20 as viewed from a direction perpendicular to the conveying direction in a horizontal plane. As shown in FIG. 1(b), the bending section 20 deforms the unnecessary part W2 inside the slit B2 of the workpiece W1 into a shape bent along the radial direction connecting the bridges B1. The bending section 20 has a second upper punch 21, a second die 22, and a second lower punch 23. The second upper punch 21 is provided in the upper mold. The second die 22 and the second lower punch 23 are provided in the lower mold. The second upper punch 21 has a substantially cylindrical shape and has a forming surface 21a on its lower end surface, which is formed in a substantially V-shape that protrudes downward and has a flat portion at its tip. It is preferable that the forming surface 21a has a flat portion at its tip. The second die 22 has a substantially cylindrical shape and has a second die hole 22a penetrating in the vertical direction. The second lower punch 23 has a generally cylindrical shape with approximately the same outer diameter as the outer diameter of the second upper punch 21, and has a forming surface 23a on its upper end surface that is recessed downward to correspond to the forming surface 21a. The second lower punch 23 is inserted into the second die hole 22a so that the forming surface 23a is positioned at approximately the same height as the upper end surface 22b of the second die 22.

[0016] FIG. 1(c) shows a cross section of the main punching section 30 and the belt conveyor 40 as viewed from the upstream side in the conveying direction. As shown in FIG. 1(c), the main punching section 30 punches out the unnecessary part W2 from the workpiece W1 so that the unnecessary part W2 deformed into a bent shape has protrusions W2a protruding radially outward at both ends. The main punching section 30 has a third upper punch 31 and a third die 32. The third upper punch 31 is provided in the upper mold. The third die 32 is provided in the lower mold. The third upper punch 31 has a substantially cylindrical shape and has protrusions 31a at both ends corresponding to the shape of the protrusions W2a. The third die 32 has a third die hole 32a penetrating in the vertical direction.

[0017] The belt conveyor 40 is a recovery means for recovering the unnecessary part W2 punched out by the main punching section 30. The belt conveyor 40 has a roller 41 and an endless belt 42 wound around the roller 41. The belt conveyor 40 is provided below the third die 32, for example, so that a conveying surface 42a of the belt 42 is aligned horizontally. The belt conveyor 40 places the unnecessary part W2 on the conveying surface 42a and transports it to a predetermined discharge position.

[0018] Next, a punching method using the punching device described above will be described. The punching method according to this embodiment has steps S1 to S4. First, step S1 is a temporary punching process in which a slit B2 is formed along a substantially circular contour in a thin plate-like workpiece W1, leaving bridges B1 at both ends. In the temporary punching process, a press process is performed by the temporary punching unit 10. Specifically, the first upper punch 11 is brought close to the first lower punch 13 to punch the workpiece W1 without separating the unnecessary part W2 from the workpiece W1 placed on the first die 12, thereby forming a slit B2 in a shape corresponding to the cutting blade part 11a in the workpiece W1. In the temporary punching process, the workpiece W1 is cut so that the unnecessary part W2 is connected to the workpiece W1 by the bridges B1 at both ends.

[0019] Step S2 is a bending process in which the unnecessary portion W2 of the workpiece W1 on the inside of the slit B2 is deformed into a shape bent along the radial direction connecting the bridges B1. In the bending process, a press process is performed by the bending unit 20. Specifically, the unnecessary portion W2 of the workpiece W1 placed on the second die 22 is pressed between the forming surface 21a of the second upper punch 21 and the forming surface 23a of the second lower punch 23 by bringing the second upper punch 21 close to the second lower punch 23, thereby deforming the unnecessary portion W2 connected to the workpiece W1. By such a bending process, a three-dimensional shape can be imparted to the unnecessary portion W2.

[0020] Step S3 is a blanking process step of punching out the unnecessary part W2 from the workpiece W1 such that protrusions W2a protruding radially outward are provided at both ends of the deformed unnecessary part W2. In the blanking process step, pressing is performed by the blanking process unit 30. Specifically, by inserting and removing the third upper punch 31 into the third die hole 32a of the third die 32 on which the workpiece W1 is placed, the unnecessary part W2 having a shape corresponding to the shape of the third upper punch 31 is punched out. The unnecessary part W2 punched out in this way has a substantially circular thin plate-shaped outer shape and has a shape bent along the radial direction connecting the protrusions W2a provided at both ends. That is, the cross-section along the thickness direction of the punched-out unnecessary part W2 has a substantially V shape. Further, a small hole W3 having a shape corresponding to the shape of the third upper punch 31 is formed in the workpiece W1 after the unnecessary part W2 is punched out. Then, the unnecessary part W2 punched out from the workpiece W1 falls downward through the third die hole 32a.

[0021] Step S4 is a recovery process step of recovering the removed unnecessary part W2. In the recovery process step, the unnecessary part W2 that has fallen through the third die hole 32a is received by the belt conveyor 40 on the conveying surface 42a.

[0022] Here, FIG. 2 is a diagram for explaining problems when punching out an unnecessary part formed in a substantially circular thin plate shape from a workpiece and recovering it onto a belt conveyor. FIG. 2 shows a state in which pressing is performed by a punching device having a punch 100 having a substantially cylindrical shape provided on the upper die and a die 200 having a substantially cylindrical shape provided on the lower die. FIG. 2 shows a cross-section of the punch 100, a cross-section of the die 200, and the belt conveyor 40 as viewed from the upstream side in the conveying direction.

[0023] In the pressing by the punch 100 and the die 200, by inserting and removing the punch 100 into the die hole 200a of the die 200 on which the workpiece W1 is placed, an unnecessary part W200 formed in a substantially circular thin plate shape corresponding to the shape of the punch 100 is punched out. Then, the unnecessary part W200 punched out from the workpiece W1 falls downward through the die hole 200a.

[0024] When the unnecessary parts W200 are punched out from the workpiece W1 by such press processing and collected on the belt conveyor 40, the unnecessary parts W200 formed in a substantially circular thin plate shape tend to roll randomly on the conveying surface 42a of the belt conveyor 40. Therefore, there is a problem that the punched out unnecessary parts W200 roll on the conveying surface 42a and fall to the side of the belt conveyor 40 or get into a gap in the belt conveyor 40, thereby stopping the press operation of the punching device.

[0025] In response to such a problem, in the punching method according to the present embodiment, the punched out unnecessary part W2 has the above-mentioned three-dimensional shape. The three-dimensionally shaped unnecessary part W2 is less likely to roll on the conveying surface 42a when collected by the belt conveyor 40, compared with the unnecessary part W200 formed in a substantially circular thin plate shape without the three-dimensional shape. Therefore, the punched out unnecessary part W2 is prevented from falling to the side of the belt conveyor 40 or getting into a gap in the belt conveyor 40, and the belt conveyor 40 can reliably collect the unnecessary part W2 on the conveying surface 42a. Thus, according to the punching method according to the present embodiment, when the unnecessary part W2 punched out after punching is collected on the belt conveyor 40 or the like, the unnecessary part W2 can be reliably collected.

[0026] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0027] 10 temporary punching portion 11 first upper punch 11a cutting edge portion 12 First die 12a First die hole 12b Upper end surface 13 First lower punch 13a Pressing surface 20 bending portion 21 second upper punch 21a forming surface 22 Second die 22a Second die hole 22b Upper end surface 23 Second lower punch 23a Forming surface 30 main punching section 31 third upper punch 31a protruding section 32 Third die 32a Third die hole 40 belt conveyor 41 roller 42 belt 42a conveying surface 100 punch 200 die 200a die hole B1 Bridge B2 Break W1 Workpiece W2, W200 Unnecessary part W2a Protrusion W3 Small hole

Claims

[Claim 1] a temporary punching process for forming a cut along a substantially circular contour in a thin plate-like workpiece while leaving bridges at both ends; a bending process step of deforming an unnecessary portion of the workpiece on the inside of the slit into a shape bent along a radial direction connecting the bridges; a punching process for punching the unnecessary portion from the workpiece so that protrusions protruding radially outward are provided at both ends of the deformed unnecessary portion; a recovery step of recovering the removed unnecessary portion; The punching method has the steps of:

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