JPH0683950B2 - Chamfering method for printed circuit boards - Google Patents

Description

The present invention relates to a method for chamfering a printed circuit board, and more particularly to chamfering a cut surface of a printed circuit board cut by a cutting machine. The chamfering method of the printed circuit board.

[Prior Art] Since a so-called burr is formed on a cut surface of a printed circuit board cut into a predetermined size by a cutting machine, a chamfering work is required to remove the burr.

Since the chamfering work has to be performed on all of the eight corners of the copper-clad side corners and the resin side corners of the printed circuit board, that is, all the outer peripheral edges of the front and back surfaces of the printed circuit board, It is extremely difficult to be automated, and for this reason, in the past, workers supplied chamfering machines one by one to perform chamfering work. The cutting machine
Usually, several or several tens of printed circuit boards are cut at the same time at the same time, so that the conventional chamfering work described above has extremely poor workability and work efficiency, and the emergence of an efficient chamfering machine has been strongly desired.

[Problems to be Solved by the Invention]

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to chamfer each corner portion of a plurality of or a large number of printed circuit boards simultaneously and continuously in the conveying process. An object of the present invention is to provide a method for chamfering a printed circuit board.

[Means and Actions for Solving the Problems]

The present invention is a method of chamfering a corner 4c on the copper-clad side and a corner 4d on the resin side of a plurality of unprocessed printed boards 4a stacked and cut in a plurality of steps or a plurality of steps, wherein the plurality of steps or a large number of The plurality of unprocessed printed circuit boards 4a stacked and cut in stages are conveyed in a predetermined direction, and during the conveyance, the plurality of unprocessed printed circuit boards 4a are first moved.
After being deformed and fixed in a rhombus direction, each raw printed circuit board
The corner 4c of the first copper-clad side of 4a with the first blade 34,
The first resin side corner portion 4d on the opposite side to the blade 34
Chamfering is simultaneously performed by the first brush 35 disposed opposite to each other, and after chamfering the first copper-clad side corner portion 4c and the resin-side corner portion 4d, the plurality of unprocessed sheets are processed. The rhombus deformed state in the first direction of the printed circuit board 4a is released, this is deformed and fixed in the rhombus in the second direction, and the second copper-clad side corner portion 4c and the resin side corner portion 4d are set to the second corner. The blade 34 and the brush 35 are chamfered at the same time, and similarly, the remaining third and fourth copper-clad side corner portions 4c and resin-side corner portions 4d are removed in the same manner. And chamfering of the four copper-clad side and resin side corners 4c and 4d of the plurality of unprocessed printed circuit boards 4a while sequentially chamfering with the brush 35. Method.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic configuration of a chamfering device 1 used for carrying out a method for chamfering a printed circuit board according to the present invention. As shown in the figure, the chamfering device 1 for a printed circuit board is
A printed circuit board supply / conveyance unit 3 connected to the discharge side of the cutting machine 2, a chamfering process unit 5 for chamfering an unprocessed printed circuit board 4a conveyed and supplied through the printed circuit board supply / conveyance unit 3, and a chamfering process. The printed circuit board 4b is ejected and conveyed, and the processed printed circuit board loading section 7 is configured to load the processed printed circuit board 4b.

The unprinted printed circuit board 4a cut by the cutting machine 2 is, for example, 4 when viewed from the plane as shown in FIGS.
Cut into 6 pieces, 9 pieces, etc. At the time of this cutting, a plurality of or a large number of fixed-sized printed circuit board original plates are stacked and cut at a time to an appropriate size as shown in FIGS. 2A to 2F. Only the cut portion shown is discharged to the printed circuit board supply / conveyance unit 3. The cut uncut printed circuit board (printed circuit board that has not been chamfered) 4a usually has a copper side corner (cutting surface corner) 4c and a resin side corner as shown in FIG. 2g. Burrs are generated in each of the four corners of the portion 4d, a total of eight corners, so it is necessary to remove the burrs. The substrate 4a is supplied.

The printed circuit board supply / conveyance unit 3 is, as shown in FIG.
It comprises a conveyor belt 8 for transportation, a conveyor driving unit 9 and a loading device (loader) 10 for the unprocessed printed circuit board.

The belt conveyor 8 has a length of 2.4 m and a width of 0.8 m, for example, and its speed is set so as to be continuously variable.

The motor of the conveyor drive unit 9 is, for example, 4P, 1.5KW (with a brake), and is set so that the belt conveyor 8 can be rotationally driven via the winding transmission medium node 11 such as a chain or a belt. Configured. Reference numeral 12 is a driving wheel, 13 is a driven wheel, and 14 is a frame portion.

The carry-in device 10 carries in the unprocessed printed circuit board 4a into the chamfer processing part 5 when the unprocessed printed circuit board 4a is supplied onto the belt conveyor 8 and conveyed to a predetermined position via the belt conveyor 8. The printed circuit board clamp section 15 and a carry-in operation section (not shown) such as an air cylinder for moving the unprocessed printed circuit board 4a clamped via the clamp section 15 into the chamfering section 5. Guide rod part that guides the movement of the clamp part 15
It is composed of 16 mag.

The printed circuit board clamp section 15 is for clamping the unprocessed printed circuit board 4a which is stopped at a predetermined position via a fixed position regulation section 17 such as a stopper which is operated to move up and down, and the clamp section 15 is a cutting machine. A plurality of stages, for example, 10 unprocessed printed circuit boards 4a, 4a, which are discharged from 2 as they are and are conveyed through the belt conveyor 8 ...
Can be clamped as it is, that is, with 10 sheets loaded. The clamp part 15 is a raw printed circuit board.
4a is clamped and moved upward by an appropriate amount, and after being loaded into the chamfering section 5 via the loading operation section, it is stopped at a predetermined position and then moved downward to move the unprocessed printed circuit board 4a to the chamfering section 5. After the sheet is placed on the transport unit 18, it is unclamped, moved upward, and then restored to the original position. In addition, 19 is a guide part.

The chamfer processing section 5 is composed of four processing mechanism sections 20, 21, 22, 23 arranged in a rectangular shape as shown in FIG. 4, and the unprocessed printed circuit board 4a is processed by these four processing sections. 10 pieces (not limited to 10 pieces, the same applies to the following) of the chamfering processing of each octagon shown in FIG. 2g by being processed by the mechanical parts 20, 21, 22, 23 It will be processed at the same time.

Of the four processing mechanism units 20, 21, 22, 23, the first processing mechanism unit 20 is for carrying the unprocessed printed circuit board 4a carried in via the carry-in device 10 of the printed circuit board supply and carrying unit 3. Transporting part 18, a diamond-shaped deforming device 25 for deforming the surface of the unprocessed printed circuit board 4a to be processed into a diamond, and a chamfering tool part 2
6. It is composed of the corner shift part 27 for the next process.

As shown in FIG. 5, the transport unit 18 comprises a transport chain conveyor 28 and a drive unit 29. The transport chain conveyor 28 is set to, for example, 8 seconds / rotation, and the transport conveyor hooks 30 for driving the transport of the unprocessed printed circuit board 4a are installed at two locations on the chain conveyor 28. Reference numeral 31 indicates a drive side sprocket, and reference numeral 32 indicates a driven side sprocket. The motor of the drive unit 29 is set to a motor of 1.5 KW, with continuously variable transmission, and with a brake, and is configured to interlock with the drive side sprocket 31 of the chain conveyor 28 via the chain 33.

The tool portion 26 is a chamfering process (deburring process) of the unprocessed printed circuit board 4a that has been deformed via the diamond-shaped deforming device 25 described later.
Blades 34 arranged to face each other.
And a brush 35. The blade 34 is for chamfering the corner portion of the unprocessed printed circuit board 4a on the copper-clad side, and is made of a cemented carbide chip or the like, and is provided with a fixed work guide and is minutely attached. It has an adjustable structure. The brush 35 is for chamfering a corner portion on the resin side of the unprocessed printed circuit board 4a, and is rotationally driven by a belt drive method via a 0.2 KW motor. The unprocessed printed circuit board 4a is deformed into a diamond shape with the copper-clad side facing up, and in this state, as shown in FIGS. 6a and 6b, the blade 34 and the brush 35 cooperate to deform the diamond shape. The copper-clad side corner portion 4c and the resin-side corner portion 4d of the cut surface are set so that they can be chamfered at the same time in a stacked state. The brush 35 is configured to be movable and adjustable via a shifter 36, and adjusts the interval between the blade 34 and the brush 35 according to the width of the unprocessed printed circuit board 4a which is the workpiece. It's getting better. That is, the brush 35
Is configured to be movable and adjustable via a shifter 36 that is moved and operated by a shift screw 37 that is rotationally driven via a motor or the like.

The corner shifter 27 uses the chamfered printed circuit board 4a through the tool section 26 as the second processing mechanism section 21 which is the next step.
And a hook portion for moving the printed circuit board 4a, as shown in FIG.
The shifter section 39 equipped with 38 is moved on the guide rod section 40 via a movement operation mechanism such as an air cylinder, so that the first chamfering process is performed on the printed circuit board 4a by the first processing mechanism section 20. The second process is the second processing mechanism section
A shift operation is performed on the transport unit 38 of 21.
The hook portion 38 corresponds to the width of the printed circuit board 4a, and
The position can be changed.

Printed circuit board 4a shifted by corner shifter 27
5 is set so as to be placed on the work receiver 41 before being placed on the transport section 38 of the second processing mechanism section 21, as shown in FIG. The work receiver 41 is the seventh
As shown in the figure, a receiver main body 42 that supports the printed circuit board 4a, a receiver main body support arm 43, a screw 44 for adjusting the interval between the receiver main body 42, a motor 45 for rotationally driving the screw 44, and a receiver. The receiver main body 42 is configured to be openable and closable via the operation member 47, and is configured by a guide rod portion 46 that guides the main body 42 to move. A motor with a 0.2 KW output equipped with a brake is used as the motor 45, and is configured so that the screw 44 can be rotationally driven via gears 48 and 49. Then, as shown in FIG. 7, it is confirmed whether the line width of the conveying device 38 in the next step (the width of the conveying portion 38 corresponding to the width of the printed board 4a which is the workpiece) is set to a predetermined width. The receiver main body 42 is opened so that the receiver body 42 is dropped from the first transfer line 50 onto the second transfer line 51 by a height e.

The transfer devices 18 and 38 need to be shift-adjusted according to the width of the printed circuit board 4a which is the workpiece, that is, the work width. This adjustment is performed via the shift screw 52 as shown in FIG. 8a. Shifter 53 to be moved and shifter
A guide rod portion 54 for moving and guiding the 53, a motor 55 for rotating the shift screw 52, and the like are included. It is composed of shifter 55 etc. The shifter 53 is fixed to the movable transfer units 18 and 38, and the transfer line width 1 can be set and adjusted to an arbitrary width by moving the shifter 53. Reference numerals 56 and 57 denote transmission gears, and reference numeral 58 denotes a fixed guide portion fixed in correspondence with the guide portion 59 of the shifter 53.

The rhombus deforming device 25 is for deforming the surface of the printed board 4a, which is a workpiece, into a rhombus as shown in FIGS. 6a and 6b so that the blade 34 and the brush 35 can chamfer the surface. As shown in FIG. 8b, a shifter 62 having a deforming operation portion 61 that is moved and operated via an air cylinder 60.
And a fixed deformation operation unit 63 and the like fixedly arranged corresponding to the deformation operation unit 61. That is, in the deformation operation portion 61 and the fixed deformation operation portion 63, the work surfaces of the ten printed circuit boards 4a are stacked in a predetermined diamond shape (as shown in FIGS. 6a and 6b,
The inclined deformation operation surfaces 61a and 63a are formed so that the corners 4c and 4d can be deformed by the blade 34 and the brush 35 into chamfering shapes.
Deformation operation portion 61 operated via, and each deformation operation surface 61a,
Due to the cooperation with 63a, the entire surface to be processed of the printed board 4a can be transformed into a substantially rhombic shape as shown in FIGS.

The second machining mechanism section 21 is for chamfering the chamfered surface machined by the first machining mechanism section 20 and the surface to be machined that is deviated by 90 degrees, and is similar to the first machining mechanism section 20. , Transport section 3
8, a rhombus deforming device 63 for deforming a portion to be processed of the printed circuit board 4a into a rhombus, a chamfering tool portion 64, a corner shift portion 65 to the next step, and the like.

As shown in FIG. 7, the transport section 38 is a first processing mechanism section.
It is for receiving and carrying the printed circuit board 4a dropped from the work receiver 41 at the end of the carrying line 20 and is provided with two hook portions 66 for applying pressure during chamfering. The configuration of the transport unit 38 is the transport unit shown in FIG.
Although the configuration and the description thereof are omitted because they are similar to the configuration of 18, they are arranged in a direction orthogonal to the transport line of the first processing mechanism unit 20. Further, the carrying section 38 has a structure similar to that shown in FIG. 8A so that the carrying line width 1 can be set and adjusted to an arbitrary width, and the carrying line width l can be adjusted to the width of the printed circuit board 4a which is the workpiece. It can be adjusted accordingly. The tool part 64 is composed of a blade 66 and a brush 67 as with the first processing mechanism part 20, and the brush 67 is moved to a width of the printed circuit board 4a by a shifter 69 which is moved and operated via a shift screw 68. It is configured so that it can be moved correspondingly. The blade 66 and the brush 67 have the same configuration as that of the first processing mechanism section 20.
The description is omitted.

The configurations of the rhombus deforming device 63 and the corner shift portion 65 are the same as the configurations shown in FIGS. 8b and 5b, and therefore the illustration and description thereof will be omitted. Further, at the end of the transfer line, the same work receiver 41 as that of the first processing mechanism 20 is provided.
Is installed and the work receiver 41 is the same as that shown in FIG.

The third machining mechanism section 22 is for chamfering a chamfered surface machined by the second machining mechanism section 21 and a surface to be machined that is deviated by 90 degrees. Similar to 20,21
The transport unit 70, a diamond-shaped deforming device 71 for deforming the surface to be processed of the printed circuit board 4a into a rhombus, a chamfering tool 72, a corner shift unit 73 for the next step, and the like.

The transport unit 70 is for receiving and transporting the printed circuit board 4a dropped from the work receiver 41 at a few ends of the transport line of the second processing mechanism unit 21, and to the transport line of the second processing mechanism unit 21. Are arranged in a direction orthogonal to each other, that is, in a direction parallel to the transport line of the first processing mechanism section 20. Transport unit 70
The configuration of is the same as that shown in FIG. 5, and therefore its illustration and description are omitted. The transport unit 70 is shown in FIG.
The conveyance line width 1 can be set and adjusted to an arbitrary width by the same structure as the structure shown in (4), and can be adjusted according to the width of the printed circuit board 4a which is the workpiece.

The tool part 72 is composed of a blade 74 and a brush 75, like the first and second processing mechanism parts 20 and 21, and the brush 75 is printed by a shifter 77 that is moved and operated via a shift screw 76. It is configured so that it can be moved and operated according to the width of the substrate 4a. Note that the configurations of the blade 74 and the brush 75 are the same as the configurations of the first processing mechanism section 20, and therefore description thereof is omitted.

Further, the configurations of the rhombus deforming device 71 and the corner shift portion 73 are the same as the configurations shown in FIGS. 8b and 5b, and therefore the illustration and description thereof will be omitted. Further, the same work receiver 41 as that shown in FIG. 7 is installed at the end of the transfer line.

The fourth machining mechanism section 23 is for chamfering a chamfered surface machined by the third machining mechanism section 22 and a surface to be machined that is deviated by 90 degrees, and each of the first and third machining mechanisms. Similar to the units 20, 21, and 22, the transport unit 78, the rhombus deformation device 79, the chamfering tool unit 80, the corner shift unit 81 to the next process, and the like are included.

The transport unit 78 is for receiving and transporting the printed circuit board 4a dropped from the work receiver 41 at the end of the transport line of the third processing mechanism unit 22, and with respect to the transport line of the third processing mechanism unit 22. Orthogonal direction, that is, the second processing mechanism portion 21
It is arranged in the direction parallel to. The configuration of the transport unit 78 is the same as that shown in FIG. 5, and therefore its illustration and description will be omitted. The carrying section 78 has a structure similar to that shown in FIG. 8A and is adapted to set and adjust the carrying line width 1 to an arbitrary width.
It can be adjusted according to the width of 4a.

The tool part 80 is composed of a blade 82 and a brush 83, like the first, second, and third processing mechanism parts 20, 21, 22.
Reference numeral 3 is configured so that it can be moved and operated in accordance with the width of the printed circuit board 4a by a shifter 85 that is moved and operated via a shift screw 84. The configurations of the blades 82 and the brushes 83 are the same as the configurations of the first processing mechanism section 20, and therefore their description is omitted.

The configurations of the rhombus deforming device 79 and the corner shift 81 are the same as the configurations shown in FIGS. 8A, 8B and 5B, and therefore the illustration and description thereof are omitted. Further, the same work receiver 41 as that shown in FIG. 7 is installed at the end of the transfer line, and is configured so that it can be dropped and discharged onto the discharge transfer unit 6 shown in FIG. is there.

FIG. 4 is a plan view of the first to fourth processing mechanism units 20, 21, 22, 23, but a second processing mechanism unit is shown as a typical configuration in order to clarify the setting configuration of each transfer line. A side sectional view of 21 is shown in FIG. In the figure, the same members as those shown in FIGS. 7 and 8 are designated by the same reference numerals. 86 is a chain conveyor suspended between a driving sprocket 87 and a driven sprocket 88, 89 is a guide roller, 90 is a transmission chain, and this transmission means is a chain 90. Needless to say, it may be by means of gears or other transmission means. The frame is indicated by 91.

The discharge / conveyance unit 6 for discharging and conveying the chamfered printed circuit board 46 and the printed circuit board loading unit 7 are configured as shown in FIGS. 10 to 12.

That is, as shown in FIG. 10 and FIG. 12, the discharging / conveying unit 6 discharges onto the printed substrate stacking unit 7 the processed printed substrate 4b falling from the work receiver 41 of the fourth processing mechanism unit 23 after the processing is completed. The guide member 93 is fixed to the frame 91 of the fourth processing mechanism portion 23 through the bracket 92.
And a pusher portion 95 having a hook portion 94 that is moved and guided by the guide member 93 to press and transfer the printed circuit board 4b toward the stacking portion 7, and a cylinder device (not shown) that moves the pusher portion 95 forward and backward. I am doing it. 96
Shown is the emission reference point.

The printed circuit board loading section 7 is for loading the processed printed circuit board 4b from the discharge transport section 6, and the pallet section 97
And a pallet lifter section 98 for vertically moving the pallet 97, and a pallet carrier section 99 for moving the pallet.

The pallet portion 97 is configured to be lifted and lowered through the cylinder 100 of the lifter portion 98 and the parallel maintaining mechanism 101, and a rail 103 is provided through a rolling wheel 102 provided at a lower portion of the lifter portion 98. It is configured so that it can move along.

A processed product receiver 104 for temporarily stocking the printed circuit boards 4b discharged from the discharging / conveying unit 6 is arranged above the pallet unit 97. As shown in the figure, the receiver main body 105 of this processed product receiver 104 is a printed circuit board 4b in a stacked state of 10 processed boards.
Is set so that it can be held in a two-row state, and an opening operation can be performed in a state of being held in a two-row state, and one cut portion shown by a hatched portion in FIGS. Is set. Since the other structure is the same as that shown in FIG. 7, the same members are designated by the same reference numerals and the description thereof is omitted.

The printed circuit board loading unit 7 is moved and operated via the pallet carrier unit 99, and is configured so that the processed printed circuit board 4b can be loaded in the same layout as the cutting state shown in FIGS. It is set so that the pallet portion 97 can be lowered by an appropriate amount via the lifter portion 98 when the layout portions shown in FIGS. Reference numeral 106 indicates a positioning stopper portion.

The chamfering method of the printed circuit board of the present invention having the above configuration will be described.

Printed circuit board 4a cut by the cutting machine 2 shown in FIG.
Among them, the hatched portion in FIG. 2 is supplied onto the printed circuit board supply / conveyance unit 3, and is carried into the chamfering processing unit 5 via the supply / conveyance unit 3 via the carry-in device 10.

Unprocessed printed circuit board 4a carried into chamfering section 5
Is chamfered by the first processing mechanism section 20. That is,
The printed circuit board 4a carried into the chamfering section 5 is deformed into a rhombus by the rhombus deforming device 25, and is pressed by the shifter 36 while holding the rhombus shape, while the hook portion 30 of the conveyor 18 terminates the conveying line. Is chamfered by being transferred in the direction. As shown in FIG. 6b, chamfering is performed by using the blade 34 to cut the copper-clad side corner portion 4c of the printed circuit board 4a.
Further, the corners 4d on the resin side are chamfered by the brush 35, and the first chamfering is performed to deburr.

The printed board 4a subjected to the first chamfering process is temporarily held by the work receiver 41 at the end of the transfer line, and the line width of the second processing mechanism section 21 is adjusted to a predetermined width. When it is open, it is opened and drops onto the transport section 38 of the second processing mechanism section 21. Then, the second chamfering process is performed via the blade 66 and the brush 67 by the same action as that of the first processing mechanism unit 20. The second chamfering process, as shown in Fig. 13, is the same as the machined surface processed by the first chamfering process.
Chamfer the misaligned surface.

The printed circuit board 4a that has been subjected to the second chamfering process is dropped onto the transfer section 70 of the third processing mechanism section 22 at the end of the transfer line. Then, as shown in FIG. 13, it is deformed through the rhombus deforming device 71 so as to be able to chamfer the unprocessed corner portion which is the same surface as the cut surface chamfered by the first chamfering processing, Chamfering is performed via the blade 74 and the brush 75.

The printed board 4a that has been subjected to the third chamfering process is dropped onto the carrying section 78 of the fourth working mechanism section 23 at the terminal end of the carrying line. Then, as shown in FIG. 13, it is deformed through the rhombus deforming device 79 so as to be able to chamfer an unprocessed corner portion which is the same surface as the cutting surface chamfered by the second chamfering processing. Chamfering is performed by using the blade 82 and the brush 83.

In each of the above steps, the chamfering of the octagonal portion of the unprocessed printed circuit board 4a can be simultaneously and automatically processed in a state of stacking ten sheets.

The printed circuit board 4b after the processing is completed is placed on the processed printed circuit board stacking section 7 through the discharging / conveying section 6 and all the steps are completed.

〔The invention's effect〕

As described above, according to the present invention, it is possible to continuously and automatically chamfer each of the eight corners of a printed circuit board stacked in a plurality of stages (a plurality of sheets) or a plurality of stages (a plurality of sheets). Therefore, the workability of the chamfering work and the work efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a schematic configuration of a chamfering device used for carrying out a chamfering method for a printed circuit board according to the present invention, and FIGS. 2 a, b, c,
d, e, f, g are explanatory views of the printed circuit board that is the workpiece, the third
Fig. 4, Fig. 5, Fig. 6, Fig. 6a, b, Fig. 7, Fig. 8 a, b,
9, 10, 11 and 12 are explanatory views showing the structure of the main part of the chamfering device used for carrying out the chamfering method of the printed circuit board of the present invention, and FIG. 13 is each step of the method of the present invention. FIG. 3 …… Supply and transport section 4a, 4b …… Printed circuit board 5 …… Chamfer processing section 6 …… Discharge transport section 7 …… Processed printed circuit board loading section 25,63,71,79 …… Rhombic deformation device 26,64,72 , 80 …… Chamfering tool section

Claims (1)

[Claims] 1. A method of chamfering a corner 4c on a copper-clad side and a corner 4d on a resin side of a plurality of unprocessed printed circuit boards 4a stacked and cut in a plurality of steps or a plurality of steps, wherein the plurality of steps or A plurality of unprocessed printed circuit boards 4a stacked and cut in a large number of stages are conveyed in a predetermined direction, and during this transfer, the plurality of unprocessed printed circuit boards 4a are first moved.
After being deformed and fixed in a rhombus direction, each raw printed circuit board
The corner 4c of the first copper-clad side of 4a with the first blade 34,
The first resin side corner portion 4d on the opposite side to the blade 34
Chamfering is simultaneously performed by the first brush 35 disposed opposite to each other, and after chamfering the first copper-clad side corner portion 4c and the resin-side corner portion 4d, the plurality of unprocessed sheets are processed. The rhombus deformed state in the first direction of the printed circuit board 4a is released, this is deformed and fixed in the rhombus in the second direction, and the second copper-clad side corner portion 4c and the resin side corner portion 4d are set to the second corner. The blade 34 and the brush 35 are chamfered at the same time, and similarly, the remaining third and fourth copper-clad side corner portions 4c and resin-side corner portions 4d are removed in the same manner. And chamfering of the four copper-clad side and resin side corners 4c and 4d of the plurality of unprocessed printed circuit boards 4a while sequentially chamfering with the brush 35. Method.