JP2006190835A - Punching method for flexible printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discharge the punching dusts of a flexible printed board from a lower die taper part one after another without flying out the dust on the surface of the lower die, even when using a die having a stroke so short that a punching-through punch inserted in the die does not reach a position, where it projects to the lower die taper part from its punch holeat the shape work such as removal of blind through-holes or unused portions of a flexible printed board. <P>SOLUTION: A flexible printed board 14 has circular lands formed on both sides of an insulation layer 17 with copper foils 16a, 16b. When punching a portion surrounded by the dashed line A, the copper foil of a part 18 inside the dashed line A is previously etched to expose the insulation layer 17. A dashed line A part is punched by a punching-through punch to make the inside portion 18 of the punching dust easy to bend, as this portion is of only the insulation layer 17. This relaxes the repulsion force of the punching dust and the lower die to prevent the dust from flying out of the lower die. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a punching method for a flexible printed circuit board used in an electronic device, and in particular, a punch for punching is used for shape processing such as non-through hole processing for removing electronic parts and removal of unnecessary parts. Thus, the present invention relates to a punching method for punching and forming an opening.

  Punching using a punch for punching is widely performed as a method for forming a non-through hole, an opening for accommodating an electronic component, or the like on a flexible printed board having flexibility. Usually, a necessary conductor circuit is formed on an insulating substrate with a copper foil or the like and covered with a coverlay, a solder resist layer or the like, and then punching is performed.

  In conventional punching, a method is known in which a flexible printed circuit board is inserted between an upper mold and a lower mold, and punching is performed while pressing the flexible printed circuit board with an upper mold holding plate (see, for example, Patent Document 1). . A mold described in Patent Document 1 is shown in FIG. The die is composed of an upper die 11 and a lower die 12, and the upper die 11 has a plate 11a on which a base end portion of a punching punch 13 is fitted and a support into which a tip end portion of the punching punch 13 is inserted. The lower die 12 has a punch hole 12a into which the front end of the punch 13 is inserted and the flexible printed circuit board is punched out. The holding plate 11c has a hole 11b (upper die plate in Patent Document 1). The lower portion of the punch hole 12a is gradually expanded in diameter to be provided with a tapered portion 12b.

  As shown in FIG. 8, a flexible printed circuit board 14 is inserted between the upper mold 11 and the lower mold 12, and although not shown, a guide hole opened in the flexible printed circuit board 14 is erected in the lower mold 12. Positioning is performed by inserting the guide pin into the guide pin.

  As shown in FIG. 9, when the upper mold 11 is lowered, first, the pressing plate 11 c sandwiches the flexible printed board 14 between the lower mold 12 and corrects the distortion or bending of the flexible printed board 14. The pressing plate 11c is fixed with the flexible printed circuit board 14 sandwiched by a spring mechanism (not shown). In this state, when the upper plate 11a and the punching punch 13 fitted thereto are lowered integrally, The leading end of the punch 13 for punching is inserted into the punch hole 12a of the lower die, and the flexible printed circuit board 14 is punched by shearing between the punch 13 for punching and the lower die 12.

  As shown in FIG. 10, when the punch 13 for punching passes through the lower punch hole 12a and is inserted to the position of the taper portion 12b, the scrap 15 of the flexible printed circuit board 14 falls below the lower mold 12, The scraper 15 is not clogged in the lower mold 12. For this purpose, it is necessary to increase the overall length of the punch 13 for punching and the stroke with the lower die 12 (the length of insertion into the lower die punch hole 12a).

  Generally, the shorter the punching punch 13 is, the better the processing accuracy is, and the shorter the protrusion length when the punching punch 13 is fitted to the upper plate 11a, the better the vertical angle accuracy. Further, the shorter the stroke with the lower mold 12, the less friction is required, and the life of the mold becomes longer. Therefore, the overall length and stroke of the punch 13 for punching are preferably as short as possible. The stroke required for punching the flexible printed circuit board 14 is such that the front end of the flexible printed circuit board 14 extends from the surface of the lower mold 12 to the punch hole 12a. It is sufficient to insert about 3 mm to 0.5 mm.

  On the other hand, the length from the surface of the lower punch hole 12a to the uppermost portion of the taper portion 12b is sufficient to ensure the strength even if the lower die 12 is made of a material having high hardness such as HS steel. It is necessary to take 2mm or more. Therefore, as described above, when the punching stroke of the flexible printed board 14 is set to about 0.3 mm to 0.5 mm, the tip of the punch 13 for punching has a lower punch hole 12a as shown in FIG. The punch 15 of the flexible printed circuit board 14 is not inserted through the position of the taper portion 12b, and the punch 15a of the flexible printed circuit board 14 is clogged in the lower punch hole 12a. become.

  If this reaches the lower mold taper portion 12b and is sequentially discharged, no problem will occur. However, as shown in FIG. 12, the scraps 15 may jump out of the punch hole 12a to the surface of the lower mold 12. .

  The reason why the punch 15 is popped out from the punch hole 12a is considered as follows. In order to form a non-through hole or the like in the flexible printed circuit board 14, when a portion having a copper foil is punched, as shown in FIG. 13, the upper copper foil portion 16 a of the scraper 15 is located on the lower side. It becomes a substantially inverted trapezoid shape larger than the copper foil portion 16b. This is because the punching process is cut by shearing.

  Therefore, as shown in FIG. 14, when the chip 15 of the flexible printed circuit board 14 is pushed into the lower punch hole 12 a, the upper surface is curved convexly as indicated by the broken line H, and the repulsive force In some cases, the scraped 15 may jump out to the surface of the lower mold 12.

  On the other hand, when punching unused portions of the flexible printed circuit board 14, if the copper foil is removed by etching and only the insulating layer is formed, the mechanical strength is low, so as shown in FIG. Will be in a folded state.

  Therefore, as shown in FIG. 16, when the chip 15 of the flexible printed circuit board 14 is pushed into the punch hole 12a of the lower mold, the bent chip 15 bent as shown by the broken line I is the lower mold. When the punch 13 for punching rises, the punch 15 is instantaneously vacuum-adsorbed to the lower surface of the front end of the punch 13 and lifted up above the lower die 12. It is considered a thing.

  As described above, when the chip 15 of the flexible printed circuit board 14 jumps out to the surface of the lower mold 12 due to any cause, the punched out chip 15 is formed when the new flexible printed circuit board 14 is punched in the next step. Is sandwiched between the lower mold 12 and the flexible printed circuit board 14, thereby causing defects such as dents in the flexible printed circuit board 14.

  For this reason, each time a new flexible printed circuit board 14 is mounted, it is confirmed that there is no chip 15 on the surface of the lower mold 12, and if there is a chip 15 it must be removed by air blow or brushing. After the residue 15 is removed, the next flexible printed circuit board 14 has to be mounted, resulting in a problem that work efficiency deteriorates.

  In order to prevent the chip 15 of the flexible printed circuit board 14 from popping out on the surface of the lower mold 12, a method is also conceivable in which the lower part of the lower mold 12 is sealed and the chip 15 is sucked and discharged by air. In the case where there are a plurality of portions to be punched in 14 and suction is performed in the same system, the suction pressure is reduced and the suction / discharge operation is continuously performed at the moment when the scrap 15 is discharged at any one of the plurality of locations. Has the disadvantage that it cannot. Suction means may be individually installed at all the places to be punched, but the mold structure is complicated and difficult in reality.

In addition, in order to prevent cracks from occurring in the periphery of the opening during punching, a method of drilling a hole smaller than the opening in advance at the location to be punched (for example, Patent Document 2 and Patent Document 3), a method of drilling a plurality of holes around the inside of the opening before punching the opening (see Patent Document 4, for example), and a slit hole forming portion with a small diameter in advance. A method is known in which a preliminary hole is opened and the preliminary hole is punched with a slit hole punch provided with a projection (see, for example, Patent Document 5).
JP 7-24792 A JP-A-64-51295 JP-A-7-256594 JP-A-6-164100 Japanese Patent Laid-Open No. 7-24793

  As described above, the invention described in Patent Document 1 improves the machining accuracy and the vertical angle accuracy because the punching punch has a long stroke from the lower punch hole to the position where it projects to the tapered portion. Is difficult and the life of the mold tends to be shortened due to a lot of friction. When the stroke is shortened, the chips are accumulated in the punch holes, and the chips may pop out on the surface of the lower mold, resulting in a problem that work efficiency is deteriorated.

  The inventions described in Patent Document 2, Patent Document 3, and Patent Document 4 all prevent cracks from being generated around the opening, and even if they are not sucked with air, the scraps pop out on the surface of the lower mold. Can be prevented. However, recently, it is difficult to drill a preliminary hole by drilling because a non-through hole having a diameter of less than 1 mm is formed by punching or a fine shape is locally punched.

  The invention described in Patent Document 5 uses a slit hole punch provided with a projection, but this also requires a preliminary hole processing, and if the projection of the punch is installed without a preliminary hole, the punching shape is deformed. It will be.

  Accordingly, the present invention provides a punching method in which an opening is punched and formed using a punch for punching in a flexible printed circuit board, such as removal of non-through holes and unnecessary portions. Even if a short stroke mold that cannot be inserted from the hole to the position where it projects to the taper part is used, the scraps of the flexible printed circuit board will be ejected from the taper part of the lower mold one by one without jumping to the surface of the lower mold. An object of the present invention is to provide a simple punching method.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a punching process in which an opening is punched and formed in a flexible printed circuit board, and the portion to be punched is an insulating layer. In the punching process when the copper foil is applied to one or both sides of the pattern, the pattern forming part inside the opening is removed in advance by etching before punching the opening. And providing a punching method for a flexible printed circuit board, wherein the insulating layer is exposed.

  According to this structure, when punching a pattern forming portion where a copper foil such as a non-through hole is punched, the inner copper foil to be the opening is removed in advance by etching. Of these, the portion from which the copper foil is removed becomes only an insulating layer, so that it is easy to bend, and the repulsive force is alleviated, so that it can be prevented from jumping out to the surface of the lower mold.

  The invention according to claim 2 is a punching process in which an opening is punched and formed in a flexible printed circuit board, and the punching process is performed by attaching a circuit board auxiliary material such as a sheet or a film on one or both sides of the insulating layer. In the punching process in the case of a worn auxiliary material part, before punching the opening, the inner auxiliary material that becomes the opening is removed in advance to expose the insulating layer. A flexible printed circuit board punching method is provided.

  According to this configuration, when punching a part where a circuit board auxiliary material such as a sheet or a film is attached to the insulating layer, the inner auxiliary material that becomes the opening is previously removed by a punching process or the like. Thus, the portion of the scraped material from which the auxiliary material is removed becomes only the insulating layer, so that it becomes easy to bend, and the repulsive force is relaxed to prevent the scraped material from jumping out to the surface of the lower mold.

  The invention according to claim 3 is a punching process in which an opening is punched and formed in a flexible printed circuit board, and the copper foil is not applied to the punching part and the insulating layer is exposed. In this punching process, before punching the opening, a copper foil is left on at least a part of one or both surfaces of the insulating layer in advance in the patterning etching process in the exposed portion inside the opening. A punching method for a flexible printed circuit board is provided.

  According to this configuration, when punching a portion where the copper foil is not applied to the flexible printed board, the copper foil is left in advance in at least a part of the portion where the inner insulating layer serving as the opening is exposed. As a result, the cross-section of the punched piece has a convex shape, which increases the mechanical strength, suppresses bending of the punched-out piece, makes it easier to catch on the inner peripheral surface of the punch hole in the lower mold, and vacuum suction to the punch for punching. Can be prevented from popping out to the upper part of the lower mold.

  The invention according to claim 4 is a punching process in which an opening is punched and formed in a flexible printed circuit board, and the copper foil is not applied to the punching part and the insulating layer is exposed. In this punching process, before punching the opening, a solder resist layer is previously formed on one or both surfaces of the insulating layer at the time of forming the solder resist layer in the exposed portion inside the opening. A flexible printed circuit board punching method is provided.

  According to this configuration, when punching a portion of the flexible printed circuit board where the copper foil is not applied, a solder resist layer shape is previously formed on at least a portion of the portion where the inner insulating layer serving as the opening is exposed. By doing so, the cross-section of the punched piece has a convex shape, which increases the mechanical strength, suppresses bending of the punched-out piece and makes it easier to catch on the inner peripheral surface of the lower punch hole, It is possible to prevent the vacuum suction from being lost and the slag from popping out to the upper part of the lower mold.

  As described above, the present invention provides a punching process in which an opening is punched and formed using a punch for non-through-hole processing for mounting electronic components on a flexible printed circuit board and removal of unnecessary portions. In the method, even if a short stroke mold is used in which the punch for punching is not inserted from the punch hole of the lower mold to the position protruding to the taper portion, the bottom of the flexible printed circuit board does not pop out on the surface of the lower mold. Since it is discharged efficiently downward from the taper portion, various problems associated with the removal can be solved. In addition, it is not necessary to confirm that the surface of the lower die is removed every time immediately before starting a new punching process, and the work efficiency can be greatly improved.

  Hereinafter, a punching method for a flexible printed circuit board according to the present invention will be described with reference to preferred embodiments. In the punching method of the flexible printed circuit board, for example, the purpose of providing a punching processing method in which the scraps of the flexible printed circuit board are sequentially discharged downward from the taper portion of the lower mold without jumping out to the surface of the lower mold. Prior to punching the opening on the flexible printed circuit board, the pattern forming portion provided with the inner copper foil serving as the opening was removed in advance by etching to expose the insulating layer.

  For convenience of explanation, the same components as those described in FIGS. 7 to 16 are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows an example of punching processing in which a circular opening (non-through hole) is formed in a pattern portion (circular land) formed of a copper foil on a flexible printed circuit board. FIG. 2) is a sectional view taken along line XX. In the flexible printed circuit board 14, circular lands (wiring pattern portions) are formed by copper foils 16a and 16b on both surfaces of the insulating layer 17, and an opening is punched out in a portion surrounded by a broken line A to form a non-through hole. Form. In the inner portion 18 of the broken line A serving as an opening, the copper foil is removed in advance by etching to expose the insulating layer 17.

  If the broken line A portion of the flexible printed circuit board 14 is punched by the punch 13 for punching, as shown in FIG. 2, the scraps 15 are accumulated in the punch holes 12a of the lower mold 12, The inner portion 18 of the scraper 15 is easily bent because the copper foils 16a and 16b are removed and only the insulating layer 17 is formed. As shown by the broken line B portion, the inner portion 18 can be easily deformed, and the broken line C portion. As shown in the figure, the repulsive force between the peripheral portion of the punching residue 15 where the copper foils 16a and 16b remain and the inner peripheral surface of the lower die punch hole 12a is relaxed, and the punching residue 15 jumps out to the surface of the lower die 12. The scrap 15 is successively reached to the lower taper portion 12b and efficiently discharged downward.

  In addition, although the deformation | transformation of the chip 15 shown to the said broken line B part changes with flexibility of the insulating layer 17 of the flexible printed circuit board 14, copper foil is removed by an etching among the parts of the broken line A punched. It is effective if the inner portion 18 is formed in a region within 0.3 mm from the broken line A. That is, the copper foils 16a and 16b are left to a position within 0.3 mm from the broken line A. Therefore, for example, when a 1.0 mmφ non-through hole is formed from a circular land, the inner portion 18 from which the copper foil is removed by hatching is set to 0.4 mmφ or more. If the alignment accuracy is good, it is preferable to further increase the inner portion 18 from which the copper foil is removed to about 0.6 mm to 0.8 mm.

  In addition, when the shape of the opening formed by punching is a dimension approximated in the longitudinal direction and the short direction, as described above, the region is the same shape as the punched shape and within 0.3 mm from the broken line A It is preferable to form a copper foil removed portion by etching. However, when the shape of the opening formed by punching has a dimensional difference of 1.5 times or more between the longitudinal direction and the short side direction, the portion where the copper foil is removed is brought close to the end in the longitudinal direction. Therefore, the opening does not necessarily have the same shape as the punched opening.

  For example, as in the modification shown in FIGS. 3 (1) to (3), even if the inner portion 18 of the broken line A is etched into various shapes to remove the copper foil, the same effect as described above can be obtained. Can do. This is because the deformation in the longitudinal direction is more likely to occur due to etching, and the repulsive force between the lower punch hole 12a and the removal 15 is more effective.

  In addition, in the flexible printed circuit board 14 in Example 1 demonstrated above, although the land with copper foil 16a, 16b was shown on both surfaces of the insulating layer 17, the same effect is acquired even when there is copper foil only on one side. Needless to say.

  Although not shown, various sheets such as an adhesive sheet, a pressure-sensitive adhesive sheet, a reinforcing plate having an adhesive or a pressure-sensitive adhesive on at least one surface, an electromagnetic shield sheet, a light shielding film, etc. When forming an opening by punching the part where circuit board auxiliary material such as film is attached, before punching the opening, the inner auxiliary material that becomes the opening is punched in advance. By removing by treatment, etc., the part where the auxiliary material is removed of the scrap is only an insulating layer, so it becomes easy to bend and the repulsion is relaxed to prevent the scrap from jumping to the surface of the lower mold it can. The region for removing the auxiliary material is the same as the punching process for removing the copper foil described with reference to FIGS.

  FIG. 4 shows an example of punching for punching and forming a circular opening that becomes a useless part in a portion where the flexible printed board does not have a copper foil and the insulating layer is exposed. FIG. 4A is a plan view. 2) is a sectional view taken along line YY. In the flexible printed circuit board 14, the copper foil is not given to the opening part shown with the broken line D, but the insulating layer 17 is exposed. In the inner portion of the broken line D, a copper foil is left on at least a part of one or both surfaces of the insulating layer 17 in advance during the pattern forming etching process, or at least one surface or both surfaces of the insulating layer 17 is previously illustrated as illustrated. Solder resist layers 21a and 21b are formed in part.

  If the inner side of the broken line D of the flexible printed circuit board 14 is punched with the punch 13 for punching, the scraps 15 are accumulated in the punch holes 12a of the lower die 12 as shown in FIG. However, since the cross section of the punch 15 has a convex shape, the mechanical strength increases, and as shown by the broken line E and the broken line F, the bending of the punch 15 is suppressed and the inner circumference of the lower punch hole 12a is reduced. It becomes easy to get caught on the surface, and the vacuum suction to the punch 13 for punching is lost, so that the punch 15 can be prevented from jumping out to the upper part of the lower die 12.

  In order to suppress the bending of the punched-out 15, it is effective to form the copper foil or solder resist layers 21 a and 21 b within a region within 0.3 mm from the broken line D in the punched broken line D portion. That is, the insulating layer 17 is exposed to a position within 0.3 mm from the broken line D. The convex portions formed by the copper foil or the solder resist layers 21a and 21b are convex portions having a cross section in a region of about 0.1 mm to 0.3 mm from the broken line D, considering that the punch 13 does not slip out. Is preferably formed. Therefore, for example, when punching out a 1.0 mmφ circle, a convex section having a cross section of about 0.4 mmφ to 0.8 mmφ is formed.

  In addition, when the shape of the opening formed by punching is a dimension approximated in the longitudinal direction and the short direction, as described above, the shape is close to the same as the punched shape and within 0.3 mm from the broken line D. It is preferable to form a convex section in cross section with copper foil or solder resist layers 21a and 21b up to the region. However, the curved portion of the cutout 15 is suppressed by the convex portion of the cross section, the cutout 15 is easily caught on the inner peripheral surface of the lower punch hole 12a, and the vacuum suction between the cutout 15 and the punch 13 for punching is alleviated. If it is a shape, it does not necessarily have to be the same shape as the opening by punching.

  For example, as in the modifications shown in FIGS. 6 (1) to 6 (3), even if the cross-section convex portions are formed with copper foil or solder resist layers 21a and 21b in various shapes inside the broken line D, they are removed. It is possible to obtain the same effect as described above by suppressing the bending of the debris.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

An example of the punching process of the flexible printed circuit board which concerns on this invention is shown, (1) is a land-shaped top view by which the copper foil is given to the punching position. (2) is a sectional view taken along line XX of (1). The longitudinal cross-sectional view which shows the behavior of the chipping in the lower mold | type when the land shape shown in FIG. 1 is punched. (1)-(3) is the explanatory top view which shows the modification of the land shape shown in FIG. An example of the punching process of the flexible printed circuit board which concerns on this invention is shown, (1) is a land-shaped top view in which the copper foil is not given to the punching position. (2) is the YY sectional view taken on the line of (1). The longitudinal cross-sectional view which shows the behavior of the chipping in the lower mold | type when the land shape shown in FIG. 4 is punched. (1)-(3) is an explanatory top view which shows the modification of the land shape shown in FIG. The longitudinal cross-sectional view which shows schematic structure of the conventional punching type | mold. The longitudinal cross-sectional view which shows the punching process method of a flexible printed circuit board using the punching type | mold shown in FIG. The longitudinal cross-sectional view which shows the next process of the punching method shown in FIG. The longitudinal cross-sectional view which shows the next process of the punching method shown in FIG. The longitudinal cross-sectional view which shows the behavior of the removal in a lower mold | type in case the stroke of a punch is short with the conventional punching type | mold. FIG. 10 is a perspective view showing a behavior in which a punching die pops out from a punch hole of a lower die when a punching stroke is short in a conventional punching die. The longitudinal cross-sectional view of the omission part when the part by which the copper foil is given to both surfaces with the conventional punching type | mold is punched. FIG. 6 is a longitudinal sectional view showing a behavior in which a portion punched out on both sides of a conventional punching mold is popped out from a punch hole in a lower mold. The longitudinal cross-sectional view of the omission part when punching the part only of an insulating layer with the conventional punching type | mold. FIG. 6 is a longitudinal sectional view showing a behavior in which a portion punched out of a lower die is punched out when a portion of only an insulating layer is punched with a conventional punching die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Upper mold | type 12 Lower mold | type 12a Punch hole 12b Taper part 13 Punch | punch for punching 14 Flexible printed circuit board 15 Debris 16a, 16b Copper foil 17 Insulating layer 18 Inner part of the broken line A 21a, 21b Solder resist layer

Claims (4)

In punching processing for punching and forming an opening in a flexible printed circuit board, where the punching processing is a pattern formation site where copper foil is applied to one or both sides of the insulating layer,
A punching method for a flexible printed circuit board, wherein, before punching the opening, the pattern forming portion inside the opening is removed in advance by etching to expose the insulating layer. A punching process for punching and forming an opening in a flexible printed circuit board, where the punching position is a part of a supplementary material in which a circuit board auxiliary material such as a sheet or film is attached to one or both sides of an insulating layer In punching in some cases,
A punching method for a flexible printed board, wherein the insulating layer is exposed by previously removing the auxiliary material inside the opening before punching the opening. In punching processing for punching and forming an opening in a flexible printed circuit board, in which the copper foil is not applied to the portion to be punched, and in the punching processing in which the insulating layer is exposed,
Before punching the opening, a copper foil is left in advance on at least a part of one or both sides of the insulating layer in the exposed portion on the inner side that becomes the opening at the time of patterning etching. Punching method for flexible printed circuit board. In punching processing for punching and forming an opening in a flexible printed circuit board, in which the copper foil is not applied to the portion to be punched, and in the punching processing in which the insulating layer is exposed,
Before punching the opening, a solder resist layer is formed in advance on one or both sides of the insulating layer at the time of forming the solder resist layer on the exposed portion inside the opening. Substrate punching method.

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