Substrate processing method

Abstract

To provide a substrate processing method that can form a flat surface for positioning, on a bottom surface of a recessed part, and also prevent burr from occurring.SOLUTION: A substrate processing method comprises a first step of forming a tip hole 20, in a first foot area in an M-shape using a drill DR with a small diameter, and a second step of performing cutting while moving a router RT along a track TK in a nearly M-shape in a direction going from the first foot area toward a second foot area. In the second step, the router RT is moved without expanding the tip hole 20 in the first foot area and is moved linearly between the first foot area and the second foot area, and the router is moved along the track KT extending to a position deeper than a bottom surface 11 of a recessed part 10, in the second foot area, which can expand an interval between deeply-dug parts 12 and 13 of both feet in a nearly M-shape to form the bottom surface 11 into a planar shape, and also can scrape off burr generated in drill processing, by router processing that is performed thereafter.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a substrate processing method for forming a narrow concave portion having a planar bottom surface in the center at the outer peripheral edge portion of a printed circuit board.

Background Art

[0002] For the outer shape processing of a printed circuit board, in order to prevent the generation of burrs and broken chips, it has become mainstream to perform the processing using a router. Router processing is a method of performing processing such as cutting while moving a columnar router bit (simply referred to as a router) with a blade on its side along a given track on the substrate in one direction. For example, Patent Documents 1 and 2 disclose methods for cutting a printed circuit board by router processing.

[0003] In the processing method described in Patent Document 1, a clockwise rotation router bit is moved to one end side of a hole portion so that the rotation direction faces the inner wall surface direction of the hole portion to cut the substrate, and the cutting is terminated when one end side of the hole portion is cut. Thereafter, a counterclockwise rotation router bit is moved to the other end side of the hole portion so that the rotation direction faces the inner wall surface direction of the hole portion to cut the substrate, and the cutting is terminated when the other end side of the hole portion is cut. Thereby, the printed circuit board is cut so as to cross the hole portion formed therein.

[0004] In the processing method described in Patent Document 2, in the case of cutting out a plurality of printed circuit boards from a single plate, by forming the corners of each printed circuit board in an arc shape that protrudes inwardly of the substrate, a V-shaped cross-section groove portion (V-cut) for separating the printed circuit boards can be formed using router processing.

[0005] Incidentally, as a positioning structure for fixing a printed circuit board to a chassis or the like, a recess may be formed at the outer peripheral edge of the printed circuit board. When the boss for fixing the substrate provided on the chassis is configured in a prismatic shape, a configuration in which the bottom surface of the recess and the plane of the boss are in surface contact is required for positioning. With the recent miniaturization of products, the printed circuit board has also been miniaturized, and accordingly, the positioning recess has become narrower. However, there is a need to form this by router processing.

[0006] Figs. 3 to 6 are diagrams showing examples of conventional processing methods for forming a recess 100 at the outer peripheral edge of a printed circuit board. Fig. 3 shows a method of forming a recess only by router processing. In Fig. 3, the dotted arrow indicates the trajectory of the router RT. Since the router RT has a cylindrical shape, the peripheral edge 102 of the bottom surface 101 of the recess 100 formed by cutting is rounded, and the width becomes narrower as it approaches the bottom surface 101. Therefore, even if the width W of the boss 200 inserted into the recess 100 is smaller than the width W1 of the opening of the recess 100 O if it is larger than the width W1 of the straight portion of the bottom surface 101 B the boss 200 cannot be in surface contact with the bottom surface 101 of the recess 100.

[0007] Fig. 4 also shows a method of forming a recess 110 only by router processing, but the trajectory of the router RT indicated by the dotted arrow is different from that in Fig. 3. Since the trajectory of the router RT shown in Fig. 4(a) has a shape similar to the alphabet "M", hereinafter, such a processing method will be referred to as "M-shaped processing". By performing M-shaped processing, a flat bottom surface 111 is formed only at the central portion of the recess 110, and there is no rounded portion where the width gradually narrows at a portion shallower than the bottom surface 111. As a result, as shown in Fig. 4(b), without widening the width W1 of the opening of the recess 110 O it is possible to bring the plane of the boss 200 having a width W (W1 B < W < W1 O ) into surface contact with the bottom surface 111 of the recess 110.

[0008] However, as shown in FIG. 5, the opening width W2 of the recess 120 required according to the width of the boss 200 O is further narrowed (W1 O >W2 O ), when performing M-shaped machining only with the router RT, the bottom surface 121 of the recess 120 itself cannot form a rounded plane, and the plane of the boss 200 cannot be brought into surface contact with the bottom surface 121 of the recess 120.

[0009] On the other hand, FIG. 6 shows a method of forming the recess 130 by M-shaped machining using a combination of slot machining with a drill and router machining. FIG. 6(a) shows a step of forming a slot 132 in accordance with the position where the recess 130 is to be formed using a drill DR having a smaller diameter than the router RT. FIG. 6(b) shows a step of forming the recess 130 by router machining performed after the slot machining. By forming the slot 132 with the drill DR to a position deeper than the position that will become the bottom surface 131 of the recess 130 before performing the router machining, it becomes unnecessary to move the router RT with a larger diameter deeper than the bottom surface 131 during the subsequent router machining.

[0010] With a machining method as shown in FIG. 6, even when forming the recess 130 with the narrowed width W2 O , it is possible to form the bottom surface 131 as a flat surface, and it is possible to bring the plane of the boss into surface contact with the bottom surface 131. However, when the router RT is moved along the trajectory of the dotted arrow in FIG. 6(b), as shown in FIG. 6(c), there is a problem that burrs 133 are generated on the peripheral portion on the rear side of the router trajectory of the bottom surface 131. This is because, due to the nature of router machining where the router RT is moved in one direction like a single stroke, there is a portion that cannot be cut off by the blade of the router RT with the burrs 133 generated during the previous slot machining. When burrs 133 are generated, it is necessary to add a burr removal process, resulting in an increase in man-hours.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0012] The present invention has been made to solve such problems, and when forming a narrow recess on the outer peripheral edge of a printed circuit board, it is possible to form a positioning plane on the bottom surface of the recess and also prevent the generation of burrs.

Means for Solving the Problems

[0013] In order to solve the above problems, in the present invention, after forming a pilot hole in a region including a position deeper than the position that becomes the bottom surface of the recess in the first leg region corresponding to one leg of the M shape using a drill smaller in diameter than the router, the router is moved along a substantially M-shaped track in the direction from the side of the first leg region where the pilot hole is formed toward the side of the second leg region corresponding to the other leg of the M shape while cutting the outer peripheral edge of the printed circuit board to form a recess. The substantially M-shaped track moves without expanding the pilot hole formed at a position deeper than the position that becomes the bottom surface of the recess in the first leg region, moves linearly in the bottom surface region between the first leg region and the second leg region, and moves to a position deeper than the position that becomes the bottom surface of the recess in the second leg region.

Effects of the Invention

[0014] According to the present invention configured as described above, when forming a recess on the outer periphery of a printed circuit board by M-shaped drilling, a pilot hole is formed using a drill with a smaller diameter than a router only in the first leg region corresponding to one leg of the M. This allows for a wider gap between the deep drilled portion of the first leg region and the deep drilled portion of the second leg region compared to when a router is used to drill deeper than the bottom of the recess in both legs of the M. Therefore, even when forming a narrow recess, a flat bottom can be formed in the center of the recess (between the first and second leg regions). Furthermore, according to the present invention, because pilot holes are formed only in the first leg region by drilling, no burrs are generated in the second leg region. Any burrs generated in the first leg region by drilling are subsequently scraped off by the router moving above the burrs. As described above, according to the present invention, when forming a narrow recess on the outer periphery of a printed circuit board, a flat positioning surface can be formed on the bottom of the recess and burrs can be prevented. [Brief explanation of the drawings]

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a recess formed in the outer peripheral edge portion of a printed circuit board by the substrate processing method of the present embodiment. As shown in FIG. 1, in the present embodiment, a narrow recess 10 having a planar bottom surface 11 at the center is formed. The term "narrow" means that the opening width W2 of the recess O is small. According to the present embodiment, even with a router of φ1 mm, in the recess 10 having an opening width W2 of only about 3 mm O it is possible to form a bottom surface 11 having a width W2 of about 0.8 mm. B

[0017] FIG. 2 is a diagram for explaining the substrate processing method according to the present embodiment, and is a diagram showing a processed portion of a printed circuit board in which the recess 10 is formed. FIG. 2(a) shows the first step of the substrate processing method, and FIG. 2(b) shows the second step. In FIG. 2(a), the shape of the recess 10 finally formed is indicated by a dotted line.

[0018] In the first step shown in FIG. 2(a), using a drill DR (for example, a drill of φ0.6 mm) having a smaller diameter than the router RT, in the first foot region corresponding to one leg of the M shape, at a position deeper than the position that will become the bottom surface 11 of the recess 10 (the deep excavation portion 12 of the first foot region), a pilot hole 20 is formed in the region including the position. In the present embodiment, instead of performing pilot hole processing in the first foot region and the second foot region corresponding to both legs of the M shape, the pilot hole 20 is formed only in the first foot region.

[0019] Here, by repeatedly performing a drilling process in which the drill DR operates vertically with respect to the printed circuit board while changing the position of the drill DR, an oblong pilot hole 20 is formed. The region including a position deeper than the position that will become the bottom surface 11 of the recess 10 means a region that satisfies the condition that the rounded portion formed by drilling using a cylindrical drill DR is at a position deeper than the bottom surface 11. The region where the pilot hole 20 is formed may be any region that satisfies this condition. That is, the pilot hole 20 does not have to be in an oblong shape, and may be in a short hole shape.

[0020] In the second step shown in FIG. 2(b), the router RT is moved along a substantially M-shaped orbit TK in a direction from the side of the first leg region where the pilot hole 20 is formed toward the side of the second leg region corresponding to the other leg of the M shape, and the outer peripheral edge of the printed circuit board is cut to form the recess 10. The orbit TK of the router RT is preset in the router processing machine, and the router processing machine moves the router RT according to the preset orbit TK. The term "substantially M-shaped" rather than "M-shaped" means that the length of the portion corresponding to one leg of the M shape and the length of the portion corresponding to the other leg are not the same.

[0021] The substantially M-shaped orbit TK moves without expanding the pilot hole 20 formed at a position deeper than the position that will become the bottom surface 11 of the recess 10 in the first leg region, moves linearly in the bottom surface region between the first leg region and the second leg region, and moves to a position deeper than the position that will become the bottom surface 11 of the recess 10 in the second leg region. By cutting the printed circuit board while the router RT moves along this series of orbits TK, the recess 10 having the shape shown in FIG. 1 is formed at the outer peripheral edge of the printed circuit board.

[0022]

[0021] That is, in the first leg region, the router RT moves from the outer peripheral edge side of the printed circuit board toward the inside (from the opening side of the recess 10 to the bottom surface side) along the pilot hole 20 in the middle and moves to the bottom surface region without digging deeper than the position that will become the bottom surface 11 of the recess 10. As a result, the deepened portion 12 of the pilot hole 20 formed by the drill DR is substantially maintained as it is.

[0023] In the subsequent bottom surface area, the router RT moves linearly. Thereby, a planar bottom surface 11 is formed. In the present embodiment, a pilot hole 20 is formed by a drill DR having a diameter smaller than that of the router RT, and the cutting of the bottom surface area is advanced while making use of the pilot hole 20. For this reason, as compared with the case where both leg regions of the M shape in FIG. 5 are each router-processed, a long distance can be ensured between the deepened portion 12a formed by the pilot hole 20 and the deepened portion 13 formed by the router processing in the next second leg region, and a planar bottom surface 11 can be formed here.

[0024] In the last second leg region, after the router RT moves to a position deeper than the position that becomes the bottom surface 11 of the recess 10, it moves toward the outer peripheral edge of the printed circuit board. The position deeper than the position that becomes the bottom surface 11 of the recess 10 means a region that satisfies the condition that a rounded portion formed by cutting using the cylindrical router RT is at a position deeper than the bottom surface 11.

[0025] The rotation direction of the router RT when moving along such a series of trajectories TK is such that when the router RT moves toward the outer peripheral edge of the printed circuit board (the opening of the recess 10) in the second leg region, the router RT presses against the peripheral edge portion on the second leg region side of the bottom surface 11. In the case of FIG. 2(b), it is the clockwise direction. By doing so, generation of burrs due to router processing can be prevented at the peripheral edge portion on the second leg region side of the bottom surface 11.

[0026] As described in detail above, in the present embodiment, when forming the recess 10 in the outer peripheral edge portion of the printed circuit board by M-shaped processing, the pilot hole 20 is formed using the drill DR having a diameter smaller than that of the router RT only in the first leg region corresponding to one leg of the M shape. As a result, as shown in FIG. 5, compared with the case where deep digging is performed to a position deeper than the position that becomes the bottom surface of the recess 120 by the router RT in both regions corresponding to both legs of the M shape, the depth of the first leg region formed by the drill DR can be increased. It is possible to widen the interval between the dug-out portion 12a and the dug-out portion 13 of the second leg region formed by the router RT.

[0027] Therefore, even when forming the narrow recess 10, it is possible to form the planar bottom surface 11 in the central portion of the recess 10 (between the first leg region and the second leg region). When forming the recess 10 with the opening width W2 O = 3 mm using the drill DR of φ0.6 mm and the router RT of φ1 mm, it is possible to form the bottom surface 11 having a flat surface with a width of 0.8 mm. Further, even when forming the recess 10 with an even narrower opening width W2 O = 2.8 mm, it is possible to form the bottom surface 11 having a flat surface with a width of 0.5 mm.

[0028] Further, according to the present embodiment, since the pilot hole 20 is formed by drilling only in the first leg region, no burrs are generated by drilling in the second leg region. The burrs generated by drilling in the first leg region are scraped off in a form that is caught by the router RT moving from above the burrs. On the other hand, since only routing is performed in the second leg region, burrs are less likely to be generated compared to drilling. Moreover, by rotating the router RT in a direction that presses the peripheral edge portion on the second leg region side of the bottom surface 11 by the router RT, it is possible to reliably prevent the generation of burrs associated with routing.

[0029] As described above, according to the substrate processing method of the present embodiment, when forming a narrow recess in the outer peripheral edge portion of the printed circuit board, a positioning plane can be formed on the bottom surface of the recess, and the generation of burrs can also be prevented. In addition, since the pilot hole processing is only required once and the burr removal process after the router processing is also unnecessary, the processing man-hours and costs can be reduced.

[0030] In the above embodiment, an example has been described in which after forming the pilot hole 20 in the first leg region of the recess 10, the router RT is moved in the direction from the first leg region toward the second leg region to cut the printed circuit board. However, the reverse may also be possible. That is, after forming the pilot hole 20 in the second leg region of the recess 10, the router RT may be moved in the direction from the second leg region toward the first leg region to cut the printed circuit board. In this case, the rotation direction of the router RT shall be counterclockwise.

[0031] In addition, each of the above embodiments merely shows an example of the implementation of the present invention, and the technical scope of the present invention should not be construed in a limited manner by this. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

Explanation of Reference Numerals

[0032] 10 Recess 11 Bottom Surface 12 Deepened Portion of the First Leg Region 13 Deepened Portion of the Second Leg Region 20 Pilot Hole RT Router DR Drill TK Substantially M-shaped Orbit of the Router

Claims

1. A substrate processing method for forming a narrow recess having a planar bottom surface at the outer peripheral edge of a printed circuit board, comprising: a first step of forming a pilot hole in a region including a position deeper than the position of the bottom surface of the recess in a first leg region corresponding to one leg of the M shape using a drill smaller in diameter than a router; a second step of forming the recess by cutting the outer peripheral edge of the printed circuit board while moving the router along a substantially M-shaped trajectory in a direction from the side of the first leg region where the pilot hole is formed toward the side of a second leg region corresponding to the other leg of the M shape; wherein the substantially M-shaped trajectory moves without expanding the pilot hole formed at a position deeper than the position of the bottom surface of the recess in the first leg region, moves linearly in the bottom surface region between the first leg region and the second leg region, and moves to a position deeper than the position of the bottom surface of the recess in the second leg region. A substrate processing method characterized by the above.

2. The substrate processing method according to claim 1, wherein the rotation direction of the router is a rotation direction such that when the router moves toward the outer peripheral edge of the printed circuit board in the second leg region, the router presses against the peripheral edge portion on the second leg region side of the bottom surface.

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