TWI523713B - Printed circuit board drilling machine - Google Patents

Description

Printed circuit board drilling machine

The present invention relates to a printed circuit board drilling machine in which a spindle which can be arbitrarily rotated at a center portion is included in a spindle group, and a presser foot (circuit board presser foot) disposed at a front end of the spindle group is used. The workpiece is processed by applying pressure to the workpiece under pressure.

In the case of processing on a printed circuit board, a plurality of printed circuit boards are laminated first, and then processed on a plurality of printed circuit boards to improve work efficiency. Further, in order to prevent the hair from being generated at the entrance of the hole after the processing, the upper plate is usually placed on the uppermost layer of the printed circuit board after lamination. In the following, the combined printed circuit board and upper board are collectively referred to as a printed circuit board. Most of the time, the board thickness of the printed circuit board is not completely uniform, so a gap will be generated in the lower direction of the printed circuit board after the layer is stacked. In such a case, the printed circuit board may be moved in the up and down direction along with the drilling of the drill bit, and thus the drill bit may be broken. Therefore, the presser foot is used to press the periphery of the processed portion on the printed circuit board in advance, and the drill bit is drilled while the printed circuit board is pressed against the table.

Further, a space formed between the presser foot and the mandrel group (hereinafter referred to as "inner foot inner space") is connected to the dust collector, and the outside air is passed through a hole provided on the presser foot for the drill bit to pass through (hereinafter referred to as a drill bit) The hole is taken out and the drilled powder produced in the process is recovered from the printed circuit board. In the case of a printed circuit board drilling machine, since the processing time (Tact) during processing is short, the dust collector is often in operation during processing of the printed circuit board.

When the drill bit is moved to the next processing position, if the distance between the printed circuit board and the presser foot is shortened, that is, the empty cutting time is shortened, the machining efficiency can be improved. However, when the presser foot is brought close to the printed circuit board, the upper plate is lifted upward due to the attraction of the dust collector, and the drill hole having the air inflow function is blocked by the hole, so that the drill cutting powder cannot be completely discharged.

Therefore, a proposal relating to a printed circuit board drilling machine that allows relative movement of the presser foot and the mandrel group when the workpiece is pressed is proposed (Patent Document 1). That is, only when the workpiece is processed, the vent hole for connecting the space inside the presser foot to the outside air is disposed on the side of the presser foot opposite to the mandrel group, and the presser foot is processed at the time of processing. The inner space is isolated from the outside air and allows the space inside the presser foot to be connected to the outside air as the bit is moved to the next machining position.

The aperture obtained by the printed circuit board drilling machine is usually 0.1 to 6.4 mm. In order to easily position the spindle in the height direction, it is the distance from the front end of the spindle to the front end of the drill (first edge) (hereinafter referred to as The length of the drill bit is set to a constant value (for example, 25 mm) regardless of the nominal outer diameter of the drill bit. Therefore, according to the technique of Patent Document 1, it is possible to surely discharge the drill cutting powder and prevent the floating of the upper plate from occurring when the drill bit moves to the next processing position.

Prior technical literature

Patent Document 1: JP-A-2008-80433.

In the case of a fine-diameter drilling, there is a problem that the machining accuracy is poor due to the vibration of the tip end of the drill at the time of high-speed rotation. In this case, if the length of the drill bit is shortened (for example, 15 mm), the machining accuracy can be improved. Hereinafter, the processing by the length of the drill having the same length as the conventional length is referred to as "normal processing", and the case where the length of the drill having the length shortened is used for processing is referred to as "high-precision machining". Further, in the case of performing high-precision machining in comparison with the assembly position of the mandrel group at the time of normal processing, the assembly position of the mandrel group is lowered with respect to the chuck for holding the mandrel group, and the bit is shortened. Prominent length.

Fig. 6 is a view showing a problem occurring in the case of using the technique of Patent Document 1, wherein (a) is a case where the position of the vent hole is placed at a position suitable for normal machining, and high-precision machining is performed, and (b) is a pass. The position of the air holes is placed in a position where normal machining is performed at a position where high-precision machining is applied.

As shown in (a), when the mandrel group 1 is horizontally moved to the next machining position in the normal machining, the spindle group 1 positioned for high-precision machining is set on the presser foot 7 The vent hole 8 is blocked, so that the pressure in the space 31 in the presser foot cannot be raised, and the upper plate floats. Further, as shown in (b), in the high-precision machining, when the front end of the drill bit 6 comes into contact with the upper end of the workpiece 20, the mandrel group 1 positioned to be suitable for normal processing leaves the vent hole 8, so the outside air The pressure in the presser foot 8 flows into the presser foot inner space 31, so that the pressure in the presser foot space 31 cannot be lowered, and the dust collecting ability is insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a printed circuit board drilling machine which can reduce the amount of air cutting and improve the machining efficiency regardless of whether it is normal machining or high-precision machining.

In order to solve the above problems, the printed circuit board drilling machine of the present invention comprises: a mandrel set held on the collet for holding the tool and allowing the tool to rotate arbitrarily; and a presser foot supported on the collet And it is arbitrarily slid along the axial direction of the tool, and is fitted to the mandrel group as if covering the front end of the mandrel group. Providing a vent hole on a side surface of the presser foot to allow a space formed by the presser foot and the mandrel group to communicate with external air, and simultaneously connecting the space to a negative pressure source, and then pressing the workpiece through the presser foot And processing the workpiece on the workpiece by the tool in a state in which the vent hole is occluded, wherein the tool is held in the spindle group closest to the workpiece side with respect to the chuck, When the front end of the tool contacts the upper surface of the workpiece, the vent hole is disposed at a position where the space and the outside air communicate with each other, and a plate-shaped shutter is disposed at the front end of the presser foot. When the workpiece is in contact, one end of the shutter is positioned such that when the front end of the presser foot is not in contact with the workpiece, a certain distance is upward from the lower end of the vent hole whose opening is outside the presser foot Position, and the distance is equal to the distance from the front end of the presser foot to the front end of the tool when the front end of the presser foot is not in contact with the workpiece, and the shutter It end, is held in the chuck, but also, the aforementioned tip tool into contact to the top of the workpiece, using the shutter will isolate the air space outside.

Whether it is normal machining or high-precision machining, the space inside the presser foot can be kept under negative pressure during machining, and the workpiece can be prevented from floating when the mandrel group is raised or moved horizontally, so that the machining efficiency can be improved. In addition, due to the simple construction of the device, the operating cost can also be reduced.

Embodiments of the present invention will be described below based on the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front partial cross-sectional view of the head of a related printed circuit board drilling machine of the present invention, showing the mandrel set being positioned at a high precision machining position. Fig. 2 is a view in the direction of arrow A in Fig. 1.

As shown in Fig. 1, a mandrel set 1 having a cylindrical outer shape is fixed to the collet 2. The collet 2 is fixed to the saddle 3 again. A pair of bearings 4 are disposed at both ends of the lower side of the chuck 2. The saddle 3 is supported by the carriage 5 and can be positioned arbitrarily in the up and down direction (Z direction). The carriage 5 is supported by a machine column not shown in the drawing, and can be positioned arbitrarily in the left-right direction (Y direction) of the figure. According to the above configuration, the mandrel group 1 can be positioned arbitrarily in the upper and lower directions of the drawing. The drill bit 6 is supported by the front end of the mandrel set 1 and can be arbitrarily rotated. In the case of the mandrel group 1 shown in the drawing, a chamfer of 45 degrees is formed at the front end portion.

The cup-shaped presser foot 7 is fitted to the front end of the mandrel group 1 and can be arbitrarily slid. The radial direction gap between the mandrel group 1 and the presser foot 7 is about 0.1 mm in diameter. A pair of support rods 15 are fixed to both ends of the presser foot 7, supported by the bearing 4, and respectively coupled to one end of the flexible coupling 16. The other end of the flexible coupling 16 is coupled to one end of a pair of cylinders 17, respectively. The other ends of the cylinders 17 are again fixed to the holders 18, respectively. The support 18 is then fixed to the saddle 3 respectively. Further, the cylinder 17 is continuously pressed against the presser foot 7 toward the lower side of the figure.

A vent hole 8 is disposed on the left side surface of the presser foot 7. The position of the vent hole 8 in the size and height direction is as will be described later.

As shown in Fig. 2, a portion of the side of the presser foot 7 for arranging the vent hole 8 is formed with a flat surface 7a. Further, the same surface 2a as the surface 7a is also formed on the side surface of the chuck 2.

The material of the shutter 50 is a metal such as stainless steel, and forms a square flat plate having a plate thickness t. The side 51a of the lower end of the shutter 50 is adhered to the surface 7a, and is fixed to the surface 2a by two screws 51.

A resin or metal bushing 9 is fixed to the lower portion of the presser foot 7. A cross-shaped groove 11 for connecting to the outer air and the drill hole 10 is formed at the lower end portion of the bushing 9. Further, since the presser foot 7 and the bushing 9 are integrally formed integrally, the lower end face of the bushing 9 is referred to as the lower end face 7b of the presser foot 7 in the following.

The hole 30 provided on the lower end side of the presser foot 7 is connected to the pipe joint 32 by the presser foot inner space 31 formed by the presser foot 7 and the mandrel group 1. The tube 33 is attached to the pipe joint 32, and the other end of the pipe 33 is connected to a dust collector not shown in the drawing.

The printed circuit board 20 as a workpiece is placed on the table 21. The table 21 can be positioned arbitrarily in the front-rear direction (X direction) perpendicular to the plane of the paper.

With the above configuration, when the fixed position of the mandrel group 1 is changed with respect to the chuck 2 in the direction of the axis O of the mandrel group 1, the length in the axis O direction of the space inside the presser foot 31 is changed.

Next, the position in the height direction of the vent hole 8 will be described.

Fig. 3 is an enlarged schematic view showing the periphery of the front end of the presser foot 7, wherein (a) shows the lower end face 7b of the presser foot 7 contacting the upper surface of the printed circuit board 20, and (b) shows the drill bit 6 When the front end contacts the upper side of the printed circuit board 20. Further, the mandrel group 1 is set at a height for high-precision machining.

Here, when the lower end surface 7b of the presser foot 7 leaves the printed circuit board 20, when the printed circuit board 20 is touched, the distance between the front end 1a of the mandrel group 1 and the lower end surface 7b of the presser foot 7 is set to L, and the distance L at the time of normal processing is Ln, and the distance L at the time of high-precision machining is Lk, Ln>Lk. However, regardless of whether the presser foot 7 is at a distance Ln or a distance Lk, the front end of the drill bit 6 is positioned at a certain distance h above the lower end surface 7b (usually 2 to 3 mm, here set to 2 mm) . Therefore, in the case of the present embodiment, when the lower end surface 7b of the presser foot 7 comes into contact with the upper surface of the printed circuit board 20, the distance between the front end 1a of the mandrel group 1 and the lower end surface 7b of the presser foot 7 is Lk, and The front end of the drill bit 6 is located at a distance h from the lower end surface 7b.

In the case of the illustration, the vent hole 8 is formed in a circular shape having a diameter of m. Further, the vent hole 8 faces the outer air side upper end 8oa and has the same Z-direction height as the upper end 8ia facing the presser foot inner space 31 side. The lower end 8ib is positioned to allow the space 31 in the presser foot to communicate with the outside air when the front end of the drill bit 6 comes into contact with the upper surface of the printed circuit board 20. That is, when the chamfered portion is formed at the front end of the mandrel group 1 as shown in the figure, the lower end 8ib is disposed at a position lower than the upper side 1j of the chamfered portion. The following setting is m=3mm. In the present embodiment, although the shape of the vent hole 8 is circular, the vent hole 8 may be an oblong hole having a small shape.

The lower end 50a of the shutter 50 is located at a distance h from the lower end 80b of the vent hole 8 when the lower end surface 7b of the presser foot 7 is separated (or is in contact with) the upper surface of the printed circuit board 20. The shutter 50 is fixed to the upper side of the collet 2. Further, the width of the shutter 50 is such that each side thereof has a length of about 2 mm or more longer than both ends of the width (caliber) m of the vent hole 8, and has a plate thickness t of 1 to 2 mm. Further, the distance H shown in the same figure (a) is when the lower end surface 7b of the presser foot 7 is separated from the upper surface of the printed circuit board 20 (or the lower end surface 7b of the presser foot 7 contacts the printed circuit board 20). The upper side is the distance from the lower end surface 7b of the presser foot 7 to the lower end 50a of the shutter 50.

Next, the operation of the present invention will be described.

When the mandrel group 1 is moved in the horizontal direction, the lower end surface 7b of the presser foot 7 is away from the printed circuit board 20, and the vent hole 8 is from the lower end surface 8ob to the position opposite to the lower end 50a of the shutter 50, It is connected to the outer gas phase. Further, since the drill hole 10 is also in an open state, the outside air flows into the presser foot space 31 through the vent hole 8 and the drill hole 10. As a result, the pressure around the drill hole 10 is close to the atmospheric pressure, and the floating phenomenon of the printed circuit board 20 does not occur.

The shutter 50 and the drill bit 6 (i.e., the spindle group 1) are simultaneously lowered as a whole while the lower end surface 7b is in contact with the printed circuit board 20 until the front end of the drill bit 6 contacts the printed circuit board 20. Therefore, during the period in which the lower end surface 7b contacts the printed circuit board 20 to the front end of the drill bit 6 and contacts the printed circuit board 20, the substantial cross-sectional area of the vent hole 8 is gradually reduced due to the lowering of the shutter 50, when the drill bit 6 is lowered. When the front end contacts the printed circuit board 20, as shown in Fig. 3(b), the vent hole 8 is isolated from the outside air via the shutter 50, and the substantial cross-sectional area of the vent hole 8 becomes zero. Therefore, at the time of processing, the space inside the presser foot 31 is maintained in a negative pressure state.

After the processing ends, after the front end of the drill bit 6 is separated from the printed circuit board 20, since the shutter 50 will rise relative to the vent hole 8, the substantial cross-sectional area of the vent hole 8 is gradually increased, when the lower end surface 7b of the presser foot 7 is When the upper surface of the printed circuit board 20 is separated, the pressure value of the space 31 in the presser foot is close to atmospheric pressure. Therefore, the printed circuit board 20 does not float upward. It has been confirmed that this effect can be achieved when the diameter of the vent hole 8 is larger than 3 mm.

Although the distance Ln during machining is usually high and the distance Lk at the time of machining is large, since the position of the chuck 2 does not change in the case of normal machining, only the position of the mandrel group 1 is changed, so the action is The above-mentioned high-precision machining is the same.

Further, the material of the shutter 50 may be a synthetic resin having a large rigidity.

Further, in the above examples, m≧h is preferable for the following reasons.

1. When h is set to be about 2 mm or less as described above, since it becomes difficult to change the processing after h becomes small, the vent hole 8 is easier to process when h is large.

2. In order to improve the airtight performance of the shutter 50, when a gasket or the like is attached to the inlet of the vent hole 8, a step may be caused on the surface of the presser foot 7, when m≧h, Since the shutter 50 can be covered on the gasket from the beginning, the shutter 50 does not interfere with the edge of the gasket or the like during the operation, and the shutter 50 can be smoothly slid.

Therefore, in the case where the above problem does not occur and it is ensured that there is a sufficient cross-sectional area, m<h may be created.

Figure 4 is a schematic view showing a derivative of the present invention. As described above, even if the vent hole 8 according to the present invention is made to have a relatively small diameter (m), it is also effective. Therefore, if the vent hole 8 has a diameter of 5 mm or less, the flat surface is not provided. The problem that the shutter 50 interferes with the edge of the gasket or the like occurs. Therefore, the vent hole 8 can be made by directly perforating the cylindrical side wall of the presser foot 7 as shown in the figure. In this case, a plurality of small-diameter vent holes 8 may be provided, and one of the integrally formed ones may be provided or an individual shutter 50 may be separately provided.

Figure 5 is a schematic diagram showing other examples of the invention. In the case of machining the hole of the depth K, the drill 6 is lowered K as shown in Fig. 4. Since the lower end 50a of the shutter 50 is also lowered K at the same time, it is necessary to ensure (H-h) ≧K in advance. That is, as shown in the figure, if the axis of the vent hole 8 is made higher in the left side, the position of the lower end 8ob of the vent hole 8 can be made higher than that of the lower end 8ib, and can be easily realized ( Hh) ≧K.

1‧‧‧Heart Group

2‧‧‧ chuck

6‧‧‧Tools (drills)

7‧‧‧Foot press

8‧‧‧Ventinel

20‧‧‧Workpiece

31‧‧‧Inside the presser foot space

50‧‧‧ occlusion device

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front partial sectional view showing the head of a machine for a related circuit board drilling machine of the present invention.

Fig. 2 is a view in the direction of arrow A in Fig. 1.

Fig. 3 (a) and (b) are enlarged views showing the periphery of the front end of the presser foot 7 in Fig. 1.

Figure 4 is a schematic view showing a derivative of the present invention.

Figure 5 is a schematic diagram showing other examples of the invention.

Fig. 6 (a) and (b) are schematic diagrams showing conventional techniques and problems.

1. . . Mandrel group

2. . . Chuck

3. . . Saddle

4. . . Bearing

5. . . Slide

6. . . Tool (drill)

7. . . Presser foot

8. . . Vent

9. . . bushing

11. . . Cross-shaped groove

15. . . Support rod

16. . . Flexible coupling

17. . . cylinder

18. . . Support

20. . . Workpiece

twenty one. . . Workbench

30. . . hole

31. . . Inside the presser foot

32. . . Pipe joint

33. . . tube

50. . . Hatch

50a. . . Lower end

51. . . Screw

2a. . . surface

Claims (1)

A printed circuit board drilling machine comprising: a mandrel set held on a collet for holding a tool and allowing the tool to arbitrarily rotate; and a presser foot supported on the collet and along an axis of the tool Sliding in any direction, and fitting on the mandrel group like the front end of the mandrel group, and providing a vent hole on the side of the presser foot to form the presser foot and the mandrel group The space is connected to the outside air, and the space is connected to the negative pressure source, and then pressed to the workpiece through the presser foot, and the workpiece is processed on the workpiece by the aforementioned tool in a state where the vent hole is closed. The method is characterized in that the tool is held in the mandrel group located closest to the workpiece side with respect to the chuck, and when the front end of the tool contacts the upper surface of the workpiece, the vent hole is disposed in the foregoing The position of the presser foot in which the space and the outside air communicate with each other, and at the same time, a plate-shaped shutter is provided, and when the front end of the presser foot is not in contact with the workpiece, the one end of the shutter is Positioning when the front end of the presser foot is not in contact with the workpiece, and a position at a distance from the lower end of the vent hole outside the presser foot to the upper end, and the distance is equal to when the front end of the presser foot is not The distance from the front end of the presser foot to the front end of the tool when contacting the workpiece, and the other end of the shutter is held on the chuck Further, when the front end of the tool comes into contact with the upper surface of the workpiece, the vent hole is closed by the shutter to isolate the space from the outside air.