HK1095785B - Drilling method - Google Patents

Description

Drilling method

Technical Field

The present invention relates to a drilling method for drilling a hole in a workpiece while exchanging a plurality of drill bits.

Background

Fig. 4 is a front view showing a section near a spindle of a printed circuit board drilling machine, and fig. 5 is a plan view showing a part of a table of the printed circuit board drilling machine.

As shown in fig. 4, a drill 15 is rotatably held at the tip of the spindle 10. The pressure base 20 fitted to the tip end of the spindle 10 is supported movably in the Z-axis direction, and is biased downward in the drawing by an air cylinder, not shown.

A plurality of printed circuit boards 2a to be processed are stacked on a base plate 2b, and are mounted on a surface 1a of a table 1 while being integrally fixed by two reference pins 3a and 3b (usually, the reference pins 3a and 3b have the same diameter). Hereinafter, the printed circuit board 2a and the chassis 2b to be processed are collectively referred to as a printed circuit board 2.

As shown in fig. 5, holes (here, slit shapes) 4, 5 are formed in the surface side of the table 1. A square first clamp 7 is disposed in the hole 4 having a V-shaped groove 6 formed in one side surface thereof. In the square hole 5, a square second clamping plate 8 is arranged. As shown in fig. 4, the clamp plates 7 and 8 are supported by a linear guide 9, which is composed of a bearing 9a and a rail 9b, disposed at the bottom of the holes 4 and 5, with the upper surfaces thereof being flush with the surface 1a of the table 1, and are movable in the Y-axis direction by a drive unit, not shown.

The diameters of holes machined in printed circuit boards range from a few to a dozen and the number of holes machined is large. Therefore, in the printed circuit board processing machine, several tens to several hundreds of tools, i.e., drills, are arranged in advance on the table 1.

Next, a processing procedure of the conventional printed circuit board drilling machine having the above-described configuration will be described.

First, as shown by solid lines in fig. 5, the printed circuit board 2 is placed on the table 1 with the clamp plates 7 and 8 moved to the right in the figure. Then, the clamp plates 7 and 8 are moved leftward in the drawing, the first reference pin 3a is brought into contact with the groove 6, and the second reference pin 3b is brought into contact with the right side surface 8 a. Then, the printed circuit board 2 is positioned in the Y-axis direction by a line O connecting the centers of the two reference pins 3a and 3b being parallel to the X-axis of the printed circuit board 2 and is also positioned in the X-axis direction by the groove 6 (patent document 1).

In this state, the table 1 is moved in the X-axis direction, the spindle 10 is moved in the Y-axis direction, and the drill 15 is positioned at the processing portion of the printed circuit board 2. Then, the spindle 10 is moved in the Z-axis direction, and the drill 15 is caused to cut into the printed circuit board 2 in a state where the printed circuit board 2 is pressed by the pressure base 20, thereby drilling the printed circuit board 2. Then, upon receiving an instruction from the machining program or a tool exchange instruction based on the tool life, the drill bit 15 is exchanged and machining is continued.

Further, although the printed circuit boards are separated into individual holes after hole processing, and patterns and the like are formed by subsequent processes such as exposure and etching, the holes into which the reference pins are inserted are deformed when the printed circuit boards are separated into individual holes. In addition to the holes required for the product, reference holes for the subsequent process (hereinafter referred to as "exposure reference holes") are also processed.

However, in the case of a printed circuit board drilling machine, an air spindle is used as the spindle, and for example, when drilling a small diameter hole of 0.3mm or less, the rotation speed is about 20 ten thousand revolutions per minute, when drilling a hole of about 1.0mm, the rotation speed is about 6 ten thousand revolutions per minute, and when drilling a hole exceeding 2.0mm, the rotation speed is about 4 ten thousand revolutions per minute.

In the case of the air spindle, since the amount of heat generation changes depending on the rotation speed of the spindle and the air pressure supplied to the spindle also changes, the axis of the spindle, i.e., the drill, deviates from the designed position depending on the rotation speed. However, the offset amount of the drill axis from the design position (hereinafter simply referred to as "offset amount") corresponding to the rotation speed of the spindle is specific to the spindle. Therefore, when the number of axes of the printed circuit board drilling machine is one, that is, when the number of spindles is one, the offset amount is obtained for each spindle rotation speed in advance, and the value is corrected and then the machining is performed, whereby the machining with good machining accuracy can be realized.

[ patent document 1 ] JP patent application laid-open No. 2003-1594

In order to improve the processing efficiency, a multi-axis printed circuit board drilling machine (i.e., a printed circuit board drilling machine having a plurality of printed circuit boards placed on one table and having the same number of spindles as the printed circuit boards) is often used as the printed circuit board drilling machine.

Fig. 6 is a surface view of a printed circuit board machined by a predetermined one axis of a multi-axis printed circuit board drilling machine, and fig. 7 is a view showing a deviation of a machining position between an exposure reference hole and a 0.2mm hole machined by a two-axis printed circuit board drilling machine.

In fig. 6, a region K surrounded by a dotted line is a region of the printed circuit board disposed as a product, and for example, tens of thousands to hundreds of thousands of holes having a diameter of 0.1mm and thousands to tens of thousands of holes having a diameter of 0.2 to 0.4mm are processed. The holes C disposed outside the region K are exposure reference holes, and in the illustrated case, two holes are processed in the diagonal direction.

In fig. 7, Acx and Acy are average values of the shift amounts of the center of the exposure reference hole machined by the first axis in multiple axes from the center on the design, and Amx and Amy are center values of the shift amount distribution of the 0.2mm hole machined by the first axis from the center on the design. Further, Bcx and Bcy are average values of the shift amounts of the center of the exposure reference hole processed by the second axis different from the first axis with respect to the center on the design, and Bmx and Bmy are central values of the shift amount distribution of the 0.2mm hole processed by the second axis with respect to the center on the design.

The radii of distribution ar, br of the offset are substantially the same regardless of which axis is the same as the pore diameter. However, the respective distribution centers are offset by different amounts from the center of the exposure reference hole, and the second axis is larger than the first axis. Therefore, when the width of the pattern to be exposed with reference to the exposure reference hole is narrow, a 0.2mm hole machined by the second axis may be deviated from the pattern.

Disclosure of Invention

The invention aims to provide a drilling processing method, which can reduce the deviation of processing precision even a multi-axis printed circuit board drilling machine and improve the processing precision of the multi-axis printed circuit board drilling machine as a whole.

In order to solve the above problems, a drilling method according to the present invention is a drilling method for performing substantially simultaneous drilling of a plurality of workpieces by relatively moving a table on which the plurality of workpieces are placed and a drill arranged corresponding to the workpieces in a horizontal direction, and positioning an axis of the drill at a center position of a machining portion, the drilling method including: the offset amount of the axial center of the drill in the X, Y direction from the designed axial center is obtained in advance at regular rotational speeds for each of the main shafts holding and rotating the drill, and when two or more kinds of holes are to be machined, the hole machining is performed for each of the main shafts for at least one kind of hole, and the hole machining is performed substantially simultaneously for the other holes by all of the main shafts.

Preferably, when machining is performed for each spindle, hole machining is performed after correcting only a difference between two offset amounts: said offset at a predetermined speed of said spindle for machining said at least one diameter hole; and the offset amount at the drill rotation speed for processing a hole of a predetermined diameter at the substantially simultaneous hole processing.

Since the exposure reference hole is processed for each axis, the processing accuracy of the multi-axis printed circuit board drilling machine as a whole can be improved.

Drawings

Fig. 1 is a perspective view of a printed circuit board drilling machine according to the present invention.

Fig. 2 is a flowchart showing the operation of the present invention.

Fig. 3 is a diagram illustrating the effect according to the present invention.

Fig. 4 is a front view showing a section near a spindle of a printed circuit board drilling machine.

Fig. 5 is a plan view showing a part of a table of a printed circuit board drilling machine.

Fig. 6 is a surface view of a printed circuit board processed by one axis specified in the multi-axis printed circuit board drilling machine.

Fig. 7 is a diagram showing a deviation of the processing positions of the exposure reference hole and the 0.2mm hole processed by the two-axis printed circuit board drilling machine.

The reference numbers are as follows:

2 printed circuit board, 10 spindle, 15 drill

Detailed Description

Fig. 1 is a perspective view of a printed circuit board drilling machine according to the present invention.

In this figure, the table 1 is supported by a guide rail 30 and is movable on a base 31 in the X-axis direction. The printed circuit board 2 is positioned on the table 1 by means of reference pins 3a, 3 b.

The cross member 32 is fixed to the base 31 so as to straddle the table 1. A guide rail 33 is provided on the front surface of the cross member 32, and a lateral sliding plate 34 is supported on the guide rail 33. The cross slide 34 is freely movable in the Y-axis direction along the guide rail 33 by a motor 35 and a feed screw 36. A plurality of (4 in the present figure) cases 37 are fixed to the front surface of the lateral sliding plate 34.

A bearing for supporting the spindle 10 to be movable in the vertical direction (the direction of arrow Z) is disposed inside the housing 37. A motor 38 fixed to the upper portion of the housing 37 moves the spindle 10 in the arrow Z direction via a shaft 39. The controller 40 controls the movement of each part and the like in accordance with the machining program. Further, the present printed circuit board drill denotes a four-axis drill having four main shafts 10, for example, a first axis, a second axis, a third axis, and a fourth axis from right to left in the drawing. The machining program describes the hole diameter and position coordinates of the machined hole. The number of times of use and the number of rotation of use are set for the drill.

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

Before use, the spindle is rotated at various rotation speeds (for example, every 1000 revolutions in a range from the minimum rotation speed to the maximum rotation speed) for a predetermined time (for example, 10 minutes) for each shaft, and the deviation from the design value of the drill axis at that time is obtained and stored in the control device 40 for each shaft.

Next, the actual processing will be described.

Fig. 2 is a flowchart showing the operation of the present invention. The aperture of the exposure reference hole is input in advance.

When a start button, not shown, is pressed, the control device 40 refers to the machining program, checks the hole diameter with the largest number of machining operations (step S10), and starts machining. First, it is checked whether or not the processed hole is an exposure reference hole (step S20), and if not, the process of step S30 is performed; otherwise, the process of step S40 is performed. In step S30, after the four main spindles 10 are simultaneously operated to perform hole machining, the process of step S50 is performed. Then, in step S40, the X coordinate and the Y coordinate of the hole to be machined are corrected for the command values by Δ X and Δ Y determined by equations 1 and 2 for each spindle, that is, for each axis, and the hole is machined, and then the process of step S50 is performed.

Δ x ═ δ xm- δ xc … formula 1

Δ y ═ δ ym- δ yc … formula 2

Wherein the content of the first and second substances,

δ xm is an offset amount in the X direction with respect to the rotational speed of the drill for machining the hole with the largest number of holes,

δ ym is an offset amount in the Y direction with respect to the rotational speed of the drill for machining the hole with the largest number,

δ xc is an offset amount in the X direction with respect to the rotational speed of the drill for processing the exposure reference hole,

δ yc is an offset amount in the Y direction with respect to the rotational speed of the drill for processing the exposure reference hole, and is a value stored in the control device 40.

Checking in step S50 whether or not all of the commanded holes have been machined, and if an unmachined hole is present, performing the process of step S20; otherwise, the process is terminated. In step S10, when the number of holes is two or more, for example, the smallest diameter hole may be used.

Fig. 3 is a diagram for explaining the effects of the present invention, and is shown in parallel with the conventional results for comparison. Furthermore, the circuit board material adopts a glass-doped epoxy resin circuit board with the thickness of 0.6 mm. The diameter of the exposure reference hole was 3.0mm, and the diameter of the most numerous holes was 0.2 mm.

As shown in the figure, according to the present invention, the positional accuracy of the 0.2mm hole with respect to the exposure reference hole can be controlled to 2 μm or less. On the other hand, in the case of the conventional case where the thickness is 10 μm or more, the present invention can improve the machining accuracy in the subsequent process, that is, the machining quality as a product.

In the present embodiment, the exposure reference hole is specified for a hole having a large number of holes to be processed, but may be specified for a hole having the smallest diameter or may be specified as a hole having a required accuracy.

Further, in the case where the exposure reference hole is machined at a low rotation speed after the spindle is used at a high rotation speed, the offset amount may be different from the case where the exposure reference hole is machined at a low rotation speed and then the spindle is used at a high rotation speed, for example, to machine a small-diameter hole. Therefore, the offset amount may be determined for both the case where the exposure reference hole is processed first and the case where the exposure reference hole is processed later.

Claims (3)

1. A drilling method for performing substantially simultaneous drilling of a plurality of workpieces by relatively moving a table on which the plurality of workpieces are placed and a drill arranged to correspond to the workpieces in a horizontal direction, and positioning an axis of the drill at a center position of a machining portion of the workpieces, the drilling method comprising:

the offset amount of the axial center of the drill in the X, Y direction from the designed axial center at various rotation speeds is obtained in advance for each main shaft for rotating the drill,

when holes of two or more diameters including exposure reference holes are to be machined, the exposure reference holes are subjected to hole machining by correcting the exposure reference holes for each of the spindles in accordance with the offset amount, and holes of other diameters are machined substantially simultaneously by all of the spindles.

2. The drilling method according to claim 1, wherein: in the case of performing the machining for each of the main shafts, the hole machining is performed after correcting only a difference between two offset amounts: the offset amount at a predetermined rotation speed of the spindle for processing the exposure reference hole; and the offset amount at the drill rotation speed for processing a hole of a predetermined diameter at the substantially simultaneous hole processing.

3. The drilling method according to claim 2, wherein: the predetermined rotation speed of the spindle is a rotation speed at which the maximum number of holes to be machined in the workpiece is machined.