JPH0749166B2 - Machining method and device using the work surface as a reference - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method and an apparatus for accurately performing a drilling or a counterbore processing of a predetermined depth on a printed circuit board.

(Prior Art) FIG. 6 shows an example of the internal structure of a multilayer printed circuit board. In the figure, a is a laminated insulating layer, b is a conductive layer made of copper foil, and c is a through hole penetrating each of these layers. , D are blind holes drilled from the upper surface to a predetermined depth.

Therefore, conventionally, in order to drill a blind hole having a predetermined depth such as the blind hole d, the work is placed on the work table of the drilling machine and the lower surface of the work is brought into close contact with the upper surface of the table as much as possible. In that state, the blind hole d was processed with the upper surface of the table as a reference.

In addition, there is another disclosed in Japanese Patent Laid-Open No. 1-188207.

(Problems to be solved by the invention) However, in the conventional machining method based on the table upper surface as described above, since the blind hole is drilled based on the upper surface of the work table, the work lower surface and the table upper surface are If there is a gap between the workpieces due to the lifting of the workpiece, or if there is an error in the workpiece thickness, there is the problem that the depth of the blind holes from the top surface of the workpiece is not constant and machining accuracy varies. It was

Further, Japanese Patent Application Laid-Open No. 1-188207 has a problem that the scale for detecting the movement amount of the pressure foot and the charge-coupled device used for detecting the position of the drill tip are expensive.

(Means for Solving the Problem) In order to solve the above-mentioned problems, in the present invention, a master bar having a reference length of a tool is attached to a spindle of a numerical control type punching machine for printed circuit boards, and a reference of the spindle is provided. The distance A from the lower end of the master bar to the table upper surface at the position is stored, then the pressure foot is lowered together with the main shaft, the pressure foot is brought into contact with the table, and the main shaft is further lowered slightly.
The movement amount B when the precision magnetic sensor is turned on is stored in relation to the relative position of the magnet dog provided on the side surface of the main shaft and the precision magnetic sensor provided on the pressure foot, and further AB = C is stored. In addition, the precision touch sensor is provided vertically on the sub-table, and the plunger is provided on the upper surface of this precision touch sensor, and the spindle equipped with the master bar is lowered from the reference position to the precision touch sensor via the plunger. The amount of movement I until this precision touch sensor is turned on is stored in memory, then the tool to be used is attached to the spindle, lowered from the reference position, and the precision touch sensor is turned on via the plunger. When the amount of movement J up to is stored, I−J = K is used as a correction value for the theoretical tool length, and the target machining depth is E,
After the spindle with the tool attached is lowered during machining and the precision magnetic sensor is turned on, C + E + K =
Try to lower it by D + K.

Further, while holding and rotating the tool, the main shaft that moves in the axial direction of the tool and the lower end portion of this main shaft are enclosed, and supported so as to be movable in the axial direction of the main shaft and placed on the table during processing. In a numerical control type printed circuit board drilling machine equipped with a pressure foot for pressing the printed circuit board, a precision magnetic sensor is provided on either one of the main shaft and the pressure foot attached to the main shaft and the magnetic dog corresponding to the sensor is provided on the other side. And a precision touch sensor is provided vertically on a sub-table fixed to the frame of the punching machine, and a plunger is provided in contact with the upper surface of the touch sensor, and is mounted on the spindle through the plunger. By touching the lower end of the master bar and the tool to activate the precision touch sensor, The correction value of the machining depth of the hole is calculated, and the upper surface of the work on the table is pressed by the pressure foot with a constant force until the precision magnetic sensor is turned on. A processing device with the upper surface of the work as a reference is constructed by drilling a blind hole having a predetermined depth that takes into consideration.

(Operation) According to the processing method of the present invention performed by using the apparatus of the present invention configured as described above, the upper surface of the work is pressed with a constant force by the pressure foot, and the work upper surface in this state is used as a reference for a predetermined depth. Since the blind hole is drilled, it is possible to always form a blind hole having a constant depth regardless of the presence or absence of a gap between the lower surface of the work and the upper surface of the table, the error in the thickness of the work, and the like.

Further, in the present invention, as described above, since the correction value for the theoretical tool length is obtained and this correction value is added to the machining method, the accuracy of the depth of the blind hole can be increased.

(Example) Hereinafter, an example of the device of the present invention and a processing method of the present invention will be described with reference to the drawings.

In the figure, 1 is a table on which a work of a numerical control type puncher for a printed circuit board is placed, 2 is a work for a printed circuit board,
3 is a blind hole drilled from the upper surface of the work 2, 4 is a spindle, 5 is a tool (drill) to be used 6
A master bar having a reference length (see FIGS. 2 and 5), 7 is a pressure foot provided so as to enclose the lower end of the spindle 4, 8 (see FIGS. 4 and 5) is a frame of a drilling machine, and 9 is This is a sub-table fixed to the frame 8.

In this embodiment, as shown in FIGS. 1 and 2, a precision magnetic sensor 10 is provided on the pressure foot 7 and
A magnet dog is attached to the side surface of the spindle 4 facing the sensor 10.
Provide 11

Further, as shown in FIGS. 4 and 5, a precision touch sensor 12 is vertically provided on the sub-table 9 and the touch sensor 12 is
A plunger 13 is provided in contact with the upper surface of the master bar 5, and the master bar 5 and the lower end of the tool 6 mounted on the spindle 4 are brought into contact with each other via the plunger 13 to operate the precision touch sensor 12. Reference numeral 14 is a ring that surrounds the precision touch sensor 12 and the plunger 13, and the sub table 9
It is provided above.

Further, in the machining method of the present invention, as shown in FIGS. 1 and 2, a master bar 5 having a reference length of a tool 6 is mounted on a spindle 4 of a numerical control type punching machine for printed circuit boards, and the spindle 4 The distance A from the lower end of the master bar 5 to the upper surface of the table 1 at the reference position (the position indicated by the solid line in FIG. 1) is measured and stored, and then the pressure foot 7 is lowered together with the spindle 4. After bringing the pressure foot 7 into contact with the table 1, as shown in the two-dot chain line in FIG. 1, the main shaft 4 is slightly lowered to adjust the relative position between the main shaft 4 and the pressure foot 7. The moving amount B when the magnetic sensor 10 is turned on is taken in from an NC device (not shown) and stored, and AB = C
When the target machining depth is set to E as shown in FIGS. 2 and 3, the spindle 4 on which the tool 6 is mounted during machining is stored.
Is lowered, and after the precision magnetic sensor 10 is turned on, it is further lowered by C + E = D.

Further, in the above machining method, in order to correct the length of the tool 6 to be used, as shown in FIG. 4, a precision touch sensor 12 is vertically provided on the sub-table 9 and the precision touch sensor 12 is provided on the upper surface thereof. A plunger 13 is provided, and the spindle 4 having the master bar 5 mounted thereon is lowered from a reference position (a straight line Z indicating the 0 level in FIG. 4) and brought into contact with the precision touch sensor 12 via the plunger 13, The movement amount I until the precision touch sensor 12 is turned on is taken in from the NC device and stored therein, and then, as shown in FIG. 5, the tool 6 to be used is attached to the spindle 4 and shown by the straight line Z. The moving amount J until the precision touch sensor 12 is turned on via the plunger 13 after being lowered from the reference position is fetched from the NC device and stored, and I−J = K is set as a correction value for the theoretical tool length.

It should be noted that F in FIG. 4 indicates the length to the lower end surface of the master bar 5 projecting downward from the lower end of the main shaft 4, and this is the reference length of the tool 6.

Further, G in FIG. 5 indicates a length from the lower end surface of the spindle 4 to the lower end of the tool 6 of the optional tool 6 mounted on the lower end of the spindle 4. That is, G-F = K = I-J
Is. Therefore, in the present invention, when the target machining depth is E, the spindle equipped with the tool is lowered during machining, and after the precision magnetic sensor is turned on,
Further, it is lowered by C + E + K = D + K.

(Effect of the Invention) In the processing method of the present invention performed using the apparatus of the present invention configured as described above, the upper surface of the work 2 is pressed by the pressure foot 7 with a constant force as described above, and the work in this state is pressed. Since the blind hole 3 having a predetermined depth E is formed with the upper surface of 2 as a reference, according to the present invention,
The blind hole 3 can always be machined to a constant depth regardless of the presence or absence of a gap between the lower surface of the work 2 and the upper surface of the table 1 and the error in the thickness of the work 2.

Further, in the present invention, as described above, the theoretical tool length F
Since the correction value K for is calculated and the correction value K is added to the processing method, the accuracy of the depth of the blind hole 3 can be increased.

Further, the above-mentioned JP-A-1-188207 has a problem that the scale for detecting the movement amount of the pressure foot and the charge-coupled device used for detecting the position of the drill tip are expensive. In the device of the present invention, the inexpensive magnetic sensor and touch sensor can be used as the detection device by using the master bar, and thus the device can be provided at low cost.

[Brief description of drawings]

1 and 2 are vertical sectional views for explaining the machining method of the present invention by the apparatus of the present invention, FIG. 3 is a partially enlarged sectional view of a workpiece, and FIGS. 4 and 5 show a method for correcting a tool length. Fig. 6 is a vertical sectional view, and Fig. 6 is a partially enlarged sectional view of the printed circuit board. 1 …… Table 2 …… Workpiece 3 …… Blind hole 4 …… Spindle 5 …… Master bar 6 …… Tool (drill) 7 …… Pressure foot 8 …… Frame 9 …… Sub table 10 …… Precision magnetic sensor 11 …… Magnet dog 12 …… Precision touch sensor 13 …… Plunger 14 …… Ring

Claims (2)

[Claims] 1. A master bar having a reference length of a tool is attached to a spindle of a numerical control type punching machine for printed circuit boards, and a distance A from a lower end of the master bar to a table upper surface at a reference position of the spindle is stored. Next, the pressure foot is lowered together with the main shaft, the pressure foot is brought into contact with the table, and then the main shaft is further lowered slightly, and a magnetic dog provided on the side surface of the main shaft and a precision magnetic sensor provided on the pressure foot. The amount of movement B when the precision magnetic sensor is turned on is stored in relation to the relative position with, and AB = C is further stored, and the precision touch sensor is installed vertically on the sub-table and A plunger is provided on the upper surface of the touch sensor, and the spindle equipped with the master bar is lowered from the reference position to insert the plunger. Te is brought into contact with the precision touch sensor,
The amount of movement I until the precision touch sensor is turned on is stored, then the tool to be used is attached to the spindle, lowered from the reference position, and the precision touch sensor is turned on via the plunger. The movement amount J is stored, and I-J
= K is a correction value for the theoretical tool length, and the target machining depth is E. When the precision magnetic sensor is turned on by lowering the spindle equipped with the tool during machining,
Further, the processing method is characterized in that the work surface is lowered by C + E + K = D + K. 2. A spindle that holds and rotates a tool, and encloses a spindle that moves in the axial direction of the tool and a lower end portion of the spindle, and is supported so as to be movable in the axial direction of the spindle, and is supported on a table during machining. In a numerical control type PCB drilling machine equipped with a pressure foot that presses a mounted PCB, a precision magnetic sensor is provided on one of the spindle and the pressure foot attached to it, and the other corresponds to the sensor. A magnetic dog is provided, and a precision touch sensor is provided vertically on a sub-table fixed to the frame of the punching machine, and a plunger is provided in contact with the upper surface of the touch sensor. By operating the precision touch sensor by contacting the lower end of the master bar and tool attached to The correction value for the machining depth of the lined hole is calculated, and the upper surface of the work on the table is pressed by the pressure foot with a constant force until the precision magnetic sensor is turned on. A processing device based on the upper surface of a work, wherein a blind hole having a predetermined depth in consideration of the value is drilled.