JPS62264812A - Drilling method for printed circuit board - Google Patents

Abstract

PURPOSE:To make such a drilling job for good quality and excellent in positional accuracy performable, by reciprocating a drill between a travel starting position and a drilling position in rapid traverse, and drilling a printed circuit board by degrees, in case of drilling the printed circuit board fixed solidly between both upper and lower plates. CONSTITUTION:A drill 4 at a travel starting position A is fed, at infeed rate, to the work fixed as one body in a way of stacking three boards 1 between an upper plate 2 and a lower plate 3, and when drilling is carried out up to an intermediate position M1 of a printed circuit board 1, it is turned over and returned to the position A at rapid traverse rate VR. Next, when it is turned over again and fed up to the position M1 at the rapid traverse rate VR, it is selected to cutting feed rate VF, and turned over after drilling up to a position M2, then it is returned to the position A at the rapid traverse rate VR again. When this operation is repeated as far as the specified partition times and the drill reaches a machining end position B, it returns to the position A at the rapid traverse rate VR, thus machining is over. Doing like this, even in case of a deep hole large in L/D, chips are eliminable, and there is no damage to the drill, thus such a drilling job for good quality and excellent in positional accuracy is performable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for drilling holes in a printed circuit board using a drill.

[Prior art]

When drilling a hole in a printed circuit board using a drill, normally a plurality of printed circuit boards 1 are used as shown in FIG.
Upper plate 2 and lower plate 3'! The drill 4 placed above it is rotated at a predetermined speed, and lowered until its tip bites into the lower plate 3.
A through hole is formed in the printed circuit board 1.

At this time, as shown in FIG. 5, the drill 4 moves at a preset cutting feed rate Vy from the movement start position A to the machining end position B reaching into the lower plate 3. The distance from machining end position B to movement start position A is set in advance.
Move at fast forward speed VR.

Here, the cutting feed rate VF and the rapid feed rate ■R are the optimum feed rates that are revised based on the quality of the hole formed on the printed circuit board (the roughness of the inner surface of the hole, the degree of occurrence of resin smear, etc.) .

This kind of hole drilling is done by stacking three printed circuit boards 1 of 1.4 x 1.6 thickness, and placing an upper board 2 with a thickness of IU and a lower board 3 with a thickness of 3 mm above and below. If they are fixed together and a 1vIL hole is formed from the upper plate 2 side to the lower plate 3, the depth Lh of the hole will be 6.8 mm.

When the diameter of the hole is 1.2+m, the ratio of Lh to diameter (Lh/D) at the depth of the hole is 5.8.

In such a case, the drill 4 should be moved as shown in FIG.
From movement start position A to machining end position f! Until tB, cutting feed rate ■1 feed 1, machining end dB to movement start position +ff
By returning to 1A at the rapid traverse speed VR, it is possible to obtain excellent quality and highly accurate hole positioning.

Further, when the diameter of the hole is 1w1L or less, for example, when the diameter is 0.8a, the ratio of the depth Lh to the diameter is 8.5.

In this way, when machining a deep hole with a large ratio of the hole depth Lh to the diameter, it becomes difficult to discharge chips.
As shown in the figure, one hole is machined in multiple steps.

For example, the area from machining start position A to machining end position iB is divided into four, and each intermediate position is divided into four.

With the position Mlt M2 + ki3, drill 4-=
Feed 1 from the movement start position A to the intermediate lid M1 at the cutting feed speed VF, return to the movement start position A at the rapid traverse speed VR, and then from the movement start position fA to the intermediate lid M1 at the rapid traverse speed VR.
After switching to cutting feed speed Vy at intermediate position HM1 and feeding to intermediate position fiM2, return to the movement start position at fast forward speed VR. By repeating such operations, machining is performed until the machining end position B is reached.

At this time, the chips stuck in the groove of the drill 4 are shaken off and taken out by the time the drill 4 is removed from the upper plate 2 and returns to the movement start position 11iA.

[Problem that the invention seeks to solve]

Furthermore, as the diameter of the hole becomes smaller, the rigidity of the drill 4 becomes smaller when the hole is drilled using the method described above. When the upper board 2 or printed circuit board 1 is
Drill 4 cannot be drilled into the surface and slips on the surface.
Sometimes it bites into a bent state and then drills a hole.

For this reason, if the bending of the drill 4 becomes large, the drill 4 will break and cannot be processed. In addition, the bend of the drill 4 is small,
Even if the hole can be drilled, problems such as a decrease in the positional phase change of the hole occur.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a method for drilling holes in printed circuit boards in which even small-diameter holes can be drilled with high quality and high position accuracy.

[Means and operations for solving the problems] The means and operations of the present invention for achieving the above objects will be explained based on FIG. 1, which corresponds to an embodiment. The figure shows the feed rate of the drill.

The cutting feed rate V set in advance is maintained between the drill start position A and the intermediate position M1 where the drill bits into the printed circuit board.
After forming a shallow positioning hole in the printed circuit board by moving 1 at z, the drill is returned to the movement start position A at a rapid traverse speed v3. After that, as in the case of Fig. 6, the fast forwarding speed υ VR
Then, feed 1 from machining start position A to intermediate position Ml, switch to cutting feed rate VF at intermediate position M1, feed to intermediate position M2, and then return to movement start position A again at rapid traverse speed VR. By repeating such operations, 1. Machining is performed until the machining end position B is reached.

At this time, the cutting feed rate Vz from the movement start position to the intermediate position M1 is such that when the drill collides with the upper plate or printed circuit board, it can cut into the upper plate or printed circuit board as it is without causing slippage. So, the cutting feed rate V? The feed rate is sufficiently small compared to .

Also, the rapid forwarding speed V from the movement start position A to the intermediate position M1 is
The drill fed in R is fed using the previously drilled positioning hole as a guide, so it will not bend even if the feed speed is fast.

In this manner, it is possible to drill holes in the printed circuit board with hole position accuracy close to the relative positioning accuracy of the drill and the printed circuit board. Also, the quality of the hole can be ensured by cutting at the optimum cutting feed speed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a first embodiment of the present invention. In the figure, 1 is a printed circuit board, 2 is an upper board, and 3 is a lower board. The printed circuit board 1, the upper plate 2, and the lower plate 3 are stacked and fixed together. 4 is a drill.

As shown in FIG. 2(A), the drill 4 at the movement start position is fed at a cutting feed rate Vl.

Then, as shown in FIG. 2(B), the drill 4 is inserted into the upper plate 2.
When the drill reaches the intermediate position ftMt where it penetrates into the printed circuit board 1, the feeding direction of the drill 4 is reversed.

Then, as shown in FIG. 2(C), the drill 4 is returned to the starting position t at a rapid forwarding speed VR. Then, drill 4
The feeding direction is reversed and the intermediate position M1 is reached at the rapid traverse speed VR.
send to Then, the feed rate of the drill 4 is switched to the cutting feed rate VFK.

Then, as shown in FIG. 2(D), the drill 4 is sent from the intermediate position M1 to the intermediate position M2. Drill 4 is in the middle position tM
When reaching z, the feed direction of the drill 4 is reversed and the feed speed is switched to the rapid feed speed VR. And the second
As shown in Figure (E), when the drill 4 returns to the movement start position A, the feed direction of the drill 4 is reversed and the rapid feed speed is
'R' to move to intermediate position M2. Then, the feed speed of the drill 4 is switched to the surprising cutting feed speed VF.

Then, as shown in FIG. 2(F), the drill 4 is sent from the intermediate position M2 to the machining end position ft1B. When the drill 4 reaches the machining end position 1ffB, the feed direction of the drill 4 is reversed and the feed rate is switched to the rapid feed rate VR.

Then, as shown in FIG. 2(G), the drill 4 is returned to the movement start position A, and the machining of one hole is completed.

By processing in this way, 1. Holes can be drilled with high quality and high positional accuracy.

The number of intermediate positions M2 to be provided is determined as appropriate depending on the diameter of the hole, the material of the printed circuit board 1, etc.

FIG. 3 shows another embodiment of the invention.

In this embodiment, when the drill 4 first moves from the movement start position to the machining start position Mo, which is set at about 0.5 to IB above the upper plate, the drill 4 is moved at the rapid traverse speed VR. , machining start position KM.

When reaching ve, the feed rate of drill 4 is changed to cutting feed rate ve
The method is to make a hole that switches to .

In this way, the idle feeding time of the drill 4 is shortened, and the time required to drill one hole is shortened.

For example, one printed circuit board IK may require several thousand to tens of thousands of holes to be drilled.

In such a device, by reducing the time for drilling one hole by 0.1 seconds, the machining time can be reduced by 1, several minutes to several hours.

〔Effect of the invention〕

As described above, according to the present invention, a hole having a large ratio of depth Lh to diameter can be drilled with high quality and high vertical accuracy.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the position and travel time of the drill according to the present invention, FIG. 2 is a track diagram showing the state of holes, and FIG. 3 is a diagram showing another embodiment of the present invention. Special note: Figure 4 is a front cross-sectional view showing the state of drilling holes in printed circuit boards, and Figures 5 and 6 show the position and travel time of the drill when drilling conventionally. It is a characteristic diagram showing a relationship. 1...Printed circuit board, 2...Top board, 3...
- Lower plate, 4... Drill, Vl... Cutting feed rate vP... Cutting feed rate VR... Rapid feed speed. K-. Figure 1 Time Figure 2 (A) (B) (C)
(D) 2121 (E) (F) (G) Figure 4

Claims (1)

[Claims] 1. On the printed circuit board with the upper and lower plates fixed together,
A printed circuit board drilling method in which a hole is formed through the upper board and the printed circuit board to reach the lower board, and the drill is rotated at a predetermined speed at a predetermined speed. Move to the cutting position where the upper plate is penetrated and cut into the printed circuit board at the cutting feed speed to form a positioning hole, return to the movement start position at a predetermined rapid feed speed, and then increase the rapid feed speed. A method for drilling a printed circuit board, which is characterized in that the printed circuit board is moved to a previous processing position, and then a hole is formed that penetrates the printed circuit board and cuts into the lower board at a predetermined cutting feed rate.