JP7054587B2 - Drilling equipment and drilling method - Google Patents

Description

The present invention relates to a drilling apparatus and a drilling method for drilling holes in a multilayer printed circuit board.

In drilling, it is common to experimentally obtain the optimum values for various machining conditions in advance, and the operator sets the optimum machining conditions in the device to start machining, but for different workpieces. Therefore, it is troublesome for the operator to set the machining conditions each time, and there is a possibility that the wrong conditions are set.
Therefore, as disclosed in Patent Document 1, for example, there is also a method in which the feeding speed of the drill, which is a drilling tool, can be automatically set by the apparatus without being set by the operator each time. be.

However, when machining a workpiece with a simple structure as disclosed in Patent Document 1 with a solid drill, it may be possible to automatically set the machining conditions, but the conductor layer and the insulating layer are alternately laminated. Further, when a multi-layer printed circuit board having a variable thickness of a conductor layer is machined with a small-diameter drill having a small load bearing capacity, the appearance is completely different.
That is, in the case of such a multilayer printed circuit board, the cutting resistance is overwhelmingly large when the conductor layer, which is a metal layer, is processed, and the thicker the conductor layer, the greater the cutting resistance. The difference between the time and the load at the end of machining has no meaning. Therefore, it is necessary to set the machining conditions according to the internal structure of the multi-layer printed circuit board that is the workpiece, otherwise the machining quality will deteriorate, the drill will be damaged, the motor heat generated by the spindle, and the rotation speed will drop. There is a problem of causing problems such as damage to the air bearing.

Japanese Unexamined Patent Publication No. 2008-55536

Therefore, it is an object of the present invention to be able to automatically detect the condition of the multi-layer printed circuit board as a work, particularly the conductor layer, and set the processing conditions.

A typical drilling apparatus disclosed in the present application is a drilling apparatus in which a multi-layer printed circuit board is drilled under set machining conditions, and the time required for the drill to pass through a conductor layer arriving in the drilling direction. The thickness detection unit that detects the total thickness of the conductor layer based on the feed speed of the drill at that time, and the optimum drill corresponding to the total value based on the total value detected by the thickness detection unit. When the multi-layer printed circuit board is processed, the storage unit is stored based on the total thickness of the conductor layer of the multi-layer printed circuit board obtained by the thickness detection unit. It is characterized by having a condition setting unit that automatically determines and newly sets the optimum drill feed speed corresponding to the unit.

Further, a typical drilling method disclosed in the present application is a drilling method in which a multilayer printed circuit board is drilled under set processing conditions, and the time for the drill to pass through a conductor layer arriving in the drilling direction. And the thickness detection step of detecting the total value of the thickness of the conductor layer based on the feed speed of the drill at that time, and the optimum value corresponding to the total value based on the total value detected by the thickness detection unit. Based on the total value of the thickness of the conductor layer of the multilayer printed circuit board obtained in the thickness detection step and the storage step in which the feed speed of the drill is experimentally obtained and stored in the storage unit and the multilayer printed circuit board is processed. It is characterized by having a machining condition setting step for automatically determining and newly setting the optimum drill feed speed corresponding to the storage unit.

According to the present invention, it is possible for the apparatus to automatically set the processing conditions for the multilayer printed circuit board without the operator setting the processing conditions each time.

It is a figure for demonstrating the operation of the drilling apparatus which becomes one Example of this invention. It is a figure which shows the structure of the drilling apparatus which becomes one Example of this invention. It is a figure for demonstrating the spindle in FIG. 2 in more detail. It is a figure for demonstrating the resonance detection part in FIG. 3 in more detail. It is a table diagram which shows the content of the optimum feed rate storage part in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 2 is a diagram showing a configuration of a drilling apparatus according to an embodiment of the present invention. Each component and connecting line in FIG. 2 mainly show what is considered necessary for explaining the present embodiment, and does not show all necessary for a drilling apparatus.
In FIG. 2, 1 is a multi-layer printed circuit board to be drilled, 2 is a processing table on which the multi-layer printed circuit board 1 is placed via a lower plate 3 made of a resin material, and 4 is a processing table for drilling holes in the multi-layer printed circuit board 1. The drill 5 is a spindle unit that holds a spindle 6 having a built-in motor for rotating the drill 4. The spindle unit 5 is driven in the vertical direction by the spindle vertical drive unit 8.
The processing table 2 is horizontally driven and positioned by the processing table driving unit 7 so that the drill 4 faces a position where a hole is to be drilled in the multilayer printed circuit board 1. The lower plate 3 is a lower plate interposed between the multilayer printed circuit board 1 and the processing table 2, and serves to prevent the drill 4 from penetrating the multilayer printed circuit board 1 and coming into contact with the processing table 2.

A pressure foot 9 for pressing the multilayer printed circuit board 1 during drilling is engaged on the lower side of the spindle 6. The pressure foot 9 is connected to the spindle unit 5 via a cylinder 10, and when the spindle unit 5 is lowered, it is lowered together with the spindle unit 5 until it comes into contact with the upper surface position of the multilayer printed circuit board 1.
The spindle unit 5 and the pressure foot 9 are engaged with each other at a predetermined interval in the height direction. When the spindle unit 5 is lowered, the spindle unit 5 and the pressure foot 9 are lowered together halfway, and the pressure foot 9 is the upper surface of the multilayer printed circuit board 1. When it comes into contact with the position, the pressure foot 9 stays at that position thereafter, and only the spindle unit 5 independently descends so that the drill 4 can make a hole. When the drilling is completed and the spindle unit 5 is raised, the pressure foot 9 is also raised from a certain position.

Reference numeral 11 denotes a substrate top surface sensor composed of a detector 12 fixed to the spindle unit 5 and a rod 13 fixed to the pressure foot 9. When the pressure foot 9 rises and the detector 12 optically detects the tip of the rod 13, an ON signal is output, and when the pressure foot 9 descends and the detector 12 does not detect the tip of the rod 13, an OFF signal is output. It has become.
Therefore, when the spindle unit 5 is lowered, the pressure foot 9 reaches the surface of the multilayer printed circuit board 1, only the pressure foot 9 cannot be lowered any further, and the spindle unit 5 and the pressure foot 9 are vertically displaced from each other. When it is detected, the board top surface sensor 11 outputs an ON signal. Further, when the spindle unit 5 is subsequently raised, the substrate top surface sensor 11 outputs an OFF signal when the pressure foot 9 is separated from the top surface position of the multilayer printed circuit board 1.

Reference numeral 14 denotes an overall control unit that controls the rotation of the spindle 6, the machining table drive unit 7, the spindle vertical drive unit 8, and the like to control the entire drilling apparatus. Inside the overall control unit 14, the thickness detection unit 15 that detects the total thickness T of the conductor layers in the multilayer printed circuit board 1, the total value T of the thicknesses of the conductor layers T, and the optimum for drilling the multilayer printed circuit board 1. An optimum feed rate storage unit 16 for storing information for which the relationship with the feed rate of the drill 4 has been experimentally obtained in advance and a feed rate selection unit 17 for selecting the feed rate of the spindle vertical drive unit 8 are provided. ing.

The overall control unit 14 has a control function other than that described here, and is also connected to a block (not shown). The overall control unit 14 is configured around, for example, a program control processing device, and each component and connection line in the overall control unit 14 includes logical ones. Further, a part of each component may be provided separately from the overall control unit 14.

The overall control unit 14 controls the machining table drive unit 7 while recognizing the two-dimensional position of the machining table 2 based on the feed position information inside the machining table drive unit 7, and also has a spindle vertical drive unit. The spindle vertical drive unit 8 is controlled while recognizing the current height position of the tip of the drill 4 by the feed position information inside the 8.

FIG. 3 is a diagram for explaining the spindle 6 in FIG. 2 in more detail, and the same spindles as in FIG. 2 are numbered the same. In FIG. 3, the spindle 6 has a structure incorporating a motor, and the rotor shaft 31 is a rotor of the motor. Reference numeral 32 denotes an electrode attached close to the rotor shaft 31 on the stator side for electrostatic coupling with the rotor shaft 31, and is also a terminal of a capacitor detected between the rotor shaft 31 and the ground. Reference numeral 33 is a resonance detection unit connected to the electrode 32, and the overall control unit 14 receives the resonance detection signal S from the resonance detection unit 33.

FIG. 4 is a diagram for explaining the resonance detection unit 33 in FIG. 3 in detail. The same items as in FIG. 3 are numbered the same. In FIG. 4, 41 is a capacitor detected between the electrode 32 and the ground, and the capacitance of the capacitor varies greatly when the tip of the drill 4 is in contact with the conductor layer of the multilayer printed circuit board 1 and when the tip of the drill 4 is not in contact with the conductor layer. Then it becomes smaller.
Reference numeral 42 is a transformer whose secondary side is connected to the electrode 32, and its secondary side is connected to the capacitor 41. 43 is an oscillation circuit that oscillates alternating current at a frequency at which the capacitor 41 causes parallel resonance when the tip of the drill 4 is in contact with the conductor layer of the multilayer printed substrate 1, and 44 is the primary of the transformer 42 where parallel resonance occurs in the capacitor 41. This is a resonance detection circuit that detects that the impedance seen from the side has increased and the voltage across the primary side has decreased, and sends out a resonance detection signal S.

The drilling device operates as follows. The multilayer printed circuit board 1 to be processed is, for example, as shown in FIG. 1, the conductor layers L1 to L4 and the insulating layers R1 to R3 made of resin are laminated so that the conductor layers and the insulating layers alternate. Taking the case as an example, it will be described with reference to FIGS. 1 and 2. It is assumed that each of the conductor layers L1 to L4 is made of copper foil, and each of the insulating layers R1 to R3 is made of resin.

The overall control unit 14 controls the spindle 6 by the spindle control line R, and lowers the spindle unit 5 by the spindle vertical drive unit 8 while rotating the drill 4 at a predetermined feed speed V0 described later. First, when the pressure foot 9 comes into contact with the surface of the multilayer printed circuit board 1, the detection signal from the substrate top surface sensor 11 is input to the overall control unit 14, and the overall control unit 14 uses the feed position information of the spindle vertical drive unit 8 at that time. Based on this, the height position of the surface of the multilayer printed circuit board 1 can be recognized.

When the spindle unit 5 is further lowered and the drill 4 advances in the machining direction, a resonance detection signal S is generated from the resonance detection circuit 44 each time the drill 4 passes through each of the conductor layers L1 to L4, and the overall control unit 14 It is received by the thickness detection unit 15 of.
The thickness detection unit 15 obtains the thicknesses of the conductor layers L1 to L4 from the product of the generation period t of the resonance detection signal S and the feed rate V0 of the drill 4 at this time, and adds them to the conductor layer L1. The total value T of the thicknesses of to L4 is obtained and stored in the optimum feed rate storage unit 16.
The total thickness T is obtained by adding the generation periods t of the resonance detection signals S in each of the conductor layers L1 to L4 to obtain the total value, and from the product of this total value and the feed rate of the drill 4 at this time. You may ask.
After obtaining the total value T of the thicknesses of the conductor layers L1 to L4, the optimum feed rate of the drill 4 corresponding to the drilling of the multilayer printed circuit board 1 is experimentally obtained, and the conductor in the optimum feed rate storage unit 16 is obtained. It is stored corresponding to the total value T of the thicknesses of the layers L1 to L4.

The above operation is performed for each of the various multilayer printed circuit boards to be processed, and in the same manner as described above, the total value T of the thicknesses of the conductor layers and the optimum feed rate are made to correspond to each other in the optimum feed rate storage unit 16. Store. The contents of the optimum feed rate storage unit 16 in this state are shown in FIG.
The optimum feed rate is set to be low because the cutting resistance increases as the thickness increases. For example, if the total value T is T2 or more and less than T3, the optimum feed rate is V3.

Next, when processing a multilayer printed circuit board in which the optimum feed rate of the drill 4 is stored in the optimum feed rate storage unit 16, the drill processing device operates as follows. It is assumed that the multilayer printed circuit board 1 to be processed has the structure shown in FIG.
The thickness detecting unit 15 of the overall control unit 14 obtains the total value T of the thicknesses of the conductor layers L1 to L4 of the multilayer printed circuit board 1 by the same method as described above. Next, the feed rate setting unit 17 selects the corresponding optimum feed rate from the optimum feed rate storage unit 16 based on the total thickness T, and the height of the tip of the drill 4 returns to the reference position H to perform the next step. At the time of P before drilling the hole, the feed speed of the drill 4 in the spindle vertical drive unit 8 is newly set.
It should be noted that the predetermined feed rate V0 is set to a speed equal to the lowest feed rate V4 among those set by the apparatus.

According to the above embodiment, the total value of the thickness of the conductor layer is automatically detected, and the feed speed of the drill 4 is automatically set to the optimum speed corresponding to the total value of the thickness based on the total value. Therefore, it is possible to prevent problems such as deterioration of processing quality, damage to the drill 4, heat generation of the motor in the spindle 6, a decrease in the rotation speed, and damage to the air bearing.
Further, since the feed rate V0 in the initial operation is set to the lowest feed rate V4 among those set by the apparatus, it is possible to prevent the initial feed rate from being too fast and causing the above - mentioned problems.

In the above embodiment, the upper plate for improving the bite of the drill 4 and preventing the occurrence of burrs and the like may be placed on the multilayer printed circuit board 1. When the upper plate is made of a metal conductor such as aluminum, this upper plate becomes a conductor layer, so that the resonance detection circuit is performed when the drill 4 passes through the conductor layers L1 to L4 in the multilayer printed circuit board 1. The resonance detection signal S is generated from 44, and the total thickness T calculated by the thickness detection unit 15 includes the thickness of the upper plate.
Since the upper plate is a metal layer, the cutting resistance is larger than that of the insulating layer 30 like the conductor layers L1 to L4 of the multilayer printed circuit board 1, and it is necessary to consider the thickness like the conductor layers L1 to L4. If the relationship between the total thickness T including the thickness of the upper plate and the optimum feed rate of the drill 4 in that case is experimentally obtained and stored in the storage unit 16, the upper plate is placed on the storage unit 16. Even in this case, the optimum feed rate of the drill 4 can be selected.

Further, in the above embodiment, when processing the multilayer printed circuit board 1, the total value of the thicknesses of the conductor layers is detected by one drilling, and the feed rate is set to the optimum value from the next drilling. , The total thickness may be detected by drilling a plurality of holes, and the optimum value may be selected by averaging the total thicknesses of the plurality of holes.

Further, in the above embodiment, the feed rate setting unit 17 selects the corresponding optimum feed rate V from the optimum feed rate storage unit 16 based on the total value of the thicknesses of the conductor layers of the multilayer printed circuit board 1. However, the corresponding optimum feed rate V may be determined by performing arithmetic processing on the total thickness value.

In the above, an embodiment in which the present invention is applied to the selection of the optimum drill feed rate corresponding to the situation of the conductor layer of the multilayer printed circuit board has been described. It can also be applied when selecting the optimum one for various machining conditions such as the number of steps including whether or not step machining is performed. In this case, not only one machining condition but also a plurality of machining conditions may be selected.

1: Multi-layer printed circuit board 2: Machining table 3: Bottom plate 4: Drill 5: Spindle unit 6: Spindle, 7: Machining table drive unit 8: Spindle vertical drive unit, 14: Overall control unit, 15: Thickness detection unit 16: Optimal feed rate storage unit, 17: Feed speed setting unit
31: Rotor shaft, 32: Electrode, 33: Resonance detector, 41: Capacitor,
42: Transformer, 43: Oscillation circuit, 44: Resonance detection circuit,
L1 to L4: conductor layer, R1 to R3: insulating layer, S: resonance detection signal,
R: Spindle control line

Claims (4)

In a drilling machine that drills a multilayer printed circuit board under the set machining conditions.
A thickness detection unit that detects the total thickness of the conductor layer based on the time for the drill to pass through the conductor layer arriving in the drilling direction and the feed rate of the drill at that time.
A storage unit in which the optimum drill feed rate corresponding to the total value is experimentally obtained and stored based on the total value detected by the thickness detection unit.
When processing the multilayer printed circuit board, the optimum drill feed rate corresponding to the storage unit is automatically determined from the storage unit based on the total thickness of the conductor layers of the multilayer printed circuit board obtained by the thickness detection unit. A drilling machine characterized by having a condition setting unit to be newly set. In the drilling apparatus according to claim 1,
A drilling apparatus characterized in that the feed speed of the drill when the thickness is detected by the thickness detection unit is set to be the lowest among the feed speeds set by the apparatus. In the drilling apparatus according to claim 1 or 2.
It is characterized in that the contact between the conductor layer and the drill when the drill passes through the conductor layer is detected based on the change in capacitance between the drill and the ground when the drill passes through the conductor layer. Drilling equipment. In the drilling method in which the multi-layer printed circuit board is drilled under the set machining conditions.
A thickness detection step for detecting the total thickness of the conductor layer based on the time for the drill to pass through the conductor layer arriving in the drilling direction and the feed rate of the drill at that time.
A storage step in which the optimum drill feed rate corresponding to the total value is experimentally obtained based on the total value detected by the thickness detection unit and stored in the storage unit .
When processing the multilayer printed circuit board, the optimum drill feed rate corresponding to the storage unit is automatically determined from the storage unit based on the total thickness of the conductor layers of the multilayer printed circuit board obtained in the thickness detection step . A drilling method characterized by having a newly set machining condition setting step.

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