A numerically controlled drilling and milling device for printed circuit boards

Abstract

The present invention relates to the technical field of circuit board processing equipment, and discloses a numerically controlled drilling and milling equipment for printed circuit boards, including a housing and a chuck seat. A permanent magnet ring is embedded at the top end of the chuck seat. A radial chute is opened on the inner wall of the housing. A first limiting ring, a second limiting ring, an electromagnet and a pressure sensor are arranged in the chute. An annular groove is opened on the inner wall of the housing. A bearing is installed in the annular groove. An axial chute is opened above the annular groove. A first transmission block is arranged in the axial chute. An installation groove is opened below the annular groove. A spring and a second transmission block are arranged in the installation groove. The first transmission block and the second transmission block are in close contact with the outer ring of the bearing. For this numerically controlled drilling and milling equipment for printed circuit boards, the electromagnet is controlled to be powered on and off by a PLC control device, and the drilling method is changed to multiple drilling to reduce the occurrence of drill breakage in drilling high aspect ratio holes, and the offset of the drill bit is detected by the numerical difference of the pressure sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board processing equipment, and particularly to a numerically controlled drilling and milling equipment for printed circuit boards. Background Technique

[0002] A printed circuit board, also known as a printed wiring board, is a provider of electrical connections for electronic components. Printed circuit boards can be classified into single-layer boards, double-layer boards, and multi-layer boards according to the number of circuit layers. The development trend of printed circuit board production manufacturing technology is towards high density, high precision, fine aperture, fine wire, small pitch, high reliability, and multi-layer in terms of performance.

[0003] Among multi-layer circuit boards, the more complex ones can reach dozens of layers. Compared with traditional circuit boards, they are thicker. In the drilling process of multi-layer circuit boards, since the current drilling diameter is small, the ratio of the board thickness of the circuit board to the drilling diameter will be large, resulting in a phenomenon of high aspect ratio. When drilling holes with a high aspect ratio at one time, the drill bit is subjected to a large force, increasing the risk of drill breakage; and after the drill bit is used for a long time, it is inevitable that the force on the drill bit is uneven and the drill bit deviates. The deviation of the drill bit will cause the diameter of the drilled hole to become larger and the drilling accuracy to be poor. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] Aiming at the deficiencies existing in the prior printed circuit board drilling and milling machine during use in the background technique, the present invention provides a numerically controlled drilling and milling equipment for printed circuit boards, which has the advantages of reducing drill breakage when processing high aspect ratio holes and being able to detect whether the drill bit deviates, and solves the technical problems proposed in the above background technique.

[0006] (II) Technical Solutions

[0007] The present invention provides the following technical solution: A numerically controlled drilling and milling device for a printed circuit board, including a backboard fixedly installed on the upper end surface of a base. A slide plate is slidably installed on the backboard, and multiple groups of spindles are equidistantly installed on the slide plate. The spindle includes a housing and a motor. The shaft of the motor is sequentially connected with a connecting block, a connecting shaft, a chuck, and a chuck seat. A permanent magnet ring is embedded at the top of the outer side surface of the chuck seat. Three sliding grooves are radially opened on the inner wall of the housing. A first limiting ring and a second limiting ring are fixedly installed in the sliding grooves in the radial direction. An electromagnet is slidably installed between the first limiting ring and the second limiting ring. An annular groove is opened on the inner wall of the housing, and a bearing is slidably installed in the annular groove. An axial sliding groove is opened at the edge position above the annular groove. The axial sliding groove communicates with the three radial sliding grooves and the annular groove. The sliding grooves are filled with transmission fluid. A first transmission block is slidably installed in the axial sliding groove. An installation groove is opened at the edge position below the annular groove, and a spring is fixedly installed in the installation groove. A second transmission block is fixedly installed above the spring. The first transmission block and the second transmission block are in close contact with the outer ring of the bearing.

[0008] Preferably, a pressure sensor is fixedly installed on the electromagnet, and the pressure sensor is located on the side where the electromagnet is in close contact with the transmission fluid.

[0009] Preferably, the length of the permanent magnet ring is twice the distance from the top of the uppermost sliding groove to the bottom of the lowermost sliding groove, and the lowermost end of the permanent magnet ring is on the same horizontal plane as the lowermost end of the lowermost electromagnet.

[0010] Preferably, the spring is always in a compressed state.

[0011] Preferably, the widths of the first transmission block and the second transmission block are the thickness of the outer ring of the bearing.

[0012] (III) Beneficial effects

[0013] The present invention has the following beneficial effects:

[0014] 1. In the present invention, a permanent magnet ring is fixedly sleeved on the top end outside the drill chuck. Three groups of symmetric radial chutes are opened on the inner wall of the main shaft housing. The three groups of radial chutes are axially equidistantly arranged on the inner wall of the housing. A first limiting ring and a second limiting ring are fixedly installed in the radial chute. An electromagnet is slidably installed in the radial chute. The electromagnet is located between the first limiting ring and the second limiting ring. An annular groove is opened on the inner wall of the main shaft housing. A bearing is slidably installed in the annular groove. An axial chute is opened at the edge position above the annular groove. The axial chute communicates the three groups of radial chutes with the annular groove. A first transmission block is slidably installed in the axial chute. The chute is filled with transmission fluid. The bottom end of the first transmission block closely abuts the upper end of the outer ring of the bearing. Installation grooves are symmetrically opened at the edge position below the annular groove. Springs are fixed in the installation grooves. The top ends of the springs are fixedly connected to the bottom ends of the second transmission blocks. The top ends of the second transmission blocks closely abut the lower ends of the outer rings of the bearings. During operation, the PLC control device controls the main shaft to move to the drilling position of the printed circuit board, so that the drill bit closely abuts the printed circuit board. At this time, the PLC control device controls the uppermost electromagnet to be energized. The uppermost electromagnet and the permanent magnet ring generate a repulsive force. The electromagnet pushes the transmission fluid to slide in the radial chute. The transmission fluid in the radial chute enters the axial chute. The transmission fluid pushes the first transmission block to move downward. The first transmission block pushes the bearing to drive the chuck seat, chuck and drill bit to move downward, so that the drill bit drills a hole of a certain depth. At this time, the PLC control device controls the uppermost electromagnet to be powered off. Under the action of the spring and the second transmission block, the bearing, chuck seat, chuck and drill bit return to their original positions, completing one drilling; then, the PLC control device controls the uppermost and middle two groups of electromagnets to be energized, so that the bearing drives the chuck seat, chuck and drill bit to move downward a deeper distance, completing the second drilling; finally, the PLC control device controls the three groups of electromagnets to be energized, and the drill bit moves downward to the deepest position, completing the third drilling, and the drilling is completed. Changing the way of drilling a high aspect ratio hole at one time to the way of drilling a high aspect ratio hole multiple times reduces the risk of drill bit breakage.

[0015] 2. In the present invention, a pressure sensor is fixedly installed on the electromagnet. The pressure sensor closely abuts the transmission fluid. During operation, the permanent magnet and the electromagnetic ring generate a repulsive force. When the chuck seat, chuck and drill bit are at the axial center position, the repulsive forces of the permanent magnet ring on the two side electromagnets are the same, and the pressure difference measured by the pressure sensors at symmetric positions is within the error range. When the drill bit is deflected, during the second or third drilling, the drill bit is subjected to a lateral force, and the drill bit drives the chuck and the chuck seat to deflect. The permanent magnet ring on the chuck seat deflects. At this time, the repulsive forces of the permanent magnet ring on the two side electromagnets are different, and the pressure difference measured by the pressure sensors at symmetric positions is not within the error range. Thus, it is judged that the drill bit has a deflection phenomenon. The PLC control device issues an alarm, and manual adjustment or replacement of the drill bit is required to avoid the phenomenon of a larger drilling diameter and poor drilling accuracy when using a deflected drill bit for drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1Schematic diagram of the structure of the present invention;

[0017] Figure 2 Schematic diagram of the main shaft structure of the present invention;

[0018] Figure 3 For the present invention Figure 2 Partial enlarged schematic diagram of the structure at position A in the present invention;

[0019] Figure 4 Schematic diagram of the working structure of the main shaft of the present invention;

[0020] Figure 5 For the present invention Figure 4 Partial enlarged schematic diagram of the structure at position B in the present invention.

[0021] In the figure: 1, base; 2, PLC control device; 3, slide rail; 4, support plate; 5, back plate; 6, slide plate; 7, main shaft; 701, housing; 702, motor; 703, connecting block; 704, connecting shaft; 705, chuck; 706, chuck seat; 707, permanent magnet ring; 708, chute; 709, first limit ring; 710, second limit ring; 711, electromagnet; 712, pressure sensor; 713, bearing; 714, first transmission block; 715, installation groove; 716, spring; 717, second transmission block; 8, drill bit. Specific implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Please refer to Figure 1 , Figure 2 and Figure 3 , a numerically controlled drilling and milling device for printed circuit boards, including a base 1, a PLC control device 2, a back plate 5 and a main shaft 7. A PLC control device 2 is fixedly installed on the upper end surface of one side of the base 1, slide rails 3 are fixedly installed equidistantly on the upper end surface of the other side of the base 1, a support plate 4 is slidably installed on the upper ends of the slide rails 3 on the base 1, a back plate 5 is provided at the rear end of the support plate 4, the back plate 5 is fixedly installed on the upper end surface of the base 1, slide rails 3 are fixedly installed in the horizontal direction on the back plate 5, a slide plate 6 is slidably installed on the slide rails 3 on the back plate 5, multiple groups of main shafts 7 are installed equidistantly on the slide plate 6, and the main shafts 7 are located above the support plate 4.

[0024] The main shaft 7 includes a housing 701, a motor 702, and a chuck seat 706. A motor 702 is fixedly installed at the top end of the housing 701. The shaft of the motor 702 is disposed within the housing 701. The shaft of the motor 702 is fixedly connected to a connecting block 703. A connecting shaft 704 is fixedly connected to the bottom end of the connecting block 703. A chuck 705 is fixedly installed at the bottom end of the connecting shaft 704. A chuck seat 706 is movably sleeved outside the chuck 705. The chuck 705 and the chuck seat 706 can slide axially relative to each other. A permanent magnet ring 707 is embedded at the top end of the outer side surface of the chuck seat 706. The outer side surface of the permanent magnet ring 707 is in the same plane as the outer side surface of the chuck seat 706. Three groups of sliding grooves 708 are radially formed on the inner wall of the housing 701. The three groups of sliding grooves 708 are symmetrically arranged on the inner wall of the housing 701. The three sliding grooves 708 on the same side are equidistantly arranged axially on the housing 701. The radially arranged sliding groove 708 is located on the side surface of the permanent magnet ring 707. A first limiting ring 709 and a second limiting ring 710 are fixedly installed in the sliding groove 708. An electromagnet 711 is slidably installed in the radially arranged sliding groove 708. The electromagnet 711 is located between the first limiting ring 709 and the second limiting ring 710. An annular groove is formed on the inner wall of the housing 701. The annular groove is located at the lower end of the sliding groove 708. A bearing 713 is slidably installed in the annular groove. The inner ring of the bearing 713 is fixedly sleeved outside the chuck seat 706. An axial sliding groove 708 is formed at the edge position above the annular groove. The axial sliding groove 708 communicates the three radial sliding grooves 708 with the annular groove. The sliding groove 708 is filled with transmission fluid. A first transmission block 714 is slidably installed in the axial sliding groove 708. The bottom end of the first transmission block 714 closely abuts the top end of the outer ring of the bearing 713. An installation groove 715 is formed at the edge position below the annular groove. A spring 716 is fixedly installed in the installation groove 715. A second transmission block 717 is fixedly installed above the spring 716. The top end of the second transmission block 717 closely abuts the bottom end of the outer ring of the bearing 713.

[0025] A pressure sensor 712 is fixedly installed on the electromagnet 711. The pressure sensor 712 is located on the side of the electromagnet 711 that closely abuts the transmission fluid.

[0026] The length of the permanent magnet ring 707 is twice the distance from the top end of the uppermost sliding groove 708 to the bottom end of the lowermost sliding groove 708. The lowermost end of the permanent magnet ring 707 is on the same horizontal plane as the lowermost end of the lowermost electromagnet 711. When the bearing 713 drives the chuck 705 to move up and down, the permanent magnet ring 707 on the chuck 705 can always generate a repulsive force facing the electromagnet 711.

[0027] The spring 716 is always in a compressed state. The spring 716 always supports the second transmission block 717 and the bearing 713 to prevent the bearing 713 from driving the chuck seat 706, the chuck 705, and the drill bit 8 to slide down when the electromagnet 711 does not push the transmission fluid.

[0028] The widths of the first drive block 714 and the second drive block 717 are the thickness of the outer ring of the bearing 713. If the widths of the first drive block 714 and the second drive block 717 are too narrow, they cannot support the sliding of the bearing 713; if the widths of the first drive block 714 and the second drive block 717 are too wide, it will affect the rotation of the inner ring of the bearing 713.

[0029] The amount of transmission fluid slid by the three groups of electromagnets 711 is exactly such that the first drive block 714 pushes the bearing 713 to slide to the lowermost end of the annular groove.

[0030] The height of the annular groove is the sum of the height of the bearing 713 and the downward movement distance of the drill bit 8 during drilling.

[0031] The electromagnet 711 and the first drive block 714 are hermetically and slidably installed in the chute 708 to prevent the transmission fluid in the chute 708 from overflowing.

[0032] The three radial chutes 708 can be designed with different diameters according to the different downward movement amounts of the drill bit 8 each time. When the downward movement amount is larger, the corresponding radial chute diameter is larger; when the downward movement amount is smaller, the corresponding radial chute diameter is smaller.

[0033] The usage method (working principle) of the present invention is as follows:

[0034] Refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 When the numerical control drilling and milling equipment is operating, the PLC control device 2 controls the spindle 7 to move to the upper end of the drilling position on the printed circuit board, and the drill bit 8 is close to the drilling position on the printed circuit board. At this time, the PLC control device 2 controls the uppermost electromagnet 711 to be energized. The uppermost electromagnet 711 generates a repulsive force with the permanent magnet ring 707. The uppermost electromagnet 711 pushes the transmission fluid to slide in the radial chute 708, and the transmission fluid in the radial chute 708 enters the axial chute 708, so that the transmission fluid pushes the first drive block 714 to slide. The first drive block 714 pushes the top end of the outer ring of the bearing 713, and the bearing 713 slides downward in the annular groove. At the same time, an inflation device (the inflation device is a prior art and not shown in the figure) fills a certain amount of gas into the connecting block 703 to ensure that the connecting shaft 704 can move downward normally. The inner ring of the bearing 713 drives the collet holder 706, the collet 705 and the drill bit 8 to slide downward, so that the drill bit 8 drills a hole of a certain depth. At this time, the PLC control device 2 controls the uppermost electromagnet 711 to be de-energized. Under the action of the spring 716 and the second drive block 717, the bearing 713, the collet holder 706, the collet 705 and the drill bit 8 return to their original positions, completing a drilling operation;

[0035] Subsequently, the PLC control device 2 controls the electromagnets 711 at the uppermost and middle positions to be energized. The electromagnets 711 at the uppermost and middle positions generate repulsive forces with the permanent magnet ring 707. The electromagnets 711 push the transmission fluid in the radial chutes 708 at the uppermost and middle positions into the axial chute 708. The transmission fluid pushes the first transmission block 714 to drive the bearing 713 to move down to a lower position. The inner ring of the bearing 713 drives the collet holder 706, the collet 705, and the drill bit 8 to move down to a deeper position. At this time, the PLC control device 2 controls the electromagnets 711 at the uppermost and middle positions to be de-energized. Under the action of the spring 716 and the second transmission block 717, the bearing 713, the collet holder 706, the collet 705, and the drill bit 8 return to their original positions, completing the secondary drilling operation;

[0036] Finally, the PLC control device 2 controls the three groups of electromagnets 711 to be energized. The three groups of electromagnets 711 generate repulsive forces with the permanent magnet ring 707. Under the action of the transmission fluid and the first transmission block 714, the bearing 713 moves down to the lowest position, and the collet 705, the collet holder 706, and the drill bit 8 move down to the lowest position, completing the third drilling. By changing the one-time drilling of a high aspect ratio hole to multiple drillings, during the drilling process, the drill bit 8 moves up and down multiple times, reducing the force on the drill bit 8, thereby reducing the risk of the drill bit 8 breaking.

[0037] During the drilling process, when the electromagnet 711 and the pressure sensor 712 push the transmission fluid to slide, the transmission fluid generates a reaction force on the pressure sensor 712. When the drill bit 8 is in a non-offset state, the axes of the drill bit 8, the collet 705, and the collet holder 706 are at the axis position of the main shaft 7. The forces exerted by the electromagnets 711 at symmetric positions on the pressure sensor 712 and the transmission fluid are the same, and the difference in the pressure values of the reaction forces of the transmission fluid measured by the pressure sensor 712 is within the error range; when the drill bit 8 is offset, during the drilling operation of the drill bit 8, the edge positions of the drilling area of the drill bit 8 are subjected to different forces, and under the drive of the drill bit 8, the collet 705 and the collet holder 706 are offset to a certain extent. The axes of the drill bit 8, the collet 705, and the collet holder 706 are not at the axis position of the PLC control device 2. At this time, the repulsive forces of the permanent magnet ring 707 on the collet holder 706 on the two symmetric electromagnets 711 are different, the forces exerted by the symmetric electromagnets 711 on the pressure sensor 712 and the transmission fluid are different, the reaction forces of the transmission fluid received by the pressure sensor 712 are different, and the difference in the pressure values measured by the pressure sensor 712 is not within the error range. At this time, the PLC control device 2 determines that the drill bit 8 is offset, and the PLC control device 2 controls the warning device to issue an alarm, reminding the staff to adjust or replace the drill bit 8 to avoid drilling with the offset drill bit 8, resulting in a larger drilling diameter and poor drilling accuracy.

[0038] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0039] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A numerically controlled drilling and milling device for a printed circuit board, which comprises a back plate (5) fixedly installed on the upper end surface of a base (1). A slide plate (6) is slidably installed on the back plate (5). A plurality of groups of main shafts (7) are equidistantly installed on the slide plate (6). The main shaft (7) comprises a housing (701) and a motor (702). The shaft of the motor (702) is sequentially connected with a connecting block (703), a connecting shaft (704), a chuck (705) and a chuck seat (706), and is characterized in that: At the top of the outer side of the collet seat (706), a permanent magnet ring (707) is embedded. On the inner wall of the housing (701), three groups of sliding grooves (708) are radially opened. In the radially arranged sliding grooves (708), a first limiting ring (709) and a second limiting ring (710) are fixedly installed. An electromagnet (711) is slidably installed between the first limiting ring (709) and the second limiting ring (710). On the inner wall of the housing (701), an annular groove is opened. A bearing (713) is slidably installed in the annular groove. At the edge position above the annular groove, an axially arranged sliding groove (708) is opened. The axially arranged sliding groove (708) communicates the three radially arranged sliding grooves (708) with the annular groove. The sliding grooves (708) are filled with transmission fluid. A first transmission block (714) is slidably installed in the axially arranged sliding groove (708). At the edge position below the annular groove, an installation groove (715) is opened. A spring (716) is fixedly installed in the installation groove (715). Above the spring (716), a second transmission block (717) is fixedly installed. The first transmission block (714) and the second transmission block (717) are in close contact with the outer ring of the bearing (713).

2. The numerically controlled drilling and milling equipment for printed circuit boards according to claim 1, characterized in that: A pressure sensor (712) is fixedly installed on the electromagnet (711). The pressure sensor (712) is located on the side where the electromagnet (711) is in close contact with the transmission fluid.

3. A numerical control drilling and milling device for printed circuit boards according to claim 1, characterized in that: The length of the permanent magnet ring (707) is twice the distance from the top of the uppermost sliding groove (708) to the bottom of the lowermost sliding groove (708). The lowermost end of the permanent magnet ring (707) is on the same horizontal plane as the lowermost end of the lowermost electromagnet (711).

4. A numerically controlled drilling and milling device for printed circuit boards according to claim 1, characterized in that: The spring (716) is always in a compressed state.

5. The numerically controlled drilling and milling equipment for printed circuit boards according to claim 1, characterized in that: The widths of the first transmission block (714) and the second transmission block (717) are the thickness of the outer ring of the bearing (713).

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