Application of cutter in back drilling processing of printed circuit board

Abstract

The invention relates to application of a cutter in printed circuit board back drilling processing. The application of the cutter in the back drilling processing of the printed circuit board comprises the following steps: the cutter body of the cutter is insulated, the conductive area of the cutter is arranged at the cutter point of the cutter, when the cutter is used for the back drilling processing, the cutter body does not form a loop with the conductive layer on the circuit board, and the cutter point is conducted with the conductive layer contacted with the cutter point to form a loop.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board manufacturing, in particular to the application of a tool in back drilling processing of a printed circuit board. Background Art

[0002] Back drilling is a special drilling technology that controls the drilling depth. In the production of multi-layer boards, such as eight-layer boards, when the first layer needs to be connected to the sixth layer, a through hole is usually drilled first (one-time drilling), and then the conductive material is plated, so that the first layer is directly connected to the eighth layer. In fact, we only need to connect the first layer to the sixth layer. At this time, the seventh and eighth layers have no lines connected, like an extra column plated with conductive material. This column will cause reflection, scattering, delay, etc. of signal transmission in high-frequency and high-speed circuit design, which will bring problems with signal integrity. Therefore, this extra column is drilled from the back side (secondary drilling), and this is called back drilling.

[0003] In the manufacturing process of multilayer printed circuit boards, the thickness of the multilayer printed circuit boards and insulating products will be uneven after being pressed together, which will cause the depth of the back drilling performed according to the conventional processing method of the printed circuit board to deviate from the depth of the actual back drilling position on the printed circuit board, resulting in the traces being drilled off or the length of the conductive material sunk in the via being too long, affecting signal transmission. Summary of the invention

[0004] Based on this, it is necessary to provide a tool for the application of back drilling processing on printed circuit boards in view of the technical problem that the depth of back drilling performed according to the conventional processing method of printed circuit boards deviates from the depth of the actual back drilling position on the printed circuit board, resulting in the traces being drilled off or the length of the conductive material sunken in the via being large, affecting signal transmission.

[0005] A tool is used in back drilling processing of a printed circuit board. The blade of the tool is insulated, and the conductive area of ​​the tool is arranged at the tip of the tool. When the tool is used for back drilling processing, the blade does not form a loop with the conductive layer on the printed circuit board, and the tip of the tool is connected to the conductive layer in contact to form a loop.

[0006] In one embodiment, the conductive area is disposed at the sharp point of the knife tip.

[0007] In one embodiment, the axial height of the sharp point area of ​​the blade tip is no greater than 0.5 mm.

[0008] In one of the embodiments, the pointed area is connected to a handle of the tool, and the handle is used to electrically connect to an electrical unit.

[0009] In one of the embodiments, the area outside the sharp point area on the knife tip is insulated.

[0010] In one embodiment, a plurality of spiral chip grooves are provided on the outer periphery of the blade of the tool.

[0011] In one embodiment, the blade body is a cylindrical structure, and the blade tip is a conical structure.

[0012] In one embodiment, the steps include:

[0013] A through hole is drilled on the sheet material by the tool along the thickness direction of the sheet material. During the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, the position of the conductive layer is determined according to the movement distance of the tool.

[0014] Plating the hole wall of the through hole with a conductive material;

[0015] Determine an area of ​​the conductive layer from which via-hole conductive material needs to be removed;

[0016] According to the position of the conductive layer, controlling the tool to remove the via-hole conductive material of the conductive layer;

[0017] Wherein, the sheet material is formed by laminating multiple layers of printed circuit boards.

[0018] In one embodiment, the through hole is drilled on the sheet material by the tool along the thickness direction of the sheet material, and during the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, the position of the conductive layer is determined according to the movement distance of the tool, specifically including:

[0019] When the conductive area of ​​the tool is in contact with the conductive layer at the target position, the acquisition board outputs a pulse signal, and the detector feeds back the movement distance of the tool to determine the current position information of the conductive layer.

[0020] In one embodiment, the step of feeding back the movement distance of the tool through the detector to determine the current position information of the conductive layer specifically includes:

[0021] The detector feeds back the position information of the initial position of the tool, and the detector feeds back the position information of the tool when the pulse signal is generated, so as to obtain the current position information of the conductive layer.

[0022] In one embodiment, before the step of “controlling the tool to remove the via-hole conductive material of the conductive layer”, the method further includes:

[0023] The tool moves to the conductive layer closest to the conductive material-plated area where electrical connection needs to be made.

[0024] In one of the embodiments, the method further includes: after the tool removes all the via-hole conductive material in the conductive layer area that needs to be removed, the tool stops moving and retracts.

[0025] Beneficial effects:

[0026] An embodiment of the present invention provides a back drilling method, comprising the following steps:

[0027] A through hole is drilled on the sheet material along the thickness direction of the sheet material. During the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, the position of the conductive layer is determined according to the movement distance of the tool.

[0028] Plating the hole wall of the through hole with a conductive material;

[0029] Determine the area of ​​the conductive layer where the via sink conductive material needs to be removed;

[0030] According to the position of the conductive layer, the via-hole conductive material of the conductive layer is removed.

[0031] In the present application, when the tool contacts the conductive layer in the sheet material during the drilling process, thereby conducting with the conductive layer to form a loop, the tool movement distance can be obtained to determine the position information of the conductive layer. Then, when the sheet material is back-drilled, the movement depth of the drill bit during back-drilling can be determined based on the known position information of the conductive layer, thereby accurately drilling out excess via-hole conductive material, avoiding the wiring in the through hole from being drilled off, and improving the signal transmission quality.

[0032] The embodiment of the present invention further provides a tool, which is used to implement the above-mentioned back drilling method, wherein the outer peripheral surface of the tool is wrapped with an insulating coating, and the area outside the insulating coating forms a conductive area. The tool can achieve at least one of the above-mentioned technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A flow chart of the back drilling method provided by the present invention;

[0035] Figure 2 A first schematic diagram of a tool processing a multilayer board in the back drilling processing method provided by the present invention;

[0036] Figure 3 A schematic diagram of a tool provided by the present invention;

[0037] Figure 4 A first waveform diagram formed when a knife tip and a conductive layer knife form a loop in the back drilling method provided by the present invention;

[0038] Figure 5 A second schematic diagram of a tool processing a multilayer board in the back drilling method provided by the present invention;

[0039] Figure 6 A second waveform diagram formed when the tool tip and the conductive layer tool form a loop in the back drilling method provided by the present invention;

[0040] Figure 7 This is a third waveform diagram formed when the tool tip and the conductive layer tool form a loop in the back drilling method provided by the present invention.

[0041] Figure numbers: 100 - tool; 110 - tool tip; 111 - tool tip apex; 120 - tool body; 130 - tool handle; 140 - chip groove; 200 - sheet material; 210 - top conductive layer; 220 - bottom conductive layer; 230 - first conductive layer; 240 - second conductive layer; 250 - through hole; 310 - metal chips. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0048] See also Figure 1 , Figure 2 and Figure 3 , Figure 1 A flow chart of the back drilling method provided by the present invention; Figure 2 A first schematic diagram of a tool processing a multilayer board in the back drilling processing method provided by the present invention; Figure 3 A back drilling method provided by an embodiment of the present invention comprises the following steps:

[0049] S100 Drilling a through hole 250 on the plate 200 along the thickness direction of the plate 200 . During the drilling process, when the conductive area of ​​the tool 100 contacts and conducts with the conductive layer at the target position on the plate 200 , the position of the conductive layer is determined according to the movement distance of the tool 100 .

[0050] Specifically, the sheet 200 is formed by laminating a plurality of layers of printed circuit boards. Since the inner layer circuit and the outer layer circuit need to be connected in the sheet 200, a signal transmission hole needs to be set in the sheet 200. During the drilling process, when the conductive area of ​​the tool 100 contacts the current conductive layer at the target position on the sheet 200, and the tool 100 can conduct with the current conductive layer to form a loop, the position information of the current conductive layer can be obtained. The through hole 250 is drilled in the sheet 200 by the tool 100, so as to accurately measure the position information of the conductive layer at the target position on the sheet 200, that is, the position of the conductive layer is measured while drilling, and the whole measurement process is simple and improves the back drilling efficiency. Among them, the conductive layer at the target position refers to the conductive layer whose position information needs to be obtained, and other conductive layers can be ignored.

[0051] Furthermore, since the tool 100 moves along the thickness direction of the plate 200 during the drilling process, the measured horizontal positions of all the conductive layers are the same, and therefore only the longitudinal coordinate position of the conductive layer needs to be measured.

[0052] S200 The hole wall of the through hole 250 is plated with a conductive material.

[0053] Specifically, after drilling is completed, the inner wall of the through hole 250 needs to be plated with a conductive material so that the through hole 250 can be used as a signal transmission hole for connecting the inner layer circuit and the outer layer circuit. Preferably, the conductive material is copper. In other embodiments, the conductive material can also be other conductive materials such as silver. It should be noted that due to process reasons, the entire inner wall of the through hole is plated with copper.

[0054] S300: Determine an area of ​​the conductive layer where the conductive material of the via sink needs to be removed.

[0055] Specifically, a portion of the through hole 250 is provided with a connecting wire, and another portion is not provided with a wire. For ease of distinction, the portion of the through hole 250 provided with a wire is defined as a non-drilling area, and the portion of the through hole 250 not provided with a wire is defined as a back-drilling area. Since the copper deposited in the via in the back-drilling area is too long, it affects the integrity of the signal transmission, so it is necessary to drill out the copper deposited in the via in the back-drilling area. Since the non-drilling area is known, the area of ​​the conductive layer of the copper deposited in the via can be determined. It should be noted that the back-drilling area and the non-drilling area in the through hole are measured by conventional methods in the prior art, which will not be repeated.

[0056] S400 removes the via-hole conductive material of the conductive layer according to the position of the conductive layer.

[0057] Specifically, after determining the via copper in the conductive layer area to be removed, according to the position information of the conductive layer at the target position obtained in S100, the tool 100 is controlled to extend from the back-drilling area into the through hole 250, and the via copper is removed from the through hole 250. When the tool 100 removes all the via copper in the conductive layer area to be removed, the tool 100 stops moving and retracts. Since the tool 100 removes all the via copper in the conductive layer area to be removed, the remaining via copper is shortened, the accuracy of the back-drilling depth is improved, and the tool 100 is prevented from damaging the wire in the through hole 250, thereby improving the signal transmission quality.

[0058] Continue reading Figure 1 , Figure 2 and Figure 3 In one embodiment, after the step of “removing the conductive material of the via hole of the conductive layer”, the method further comprises:

[0059] The tool 100 moves to the conductive layer closest to the copper-plated area where electrical connection is required.

[0060] Specifically, since it is only necessary to completely remove all the via copper deposits on the side of the conductive layer located in the back-drilled area and closest to the non-drilled area and away from the non-drilled area, the remaining via copper deposits can be minimized.

[0061] The final drilling position is located at the position of the conductive layer in the back drilling area and closest to the non-drilling area, that is, only the position information of the final drilling position needs to be determined to determine the depth of the tool 100 moving from the initial position to the conductive layer, which is more concise and completely eliminates the adverse effects on the thickness of the sheet 200 during the lamination process of the multilayer board, greatly improving the back drilling depth accuracy. It should be noted that the final drilling position is the position of the tool 100 on the sheet 200 when the back drilling process is completed.

[0062] This embodiment is based on the specification Figure 2For example, the conductive layer at the target position includes the first conductive layer 230 and the second conductive layer 240, and the transition position between the backdrilling area and the non-drilling area is defined to be between the first conductive layer 230 and the second conductive layer 240. When the backdrilling area is located at the bottom, the first conductive layer 230 is the conductive layer closest to the non-drilling area, and when the backdrilling area is located at the top, the second conductive layer 240 is the conductive layer closest to the backdrilling area. Through the measurement in S100, the position information of the first conductive layer 230 and the second conductive layer 240 is known. When backdrilling is performed, assuming that the backdrilling area is located at the bottom, the distance that the tool 100 moves to the first conductive layer 230 in the backdrilling area can be determined through the position information of the first conductive layer 230 and the position information of the tool 100 at the initial position, that is, the backdrilling depth can be accurately determined, so that the via copper deposition is shorter and the signal transmission efficiency is improved.

[0063] Furthermore, since there is still a certain distance between the transition position and the first conductive layer 230, the corrected distance value between the transition position and the first conductive layer 230 can be obtained according to the theoretical distance value between the transition position and the first conductive layer 230 and the ratio of the actual distance value between the first conductive layer 230 and the second conductive layer 240 to the theoretical distance value, that is, the ordinate value of the final drilling position is the sum of the ordinate value of the first conductive layer 230 and the corrected distance value, so that the final drilling position is closer to the transition position, the residual via copper is shorter, and the signal transmission efficiency is higher. It should be noted that the smaller the distance value between the first conductive layer 230 and the second conductive layer 240, the closer the corrected distance value between the transition position and the first conductive layer 230 is to the actual distance value between the transition position and the first conductive layer 230.

[0064] See also Figure 1 , Figure 2 and Figure 3 In one embodiment, in the step of "drilling a through hole in the sheet material along the thickness direction of the sheet material, and during the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, determining the position of the conductive layer according to the movement distance of the tool", the method further includes:

[0065] When the conductive area of ​​the tool 100 contacts and conducts with the conductive layer at the target position, the acquisition board outputs a pulse signal, and the detector feeds back the movement distance of the tool to determine the current position information of the conductive layer.

[0066] Specifically, the conductive area of ​​the tool 100 is electrically connected to the detector, and when the conductive area is in contact with the conductive layer, the detector can obtain the position information of the tool 100 when the corresponding pulse signal is generated, thereby conveniently and accurately obtaining the position information of the conductive layer at the target position on the sheet 200. Preferably, the detector is a grating ruler.

[0067] In another embodiment, when the conductive area of ​​the tool 100 is in contact with the conductive layer, the acquisition board can send a pulse signal to determine the distance the tool 100 moves from the initial position to the current conductive layer through the time between the initial position and the moment the pulse signal is triggered and the movement speed of the tool 100.

[0068] See also Figure 2 , Figure 3 and Figure 4 , Figure 4 The first waveform diagram is formed when the tool tip 110 and the conductive layer tool form a loop in the back drilling method provided by the present invention. In one embodiment, the method of determining the position information of the current conductive layer by feeding back the movement distance of the tool through a detector is: the position information of the current conductive layer is obtained by feeding back the initial position of the tool and the position of the conductive layer at the target position through the detector.

[0069] Specifically, when the conductive area of ​​the tool 100 contacts and conducts with the conductive layer, a loop is formed. At this time, the acquisition board outputs a pulse signal, which will give a high-potential square wave, that is, the output signal of the acquisition board flips from 0 to 1, until the conductive area of ​​the tool 100 is separated from the current conductive layer, causing the loop to be disconnected, causing the output signal of the acquisition board to flip from 1 to 0. When the tool 100 passes through several conductive layers and completes drilling, it will be obtained. Figure 4 When the acquisition board outputs a pulse signal, the position information of the tool 100 when the corresponding signal is generated can be obtained through the detector, and then the information of the initial position of the tool 100 is fed back by the detector, so that the distance value between the current conductive layer and the initial position of the tool 100 can be obtained, and then the position information of the current conductive layer can be obtained.

[0070] For further information, see the Appendix Figure 2 , the conductive layer at the target position also includes a top conductive layer 210 and a bottom conductive layer 220, which are respectively located at the top and bottom of the sheet 200. The tool 100 can directly obtain the distance value between the current conductive layer and the top conductive layer 210 or the bottom conductive layer 220 based on the top conductive layer 210 or the bottom conductive layer 220 during the movement. When back drilling is required, the sheet 200 can be directly processed based on the distance value between the first conductive layer 230 and the bottom conductive layer 220 after the sheet 200 is turned over, so that there is no need to measure the initial position of the tool 100, making the measurement process more concise and more efficient.

[0071] It should be noted that during the back drilling process, since the top conductive layer 210 and the bottom conductive layer 220 have been drilled away, it is necessary to cover the sheet 200 with an aluminum plate, and define the position when the tool 100 is connected to the aluminum plate as the reference point. The vertical coordinate value of the final drilling position is the sum of the distance value between the first conductive layer 230 and the bottom conductive layer 220, the corrected distance value (the corrected distance value between the transition position and the first conductive layer 230) and the thickness of the aluminum plate.

[0072] Among them, since the conductive layer has a certain thickness, the conduction between the conductive area and the conductive layer will last for a period of time, so that the thickness of the conductive layer at the target position can be determined by the duration of the high potential and the movement speed of the tool 100, that is, according to the thickness of the first conductive layer 230, more accurate final drilling position information can be obtained, so that the via copper deposition is shorter and the signal transmission quality is higher.

[0073] See also Figure 3 , Figure 4 , Figure 5 and Figure 6 , Figure 5 A second schematic diagram of a tool processing a multilayer board in the back drilling method provided by the present invention; Figure 6 The second waveform diagram is formed when the tool tip and the conductive layer tool form a loop in the back drilling method provided by the present invention. In one embodiment, a plurality of spiral chip grooves 140 are provided on the outer periphery of the tool body 120 of the tool 100 .

[0074] Specifically, when the tool 100 drills the conductive layer, the metal chips 310 generated by the conductive layer cannot be discharged in time and will accumulate between the tool 100 and the hole wall. When one end of the metal chips 310 abuts against the conductive area of ​​the tool 100 and the other end abuts against the conductive layer, the tool 100 and the conductive layer are connected, so that the acquisition board outputs a high potential, as shown in the attached figure. Figure 6 The waveform diagram shown is abnormal because the occurrence of this situation is random, and it is impossible to determine whether the high potential is triggered by the contact between the tool 100 and the current conductive layer during the drilling process, or the loop formed by the conductive area of ​​the tool 100 and the conductive layer of other layers through the metal chips 310, so it is difficult to accurately determine the position of the conductive layer at the target position. Since the outer periphery of the blade 120 of the tool 100 is provided with a plurality of spiral chip grooves 140, the metal chips 310 generated by the conductive layer during the drilling process can be discharged as soon as possible, thereby improving the accuracy of obtaining the conductive layer position to a certain extent.

[0075] See also Figure 3 , Figure 4 , Figure 5 and Figure 6 In one embodiment, the conductive area is disposed at the tip 110 of the knife 100, and the blade 120 of the knife 100 is insulated.

[0076] Specifically, when the chip groove 140 on the tool 100 does not discharge chips well, there is still a possibility that the conductive area of ​​the tool 100 is connected to other conductive layers through the metal chips 310. In the present application, since the conductive area is set at the tip 110 of the tool 100 and the blade 120 of the tool 100 is insulated, when the metal chips 310 are discharged through the chip groove 140 and contact the blade 120 and other conductive layers of the tool 100, the tool 100 will not form a loop with other conductive layers, but only contact and conduct with the conductive layer currently contacted by the tip 110 to form a loop, thereby achieving the attached Figure 4 The ideal waveform shown in the figure accurately measures the position information of the conductive layer, thereby effectively solving the problem that when back drilling a hole, the position signal of the current conductive layer detected by the tool 100 is messy due to the random discharge of metal chips 310, and it is difficult to determine the required copper layer position. It should be noted that the tip 110 of the tool 100 refers to the tapered portion at the lower end of the tool 100.

[0077] See also Figure 3 , Figure 4 , Figure 5 and Figure 7 , Figure 7 The third waveform diagram is formed when the tool tip 110 and the conductive layer tool form a loop in the back drilling method provided by the present invention. In one embodiment, the conductive area is set at the sharp point area 111 of the tool tip 110, and the area outside the sharp point area 111 on the tool tip 110 is insulated from the blade body 120 of the tool 100.

[0078] Specifically, since the tip 110 of the tool 100 has a drill point angle, it takes a certain amount of time for the tip 110 to completely penetrate the metal layer and leave the metal layer when the drill tip hits the conductive layer. When the distance between two conductive layers is not enough, a layer signal will be lost. Figure 7 As shown in the waveform diagram, the blade tip 110 has not yet disconnected from the current conductive layer, but has already contacted the next conductive layer of the current conductive layer. In this way, the triggering moment of the next conductive layer and the blade tip 110 cannot be determined, and the next conductive layer cannot be separated relative to the current conductive layer, and the position information of the conductive layer at the target position cannot be accurately determined.

[0079] Since the conductive area is set at the sharp point area 111 of the blade tip 110, and the area outside the sharp point area 111 of the blade tip 110 is insulated from the blade body 120 of the tool 100, the sharp point area 111 of the blade tip 110 will only contact the current conductive layer when drilling the current conductive layer. Once the current conductive layer is drilled through, the sharp point area 111 of the blade tip 110 will be separated from the current conductive layer, thereby reducing the possibility that the tool 100 has not been disconnected from the current conductive layer and has already contacted the next conductive layer of the current conductive layer, thereby improving the accuracy of the measurement of the conductive layer position information. The axial height of the vertex area of ​​the blade tip 110 is defined to be no greater than 0.5 mm.

[0080] See also Figure 2 , Figure 3 and Figure 5 In one embodiment, the blade tip 110 is electrically connected to the handle 130 of the tool 100, and the handle 130 is electrically connected to the electrical unit.

[0081] Specifically, the electrical unit refers to other components in the circuit. The acquisition board is electrically connected to the handle 130 through the electrical unit. When the tip 110 contacts the conductive layer, the tip 110 and the handle 130 are conductive, thereby forming a loop, so that the acquisition board can collect signals. This embodiment does not limit the electrical unit.

[0082] Furthermore, the knife 100 is made of metal material and is integrally formed, and the handle 130 and the area other than the sharp point area 111 of the knife tip 110 are insulated, for example, by plating an insulating material. In other embodiments, the knife 100 may also be made of a combination of conductive material and non-conductive material, as long as the handle 130 and the sharp point area 111 of the knife tip 110 of the knife 100 are electrically connected and conductive.

[0083] See also Figure 2 and Figure 3 An embodiment of the present invention further provides a tool 100, which is used to implement the above-mentioned back drilling processing method. The outer peripheral surface of the tool 100 is wrapped with an insulating coating, and the area outside the insulating coating forms a conductive area.

[0084] Specifically, because the tool 100 has a conductive area, when the tool 100 is connected to the conductive layer in the sheet 200 to form a loop during the drilling process, the conductive layer position information of the target position in the sheet 200 can be obtained. In the present application, the drilling of the through hole 250 and the measurement of the position information of the conductive layer at the target position are achieved in one drilling process, which makes the entire measurement process simple and improves the back drilling efficiency. At the same time, the tool 100 in the present application can accurately conduct with the current conductive layer and determine the position information of the conductive layer at the target position through an electrical signal, so that during back drilling, the drilling depth of the tool 100 can be accurately controlled, so that the excess via copper can be accurately drilled out, and the wiring in the through hole 250 can be prevented from being drilled off, thereby improving the signal transmission quality.

[0085] See also Figure 3 In one embodiment, the tool 100 includes a tool tip 110 with a conical structure and a tool body 120 with a cylindrical structure.

[0086] Specifically, the conductive area is located at the tip region 111 of the conical tool tip 110, thereby reducing the possibility that the tool 100 has contacted the next conductive layer of the current conductive layer before being disconnected from the current conductive layer, thereby improving the accuracy of measuring the position information of the conductive layer.

[0087] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. Application of a tool in back drilling of printed circuit boards, characterized in that: The blade of the tool is insulated, and the conductive area of ​​the tool is arranged at the tip of the tool. When the tool is used for back drilling, the blade does not form a loop with the conductive layer on the printed circuit board, and the tip of the tool is connected with the conductive layer to form a loop.

2. The use of the tool according to claim 1 in back drilling of printed circuit boards, characterized in that: The conductive area is arranged at the sharp point area of ​​the knife tip.

3. The use of the tool according to claim 2 in back drilling of printed circuit boards, characterized in that: The axial height of the sharp point area of ​​the blade tip is no greater than 0.5 mm.

4. The use of the tool according to claim 2 in back drilling of printed circuit boards, characterized in that: The pointed area is in conduction with a handle of the tool, and the handle is used to electrically connect to an electrical unit.

5. The use of the tool according to claim 2 in back drilling of printed circuit boards, characterized in that: The area on the blade tip other than the sharp point area is insulated.

6. The use of the tool according to claim 1 in back drilling of printed circuit boards, characterized in that: The outer periphery of the blade of the tool is provided with a plurality of spiral chip grooves.

7. The use of the tool according to claim 1 in back drilling of printed circuit boards, characterized in that: The blade body is in a cylindrical structure, and the blade tip is in a conical structure.

8. Application of the tool according to any one of claims 1 to 7 in back drilling of printed circuit boards, characterized in that: The steps include: A through hole is drilled on the sheet material by the tool along the thickness direction of the sheet material. During the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, the position of the conductive layer is determined according to the movement distance of the tool. Plating the hole wall of the through hole with a conductive material; Determine an area of ​​the conductive layer from which via-hole conductive material needs to be removed; According to the position of the conductive layer, controlling the tool to remove the via-hole conductive material of the conductive layer; Wherein, the sheet material is formed by laminating multiple layers of printed circuit boards.

9. The use of the tool according to claim 8 in back drilling of printed circuit boards, characterized in that: The method of drilling a through hole on the sheet material along the thickness direction of the sheet material by the tool, during the drilling process, when the conductive area of ​​the tool contacts and conducts with the conductive layer at the target position on the sheet material, determining the position of the conductive layer according to the movement distance of the tool, specifically includes: When the conductive area of ​​the tool is in contact with the conductive layer at the target position, the acquisition board outputs a pulse signal, and the detector feeds back the movement distance of the tool to determine the current position information of the conductive layer.

10. Application of the tool according to claim 9 in back drilling of printed circuit boards, characterized in that: Feedback of the movement distance of the tool by the detector to determine the current position information of the conductive layer specifically includes: The detector feeds back the position information of the initial position of the tool, and the detector feeds back the position information of the tool when the pulse signal is generated, so as to obtain the current position information of the conductive layer.

11. Application of the tool according to claim 8 in back drilling of printed circuit boards, characterized in that: Before the step of "controlling the tool to remove the via-hole conductive material of the conductive layer", the method further includes: The tool moves to the conductive layer closest to the conductive material-plated area where electrical connection needs to be made.

12. Application of the tool according to claim 8 in back drilling of printed circuit boards, characterized in that: The method further includes: after the tool removes all the via-hole conductive materials in the conductive layer area that needs to be removed, the tool stops moving and retracts.

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