Printed circuit board back drilling system and back drilling method

Abstract

The present invention belongs to the field of back drilling processing technology for printed circuit boards, and discloses a printed circuit board back drilling system and a back drilling method. The back drilling system includes a replacement device, the replacement device includes at least one replacement component, and the replacement component includes a first replacement part and a second replacement part; the first replacement part has a first replacement conductive layer, and the second replacement part has a second replacement conductive layer. When the first replacement conductive layer is conductive and the second replacement conductive layer is not conductive, the drill bit processes the conductive connection layer corresponding to the second target signal layer on the via hole at the same height. Therefore, there is no need to set a drilling conductive layer in the printed circuit board, which simplifies the structure of the printed circuit board, reduces the manufacturing difficulty and manufacturing cost of the printed circuit board, and facilitates the high-precision removal of redundant parts of different heights on the same printed circuit board. The system has a wide range of applications, is easy to promote and apply, and has high economic utilization value.

Description

Technical Field

[0001] The invention relates to the technical field of back drilling processing of printed circuits, and in particular to a printed circuit board back drilling system and a back drilling method. Background Art

[0002] Printed circuit, also known as printed circuit board or printed circuit board, is an important component of the physical support and signal transmission of electronic products.

[0003] Metallized holes are provided on the printed circuit board, and the metallized holes can connect different conductive layers to transmit signals.

[0004] Due to the manufacturing process, there will be redundant parts in the metallized holes. The redundant parts are not used for signal transmission. The redundant parts will also increase the signal transmission loss and need to be removed using the back drilling process.

[0005] Some printed circuit boards will have a drilling conductive layer, also known as the must-break line layer, the final drilling conductive layer or the conductive reference layer. Then, an electrical signal is applied to the drilling conductive layer. When the drill drills through the drilling conductive layer, a conductive loop is formed. Then, drilling is stopped or drilled for a certain distance to improve the back drilling accuracy.

[0006] However, setting a drilled conductive layer increases the thickness, manufacturing cost and manufacturing difficulty of the printed circuit board. Moreover, if the sizes of the redundant parts of metallized holes at different positions on the same circuit board are different, setting a drilled conductive layer has no effect. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a printed circuit board back drilling system, which does not require a drilling conductive layer to be set in the printed circuit board, simplifies the structure of the printed circuit board, reduces the manufacturing difficulty and manufacturing cost of the printed circuit board, and facilitates the high-precision removal of redundant parts of different heights on the same printed circuit board. It has a wide range of applications, is easy to promote and apply, and has high economic utilization value.

[0008] The present invention also provides a printed circuit board back drilling method using the printed circuit board back drilling system.

[0009] According to a first aspect of an embodiment of the present invention, a printed circuit board back drilling system comprises a first target signal layer, a second target signal layer, a plurality of vias and a conductive connection layer, wherein the first target signal layer and the second target signal layer are stacked, the vias penetrate the first target signal layer and the second target signal layer, the conductive connection layer is located in the vias, and the conductive connection layer covers the inner walls of the first target signal layer and the second target signal layer, wherein the back drilling system comprises:

[0010] A back drilling machine, comprising a drill bit and a workbench, wherein the workbench has a first drilling area and a second drilling area, wherein the first drilling area is used to fix the printed circuit board;

[0011] a replacement device, disposed in the second drilling area, comprising at least one replacement component, the replacement component corresponding to the via;

[0012] The replacement assembly includes a first replacement part and a second replacement part;

[0013] The bottom of the first replacement part is placed and fixed at the same height as the bottom of the printed circuit board, the first replacement part includes a first replacement layer corresponding to the same thickness as the first target signal layer, and a second replacement layer corresponding to the same thickness as the second target signal layer, the second replacement layer is located on top of the first replacement layer, the second replacement layer includes a first replacement conductive layer, and the first replacement conductive layer is closely attached to the first replacement layer;

[0014] The bottom of the second replacement part is placed and fixed at the same height as the bottom of the printed circuit board, the second replacement part includes a third replacement layer corresponding to the same thickness as the first target signal layer, and a fourth replacement layer corresponding to the same thickness as the second target signal layer, the fourth replacement layer is located on top of the third replacement layer, the third replacement layer includes a second replacement conductive layer, and the second replacement conductive layer is closely attached to the fourth replacement layer;

[0015] The drill bit sequentially processes the second replacement layer of the first replacement part and the fourth replacement layer of the second replacement part at the same height. When the first replacement conductive layer is conductive and the second replacement conductive layer is not conductive, the drill bit processes the conductive connection layer on the via corresponding to the second target signal layer at the same height.

[0016] A printed circuit board back drilling system according to the first aspect of the present invention has at least the following beneficial effects:

[0017] The present invention provides a first replacement part so that the first replacement part has a first replacement conductive layer. Therefore, when the first replacement part and the printed circuit board are placed at the same height, the drill bit is lowered to the same height and the same depth can be drilled on the first replacement part and the printed circuit board. Furthermore, when the first replacement conductive layer touches the drill bit to achieve circuit conduction, it is equivalent to the original drilled conductive layer touching the drill bit to achieve circuit conduction, which can improve the accuracy of the drilling depth and avoid setting a drilled conductive layer on the printed circuit board, simplifying the structure of the printed circuit board, reducing the manufacturing cost and difficulty, and the first replacement part can be drilled multiple times to achieve reuse, with high utilization rate, and the additional cost of setting the first replacement part is limited.

[0018] The present invention provides a second replacement part so that the second replacement part has a second replacement conductive layer. Therefore, when the second replacement part and the printed circuit board are placed at the same height, the drill bit is lowered to the same height and can drill the same depth on the first replacement part, the second replacement part and the printed circuit board. Furthermore, when the first replacement conductive layer touches the drill bit and the circuit is turned on while the second replacement conductive layer does not touch the drill bit and the circuit is not turned on, it can be ensured that the drill bit contacts the first replacement conductive layer but does not touch the second replacement conductive layer, thereby avoiding excessive drilling by the drill bit and avoiding affecting the normal operation of the printed circuit board. Moreover, the second replacement part can be drilled multiple times to achieve repeated use, with high utilization rate, and the additional cost of providing the second replacement part is limited.

[0019] At the same time, by making the replacement components correspond to the vias, and then using different substitute parts to indicate the removal benchmark of the redundant parts on different vias, it is convenient to carry out differentiated removal and high-precision removal, has a wide range of applications, is easy to promote and apply, and has high economic utilization value.

[0020] The present invention also provides a printed circuit board back drilling method, which has the above beneficial effects.

[0021] According to a printed circuit board back drilling system of the first aspect of the present invention, the first replacement layer and the second replacement layer are detachable, the third replacement layer and the fourth replacement layer are detachable, and the first replacement layer and the fourth replacement layer are insulating plates.

[0022] According to a printed circuit board back drilling system of an embodiment of the first aspect of the present invention, the replacement device includes a center-locking pressure plate, the pressure plate is used to install and fix the first replacement part and the second replacement part, the pressure plate is provided with a first through hole for accommodating the drill bit to process the first replacement part, and a second through hole for accommodating the drill bit to process the second replacement part, and the replacement device includes a fixing shell, the fixing shell is provided with a first positioning hole for accommodating the first replacement part, and a second positioning hole for accommodating the second replacement part.

[0023] According to a printed circuit board back drilling system of an embodiment of the first aspect of the present invention, the back drilling machine is equipped with a Z-axis displacement sensor, and the back drilling machine is equipped with a height detector, the height detector includes a detection head and a detection rod, the height detector is raised and lowered synchronously with the drill bit, and the bottom end of the detection rod is used to abut the top surface of the printed circuit board, the first replacement part and the second replacement part, so that the top end of the detection rod is raised and lowered relative to the detection head.

[0024] According to a printed circuit board back drilling system of an embodiment of the first aspect of the present invention, the replacement device also includes a laser detection component, the laser detection component includes a third replacement part, the third replacement part is provided with a third through hole corresponding to the via hole, and a laser detector is radially arranged in the third through hole. When the drill bit extends into the third through hole at the same height, the laser detector detects the bottom end position of the drill bit.

[0025] According to a printed circuit board back drilling system of an embodiment of the first aspect of the present invention, the bottom end position of the drill bit includes the low point position of the end edge and the low point position of the peripheral edge of the drill bit.

[0026] According to a printed circuit board back drilling system of an embodiment of the first aspect of the present invention, the replacement device includes a fixed shell, which is open up and down, and one side wall of the fixed shell forms a side mold abutting the replacement part, the other side wall of the fixed shell is provided with a side pressure plate, the side pressure plate is provided with an inclined conductive strip, and the replacement part is provided with an inclined notch for accommodating the inclined conductive strip, the fixed shell is provided with a downwardly open slide groove, the side pressure plate is connected to a slide rail cooperating with the slide groove, a handle is provided at one end of the slide rail away from the side pressure plate, and the fixed shell is provided with a side spring for driving the side pressure plate to approach the side mold.

[0027] A printed circuit board back drilling method according to a second aspect of an embodiment of the present invention is applied to a printed circuit board back drilling system, and the back drilling method comprises:

[0028] First, the drill bit is moved to the first drilling area, the drill tip of the drill bit contacts the top surface of the second target signal layer, and a height zero point of the relative coordinate system is set, and the drilling program for processing the printed circuit board uses the height zero point as a reference for drilling;

[0029] Then, an electrical signal is passed through the first replacement conductive layer of the first replacement part, and an electrical signal is passed through the second replacement conductive layer of the second replacement part;

[0030] Next, the drill moves to the second drilling area, executes a drilling procedure for processing the printed circuit board, and drills holes in the first substitute part and the second substitute part;

[0031] Finally, when the first replacement conductive layer is conductive and the second replacement conductive layer is not conductive, the drill head returns to the first drilling area and processes the printed circuit board.

[0032] A printed circuit board back drilling method according to a third aspect of an embodiment of the present invention is applied to the printed circuit board back drilling system, and the back drilling method includes:

[0033] First, the drill bit is moved to the first drilling area, the drill tip of the drill bit contacts the top surface of the second target signal layer, the height zero point of the relative coordinate system is set, and the drilling program for processing the printed circuit board drills the hole based on the height zero point, and at the same time, the value H1 of the Z-axis displacement sensor and the value h1 of the height detector are recorded;

[0034] Then, an electrical signal is passed through the first replacement conductive layer of the first replacement part, and an electrical signal is passed through the second replacement conductive layer of the second replacement part;

[0035] Next, the drill moves to the second drilling area, the drill drops down and contacts the first substitute, and records the value H2 of the Z-axis displacement sensor and the value h2 of the height detector; the drill drops down and contacts the second substitute, and records the value H3 of the Z-axis displacement sensor and the value h3 of the height detector;

[0036] When the value H1, the value H2 and the value H3 are equal, and the value h1, the value h2 and the value h3 are equal, executing a drilling program for processing the printed circuit board to drill holes in the first substitute part and the second substitute part;

[0037] Finally, when the first replacement conductive layer is conductive and the second replacement conductive layer is not conductive, the drill head returns to the first drilling area and processes the printed circuit board.

[0038] A printed circuit board back drilling method according to the third aspect of the present invention has at least the following beneficial effects:

[0039] The present invention can ensure that the drill bit descends to the same depth by evaluating the values ​​H1, H2 and H3 as well as the values ​​h1, h2 and h3, and that the printed circuit board, the first alternative part and the second alternative part are at the same height, thereby ensuring that drilling the first alternative part, drilling the second alternative part and the printed circuit board are consistent processes, reducing the impact of clamping differences and manufacturing differences, and thereby improving the authenticity and reliability of the alternative evaluation.

[0040] A printed circuit board back drilling method according to a fourth aspect of an embodiment of the present invention is applied to the printed circuit board back drilling system, and the back drilling method includes:

[0041] First, the drill bit is moved to the first drilling area, the drill tip of the drill bit contacts the top surface of the second target signal layer, and a height zero point of the relative coordinate system is set, and the drilling program for processing the printed circuit board uses the height zero point as a reference for drilling;

[0042] Then, an electrical signal is passed through the first replacement conductive layer of the first replacement part, and an electrical signal is passed through the second replacement conductive layer of the second replacement part;

[0043] Next, the drill moves to the second drilling area to perform a drilling procedure for processing the printed circuit board, the drill extends into the third through hole and stops rotating, and the laser detector detects the bottom end position of the drill;

[0044] When the bottom end position of the drill bit is qualified, a drilling procedure for processing the printed circuit board is executed, and the drill bit drills holes in the first substitute part and the second substitute part;

[0045] Finally, when the first replacement conductive layer is conductive and the second replacement conductive layer is not conductive, the drill head returns to the first drilling area and processes the printed circuit board.

[0046] A printed circuit board back drilling method according to the fourth aspect of the present invention has at least the following beneficial effects:

[0047] By setting a third substitute part, the present invention can obtain the depth of the static drill bit entering the third substitute part and evaluate the descent accuracy of the drill bit, thereby logically supporting the substitute evaluation in multiple dimensions and truly reflecting the back drilling processing situation of the printed circuit board.

[0048] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art 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 paying creative work.

[0050] Figure 1 A schematic diagram of the composition of a printed circuit board back drilling system according to an embodiment of the present invention;

[0051] Figure 2 for Figure 1 A schematic diagram of the structure of the alternative device;

[0052] Figure 3 for Figure 2 A schematic diagram of a structure of a method of fixing a replacement component in a replacement device;

[0053] Figure 4 for Figure 2 A schematic diagram of another method of fixing a replacement component in a replacement device;

[0054] Figure 5For application Figure 1 A work flow chart of a first mode of a printed circuit board back drilling method of a printed circuit board back drilling system.

[0055] Figure 6 For application Figure 1 A working flow chart of the method 2 of the printed circuit board back drilling method of the printed circuit board back drilling system.

[0056] Figure 7 For application Figure 1 A work flow diagram of mode three of the printed circuit board back drilling method of the printed circuit board back drilling system.

[0057] Figure numerals: 100 - back drill, 110 - first drilling area, 120 - second drilling area, 130 - first alternative part, 140 - first alternative layer, 150 - second alternative layer, 160 - first alternative conductive layer, 170 - second alternative part, 180 - third alternative layer, 190 - fourth alternative layer, 200 - second alternative conductive layer, 210 - pressure plate, 220 - first through hole, 230 - second through hole, 240 - first positioning hole, 250 - second positioning hole, 260 - third alternative part, 270 - fixed shell, 280 - side support mold, 290 - side pressure plate, 300 - inclined conductive strip, 310 - slide rail, 320 - side spring, 330 - handle. DETAILED DESCRIPTION

[0058] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0059] In the description of the present invention, it is necessary to understand that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0060] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of first and second, this is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0061] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation, connection and connection" 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] A printed circuit board back drilling system and a back drilling method according to embodiments of the present invention are described below with reference to the accompanying drawings.

[0063] In the prior art, the patent document with publication number CN113163590A and invention name "A circuit board with easily controllable back drilling depth and a back drilling method thereof" records that the circuit layer must be broken.

[0064] In the prior art, the invention with publication number CN114828449A and titled A circuit board and back drilling processing method thereof and a back drilling system discloses a conductive reference layer.

[0065] In the prior art, the patent document with publication number CN113727518A and invention name of printed circuit prefabricated board and back drilling method, printed circuit board records: the printed circuit prefabricated board includes a first target signal layer and a second target signal layer, and a final drilling conductive layer sandwiched between the first target signal layer and the second target signal layer. The printed circuit prefabricated board also includes a via hole penetrating the first target signal layer, the final drilling conductive layer and the second target signal layer. A conductive connection layer is provided in the via hole. A gap is provided between the final drilling conductive layer and the conductive connection layer, thereby being insulated from the conductive connection layer. When back drilling the printed circuit board, an electrical signal can be input into the final drilling conductive layer. Since the final drilling conductive layer and the conductive connection layer are insulated, it is possible to avoid forming a conductive loop when the drill bit hits the conductive connection layer, so that the drill bit can penetrate into the position of the final drilling conductive layer. In this way, the redundant conductive connection layer in the printed circuit prefabricated board can be fully removed, and the back drilling accuracy can be improved.

[0066] That is to say, some printed circuit boards will have a drilling conductive layer, also known as the must-break line layer, the final drilling position conductive layer or the conductive reference layer. Then, an electrical signal is passed through the drilling conductive layer. When the drill bit drills through the drilling conductive layer, a conductive loop is formed. Then, drilling is stopped or drilled for another distance to improve the back drilling accuracy.

[0067] Accordingly, setting a drilled conductive layer will increase the metal material, increase the manufacturing cost, and increase the thickness of the printed circuit board. At the same time, the above patent documents also require that the drilled conductive layer and the conductive connection layer in the via hole do not contact to maintain insulation, which increases the manufacturing difficulty.

[0068] At the same time, considering that for metallized holes at different positions on the same circuit board, the sizes of the redundant parts may be different due to the different signal layers connected, then the only drilled conductive layer can only improve the back drilling accuracy of a part of the metallized holes, while for the remaining metallized holes, the drilled conductive layer has no effect and cannot improve the back drilling accuracy as a whole.

[0069] In order to solve the above problems, the present invention aims to provide a printed circuit board back drilling system.

[0070] A printed circuit board back drilling system in the present embodiment does not need to set a drilling conductive layer in the printed circuit board, simplifies the structure of the printed circuit board, reduces the manufacturing difficulty and manufacturing cost of the printed circuit board, and is convenient for high-precision removal of redundant parts of different heights on the same printed circuit board. It has a wide range of applications, is easy to promote and apply, and has high economic utilization value.

[0071] In this embodiment, the object processed by the printed circuit board back drilling system is a printed circuit board. The main components of the printed circuit board are: the printed circuit board includes a first target signal layer, a second target signal layer, a plurality of vias and a conductive connection layer. The first target signal layer and the second target signal layer are stacked, the vias penetrate the first target signal layer and the second target signal layer, the conductive connection layer is located in the vias, and the conductive connection layer covers the inner walls of the first target signal layer and the second target signal layer.

[0072] The above is a general description of the structure of the printed circuit board. For the detailed structure, please refer to the patent document with publication number CN113727518A and invention name Printed Circuit Prefabricated Board and Back Drilling Method, Printed Circuit Board, but the conductive layer at the final drilling position is cancelled.

[0073] For reference Figures 1 to 4 , the printed circuit board back drilling system mainly includes a back drilling machine 100 and a replacement device.

[0074] The back drilling machine 100 includes a drill bit and a workbench, the drill bit can be translated and raised, and the drill bit itself can rotate, so that holes can be drilled at any position within the travel range. The workbench has a first drilling area 110 and a second drilling area 120, and the first drilling area 110 is used to fix the printed circuit board.

[0075] In some specific embodiments of the present invention, the workbench can be fixed, and the drill bit can perform translation in the X-axis and Y-axis directions and lifting in the Z-axis direction, thereby simplifying the setting of the workbench.

[0076] In some specific embodiments of the present invention, the workbench can be made to perform translation in the X-axis or Y-axis direction, so that the drill bit is arranged in a gantry structure, which helps to improve the stability of the drill bit.

[0077] In some specific embodiments of the present invention, the workbench can be made to perform translation in the X-axis and Y-axis directions, but the overturning moment at the end points of the stroke needs to be considered. If necessary, a support structure is provided to prevent the workbench from being slightly tilted and affecting the back drilling quality.

[0078] For the replacement device, the replacement device is disposed in the second drilling area 120 and includes at least one replacement component, and the replacement component corresponds to the via hole;

[0079] Specifically, the replacement component includes a first replacement part 130 and a second replacement part 170. The bottom of the first replacement part 130 is placed and fixed at the same height as the bottom of the printed circuit board, and the bottom of the second replacement part 170 is placed and fixed at the same height as the bottom of the printed circuit board. That is, on the workbench of the back drill rig 100, the first replacement part 130, the second replacement part 170 and the printed circuit board have the same thickness and are placed at the same height. Moreover, the top surface of the first replacement part 130, the second replacement part 170 and the printed circuit board are at the same height.

[0080] In some specific embodiments of the present invention, the first replacement component 130, the second replacement component 170 and the bottom of the printed circuit board may be provided with spacers of equal thickness, thereby maintaining equal height placement and reducing the difficulty of fixing.

[0081] Among them, the first replacement part 130 includes a first replacement layer 140 corresponding to the first target signal layer and a second replacement layer 150 corresponding to the second target signal layer and the second replacement layer 150 is located on the top of the first replacement layer 140. The second replacement layer 150 includes a first replacement conductive layer 160, and the first replacement conductive layer 160 is arranged close to the first replacement layer 140.

[0082] That is to say, when the first replacement part 130 and the printed circuit board are placed and fixed at the same height on the workbench, due to the back drilling machine 100 itself, the position accuracy of the drill bit lifting and lowering is high, that is, the drill bit can repeatedly descend to the same height. If the drill bit processes to the first replacement conductive layer 160, then the drill bit also processes to the edge position of the second target signal layer close to the first target signal layer.

[0083] Among them, the second replacement part 170 includes a third replacement layer 180 corresponding to the first target signal layer and a fourth replacement layer 190 corresponding to the second target signal layer. The fourth replacement layer 190 is located on the top of the third replacement layer 180. The third replacement layer 180 includes a second replacement conductive layer 200, and the second replacement conductive layer 200 is arranged close to the fourth replacement layer 190.

[0084] That is to say, when the second replacement part 170 and the printed circuit board are placed and fixed at the same height on the workbench, due to the back drilling machine 100 itself, the position accuracy of the drill bit is high, that is, the drill bit can repeatedly descend to the same height. If the drill bit processes to the second replacement conductive layer 200, then the drill bit passes through the second target signal layer and processes the edge portion of the first target signal layer. It is necessary to reduce the descent height of the drill bit.

[0085] After the above adjustment and confirmation, when the first replacement conductive layer 160 is conductive and the second replacement conductive layer 200 is not conductive, that is, the drill bit is lowered to a depth such that the drill bit contacts the first replacement conductive layer 160 but does not contact the second replacement conductive layer 200 .

[0086] Therefore, the drill bit uses the most recently adjusted descending height to uniformly process the conductive connection layer on the via hole corresponding to the second target signal layer, thereby achieving high-precision processing of the printed circuit board.

[0087] In summary, firstly, the present invention sets the first replacement part 130 so that the first replacement part 130 has the first replacement conductive layer 160. Therefore, when the first replacement part 130 and the printed circuit board are placed at the same height, the drill bit drops to the same height and can drill the same depth on the first replacement part 130 and the printed circuit board. Furthermore, when the first replacement conductive layer 160 touches the drill bit to achieve circuit conduction, it is equivalent to the original drilled conductive layer touching the drill bit to achieve circuit conduction, which can improve the accuracy of the drilling depth and avoid setting a drilled conductive layer on the printed circuit board, thereby simplifying the structure of the printed circuit board and reducing the manufacturing cost and difficulty. Moreover, the first replacement part 130 can be drilled multiple times to achieve reuse, with high utilization rate, and the increased cost of setting the first replacement part 130 is limited.

[0088] Secondly, the present invention provides a second replacement part 170 so that the second replacement part 170 has a second replacement conductive layer 200. Therefore, when the second replacement part 170 and the printed circuit board are placed at the same height, the drill bit is lowered to the same height and can drill the first replacement part 130, the second replacement part 170 and the printed circuit board to the same depth. Furthermore, when the first replacement conductive layer 160 touches the drill bit and the circuit is turned on while the second replacement conductive layer 200 does not touch the drill bit and the circuit is not turned on, it can be ensured that the drill bit contacts the first replacement conductive layer 160 but does not touch the second replacement conductive layer 200, thereby avoiding over-drilling by the drill bit and affecting the normal operation of the printed circuit board. Moreover, the second replacement part 170 can be drilled multiple times to achieve reuse, with high utilization rate, and the additional cost of providing the second replacement part 170 is limited.

[0089] At the same time, by making the replacement components correspond to the vias, and then using different substitute parts to indicate the removal benchmark of the redundant parts on different vias, it is convenient to carry out differentiated removal and high-precision removal, has a wide range of applications, is easy to promote and apply, and has high economic utilization value.

[0090] In some specific embodiments of the present invention, the first replacement layer 140 and the second replacement layer 150 can be detachably arranged, the third replacement layer 180 and the fourth replacement layer 190 can be detachably arranged, and the first replacement layer 140 and the fourth replacement layer 190 are insulating plates.

[0091] It is easy to understand that in this embodiment, the first replacement layer 140 and the second replacement layer 150 are detachable, and the third replacement layer 180 and the fourth replacement layer 190 are detachable. Therefore, different insulating plates can be combined according to actual needs to form first replacement parts 130 and second replacement parts 170 of different thicknesses to be suitable for different printed circuit boards, thereby reducing the difficulty of manufacturing.

[0092] In some specific embodiments of the present invention, the insulating plate can be made of an acrylic plate, a plastic plate, etc., to reduce the difficulty of manufacturing.

[0093] In some specific embodiments of the present invention, an auxiliary tool may be provided to clamp the edge of the first replacement member 130 to complete the fixation of the first replacement layer 140 and the second replacement layer 150 .

[0094] In some specific embodiments of the present invention, the auxiliary tool may be a frame-shaped structure, and the edge of the first replacement part 130 is inserted into a slideway inside the frame-shaped structure.

[0095] Reference Figure 3 In some specific embodiments of the present invention, the replacement device can include a center-locking pressure plate 210, which is used to install and fix the first replacement part 130 and the second replacement part 170. The pressure plate 210 is provided with a first through hole 220 for accommodating a drill bit to process the first replacement part 130, and a second through hole 230 for accommodating a drill bit to process the second replacement part 170. The replacement device includes a fixed shell 270, and the fixed shell 270 is provided with a first positioning hole 240 for accommodating the first replacement part 130, and a second positioning hole 250 for accommodating the second replacement part 170.

[0096] It is easy to understand that in this embodiment, by setting a pressure plate 210, the first replacement part 130 and the second replacement part 170 can be fixed, and the pressure plate 210 adopts center locking to evenly press the pressure of the first replacement part 130 and the second replacement part 170, thereby avoiding uneven force and causing slight height differences between the first replacement part 130 and the second replacement part 170, thereby avoiding affecting the accuracy improvement.

[0097] The first through hole 220 and the second through hole 230 are provided to facilitate the drill to penetrate and process the corresponding replacement parts, thereby reducing the deformation of the replacement parts and eliminating the influence of warping deformation of the replacement parts.

[0098] The first positioning hole 240 and the second positioning hole 250 are provided to accurately place the replacement part, and also facilitate identification and differentiation, thereby reducing errors.

[0099] In some specific embodiments of the present invention, the first replacement part 130 and the second replacement part 170 can be arranged in rows and columns, so that they are suitable for mass production and convenient to use in the process of processing printed circuit boards to avoid drill bit wear affecting back drilling accuracy.

[0100] That is, before processing a whole printed circuit board, the drill bit must process a set of alternative components, and after processing multiple printed circuit boards, the drill bit must process another set of alternative components to promptly detect looseness, wear, etc. of the drill bit and reduce the production of defective products.

[0101] Reference Figure 4 In some specific embodiments of the present invention, the replacement device can include a fixed shell 270, which is open up and down, and one side wall of the fixed shell 270 forms a side mold 280 that abuts the replacement part, and the other side wall of the fixed shell 270 is provided with a side pressure plate 290, and the side pressure plate 290 is provided with an inclined conductive strip 300, and the replacement part is provided with an inclined notch for accommodating the inclined conductive strip 300, and the fixed shell 270 is provided with a downwardly open slide groove, and the side pressure plate 290 is connected to a slide rail 310 that cooperates with the slide groove, and a handle 330 is provided at one end of the slide rail 310 away from the side pressure plate 290, and the fixed shell 270 is provided with a side spring 320 that drives the side pressure plate 290 to approach the side mold 280.

[0102] It is easy to understand that in this embodiment, by pulling the handle 330, the side pressure plate 290 can be moved away from the side support mold 280 to facilitate the insertion of the replacement part. Then, by releasing the handle 330, the side pressure plate 290 is moved close to the side support mold 280 to fix the printed circuit board.

[0103] The oblique conductive strip 300 will be pressed into the inclined notch of the replacement part, thereby increasing the contact between the oblique conductive strip 300 and the replacement conductive layer, making it easier to pass electrical signals.

[0104] In some specific embodiments of the present invention, the replacement device may also include a laser detection component, which includes a third replacement part 260. The third replacement part 260 is provided with a third through hole corresponding to the through hole. A laser detector is radially arranged in the third through hole. When the drill bit is inserted into the third through hole at a certain height, the laser detector detects the bottom end position of the drill bit.

[0105] It is easy to understand that, in this embodiment, by providing the third substitute part 260, the descending position of the drill bit can be measured before the drill bit processes the first substitute part 130, the second substitute part 170 and the printed circuit board.

[0106] In some specific embodiments of the present invention, the bottom end position of the drill bit may include the low point position of the end cutting edge and the low point position of the peripheral cutting edge of the drill bit.

[0107] It is easy to understand that this embodiment can evaluate the influence of the tip shape of the drill bit on the drilling accuracy by obtaining the low point position of the end blade of the drill bit and the low point position of the peripheral blade, avoid the end blade of the drill bit contacting the first alternative conductive layer 160 and the end blade away from the first alternative conductive layer 160, and prevent a large amount of redundant parts from remaining.

[0108] In some specific embodiments of the present invention, the back drill 100 can be configured with a Z-axis displacement sensor, and the back drill 100 can be configured with a height detector. The height detector includes a detection head and a detection rod. The height detector rises and falls synchronously with the drill bit, and the bottom end of the detection rod is used to abut the top surfaces of the printed circuit board, the first replacement part 130 and the second replacement part 170, so that the top end of the detection rod can be raised and lowered relative to the detection head. For details, please refer to the patent document with publication number CN208462159U and invention name A Z-axis depth control mechanism for a PCB CNC milling machine, so as to know the top surfaces of the printed circuit board, the first replacement part 130 and the second replacement part 170, and confirm that the top surfaces of the printed circuit board, the first replacement part 130 and the second replacement part 170 are at the same height position, so as to avoid the reference deviation from affecting the accuracy and reliability of the back drilling system.

[0109] Reference Figure 5 At the same time, the present invention also proposes a first embodiment of a printed circuit board back drilling method using the above-mentioned printed circuit board back drilling system.

[0110] The back drilling method of this embodiment includes:

[0111] Step S001, move the drill bit to the first drilling area 110, make the drill tip of the drill bit contact the top surface of the second target signal layer, set the height zero point of the relative coordinate system, and use the height zero point as the reference for drilling in the drilling program for processing the printed circuit board.

[0112] Step S002 , an electrical signal is passed through the first replacement conductive layer 160 of the first replacement component 130 , and an electrical signal is passed through the second replacement conductive layer 200 of the second replacement component 170 .

[0113] Step S003 : the drill moves to the second drilling area 120 , executes a drilling procedure for processing a printed circuit board, and drills holes in the first replacement part 130 and the second replacement part 170 .

[0114] It is easy to understand that executing the drilling program for processing printed circuit boards to drill holes in the first alternative part 130 and the second alternative part 170 means that, except for the different X-axis and Y-axis coordinates, the drilling method and the descent position of the drill bit are exactly the same. At the same time, in the software program, a cyclic calling subroutine should be used to run the drilling of the first alternative part 130 and the second alternative part 170 to avoid misjudgment of the results due to differences in program settings.

[0115] Step S004 , when the first replacement conductive layer 160 is conductive and the second replacement conductive layer 200 is not conductive, the drill returns to the first drilling area 110 and processes the printed circuit board.

[0116] If the first replacement conductive layer 160 is not conductive, increase the drilling distance to ensure that the first replacement conductive layer 160 is conductive. If the second replacement conductive layer 200 is conductive, change another set of replacement components for trial drilling and reduce the drilling distance.

[0117] Reference Figure 6 At the same time, the present invention also proposes a second embodiment of a printed circuit board back drilling method using the above-mentioned printed circuit board back drilling system.

[0118] The back drilling method of this embodiment includes:

[0119] Step S001, move the drill bit to the first drilling area 110, make the drill tip of the drill bit contact the top surface of the second target signal layer, set the height zero point of the relative coordinate system, and use the height zero point as the reference for drilling in the drilling program for processing the printed circuit board. At the same time, record the value H1 of the Z-axis displacement sensor and the value h1 of the height detector.

[0120] Step S002 , an electrical signal is passed through the first replacement conductive layer 160 of the first replacement component 130 , and an electrical signal is passed through the second replacement conductive layer 200 of the second replacement component 170 .

[0121] Step S003, the drill bit moves to the second drilling area 120, the drill bit descends and contacts the first replacement part 130, and records the value H2 of the Z-axis displacement sensor and the value h2 of the height detector; the drill bit descends and contacts the second replacement part 170, and records the value H3 of the Z-axis displacement sensor and the value h3 of the height detector.

[0122] Step S004 , when the value H1 , the value H2 and the value H3 are equal, and the value h1 , the value h2 and the value h3 are equal, a drilling program for processing a printed circuit board is executed to drill holes in the first replacement part 130 and the second replacement part 170 .

[0123] Step S005 , when the first replacement conductive layer 160 is conductive and the second replacement conductive layer 200 is not conductive, the drill returns to the first drilling area 110 and processes the printed circuit board.

[0124] If the first replacement conductive layer 160 is not conductive, increase the drilling distance to ensure that the first replacement conductive layer 160 is conductive. If the second replacement conductive layer 200 is conductive, change another set of replacement components for trial drilling and reduce the drilling distance.

[0125] In summary, the present invention can ensure that the drill bit has the same descent depth by evaluating the values ​​H1, H2 and H3 as well as the values ​​h1, h2 and h3, and that the printed circuit board, the first alternative part 130 and the second alternative part 170 are at the same height, thereby ensuring that drilling the first alternative part 130, drilling the second alternative part 170 and the printed circuit board are consistent processes, reducing the impact of clamping differences and manufacturing differences, and thereby improving the authenticity and reliability of the alternative evaluation.

[0126] Reference Figure 7 At the same time, the present invention also proposes a third embodiment of a printed circuit board back drilling method using the above-mentioned printed circuit board back drilling system.

[0127] The back drilling method of this embodiment includes:

[0128] Step S001, move the drill bit to the first drilling area 110, make the drill tip of the drill bit contact the top surface of the second target signal layer, set the height zero point of the relative coordinate system, and use the height zero point as the reference for drilling in the drilling program for processing the printed circuit board.

[0129] Step S002 , an electrical signal is passed through the first replacement conductive layer 160 of the first replacement component 130 , and an electrical signal is passed through the second replacement conductive layer 200 of the second replacement component 170 .

[0130] In step S003, the drill moves to the second drilling area 120 to execute a drilling procedure for processing a printed circuit board. The drill extends into the third through hole and stops rotating. The laser detector detects the bottom end position of the drill.

[0131] Step S004 , when the bottom end position of the drill bit is qualified, a drilling procedure for processing a printed circuit board is executed, and the drill bit drills holes in the first replacement part 130 and the second replacement part 170 .

[0132] Step S005 , when the first replacement conductive layer 160 is conductive and the second replacement conductive layer 200 is not conductive, the drill returns to the first drilling area 110 and processes the printed circuit board.

[0133] In summary, the present invention sets a third alternative part 260, thereby obtaining the depth of the static drill bit entering the third alternative part 260 and evaluating the accuracy of the drill bit's descent, thereby logically supporting the alternative evaluation in multiple dimensions, and further, truly reflecting the back drilling processing of the printed circuit board, eliminating the need for modification of the printed circuit board, reducing costs, and being applicable to the situation where the relationship between the first target signal layer and the second target signal layer of the printed circuit board is changeable, to meet the needs of diversified production and manufacturing.

[0134] In the description of this specification, the description with reference to the terms "one embodiment, some embodiments, illustrative embodiments, examples, specific examples or some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0135] The terms "first, second, third, fourth", etc. (if any) in the specification and claims of this application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that shown or described herein.

[0136] It should also be noted that in the description of this specification, relational terms such as first and second, etc. are merely 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.

[0137] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may also include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0138] Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0139] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A printed circuit board back drilling system, the printed circuit board comprising a first target signal layer, a second target signal layer, a plurality of vias and a conductive connection layer, the first target signal layer and the second target signal layer are stacked, the vias penetrate the first target signal layer and the second target signal layer, the conductive connection layer is located in the vias, and the conductive connection layer covers the inner walls of the first target signal layer and the second target signal layer, characterized in that: The back drilling system comprises: A back drilling machine (100) comprises a drill bit and a workbench, the workbench having a first drilling area (110) and a second drilling area (120), the first drilling area (110) being used to fix the printed circuit board; A replacement device, arranged in the second drilling area (120), comprising at least one replacement component, the replacement component corresponding to the via hole; The replacement assembly includes a first replacement part (130) and a second replacement part (170); The bottom of the first replacement part (130) is placed and fixed at the same height as the bottom of the printed circuit board, the first replacement part (130) comprises a first replacement layer (140) having the same thickness as the first target signal layer, and a second replacement layer (150) having the same thickness as the second target signal layer, the second replacement layer (150) being located on top of the first replacement layer (140), the second replacement layer (150) comprising a first replacement conductive layer (160), and the first replacement conductive layer (160) being arranged closely to the first replacement layer (140); The bottom of the second replacement part (170) is placed and fixed at the same height as the bottom of the printed circuit board, the second replacement part (170) comprises a third replacement layer (180) having the same thickness as the first target signal layer, and a fourth replacement layer (190) having the same thickness as the second target signal layer, the fourth replacement layer (190) being located on top of the third replacement layer (180), the third replacement layer (180) comprising a second replacement conductive layer (200), and the second replacement conductive layer (200) being arranged in close contact with the fourth replacement layer (190); The drill bit sequentially processes the second replacement layer (150) of the first replacement part (130) and the fourth replacement layer (190) of the second replacement part (170) at the same height. When the first replacement conductive layer (160) is conductive and the second replacement conductive layer (200) is not conductive, the drill bit processes the conductive connection layer on the via hole corresponding to the second target signal layer at the same height.

2. A printed circuit board back drilling system according to claim 1, characterized in that: The first replacement layer (140) and the second replacement layer (150) are detachable, the third replacement layer (180) and the fourth replacement layer (190) are detachable, and the first replacement layer (140) and the fourth replacement layer (190) are insulating plates.

3. A printed circuit board back drilling system according to claim 2, characterized in that: The replacement device comprises a center-locking pressure plate (210), the pressure plate (210) being used to install and fix the first replacement part (130) and the second replacement part (170), the pressure plate (210) being provided with a first through hole (220) for accommodating the drill bit to process the first replacement part (130), and a second through hole (230) for accommodating the drill bit to process the second replacement part (170), the replacement device comprises a fixing shell (270), the fixing shell (270) being provided with a first positioning hole (240) for accommodating the first replacement part (130), and a second positioning hole (250) for accommodating the second replacement part (170).

4. A printed circuit board back drilling system according to claim 1, characterized in that: The back drill (100) is equipped with a Z-axis displacement sensor, and the back drill (100) is equipped with a height detector, the height detector comprising a detection head and a detection rod, the height detector is raised and lowered synchronously with the drill head, and the bottom end of the detection rod is used to abut against the top surfaces of the printed circuit board, the first replacement part (130) and the second replacement part (170), so that the top end of the detection rod is raised and lowered relative to the detection head.

5. A printed circuit board back drilling system according to claim 1, characterized in that: The replacement device also includes a laser detection component, which includes a third replacement part (260). The third replacement part (260) is provided with a third through hole corresponding to the through hole. A laser detector is radially arranged in the third through hole. When the drill bit is inserted into the third through hole at the same height, the laser detector detects the bottom end position of the drill bit.

6. A printed circuit board back drilling system according to claim 5, characterized in that: The bottom end position of the drill bit includes the low point position of the end edge and the low point position of the peripheral edge of the drill bit.

7. A printed circuit board back drilling system according to claim 1, characterized in that: The replacement device comprises a fixed shell (270), the fixed shell (270) is open at the top and the bottom, one side wall of the fixed shell (270) forms a side support mold (280) abutting against the replacement part, the other side wall of the fixed shell (270) is provided with a side pressure plate (290), the side pressure plate (290) is provided with an inclined conductive strip (300), the replacement part is provided with an inclined notch for accommodating the inclined conductive strip (300), the fixed shell (270) is provided with a downwardly open slide groove, the side pressure plate (290) is connected to a slide rail (310) cooperating with the slide groove, the slide rail (310) is provided with a handle (330) at one end away from the side pressure plate (290), and the fixed shell (270) is provided with a side spring (320) for driving the side pressure plate (290) to approach the side support mold (280).

8. A printed circuit board back drilling method, characterized in that: A printed circuit board back drilling system according to any one of claims 1 to 7, wherein the back drilling method comprises: First, the drill bit is moved to the first drilling area (110), the drill tip of the drill bit contacts the top surface of the second target signal layer, a height zero point of the relative coordinate system is set, and a drilling program for processing the printed circuit board uses the height zero point as a reference for drilling; Then, an electrical signal is passed through the first replacement conductive layer (160) of the first replacement member (130), and an electrical signal is passed through the second replacement conductive layer (200) of the second replacement member (170); Next, the drill bit moves to the second drilling area (120), executes a drilling procedure for processing the printed circuit board, and drills holes in the first replacement part (130) and the second replacement part (170); Finally, when the first replacement conductive layer (160) is conductive and the second replacement conductive layer (200) is not conductive, the drill returns to the first drilling area (110) and processes the printed circuit board.

9. A printed circuit board back drilling method, characterized in that: A printed circuit board back drilling system as claimed in claim 4, wherein the back drilling method comprises: First, the drill bit is moved to the first drilling area (110), the drill tip of the drill bit contacts the top surface of the second target signal layer, a height zero point of the relative coordinate system is set, and a drilling program for processing the printed circuit board drills based on the height zero point, and at the same time, a value H1 of the Z-axis displacement sensor and a value h1 of the height detector are recorded; Then, an electrical signal is passed through the first replacement conductive layer (160) of the first replacement member (130), and an electrical signal is passed through the second replacement conductive layer (200) of the second replacement member (170); Next, the drill bit moves to the second drilling area (120), the drill bit descends and contacts the first replacement part (130), and records the value H2 of the Z-axis displacement sensor and the value h2 of the height detector; the drill bit descends and contacts the second replacement part (170), and records the value H3 of the Z-axis displacement sensor and the value h3 of the height detector; When the value H1, the value H2 and the value H3 are equal, and the value h1, the value h2 and the value h3 are equal, executing a drilling program for processing the printed circuit board to drill holes in the first replacement part (130) and the second replacement part (170); Finally, when the first replacement conductive layer (160) is conductive and the second replacement conductive layer (200) is not conductive, the drill returns to the first drilling area (110) and processes the printed circuit board.

10. A printed circuit board back drilling method, characterized in that: A printed circuit board back drilling system as claimed in claim 5, wherein the back drilling method comprises: First, the drill bit is moved to the first drilling area (110), the drill tip of the drill bit contacts the top surface of the second target signal layer, a height zero point of the relative coordinate system is set, and a drilling program for processing the printed circuit board uses the height zero point as a reference for drilling; Then, an electrical signal is passed through the first replacement conductive layer (160) of the first replacement member (130), and an electrical signal is passed through the second replacement conductive layer (200) of the second replacement member (170); Next, the drill moves to the second drilling area (120) to execute a drilling procedure for processing the printed circuit board, the drill extends into the third through hole and stops rotating, and the laser detector detects the bottom end position of the drill; When the bottom end position of the drill bit is qualified, a drilling procedure for processing the printed circuit board is executed, and the drill bit drills holes in the first replacement part (130) and the second replacement part (170); Finally, when the first replacement conductive layer (160) is conductive and the second replacement conductive layer (200) is not conductive, the drill returns to the first drilling area (110) and processes the printed circuit board.

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