A high multilayer circuit board press positioning jig and method thereof

Abstract

The present application relates to the field of circuit board pressing positioning, in particular to a high multilayer circuit board pressing positioning jig and method thereof, which technical scheme is: comprising a positioning jig and a servo drilling device; the positioning jig comprises a positioning jig base, a horizontal positioning pin sliding platform is installed on the top of the positioning jig base, a vertical positioning pin sliding platform is installed on the top of the horizontal positioning pin sliding platform, a positioning platform is installed on the top of the vertical positioning pin sliding platform, the top of the positioning platform is used for stacking multilayer core boards, a sliding positioning pin group is slidably installed in the horizontal positioning pin sliding platform and the vertical positioning pin sliding platform, and a plurality of positioning pin pushing devices are installed around the jig base; the beneficial effects of the present application are: the present application independently measures each layer by X-Ray equipment before pressing, and the positioning pin pushing device and the sliding positioning pin are used for mechanical compensation, so that the independent deformation of each layer core board caused by the previous process is offset in advance.

Description

Technical Field

[0001] This invention relates to the field of circuit board lamination and positioning, and specifically to a high-multilayer circuit board lamination and positioning fixture and method thereof. Background Technology

[0002] With the rapid development of 5G communication, AI servers, and aerospace electronics, printed circuit boards (PCBs) are evolving towards higher layer counts, higher density, and higher precision interconnections. The core of manufacturing high-multilayer circuit boards lies in the lamination process, which involves stacking multiple inner core boards with prepreg (PP) and pressing them together to form a whole. However, in the existing lamination manufacturing technology, the following technical bottlenecks still urgently need to be addressed: 1. After the multilayer circuit board is stacked, the target of the inner core board will be completely blocked by the copper foil, prepreg and core board of the upper layer. Traditional CCD vision positioning technology can only capture the optical features of the board surface and cannot penetrate the outer layer to obtain the target information of the inner layer. This means that the existing technology often has to rely on the outer layer or edge marks for rough alignment and cannot know the actual position of the inner core board before lamination, which poses a great risk of layer misalignment. 2. Multilayer circuit boards are composed of various materials such as resin, fiberglass cloth, and copper foil. The coefficient of thermal expansion (CTE) of each layer of materials has significant differences. Existing alignment processes usually perform static alignment at room temperature. However, the lamination process requires heating to about 175°C. Due to the inconsistent expansion rates of each layer of materials at high temperatures (such as the expansion difference between FR-4 and copper foil), circuit boards that are perfectly aligned at room temperature may experience uncontrollable misalignment after lamination and heating, which seriously affects the interconnection accuracy of blind and buried vias. 3. To fix the laminated structure, existing technologies often use pins for mechanical locking. However, under the high temperature and pressure environment of pressing, the resin flow will generate huge shear force. The traditional solid positioning pin is usually in rigid contact with the hole wall, lacking stress buffer space. This not only easily hinders the normal flow of resin, but also easily causes the positioning pin to be sheared under the action of interlayer shear force, or to generate micro-cracks around the hole wall, resulting in the scrapping of the board. 4. Traditional processes typically measure the overall deviation after lamination and then use a uniform coefficient to compensate for the next batch. Since the deformation of each core layer in the preceding process (such as etching and browning) is independent, this "one-size-fits-all" uniform compensation cannot pre-emptively offset the independent deformation of each layer, resulting in excessively large interlayer cumulative errors, making it difficult to meet the stringent yield requirements of multilayer boards. Therefore, it is necessary to invent a high-multilayer circuit board pressing and positioning fixture and its method. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides the following technical solution: a high-multilayer circuit board pressing and positioning fixture, comprising a positioning fixture and a servo drilling device; The positioning fixture includes a positioning fixture base, a transverse positioning pin sliding platform mounted on the top of the positioning fixture base, a longitudinal positioning pin sliding platform mounted on the top of the transverse positioning pin sliding platform, and a positioning platform mounted on the top of the longitudinal positioning pin sliding platform. The top of the positioning platform is used to stack multiple core boards. Chip storage grooves are embedded around the positioning platform, and locking pins can be inserted into the chip storage grooves. Sliding positioning pin groups are slidably installed in the transverse and longitudinal positioning pin sliding platforms. The sliding positioning pin groups are used to drive different core boards to move to different positions. Several positioning pin pushing devices are installed around the fixture base. The positioning pin pushing devices are used to push different positioning pins in the sliding positioning pin groups. The servo drilling device includes a servo lifting housing, which is installed on the top surface of a positioning platform on one side of the chip storage tank. A lifting bracket is slidably installed on one side of the servo lifting housing, and a drilling motor is installed on the lifting bracket. The lower output end of the drilling motor is connected to a drilling screw, which is positioned directly above the chip storage tank. The multi-layer core board includes a first core board, a second core board, a third core board, and a fourth core board. The first, second, third, and fourth core boards have four-slot positioning holes, clearance holes, and targets of different shapes distributed around their surfaces. The targets can be scanned and identified by an X-Ray device. The four-slot positioning holes on different core boards are used to connect to the corresponding positioning pins in the sliding positioning pin group.

[0004] Preferably, the No. 1 core board, No. 2 core board, No. 3 core board and No. 4 core board are stacked sequentially from bottom to top on the top surface of the positioning platform. Semi-cured sheets are sandwiched between each core board during stacking. A No. 1 target is provided on the No. 1 core board, a No. 2 target is provided on the No. 2 core board, a No. 3 target is provided on the No. 3 core board and a No. 4 target is provided on the No. 4 core board.

[0005] Preferably, the positioning platform, the longitudinal positioning pin sliding platform, the transverse positioning pin sliding platform, and the positioning fixture base together constitute the positioning main board. The positioning main board is provided with several slots around its perimeter. The number of slots is twice the number of positioning pins in the sliding positioning pin group. Each of the slots can accommodate a positioning pin pushing device.

[0006] Preferably, the sliding positioning pin group includes a first layer of longitudinal positioning pins, a second layer of longitudinal positioning pins, a third layer of longitudinal positioning pins, and a fourth layer of longitudinal positioning pins. The first layer of longitudinal positioning pins, the second layer of longitudinal positioning pins, the third layer of longitudinal positioning pins, and the fourth layer of longitudinal positioning pins are longitudinally slidably installed in the longitudinal positioning pin sliding platform, and their two ends extend into the slots on both sides of the positioning motherboard that are longitudinally opposite.

[0007] Preferably, the sliding positioning pin group further includes a first layer of horizontal positioning pins, a second layer of horizontal positioning pins, a third layer of horizontal positioning pins, and a fourth layer of horizontal positioning pins. The first layer of horizontal positioning pins, the second layer of horizontal positioning pins, the third layer of horizontal positioning pins, and the fourth layer of horizontal positioning pins are horizontally slidably installed in the horizontal positioning pin sliding platform, and their two ends extend into the horizontally opposite slots on both sides of the positioning motherboard.

[0008] Preferably, the four-slot positioning holes are flat and round. On the first core board, a pair of longitudinally opposite four-slot positioning holes are connected to a layer of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to a layer of lateral positioning pins. On the second core board, a pair of longitudinally opposite four-slot positioning holes are connected to two layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to two layers of lateral positioning pins. On the third core board, a pair of longitudinally opposite four-slot positioning holes are connected to three layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to three layers of lateral positioning pins. On the fourth core board, a pair of longitudinally opposite four-slot positioning holes are connected to four layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to four layers of lateral positioning pins.

[0009] Preferably, the clearance holes are circular. The clearance holes on the surface of the first core board correspond to the remaining positioning pins except for one layer of longitudinal positioning pins and one layer of transverse positioning pins. The clearance holes on the surface of the second core board correspond to the remaining positioning pins except for two layers of longitudinal positioning pins and two layers of transverse positioning pins. The clearance holes on the surface of the third core board correspond to the remaining positioning pins except for three layers of longitudinal positioning pins and three layers of transverse positioning pins. The clearance holes on the surface of the fourth core board correspond to the remaining positioning pins except for four layers of longitudinal positioning pins and four layers of transverse positioning pins.

[0010] Preferably, the clearance holes are circular. The clearance holes on the surface of the first core board correspond to the remaining positioning pins except for one layer of longitudinal positioning pins and one layer of transverse positioning pins. The clearance holes on the surface of the second core board correspond to the remaining positioning pins except for two layers of longitudinal positioning pins and two layers of transverse positioning pins. The clearance holes on the surface of the third core board correspond to the remaining positioning pins except for three layers of longitudinal positioning pins and three layers of transverse positioning pins. The clearance holes on the surface of the fourth core board correspond to the remaining positioning pins except for four layers of longitudinal positioning pins and four layers of transverse positioning pins.

[0011] Preferably, the lower end of the servo lifting housing is equipped with a second bolt that can be threaded onto the top surface of the positioning platform, the upper end of the servo lifting housing is equipped with a second servo motor, the lower output end of the second servo motor is equipped with a second threaded rod, the outer wall of the second threaded rod is threaded with an internal threaded lifting ring, the lifting bracket extends into the servo lifting housing and is fixedly connected to the internal threaded lifting ring, the drilling screw can open locking holes downward on the first core plate, the second core plate, the third core plate and the fourth core plate, and the locking pin can pass through each locking hole and be inserted and fixed in the corresponding chip storage groove.

[0012] A processing method for a high-multilayer circuit board pressing and positioning fixture according to any one of the above claims includes S1-S6. S1. First, in the pre-processing of core board No. 1, core board No. 2, core board No. 3 and core board No. 4, four slot positioning holes and clearance holes are pre-punched on their surfaces to ensure that the four slot positioning holes on each core board are staggered in the vertical projection direction. At the same time, different targets with different shapes and staggered positions are punched on the edges of each core board. S2. Next, place the No. 1 core board on the positioning platform, ensuring that one layer of longitudinal positioning pins and one layer of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; then place the No. 2 core board, ensuring that two layers of longitudinal positioning pins and two layers of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; next, place the No. 3 core board, ensuring that three layers of longitudinal positioning pins and three layers of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; finally, place the No. 4 core board, ensuring that four layers of longitudinal positioning pins and four layers of transverse positioning pins pass through the four-slot positioning holes on its surface. S3. Subsequently, the positioning pin pusher device is inserted into the slots around the positioning motherboard one by one. At the same time, the servo drilling device is installed around the top surface of the positioning platform. Then, the positioning motherboard is sent into the independent X-Ray device and the X-Ray device is started. The X-Ray camera penetrates the outer material, identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core board. Then, through the CTE dynamic compensation algorithm built into the central control system, the theoretical deformation field at the pressing target temperature is calculated in reverse according to the Tg value and thermal expansion coefficient of each material, and the compensation command is calculated. S4. The central control system activates the corresponding positioning pin propulsion device through compensation commands. The first servo motor in the positioning pin propulsion device drives the gearbox to rotate the first screw. The first screw controls the internal thread propulsion rod to slowly push out, driving the corresponding sliding positioning pin to perform micron-level translation and expansion compensation on each core plate, so that it reserves a reverse pre-offset amount at room temperature. During the execution of the positioning pin propulsion device, the X-Ray camera identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core plate in real time and feeds them back to the central control system, so as to realize the independent and accurate pre-alignment of the targets in each core plate. S5. After each core board is independently aligned, the central control system starts the servo drilling device. The second servo motor and the drilling motor in the servo drilling device are started. The second servo motor drives the internal thread lifting ring and the lifting bracket to descend, driving the rotating drilling screw to penetrate all the core boards in one go and drill out the locking hole. The debris generated by drilling falls into the bottom of the debris storage tank. Then, a locking pin is inserted into the locking hole to lock the originally loose layers tightly. Note that a micron-level stress buffer gap is reserved between the locking pin and the inner wall of the locking hole to provide release space for subsequent resin flow. S6. Next, the positioning motherboard and its locked multilayer core board are sent into a low-temperature oven and kept at 120°C below the resin Tg value for a period of time to eliminate the residual mechanical stress caused by mechanical pulling and alignment. Then, it is transferred to a high-temperature press and pressed according to the set gradient heating and pressing program. After pressing, the multilayer core board is removed from the positioning motherboard. In the subsequent process, the four slot positioning holes, clearance holes and locking holes that have lost their function on the edge of the board are cut off. The interlayer deviation of the multilayer core board is scanned and detected again using X-Ray equipment. After passing the test, it can be packaged and stored.

[0013] The beneficial effects of this invention are: 1. This invention introduces X-ray imaging technology. By punching different targets of varying shapes and staggered positions on the edges of each core plate, the target coordinates of the inner core plate that is blocked are directly obtained by utilizing the penetrating characteristics of X-rays on materials of different densities. Combined with the positioning pin pushing device and the sliding positioning pin group, the independent alignment of each core plate is achieved, so as to ensure that each core plate is in the theoretically designed position before pressing, thus fundamentally eliminating the blind zone of inner layer misalignment. 2. This invention introduces a CTE dynamic compensation algorithm into the central control system. The system calculates the theoretical deformation field at the target pressing temperature based on the Tg value and CTE parameters of each core board material. It also uses a positioning pin pushing device and a sliding positioning pin group to control each core board to reserve a reverse pre-offset amount at room temperature. This ensures that the thermal expansion of each core board just offsets the pre-offset amount during subsequent high-temperature pressing, thereby achieving dynamic perfect overlap of each core board under high temperature and high pressure conditions, which significantly improves the alignment accuracy of multilayer circuit boards. 3. This invention uses a servo drilling device to drill holes in each core board layer after each layer is independently and precisely aligned, and then inserts locking pins for rigid locking. At the same time, a micron-level buffer gap is reserved between the locking pin and the hole wall, so that each layer forms a whole before entering the press. This avoids the physical interference between the material thermal expansion and contraction under high temperature and high pressure and the positioning pin. In addition, the micron-level buffer gap and the gap in the clearance hole also provide stress release space for resin flow, effectively preventing pin breakage and micro-cracks. 4. Before lamination, the present invention performs independent optical measurements on each layer using an X-ray device, and uses a positioning pin advancing device and a sliding positioning pin for mechanical compensation to achieve the effect of pre-counteracting the independent deformation of each core board caused by the previous process. This segmented precision control intercepts errors before lamination, so that the measurement and compensation after lamination only need to solve the unpredictable deformation during the lamination process, which greatly reduces the layer deviation defect rate of multilayer boards. Attached Figure Description

[0014] Figure 1 This is a front view provided for the present invention; Figure 2 This is a schematic diagram of the positioning motherboard and top core board provided by the present invention; Figure 3 This is a schematic diagram of the locking pin insertion provided by the present invention; Figure 4 This is a schematic diagram of the stacking of the top core board of the positioning motherboard provided by the present invention; Figure 5 This is a schematic diagram of the positioning motherboard structure provided by the present invention; Figure 6 A cross-sectional view of the positioning motherboard provided by the present invention; Figure 7 The schematic diagrams of the core board structures provided by this invention are as follows; Figure 8 A schematic diagram of the installation of the positioning pin pushing device and the servo drilling device provided by the present invention; Figure 9 A cross-sectional view of the servo drilling device provided by the present invention; Figure 10 A cross-sectional view of the locking pin insertion provided by the present invention; Figure 11 A schematic diagram of the insertion of the positioning pin pushing device provided by the present invention; Figure 12 A cross-sectional view of the positioning pin pushing device provided by the present invention.

[0015] In the diagram: 001, Target No. 1; 002, Target No. 2; 003, Target No. 3; 004, Target No. 4; 101, Core Board No. 1; 102, Core Board No. 2; 103, Core Board No. 3; 104, Core Board No. 4; 105, Four-slot positioning hole; 106, Clearance hole; 107, Locking hole; 111, Positioning platform; 112, Longitudinal positioning pin sliding platform; 113, Lateral positioning pin sliding platform; 114, Positioning fixture base; 115, Chip storage groove; 116, Locking pin; 121, First layer longitudinal positioning pin; 122, First layer lateral positioning pin; 123, Second layer longitudinal positioning pin; 12 4. Second-layer transverse positioning pin; 125. Third-layer longitudinal positioning pin; 126. Third-layer transverse positioning pin; 127. Fourth-layer longitudinal positioning pin; 128. Fourth-layer transverse positioning pin; 131. Servo propulsion housing; 132. Gearbox; 133. First servo motor; 134. First bolt; 135. First screw; 136. Slide rail; 137. Internal threaded propulsion rod; 141. Servo lifting housing; 142. Second threaded rod; 143. Second servo motor; 144. Second bolt; 145. Internal threaded lifting ring; 146. Lifting bracket; 147. Drilling motor; 148. Drilling screw. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0017] like Figure 1 - Figure 7 As shown, a high-multilayer circuit board lamination and positioning fixture includes a positioning fixture and a servo drilling device. The positioning fixture includes a positioning fixture base 114, a transverse positioning pin sliding platform 113 mounted on the top of the positioning fixture base 114, a longitudinal positioning pin sliding platform 112 mounted on the top of the transverse positioning pin sliding platform 113, and a positioning platform 111 mounted on the top of the longitudinal positioning pin sliding platform 112. The top of the positioning platform 111 is used to stack multiple core boards. Chip storage grooves 115 are embedded around the positioning platform 111. Locking pins 116 can be inserted into the chip storage grooves 115. Sliding positioning pin groups are slidably installed in the transverse positioning pin sliding platform 113 and the longitudinal positioning pin sliding platform 112. The sliding positioning pin groups are used to drive different core boards to move to different positions. Several positioning pin pushing devices are installed around the fixture base 114. The positioning pin pushing devices are used to push different positioning pins in the sliding positioning pin groups. The servo drilling device includes a servo lifting housing 141, which is installed on the top surface of the positioning platform 111 on one side of the chip storage tank 115. A lifting bracket 146 is slidably installed on one side of the servo lifting housing 141. A drilling motor 147 is installed on the lifting bracket 146. The lower output end of the drilling motor 147 is connected to a drilling screw 148, which is located directly above the chip storage tank 115. The multilayer core board includes a first core board 101, a second core board 102, a third core board 103, and a fourth core board 104. The surfaces of the first core board 101, the second core board 102, the third core board 103, and the fourth core board 104 are distributed with four-slot positioning holes 105, clearance holes 106, and targets of various shapes. The targets can be scanned and identified by X-Ray equipment. The four-slot positioning holes 105 on different core boards are used to connect the corresponding positioning pins in the sliding positioning pin group.

[0018] In the above embodiment, it should be noted that the first core board 101, the second core board 102, the third core board 103 and the fourth core board 104 are stacked on the positioning platform 111 in sequence. During the stacking process, a semi-cured sheet is inserted between the first core board 101, the second core board 102, the third core board 103 and the fourth core board 104. The semi-cured sheet has clearance holes 106 distributed around its surface, but no four-slot positioning holes 105. Therefore, the sliding positioning pin group cannot move the semi-cured sheet, and the semi-cured sheet will not affect the normal operation of the sliding positioning pin group. This invention pre-punches differentiated targets of varying shapes and staggered positions on the edges of each core plate. Then, by stacking core plates 101, 102, 103, and 104 in sequence on the positioning platform 111, and using X-ray imaging technology, the target coordinates of the obscured inner core plates are directly obtained by utilizing the penetrating characteristics of X-rays on materials of different densities. At the same time, the positioning pin pushing device and sliding positioning pin group are used to achieve independent alignment of each core plate, so as to ensure that each core plate is in the theoretically designed position before pressing, fundamentally eliminating the blind zone of inner layer misalignment. After each layer is independently and precisely aligned, the No. 1 core board 101, No. 2 core board 102, No. 3 core board 103 and No. 4 core board 104 are uniformly drilled using a servo drilling device, and locking pins 116 are inserted for rigid locking. Furthermore, all motors in this invention are connected to a unified central control system, and a CTE dynamic compensation algorithm is introduced into the central control system. The system calculates the theoretical deformation field at the target pressing temperature based on the Tg value and CTE parameters of each core board material. It also controls each core board to reserve a reverse pre-offset amount at room temperature in conjunction with the positioning pin pushing device and the sliding positioning pin group. This ensures that the thermal expansion of each core board just offsets the pre-offset amount during subsequent high-temperature pressing, thereby achieving the effect of dynamic perfect overlap of each core board under high temperature and high pressure, which significantly improves the alignment accuracy of multilayer circuit boards. The central control system mainly consists of the following core electronic components: (1) Main control processing chip (CPU / MCU): adopts high-performance ARM Cortex-M series, DSP (digital signal processor) or x86 architecture industrial-grade CPU, which is responsible for running complex visual image processing, thermodynamic model calculation and multi-axis motor cooperative control law calculation. (2) Programmable Logic Array (FPGA / CPLD): Used to process the high-speed concurrent logic of the underlying hardware to ensure that the servo motor can achieve microsecond-level synchronous response when it receives instructions; (3) Serial communication interface (RS-232 / RS-485 / RS-422): used to connect and control X-ray imaging equipment, press, etc.; (4) Network communication module (TCP / IP port): used to access the factory's industrial LAN and realize data docking with the upper-level MES (Manufacturing Execution System); (5) Industrial bus interface (such as EtherCAT / CANopen): used to realize real-time, high-precision synchronous control of multiple motor drivers, ensuring that the positioning pin push device moves with absolute precision during pre-alignment; (6) Motor drive module: used to drive servo motor driver, receive pulse or bus commands from central control system, and realize micron-level displacement compensation; The difference in the rate of thermal expansion of materials in a circuit board: (1) Standard FR-4 substrate: Below the glass transition temperature (Tg), its XY axis CTE is about 12-18 ppm / °C, while the Z axis (thickness direction) CTE is as high as 50-80 ppm / °C; (2) Electrolytic copper foil: CTE is approximately 17 ppm / °C; (3) Silicon chip: CTE is only 2.6-3ppm / °C; Conclusion: Because high-multilayer circuit boards (PCBs) are composed of different materials such as resin, fiberglass cloth, and copper foil, significant dimensional changes will occur between layers due to CTE mismatch during the lamination and heating process (e.g., to 175℃). In precision manufacturing, even a 0.01% expansion and contraction deviation can lead to blind via misalignment of up to 2.5μm. For 4-layer boards, the interlayer alignment must be ≤50μm, and for high-multilayer boards with 8 or more layers, the requirements are even more stringent, requiring ≤35μm. Therefore, minute thermal deformations can be amplified in precision manufacturing, leading to fatal defects. The CTE dynamic compensation algorithm introduced in this solution, which presets the reverse offset at room temperature, can strictly control the layer misalignment after lamination to within 35μm, meeting the alignment requirements of high-density interconnect (HDI) and micro-blind vias. This invention performs independent optical measurements on each layer using an X-ray device before lamination, and uses a positioning pin advancing device and a sliding positioning pin for mechanical compensation to pre-compensate the independent deformation of each core layer caused by the previous process. This segmented precision control intercepts errors before lamination, so that the measurement and compensation after lamination only need to address the unpredictable deformation during the lamination process, which greatly reduces the layer deviation defect rate of multilayer boards.

[0019] like Figure 4 and Figure 7 As shown, a high-multilayer circuit board pressing and positioning fixture further includes a first core board 101, a second core board 102, a third core board 103, and a fourth core board 104 stacked sequentially from bottom to top on the top surface of the positioning platform 111. Semi-cured sheets are sandwiched between the core boards during stacking. A first target 001 is provided on the first core board 101, a second target 002 is provided on the second core board 102, a third target 003 is provided on the third core board 103, and a fourth target 004 is provided on the fourth core board 104.

[0020] In the above embodiments, it should be noted that in order for the X-Ray device to perform independent optical measurements on each layer, the targets on the first core plate 101, the second core plate 102, the third core plate 103, and the fourth core plate 104 are all different. The first target 001 is triangular, the second target 002 is rectangular, the third target 003 is pentagonal, and the fourth target 004 is hexagonal. The targets are staggered in the vertical projection direction.

[0021] like Figure 1 - Figure 8 , Figure 11 and Figure 12As shown, a high-multilayer circuit board pressing and positioning fixture further includes a positioning platform 111, a longitudinal positioning pin sliding platform 112, a transverse positioning pin sliding platform 113, and a positioning fixture base 114, which together constitute a positioning main board. The positioning main board has several slots around its perimeter, the number of which is twice the number of positioning pins in the sliding positioning pin group. Each slot can accommodate a positioning pin pushing device. The sliding positioning pin group includes a first layer of longitudinal positioning pins 121, a second layer of longitudinal positioning pins 123, a third layer of longitudinal positioning pins 125, and a fourth layer of longitudinal positioning pins 127. The first layer of longitudinal positioning pins 121, the second layer of longitudinal positioning pins 123, the third layer of longitudinal positioning pins 125, and the fourth layer of longitudinal positioning pins 127 are longitudinally slidably installed within the longitudinal positioning pin sliding platform 112. The sliding positioning pin group also includes a first layer of horizontal positioning pins 122, a second layer of horizontal positioning pins 124, a third layer of horizontal positioning pins 126, and a fourth layer of horizontal positioning pins 128. These four pins are horizontally slidably installed within the horizontal positioning pin sliding platform 113, with both ends extending into the horizontally opposite slots on the positioning motherboard. The four-slot positioning holes 105 are flat and round. On the first core board 101, a pair of vertically opposite four-slot positioning holes 105 are connected to a first layer of vertical positioning pins 121, and a pair of horizontally opposite four-slot positioning holes 105 are connected to a first layer of horizontal positioning pins 122. On the second core board 102... A pair of longitudinally opposite four-slot positioning holes 105 are connected to two layers of longitudinal positioning pins 123, and a pair of laterally opposite four-slot positioning holes 105 are connected to two layers of laterally positioning pins 124. On core board 103, a pair of longitudinally opposite four-slot positioning holes 105 are connected to three layers of longitudinal positioning pins 125, and a pair of laterally opposite four-slot positioning holes 105 are connected to three layers of laterally positioning pins 126. On core board 104, a pair of longitudinally opposite four-slot positioning holes 105 are connected to four layers of longitudinal positioning pins 127, and a pair of laterally opposite four-slot positioning holes 105 are connected to four layers of laterally positioning pins 128. The clearance holes 106 are circular. The clearance holes 106 on the surface of core board 101 pass through one layer of longitudinal positioning pins 121 and one layer of laterally positioning pins 128 respectively. The remaining positioning pins of core plate 102 have clearance holes 106 on their surfaces corresponding to the remaining positioning pins except for the second-layer longitudinal positioning pin 123 and the second-layer transverse positioning pin 124. The clearance holes 106 on the surface of core plate 103 correspond to the remaining positioning pins except for the third-layer longitudinal positioning pin 125 and the third-layer transverse positioning pin 126. The clearance holes 106 on the surface of core plate 104 correspond to the remaining positioning pins except for the fourth-layer longitudinal positioning pin 127 and the fourth-layer transverse positioning pin 128. The positioning pin pushing device includes a servo pushing housing 131, which is inserted into slots set around the positioning main plate. A gearbox 132 is fixedly installed at one end of the servo pushing housing 131, and an internally threaded pushing rod 137 is inserted into the other end.A first servo motor 133 is installed at the input end of the gearbox 132, and a first screw 135 is connected to the output end. An internally threaded push rod 137 is threaded onto the first screw 135. Slide rails 136 are installed on both sides of the inner wall of the servo push housing 131, and the internally threaded push rod 137 is slidably mounted on the slide rails 136. First bolts 134, capable of being threaded onto the sides of the positioning fixture base 114, are installed on both sides of the gearbox 132.

[0022] In the above embodiments, it should be noted that after the servo propulsion housing 131 is inserted into the slots set around the positioning motherboard by the first bolt 134, the control system receives the measured three-dimensional coordinates of the differentiated targets of each core board obtained by the X-Ray device, and calculates the compensation command according to the built-in CTE dynamic compensation algorithm, and drives the corresponding first servo motor 133 to start. The first servo motor 133 provides power to the gearbox 132, and slowly and accurately drives the first screw 135 to rotate. The first screw 135 drives the internal thread propulsion rod 137 to extend, so as to achieve the effect of controlling the designated positioning pin to drive the designated core board to move. The first layer of longitudinal positioning pin 121 and the first layer of transverse positioning pin 122 are used to drive the longitudinal and transverse movement of the first core board 101, respectively; the second layer of longitudinal positioning pin 123 and the second layer of transverse positioning pin 124 are used to drive the longitudinal and transverse movement of the second core board 102, respectively; the third layer of longitudinal positioning pin 125 and the third layer of transverse positioning pin 126 are used to drive the longitudinal and transverse movement of the third core board 103, respectively; the fourth layer of longitudinal positioning pin 127 and the fourth layer of transverse positioning pin 128 are used to drive the longitudinal and transverse movement of the fourth core board 104, respectively. The inner diameter of the clearance hole 106 is larger than that of each locating pin. The extension length of the threaded push rod 137 determines the maximum movement range of the locating pin. The extension length is less than the radius of the clearance hole 106. The locating pin moves within the set maximum movement range and will not touch the inner wall of the clearance hole 106 when it moves. like Figure 1 - Figure 4 , Figure 9 and Figure 10 As shown, a high-multilayer circuit board pressing and positioning fixture further includes: a second bolt 144 that can be threadedly fixed to the top surface of the positioning platform 111 is installed at the lower end of a servo lifting housing 141; a second servo motor 143 is installed at the upper end of the servo lifting housing 141; a second threaded rod 142 is installed at the lower output end of the second servo motor 143; an internal threaded lifting ring 145 is threadedly fitted onto the outer wall of the second threaded rod 142; a lifting bracket 146 extends into the servo lifting housing 141 and is fixedly connected to the internal threaded lifting ring 145; a drilling screw 148 can open locking holes 107 on the first core board 101, the second core board 102, the third core board 103, and the fourth core board 104; and a locking pin 116 can pass through each locking hole 107 and be inserted and fixed in the corresponding chip storage groove 115.

[0023] In the above embodiment, it should be noted that the second servo motor 143 and the drilling motor 147 are started by the central control system. The drilling motor 147 drives the drilling screw 148 to rotate at high speed. At the same time, the second servo motor 143 drives the internal thread lifting ring 145 and the lifting bracket 146 to descend. The rotating drilling screw 148 drives downward to penetrate all the core plates in one go, so as to achieve the effect of drilling the locking hole 107. The debris generated by drilling falls into the bottom of the chip storage groove 115. Then, the locking pin 116 is inserted into the locking hole 107 to lock the stack of core plates. The outer diameter of the locking pin 116 is smaller than the drilling diameter of the servo drilling device. By reserving a micron-level buffer gap between the locking pin 116 and the hole wall, each layer forms a whole before entering the press. This avoids the physical interference between the thermal expansion and contraction of the material under high temperature and high pressure and the positioning pin. In addition, the micron-level buffer gap and the clearance in the clearance hole also provide stress release space for resin flow, effectively preventing pin breakage and microcracks.

[0024] The processing method of a high-multilayer circuit board lamination and positioning fixture of the present invention is as follows: including S1-S6; S1. First, in the preliminary processing of core board 101, core board 102, core board 103 and core board 104, four slot positioning holes 105 and clearance holes 106 are pre-punched on their surfaces to ensure that the four slot positioning holes 105 on each core board are staggered in the vertical projection direction. At the same time, different targets with different shapes and staggered positions are punched on the edges of each core board. S2. Next, place the first core board 101 on the positioning platform 111, ensuring that one layer of longitudinal positioning pins 121 and one layer of transverse positioning pins 122 pass through the four-slot positioning holes 105 on its surface, and then place a prepreg on its top surface; then place the second core board 102, ensuring that two layers of longitudinal positioning pins 123 and two layers of transverse positioning pins 124 pass through the four-slot positioning holes 105 on its surface, and then place a prepreg on its top surface; next, place the third core board 103, ensuring that three layers of longitudinal positioning pins 125 and three layers of transverse positioning pins 126 pass through the four-slot positioning holes 105 on its surface, and then place a prepreg on its top surface; finally, place the fourth core board 104, ensuring that four layers of longitudinal positioning pins 127 and four layers of transverse positioning pins 128 pass through the four-slot positioning holes 105 on its surface; S3. Subsequently, the positioning pin pusher device is inserted into the slots around the positioning motherboard one by one. At the same time, the servo drilling device is installed around the top surface of the positioning platform 111. Then, the positioning motherboard is sent into the independent X-Ray device and the X-Ray device is started. The X-Ray camera penetrates the outer material, identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core board. Then, through the CTE dynamic compensation algorithm built into the central control system, the theoretical deformation field at the pressing target temperature is calculated in reverse according to the Tg value and thermal expansion coefficient of each material, and the compensation command is calculated. S4. The central control system activates the corresponding positioning pin pushing device through the compensation command. The first servo motor 133 in the positioning pin pushing device drives the gearbox 132 to rotate the first screw 135. The first screw 135 controls the internal thread push rod 137 to slowly push out, driving the corresponding sliding positioning pin to perform micron-level translation and expansion compensation on each core plate, so that it reserves a reverse pre-offset amount at room temperature. During the execution of the positioning pin pushing device, the X-Ray camera identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core plate in real time and feeds them back to the central control system, realizing the independent and accurate pre-alignment of the targets in each core plate. S5. After each core board is independently aligned, the central control system starts the servo drilling device. The second servo motor 143 and the drilling motor 147 in the servo drilling device are started. The second servo motor 143 drives the internal thread lifting ring 145 and the lifting bracket 146 to descend, driving the rotating drilling screw 148 to penetrate all the core boards in one go and drill out the locking hole 107. The debris generated by drilling falls into the bottom of the chip storage tank 115. Then, the locking pin 116 is inserted into the locking hole 107 to lock the originally loose layers tightly. Note that a micron-level stress buffer gap is reserved between the locking pin 116 and the inner wall of the locking hole 107 to provide release space for subsequent resin flow. S6. Next, the positioning motherboard and its locked multilayer core board are sent into a low-temperature oven and kept at 120°C below the resin Tg value for a period of time to eliminate the residual mechanical stress caused by mechanical pulling and alignment. Then, it is transferred to a high-temperature press and pressed according to the set gradient heating and pressing program. After pressing, the multilayer core board is removed from the positioning motherboard. In the subsequent process, the four slot positioning holes 105, clearance holes 106 and locking holes 107 that have lost their function on the edge of the board are cut off. The interlayer deviation of the multilayer core board is scanned and detected again using X-Ray equipment. After passing the test, it can be packaged and stored.

[0025] The above description is merely a preferred embodiment of the present invention. Any person skilled in the art can modify the present invention or modify it into an equivalent technical solution using the technical solutions described above. Therefore, any simple modifications or equivalent substitutions made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-multilayer circuit board lamination and positioning fixture, comprising a positioning fixture and a servo drilling device, characterized in that: The positioning fixture includes a positioning fixture base, a transverse positioning pin sliding platform mounted on the top of the positioning fixture base, a longitudinal positioning pin sliding platform mounted on the top of the transverse positioning pin sliding platform, and a positioning platform mounted on the top of the longitudinal positioning pin sliding platform. The top of the positioning platform is used to stack multiple core boards. Chip storage grooves are embedded around the positioning platform, and locking pins can be inserted into the chip storage grooves. Sliding positioning pin groups are slidably installed in the transverse and longitudinal positioning pin sliding platforms. The sliding positioning pin groups are used to drive different core boards to move to different positions. Several positioning pin pushing devices are installed around the fixture base. The positioning pin pushing devices are used to push different positioning pins in the sliding positioning pin groups. The servo drilling device includes a servo lifting housing, which is installed on the top surface of a positioning platform on one side of the chip storage tank. A lifting bracket is slidably installed on one side of the servo lifting housing, and a drilling motor is installed on the lifting bracket. The lower output end of the drilling motor is connected to a drilling screw, which is positioned directly above the chip storage tank. The multi-layer core board includes a first core board, a second core board, a third core board, and a fourth core board. The first, second, third, and fourth core boards have four-slot positioning holes, clearance holes, and targets of different shapes distributed around their surfaces. The targets can be scanned and identified by an X-Ray device. The four-slot positioning holes on different core boards are used to connect to the corresponding positioning pins in the sliding positioning pin group.

2. The high-multilayer circuit board pressing and positioning fixture according to claim 1, characterized in that: The No. 1 core board, No. 2 core board, No. 3 core board and No. 4 core board are stacked sequentially from bottom to top on the top surface of the positioning platform. Semi-cured sheets are sandwiched between each core board during stacking. The No. 1 core board is equipped with a No. 1 target, the No. 2 core board is equipped with a No. 2 target, the No. 3 core board is equipped with a No. 3 target, and the No. 4 core board is equipped with a No. 4 target.

3. The high-multilayer circuit board pressing and positioning fixture according to claim 1, characterized in that: The positioning platform, the longitudinal positioning pin sliding platform, the transverse positioning pin sliding platform, and the positioning fixture base together constitute the positioning main board. The positioning main board is provided with several slots around its perimeter. The number of slots is twice the number of positioning pins in the sliding positioning pin group. Each of the slots can accommodate a positioning pin pushing device.

4. The high-multilayer circuit board pressing and positioning fixture according to claim 3, characterized in that: The sliding positioning pin group includes a first layer of longitudinal positioning pins, a second layer of longitudinal positioning pins, a third layer of longitudinal positioning pins, and a fourth layer of longitudinal positioning pins. The first layer of longitudinal positioning pins, the second layer of longitudinal positioning pins, the third layer of longitudinal positioning pins, and the fourth layer of longitudinal positioning pins are slidably installed in the longitudinal positioning pin sliding platform, and their two ends extend into the slots on both sides of the positioning motherboard that are longitudinally opposite.

5. The high-multilayer circuit board pressing and positioning fixture according to claim 4, characterized in that: The sliding positioning pin group also includes a first layer of horizontal positioning pins, a second layer of horizontal positioning pins, a third layer of horizontal positioning pins, and a fourth layer of horizontal positioning pins. The first layer of horizontal positioning pins, the second layer of horizontal positioning pins, the third layer of horizontal positioning pins, and the fourth layer of horizontal positioning pins are horizontally slidably installed in the horizontal positioning pin sliding platform, and their two ends extend into the slots on both sides of the positioning motherboard that are horizontally opposite to each other.

6. The high-multilayer circuit board pressing and positioning fixture according to claim 5, characterized in that: The four-slot positioning holes are flat and round. On the first core board, a pair of longitudinally opposite four-slot positioning holes are connected to a layer of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to a layer of lateral positioning pins. On the second core board, a pair of longitudinally opposite four-slot positioning holes are connected to two layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to two layers of lateral positioning pins. On the third core board, a pair of longitudinally opposite four-slot positioning holes are connected to three layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to three layers of lateral positioning pins. On the fourth core board, a pair of longitudinally opposite four-slot positioning holes are connected to four layers of longitudinal positioning pins, and a pair of laterally opposite four-slot positioning holes are connected to four layers of lateral positioning pins.

7. The high-multilayer circuit board pressing and positioning fixture according to claim 6, characterized in that: The clearance holes are perfectly circular. The clearance holes on the surface of the first core board correspond to the remaining positioning pins except for one layer of longitudinal positioning pins and one layer of transverse positioning pins. The clearance holes on the surface of the second core board correspond to the remaining positioning pins except for two layers of longitudinal positioning pins and two layers of transverse positioning pins. The clearance holes on the surface of the third core board correspond to the remaining positioning pins except for three layers of longitudinal positioning pins and three layers of transverse positioning pins. The clearance holes on the surface of the fourth core board correspond to the remaining positioning pins except for four layers of longitudinal positioning pins and four layers of transverse positioning pins.

8. The high-multilayer circuit board pressing and positioning fixture according to claim 3, characterized in that: The positioning pin pushing device includes a servo pushing housing, which is inserted into slots around the positioning main board. A gearbox is fixedly installed at one end of the servo pushing housing, and an internally threaded pushing rod is inserted into the other end. A first servo motor is installed at the input end of the gearbox, and a first screw is connected to the output end. The internally threaded pushing rod is threaded onto the first screw. Slide rails are installed on both sides of the inner wall of the servo pushing housing, and the internally threaded pushing rod is slidably installed on the slide rails. First bolts that can be threadedly fixed to the side of the positioning fixture base are installed on both sides of the gearbox.

9. The high-multilayer circuit board pressing and positioning fixture according to claim 1, characterized in that: The lower end of the servo lifting housing is equipped with a second bolt that can be threaded onto the top surface of the positioning platform. The upper end of the servo lifting housing is equipped with a second servo motor. The lower output end of the second servo motor is equipped with a second threaded rod. An internal threaded lifting ring is threaded onto the outer wall of the second threaded rod. The lifting bracket extends into the servo lifting housing and is fixedly connected to the internal threaded lifting ring. The drilling screw can open locking holes downward on the No. 1 core plate, No. 2 core plate, No. 3 core plate, and No. 4 core plate. The locking pin can pass through each locking hole and be inserted and fixed in the corresponding chip storage groove.

10. A processing method using a high-multilayer circuit board pressing and positioning fixture according to any one of claims 1-9, characterized in that: Including S1-S6; S1. First, in the pre-processing of core board No. 1, core board No. 2, core board No. 3 and core board No. 4, four slot positioning holes and clearance holes are pre-punched on their surfaces to ensure that the four slot positioning holes on each core board are staggered in the vertical projection direction. At the same time, different targets with different shapes and staggered positions are punched on the edges of each core board. S2. Next, place the No. 1 core board on the positioning platform, ensuring that one layer of longitudinal positioning pins and one layer of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; then place the No. 2 core board, ensuring that two layers of longitudinal positioning pins and two layers of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; next, place the No. 3 core board, ensuring that three layers of longitudinal positioning pins and three layers of transverse positioning pins pass through the four-slot positioning holes on its surface, and then place a prepreg on its top surface; finally, place the No. 4 core board, ensuring that four layers of longitudinal positioning pins and four layers of transverse positioning pins pass through the four-slot positioning holes on its surface. S3. Subsequently, the positioning pin pusher device is inserted into the slots around the positioning motherboard one by one. At the same time, the servo drilling device is installed around the top surface of the positioning platform. Then, the positioning motherboard is sent into the independent X-Ray device and the X-Ray device is started. The X-Ray camera penetrates the outer material, identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core board. Then, through the CTE dynamic compensation algorithm built into the central control system, the theoretical deformation field at the pressing target temperature is calculated in reverse according to the Tg value and thermal expansion coefficient of each material, and the compensation command is calculated. S4. The central control system activates the corresponding positioning pin propulsion device through compensation commands. The first servo motor in the positioning pin propulsion device drives the gearbox to rotate the first screw. The first screw controls the internal thread propulsion rod to slowly push out, driving the corresponding sliding positioning pin to perform micron-level translation and expansion compensation on each core plate, so that it reserves a reverse pre-offset amount at room temperature. During the execution of the positioning pin propulsion device, the X-Ray camera identifies and extracts the measured three-dimensional coordinates of the differentiated targets of each core plate in real time and feeds them back to the central control system, so as to realize the independent and accurate pre-alignment of the targets in each core plate. S5. After each core board is independently aligned, the central control system starts the servo drilling device. The second servo motor and the drilling motor in the servo drilling device are started. The second servo motor drives the internal thread lifting ring and the lifting bracket to descend, driving the rotating drilling screw to penetrate all the core boards in one go and drill out the locking hole. The debris generated by drilling falls into the bottom of the debris storage tank. Then, a locking pin is inserted into the locking hole to lock the originally loose layers tightly. Note that a micron-level stress buffer gap is reserved between the locking pin and the inner wall of the locking hole to provide release space for subsequent resin flow. S6. Next, the positioning motherboard and its locked multilayer core board are sent into a low-temperature oven and kept at 120°C below the resin Tg value for a period of time to eliminate the residual mechanical stress caused by mechanical pulling and alignment. Then, it is transferred to a high-temperature press and pressed according to the set gradient heating and pressing program. After pressing, the multilayer core board is removed from the positioning motherboard. In the subsequent process, the four slot positioning holes, clearance holes and locking holes that have lost their function on the edge of the board are cut off. The interlayer deviation of the multilayer core board is scanned and detected again using X-Ray equipment. After passing the test, it can be packaged and stored.

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