A method for drilling a buried copper block of a power panel

Abstract

This invention relates to a method for drilling holes in embedded copper blocks on a power board, comprising the following steps: S1, providing a board to be processed with embedded copper blocks; S2, dividing the embedded copper blocks into a processing matrix consisting of several rows and several columns, the processing matrix including multiple matrix units, each matrix unit corresponding to a hole position; S3, planning the processing sequence of the drill bit according to the processing matrix, such that in a continuous processing sequence, the current hole position and the next hole position are separated by at least one matrix unit in the row direction and / or column direction, and the center distance between them is greater than a preset safety distance threshold; S4, drilling is performed according to the planned processing sequence until all hole positions are processed.

Description

Technical Field

[0001] This invention relates to the field of circuit board processing, and more specifically, to a method for drilling holes in embedded copper blocks of a power board. Background Technology

[0002] With the increasing demand for AI computing power, power supply board designs have begun to incorporate thick embedded copper blocks to meet the requirements of ultra-high current carrying capacity and heat dissipation. However, the thickness of such embedded copper blocks is usually more than 3.5mm, and the total thickness of the board exceeds 8mm. Copper conducts heat extremely quickly, and the heat generated by the intense friction between the drill bit and the copper material during drilling cannot be conducted and dissipated in time. High temperatures can easily cause copper chips to melt and adhere to the drill bit, thus frequently causing the drill bit to break. Summary of the Invention

[0003] The purpose of this invention is to provide a method for drilling embedded copper blocks in power boards, which can effectively avoid heat accumulation in the embedded copper blocks during the drilling process, thereby improving processing stability and drill bit life.

[0004] A method for drilling holes in embedded copper blocks on a power supply board includes the following steps: S1. Provide a board to be processed with embedded copper blocks; S2. Divide the copper block into a processing matrix consisting of several rows and several columns. The processing matrix includes multiple matrix units, and each matrix unit corresponds to a hole position. S3. Based on the processing matrix, plan the processing sequence of the drill bit, such that in the continuous processing sequence, the current hole position and the next hole position are separated by at least one matrix unit in the row direction and / or column direction, and the center distance between them is greater than a preset safety distance threshold. S4. Drill holes according to the planned processing sequence until all holes are processed.

[0005] In the above technical solution, by dividing the holes on the embedded copper block into matrix units, and in the continuous processing sequence, the current hole position is spaced apart from the next hole position by at least one matrix unit, so that the continuous drill positions are spatially spaced, avoiding the heat accumulation caused by the drill bit working continuously in the same area, providing sufficient cooling time for the drill bit and the copper block, effectively avoiding the phenomenon of copper chips being fused to the drill bit due to high temperature, thereby reducing the risk of tool breakage and improving processing stability and drill bit life.

[0006] Furthermore, in step S3, each hole position is pre-drilled, enlarged, and sized sequentially; wherein, pre-drilling uses a first drill bit with a diameter smaller than the target hole diameter, enlargement uses a second drill bit with a diameter between the first drill bit and the target hole diameter, and sizing uses a third drill bit with a diameter equal to the target hole diameter.

[0007] In the above technical solution, a three-step drilling process is adopted for the same hole position. First, a small-diameter drill bit is used to pre-drill to form a precise guide hole, which prevents the large drill bit from deflecting and breaking when directly drilling into the thick copper block. Then, an intermediate-diameter drill bit is used to enlarge the hole, and residual copper and burrs are removed in stages, which reduces the single cutting load. Finally, the hole wall is sized and smoothed with the target hole diameter, which effectively solves the problem of rough hole wall and delamination caused by complex interlayer structure, and ensures the hole diameter accuracy and hole wall smoothness.

[0008] Furthermore, the diameter of the first drill bit is 80% to 90% of the target hole diameter, and the diameter of the second drill bit is 90% to 98% of the target hole diameter.

[0009] In the above technical solution, the diameter of the drill bit for pre-drilling and reaming is limited to a specific percentage range of the target hole diameter, which ensures that the allowance removed in each process is reasonable and balanced. This avoids the pre-drilling diameter being too large and losing its guiding function or the cutting force being too large, and also prevents the reaming allowance from being too small and unable to effectively repair the defects in the previous process, thereby ensuring processing efficiency and quality.

[0010] Furthermore, in step S3, the drilling depth is divided into copper block region and non-copper medium region according to the stacked structure of the board to be processed, and the feed rate is set for the copper block region and non-copper medium region respectively.

[0011] In the above technical solution, the drilling depth is divided into copper block area and non-copper medium area according to the stacked structure of the board to be processed, and the processing parameters are set accordingly. This effectively adapts to the differences in cutting performance of different materials and eliminates the problems of hole wall delamination and copper nodules caused by single full drilling.

[0012] Furthermore, for non-copper medium areas, a first feed rate is used for drilling; for copper block areas, a second feed rate is used for drilling; wherein the second feed rate is 40% to 60% of the first feed rate.

[0013] In the above technical solution, the feed rate of the copper block area is controlled to 40% to 60% of that of the non-copper medium area. By significantly reducing the cutting speed in the copper layer, the instantaneous frictional heat between the drill bit and the copper material is significantly reduced, thus avoiding continuous long chips wrapping around the drill bit and copper chip welding.

[0014] Furthermore, for the copper block area, the depth of penetration for each drilling operation is less than the depth of retraction.

[0015] In the above technical solution, setting the depth of each drilling pass in the copper block area to be less than the depth of retraction can effectively break and remove copper chips, prevent copper chips from accumulating, squeezing, and generating heat through friction in the hole, and at the same time facilitate the penetration of coolant into the cutting area, further enhancing the chip removal and heat dissipation capabilities when drilling thick copper blocks, and ensuring the quality of hole wall processing.

[0016] Furthermore, the first drill bit, the second drill bit, and the third drill bit are all made of grained tungsten steel and are coated with a high-temperature resistant coating.

[0017] In the above technical solution, the drill bits for all three processes are made of grained tungsten steel and coated with a high-temperature resistant coating. This allows them to withstand the high temperature and pressure generated when drilling thick copper blocks, delaying drill bit wear and cutting edge breakage, ensuring dimensional consistency and drilling quality during long-term processing, and reducing the cost of frequent needle replacements.

[0018] Furthermore, during pre-drilling, the first drill bit uses a first rotational speed; during hole reaming, the second drill bit uses a second rotational speed greater than the first rotational speed; and during sizing, the third drill bit uses a third rotational speed between the first and second rotational speeds.

[0019] In the above technical solution, the low speed during pre-drilling ensures the rigidity and centering accuracy of the small-diameter drill bit, the high speed during hole enlargement improves the material removal efficiency and disperses cutting heat, and the medium speed during sizing takes into account both the finishing effect and the hole diameter stability, so that the final hole wall is smooth and the dimensions are accurate, providing a good foundation for the subsequent electroplating process.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: by dividing the holes on the embedded copper block into matrix units, and in the continuous processing sequence, the current hole position is spaced apart from the next hole position by at least one matrix unit, so that the continuous drill positions are spatially spaced, avoiding the heat accumulation caused by the drill bit working continuously in the same area, providing sufficient cooling time for the drill bit and the copper block, effectively avoiding the phenomenon of copper chips being fused to the drill bit due to high temperature, thereby reducing the risk of tool breakage and improving processing stability and drill bit life. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for drilling holes in a copper block on a power board, according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the borehole diameter in a step-by-step drilling method according to an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0025] Please refer to Figure 1 and Figure 2 In a preferred embodiment, the method for drilling holes in the embedded copper block of the power board according to the present invention includes the following steps: S1. Provide a board to be processed with embedded copper blocks; S2. Divide the copper block into a processing matrix consisting of several rows and columns. The processing matrix includes multiple matrix units, and each matrix unit corresponds to a hole position. S3. Based on the processing matrix, plan the processing sequence of the drill bit, so that in the continuous processing sequence, the current hole position and the next hole position are separated by at least one matrix unit in the row direction and / or column direction, and the center distance between them is greater than the preset safety distance threshold. S4. Drill holes according to the planned processing sequence until all holes are processed.

[0026] By dividing the holes on the embedded copper block into matrix units, and in a continuous processing sequence, the current hole position is spaced apart from the next hole position by at least one matrix unit, the continuous drill positions are spatially spaced, avoiding heat accumulation caused by the drill bit operating continuously in the same area. This provides sufficient cooling time for the drill bit and the copper block, effectively preventing copper chips from being welded to the drill bit due to high temperature, thereby reducing the risk of tool breakage and improving processing stability and drill bit life.

[0027] In step S3, each hole is pre-drilled, enlarged, and sized sequentially; wherein, pre-drilling uses a first drill bit with a diameter smaller than the target hole diameter, enlargement uses a second drill bit with a diameter between the first drill bit and the target hole diameter, and sizing uses a third drill bit with a diameter equal to the target hole diameter.

[0028] Specifically, taking a target hole diameter of 1.1mm as an example, the first drill bit can be a 0.9mm diameter drill bit, the second drill bit can be a 1.0mm diameter drill bit, and the third drill bit can be a 1.1mm diameter drill bit. This size ratio can take into account the needs of guidance, allowance distribution, and final finishing.

[0029] A three-step drilling process is used for the same hole position. First, a small-diameter drill bit is used to pre-drill a precise guide hole, which prevents the large drill bit from deflecting and breaking when drilling directly into the thick copper block. Then, an intermediate-diameter drill bit is used to enlarge the hole, removing residual copper and burrs in stages, reducing the single cutting load. Finally, the hole wall is sized and smoothed with the target hole diameter, which effectively solves the problem of rough hole wall and delamination caused by complex interlayer structure, ensuring hole diameter accuracy and hole wall smoothness.

[0030] In this embodiment, the diameter of the first drill bit is 80% to 90% of the target hole diameter, and the diameter of the second drill bit is 90% to 98% of the target hole diameter. By limiting the diameters of the pre-drilling and reaming drill bits to specific percentages of the target hole diameter, it ensures that the allowance removed in each process is reasonably balanced. This avoids the pre-drilling diameter being too large, resulting in loss of guiding function or excessive cutting force, and also prevents the reaming allowance from being too small, which would not be able to effectively repair defects in the previous process, thereby ensuring processing efficiency and quality.

[0031] Step S3 further includes dividing the drilling depth into copper block regions and non-copper medium regions according to the stacked structure of the board to be processed, and setting feed rates for the copper block regions and non-copper medium regions respectively. Dividing the drilling depth into copper block regions and non-copper medium regions according to the stacked structure of the board to be processed, and setting processing parameters accordingly, effectively adapts to the differences in cutting performance of different materials and eliminates the problems of hole wall delamination and copper nodules caused by single full drilling.

[0032] For non-copper medium areas, a first feed rate is used for drilling; for copper block areas, a second feed rate is used for drilling; wherein the second feed rate is 40% to 60% of the first feed rate.

[0033] For example, the depth of drilling through the entire hole can be divided into five continuous regions according to the layered structure: the surface non-copper medium region, the first embedded copper block region, the intermediate non-copper medium region, the second embedded copper block region, and the bottom non-copper medium region, with different cutting strategies employed in each region. For instance, in the pre-drilling process, the feed rate in the surface non-copper medium region can be 1 m / min, while after entering the first embedded copper block region, the feed rate immediately drops to 0.5 m / min, which conforms to the defined proportional range to achieve safe cutting.

[0034] By controlling the feed rate in the copper block region to 40%–60% of that in the non-copper medium region, and significantly reducing the cutting speed in the copper layer, the instantaneous frictional heat between the drill bit and the copper material is significantly reduced, thus avoiding continuous long chips wrapping around the drill bit and copper chip welding.

[0035] For areas with copper blocks, the depth of cut for each drilling pass should be less than the depth of retraction. Specifically, when drilling through embedded copper blocks, a G73 chip-breaking cycle can be used. For example, set the depth of cut for each pass to 0.15 mm and the depth of retraction to 0.1 mm to force the formation of small, short chips and quickly remove them.

[0036] By setting the depth of cut for each hole in the copper block area to be less than the depth of retraction, copper chips can be effectively broken off and discharged, preventing them from accumulating, squeezing, and generating heat through friction in the hole. At the same time, it facilitates the penetration of coolant into the cutting area, further enhancing the chip removal and heat dissipation capabilities when drilling thick copper blocks, and ensuring the quality of hole wall processing.

[0037] The first, second, and third drill bits are all made of grained tungsten steel and coated with a high-temperature resistant coating. Using grained tungsten steel with a high-temperature resistant coating for all three drill bits enables them to withstand the high temperature and pressure generated during drilling thick copper blocks, delaying drill bit wear and cutting edge breakage. This ensures dimensional consistency and drilling quality during long-term machining processes and reduces the cost of frequent drill bit changes.

[0038] As a preferred option, the first drill bit can be made of grained tungsten steel and coated with TiAlN, while the second and third drill bits can be made of ultrafine grained tungsten steel and also coated with TiAlN, to meet the different load requirements of the pre-drilling, reaming and sizing processes respectively.

[0039] In this embodiment, the first drill bit uses a first rotational speed during pre-drilling, the second drill bit uses a second rotational speed greater than the first rotational speed during hole reaming, and the third drill bit uses a third rotational speed between the first and second rotational speeds during sizing.

[0040] For example, the first rotation speed can be set to 60,000 rpm, the second rotation speed to 70,000 rpm, and the third rotation speed slightly reduced to 67,500 rpm to obtain more stable finishing quality. Use thresholds are set for the first, second, and third drill bits, and they are forcibly replaced after reaching the corresponding thresholds. By precisely controlling the drill bit lifespan, the risk of decreased machining accuracy and needle breakage due to excessive drill bit wear is avoided. In specific implementation, the first drill bit can be forcibly replaced after drilling 100 holes, the second drill bit after drilling 200 holes, and the third drill bit after drilling 100 to 150 holes, to ensure that the drill bits are in optimal cutting condition at each step of the process.

[0041] As can be seen from the above technical solutions, the low rotation speed during pre-drilling ensures the rigidity and centering accuracy of the small-diameter drill bit, the high rotation speed during hole enlargement improves the material removal efficiency and disperses cutting heat, and the medium rotation speed during sizing takes into account both the finishing effect and the hole diameter stability, so that the final hole wall is smooth and the dimensions are accurate, providing a good foundation for the subsequent electroplating process.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for drilling holes in embedded copper blocks on a power supply board, characterized in that, Includes the following steps: S1. Provide a board to be processed with embedded copper blocks; S2. Divide the copper block into a processing matrix consisting of several rows and several columns. The processing matrix includes multiple matrix units, and each matrix unit corresponds to a hole position. S3. Based on the processing matrix, plan the processing sequence of the drill bit, such that in the continuous processing sequence, the current hole position and the next hole position are separated by at least one matrix unit in the row direction and / or column direction, and the center distance between them is greater than a preset safety distance threshold. S4. Drill holes according to the planned processing sequence until all holes are processed.

2. The method for drilling holes in embedded copper blocks on a power board according to claim 1, characterized in that, In step S3, each hole is pre-drilled, enlarged, and sized sequentially; wherein, pre-drilling uses a first drill bit with a diameter smaller than the target hole diameter, enlargement uses a second drill bit with a diameter between the first drill bit and the target hole diameter, and sizing uses a third drill bit with a diameter equal to the target hole diameter.

3. The method for drilling holes in embedded copper blocks on a power board according to claim 2, characterized in that, The diameter of the first drill bit is 80% to 90% of the target hole diameter, and the diameter of the second drill bit is 90% to 98% of the target hole diameter.

4. The method for drilling holes in the embedded copper block of a power board according to claim 2 or 3, characterized in that, In step S3, the drilling depth is divided into copper block region and non-copper medium region according to the stacked structure of the board to be processed, and the feed rate is set for the copper block region and non-copper medium region respectively.

5. The method for drilling holes in embedded copper blocks on a power board according to claim 4, characterized in that, For non-copper dielectric areas, drilling is performed using the first feed rate; For the copper block area, the second feed rate is used for drilling; The second feed rate is 40% to 60% of the first feed rate.

6. The method for drilling holes in embedded copper blocks on a power board according to claim 5, characterized in that, For the copper block area, the depth of penetration for each drilling operation is less than the depth of retraction.

7. The method for drilling holes in embedded copper blocks on a power board according to claim 2, characterized in that, The first drill bit, the second drill bit, and the third drill bit are all made of grained tungsten steel and are coated with a high-temperature resistant coating.

8. The method for drilling holes in embedded copper blocks on a power board according to claim 2, characterized in that, During pre-drilling, the first drill bit uses a first rotational speed; during hole reaming, the second drill bit uses a second rotational speed greater than the first rotational speed; and during sizing, the third drill bit uses a third rotational speed between the first and second rotational speeds.

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