PCB structure for solving offset of back-drilling and copper-plated through hole

Abstract

The utility model discloses a kind of PCB board structure for solving back drilling and copper-plated through-hole offset, including PCB board ontology, three target holes of L type distribution are arranged on the PCB board ontology, it is characterized in that, two long plate edges of the PCB board ontology are respectively provided with a row of back drilling positioning through-hole group, which is processed with three target holes as drilling rig positioning reference point.This utility model effectively solves the problem of back drilling and copper-plated through-hole offset in the existing back drilling processing technology, which affects product quality.

Description

Technical Field

[0001] This utility model relates to the field of PCB manufacturing and processing, specifically to a PCB board structure that solves the misalignment between back-drilled holes and copper-plated through holes. Background Technology

[0002] In today's highly developed electronics and information industry, printed circuit boards (PCBs) are an indispensable key component in electronic devices, and their performance and quality directly affect the performance and reliability of the entire electronic product. Especially in the field of PCB manufacturing for high-speed digital and radio frequency signal transmission, with the continuous increase in signal transmission frequency and the rapid growth of data transmission rates, the requirements for PCB signal integrity are becoming increasingly stringent. During signal transmission on the PCB, even the slightest interference or loss can lead to signal distortion and increased bit error rate, thereby affecting the stability and performance of the entire electronic system.

[0003] Back-drilling, a key technology for improving PCB signal integrity, plays a crucial role in the manufacturing of circuit boards for high-speed digital and radio frequency signal transmission. The core principle of back-drilling lies in precisely controlling the depth and accuracy of the drilled holes to remove excess and unnecessary copper pillars from the PCB. These excess copper pillars can cause reflections, attenuation, and crosstalk during signal transmission, severely impacting signal quality. Back-drilling effectively reduces these problems, significantly improving signal transmission quality and ensuring stable and efficient signal transmission on the PCB.

[0004] In existing back-drilling machining techniques, three target holes arranged in an L-shape are commonly used as positioning references, such as... Figure 1 As shown. The specific operation process is as follows: First, using an optical recognition system or mechanical positioning device, the three pre-designed L-shaped target holes on the PCB board are precisely aligned with the coordinate system of the drilling machine. Then, based on the design thickness of the PCB board and related design parameters, the back drilling depth is determined through a specific calculation method. Finally, based on the calculated back drilling depth, the drilling machine performs back drilling on the PCB board, thus completing the entire back drilling process.

[0005] However, because the three L-shaped target holes undergo copper plating and other processes during PCB manufacturing, the copper layer formed on the hole walls has a certain thickness. When these target holes with copper layers are used as positioning holes for back drilling, the back drill hole and the copper-plated through hole are prone to misalignment due to the influence of the copper layer, affecting product quality. Utility Model Content

[0006] The purpose of this utility model is to provide a PCB board structure that solves the problem of misalignment between back-drilled holes and copper-plated through holes in existing back-drilling processing technology, thereby addressing the issue of misalignment between back-drilled holes and copper-plated through holes affecting product quality.

[0007] The technical solution of this utility model is as follows:

[0008] A PCB board structure for solving the misalignment between back-drilled holes and copper-plated through holes includes a PCB board body, on which three target holes are arranged in an L-shape, and on each of the two long sides of the PCB board body, a row of back-drilled positioning through holes machined with the three target holes as the drilling machine positioning reference is provided.

[0009] As a preferred embodiment of this utility model, the inner wall of the target hole is plated with a copper layer.

[0010] As a preferred embodiment of the present invention, one of the target holes is located in the middle of one of the short sides of the PCB board body, and the other two target holes are located in the middle of the other short side of the PCB board body.

[0011] As a preferred embodiment of this utility model, the back drill positioning through hole group includes at least two vertically uniformly arranged back drill positioning through holes.

[0012] As a preferred embodiment of this utility model, the back drill positioning through hole group includes three vertically uniformly arranged back drill positioning through holes.

[0013] As a preferred embodiment of this utility model, the back drill positioning through hole group includes two vertically uniformly arranged back drill positioning through holes.

[0014] As a preferred embodiment of this utility model, the back drill positioning through hole group includes four vertically uniformly arranged back drill positioning through holes.

[0015] As a preferred embodiment of this utility model, the diameter of the back drill positioning through hole is 3mm-3.5mm.

[0016] As a preferred embodiment of this utility model, the diameter of the back drill positioning through hole is 3.175mm.

[0017] In a preferred embodiment of this utility model, the diameter of the target hole is the same as the diameter of the back drill positioning through hole.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. This utility model sets a row of back-drill positioning through holes on the two long sides of the PCB board body, with three target holes as the drilling positioning reference. The holes are not copper-plated, so there is no copper layer affecting the back-drilling. During the back-drilling process, the PCB board body is repositioned in conjunction with the back-drill positioning through holes, which can achieve more accurate back-drilling positioning. This effectively avoids the positioning offset problem caused by the copper layer of the target holes, ensuring that the back-drilling holes can accurately reach the position and depth required by the design, and improving the electrical performance and signal integrity of the product.

[0020] 2. Based on the original three target holes for preliminary positioning, this utility model adds a back-drill positioning through-hole group, which has a certain compatibility with the existing PCB manufacturing process and back-drilling processing technology. It does not require large-scale modification of existing production equipment and processes, thus reducing the technology upgrade cost for enterprises.

[0021] 3. Since only the two long sides of the PCB board body are added with back-drilled positioning through holes, the structure is relatively simple, will not have an adverse effect on other performance and functions of the PCB board, and is easy to implement, and will not bring too many technical difficulties to the production of the PCB board. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural diagram of a traditional PCB board.

[0024] Figure 2 This is a schematic diagram of a PCB board structure for solving the misalignment between back-drilled holes and copper-plated through holes in one embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of a PCB board structure for solving the misalignment between back-drilled holes and copper-plated through holes in another embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of a PCB board structure for solving the misalignment between back-drilled holes and copper-plated through holes in another embodiment of the present invention.

[0027] In the diagram,

[0028] 1. PCB board body; 2. Target hole; 3. Back-drilled positioning through hole. Detailed Implementation

[0029] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also declared that the embodiments described below are only for explaining this utility model and are not intended to limit this utility model.

[0030] It should be noted that the terms "installation," "setting," "connection," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Indications of orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used in the application's product, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0031] In existing back-drilling techniques, three L-shaped target holes 2 are commonly used as positioning references, such as... Figure 1 The traditional PCB structure shown includes a PCB body 1 with three L-shaped target holes 2, the inner walls of which are plated with copper. The specific operation process is as follows: First, using an optical recognition system or mechanical positioning device, the three pre-designed L-shaped target holes 2 on the PCB body 1 are precisely aligned with the coordinate system of the drilling machine. Then, based on the design thickness of the PCB body 1 and related design parameters, the back-drilling depth is determined using a specific calculation method. Finally, based on the calculated back-drilling depth, the drilling machine performs back-drilling on the PCB body 1, thus completing the entire back-drilling process. However, because the three L-shaped target holes 2 undergo copper plating and other processes during PCB manufacturing, the copper layer formed on the hole wall surface has a certain thickness. When these copper-plated target holes 2 are used as positioning holes for back-drilling, misalignment can easily occur between the back-drilled holes and the copper-plated through-holes due to the influence of the copper layer, affecting product quality.

[0032] To resolve the above issues, please refer to Figure 2This utility model provides a PCB board structure that solves the misalignment between back-drilled holes and copper-plated through-holes. The structure includes a PCB board body 1 with three L-shaped target holes 2. One target hole 2 is located in the middle of one of the shorter sides of the PCB board body 1, and the other two target holes 2 are located in the middle of the other shorter side. The inner walls of the target holes 2 are plated with copper. Two longer sides of the PCB board body 1 are each provided with a row of back-drilled positioning through-holes machined using the three target holes 2 as drilling rig positioning references. Each back-drilled positioning through-hole group includes at least two vertically evenly arranged back-drilled positioning through-holes 3. The holes 3 are not copper-plated, meaning they have no copper layer. The back-drilled positioning through-holes 3 are used for positioning during back-drilling of the PCB board body. The processing steps for the back-drilled positioning through-hole 3 and the back-drilled hole are as follows: First, the PCB board body 1 is positioned on the drilling machine table through three L-shaped target holes 2. Then, a row of back-drilled positioning through-holes is drilled on the two long sides of the PCB board body 1 by the drilling machine to complete the processing. Finally, positioning pins corresponding to the positions of the back-drilled positioning through-hole 3 are installed on the drilling machine table. With the back-drilled positioning through-hole 3, the PCB board body 1 is repositioned on the drilling machine table. This allows for precise back-drilling of the PCB board according to the design, effectively solving the problem of misalignment between the back-drilled hole and the copper-plated through-hole, and improving product quality.

[0033] Please see Figure 2 In one embodiment, the back-drilling positioning through-hole group includes three vertically evenly arranged back-drilling positioning through-holes 3, meaning that the PCB board body has six back-drilling positioning through-holes 3. The distribution of the six back-drilling positioning through-holes 3 can better constrain the position of the PCB board body on the drilling table, reduce shaking, and further improve positioning accuracy. Of course, in other embodiments, the back-drilling positioning through-hole group may also include two vertically evenly arranged back-drilling positioning through-holes 3, such as... Figure 3 As shown, or including four or more vertically evenly arranged back-drill positioning through holes 3, such as Figure 4 As shown, this utility model does not limit the number of back drill positioning through holes 3 in the back drill positioning through hole group, and those skilled in the art can adjust it according to actual production needs.

[0034] In one embodiment, the diameter of the back-drilled positioning through-hole 3 is 3mm-3.5mm. A diameter of 3mm-3.5mm ensures uniform force on the drill bit during drilling (high matching degree between drill bit diameter and hole diameter), reducing the probability of drilling deviation and hole bursting. A diameter of 3mm-3.5mm results in a moderate hole wall thickness at the PCB board edge, avoiding insufficient positioning strength due to an excessively small hole diameter, while also preventing the hole diameter from weakening the board edge structure due to an excessively large hole diameter.

[0035] Preferably, the diameter of the back-drill positioning through-hole 3 is 3.175mm, and the diameter of the positioning pin on the drilling machine table that mates with the back-drill positioning through-hole 3 is 3.15mm. This slight dimensional difference creates a reasonable fit clearance, allowing the positioning pin to easily insert into the back-drill positioning through-hole 3 while ensuring sufficient contact area and friction, achieving a stable positioning effect and ensuring the consistency of the PCB board position during each processing cycle, thereby improving the quality and accuracy of back-drilling. 3.175mm is a common standard drill bit specification (e.g., 1 / 8 inch), widely used in PCB processing equipment. Using this hole diameter allows the direct use of general-purpose drill bits, reducing the need for custom tools and lowering tool procurement costs and inventory pressure. Furthermore, most drilling machines' positioning pins or fixtures are designed to be compatible with 3.175mm hole diameters, achieving precise positioning through interference fits or clearance fits. Additionally, standardized hole diameters reduce PCB edge waste caused by non-standard hole diameters.

[0036] In one embodiment, the diameter of the target hole 2 is the same as the diameter of the back-drilled positioning through-hole 3. During PCB manufacturing, using drill bits of the same diameter to machine the target hole 2 and the back-drilled positioning through-hole 3 simplifies the machining process and equipment configuration. Machinists do not need to frequently change drill bits of different diameters, reducing tool change time and operational complexity, and improving production efficiency. Furthermore, uniform machining dimensions also help improve machining consistency and stability, reducing machining quality problems caused by drill bit changes or dimensional differences.

[0037] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0038] The present utility model patent has been described above with reference to the accompanying drawings. Obviously, the implementation of the present utility model patent is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present utility model patent, or the direct application of the inventive concept and technical solution of the present utility model patent to other occasions without modification, are all within the protection scope of the present utility model.

Claims

1. A PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through-holes, comprising a PCB board body, wherein the PCB board body has three target holes arranged in an L-shape, characterized in that, The two long sides of the PCB board body are each provided with a row of back-drill positioning through holes, which are machined with the three target holes as the drilling positioning reference.

2. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 1, characterized in that, The inner wall of the target hole is plated with a copper layer.

3. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 1, characterized in that, One of the target holes is located in the middle of one of the short sides of the PCB board body, and the other two target holes are located in the middle of the other short side of the PCB board body.

4. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 1, characterized in that, The back-drilled positioning through-hole group includes at least two vertically uniformly arranged back-drilled positioning through-holes.

5. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 4, characterized in that, The back-drill positioning through-hole group includes three vertically uniformly arranged back-drill positioning through-holes.

6. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 4, characterized in that, The back-drill positioning through-hole group includes two vertically uniformly arranged back-drill positioning through-holes.

7. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 4, characterized in that, The back-drill positioning through-hole group includes four vertically evenly arranged back-drill positioning through-holes.

8. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 4, characterized in that, The diameter of the back-drilled positioning through hole is 3mm-3.5mm.

9. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 8, characterized in that, The diameter of the back-drilled positioning through hole is 3.175 mm.

10. The PCB board structure for resolving the misalignment between back-drilled holes and copper-plated through holes according to claim 4, characterized in that, The diameter of the target hole is the same as the diameter of the back drill positioning through hole.

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