A method for milling and fishing stepped gold finger PCB board and a PCB board

Abstract

The application discloses a kind of ladder gold finger PCB board milling fishing method and PCB board, method includes the following steps: step one, set through hole, one end of the through hole is connected gold finger layer by inner layer conductive wire, the other end is connected PCB board surface, blind slot area is arranged between the gold finger layer and PCB board surface layer;Step two, host control fishing needle is fished in blind slot area for the first time and the first preset depth is down;Step three, return fishing needle until fishing needle and first conductive layer are disconnected;Step four, when fishing needle is fished in first measuring point and contacts gold finger layer, form conductive loop, host records the depth value H1 when this position is on, then host controls fishing needle and disconnects gold finger layer;The depth value of gold finger layer of other measuring points in blind slot area is measured in the same way and is automatically recorded;Step five, according to the depth value of gold finger layer of each measuring point obtained in step four, control fishing needle continues to fish on the basis of the depth value of gold finger layer of each measuring point, finally form inner layer ladder gold finger.

Description

TECHNICAL FIELD

[0001] The application relates to the field of PCB manufacturing, and in particular to a stepped gold finger PCB milling method and a PCB. BACKGROUND

[0002] Under the background of rapid development of the communication industry, the performance consistency of PCBs is increasingly required, and with the market's continuous demand for small size of electronic products, in order to reduce the thickness of the products, part of the electronic devices is inserted into the circuit board, and part of the area of the circuit board is recessed into the board to form a stepped area, so the multi-layer printed circuit board with the stepped groove becomes a stepped circuit board. The stepped circuit board not only maximally utilizes the advantages of the space in the circuit board, but also has the advantage that other components can be avoided when welding components. The existing stepped gold finger product is mainly applied to high-end servers and speed cards, and the overall market demand is continuously rising. Because the stepped gold finger is affected by the difference in the thickness of the PCB after being pressed, the stepped gold finger has ups and downs in the PCB, and the copper thickness of the inner layer gold finger is generally only about 1 mil-2 mil. The existing milling method can only mill at a fixed depth or residual thickness, because the thickness of the stepped gold finger area is generally different by 2-3 mil, and the thicker the thickness of the board is, the greater the difference will be. Therefore, the existing milling method cannot mill the entire gold finger area at one time. At present, one of the process methods is a one-time pressing and taping method, which involves processes such as milling PP, taping high-temperature tape and the like, but there is a residual glue problem. The other method is a two-time pressing method, which has the problem of needing to process two sub-boards in the pressing method, and the process is long and the processing cost is high, so the competitiveness is low. SUMMARY

[0003] The application aims to overcome the deficiencies in the prior art and provide a stepped gold finger PCB milling method and a PCB.

[0004] To solve the problems in the prior art, the application discloses a stepped gold finger PCB milling method, which comprises the following steps:

[0005] Step one, a through hole is arranged, one end of the through hole is connected to a gold finger layer through an inner layer conductive wire, and the other end is connected to the surface of a PCB, and a blind groove area is arranged between the gold finger layer and the surface layer of the PCB;

[0006] Step two, a first conductive layer of the PCB is connected to a host computer, and the host computer controls a fishing needle to be fished down in the blind groove area at a first preset depth, the first preset depth is located in the first conductive layer, and the first preset depth is located above the gold finger layer;

[0007] Step three, the fishing needle is withdrawn until the fishing needle is disconnected from the first conductive layer;

[0008] Step four, connect the PCB surface layer to the host, set the measuring point spacing of each gold finger layer in the blind slot area; when the probe contacts the gold finger layer and forms a conductive loop at the first measuring point, the host records the depth value H1 at this position, then the host controls the probe to separate from the gold finger layer; move the probe to the second measuring point, when the probe contacts the gold finger layer and forms a conductive loop, the host records the depth value H2 at this position again; in the same way, the depth values of the gold finger layers at other measuring points in the blind slot area are measured and recorded automatically.

[0009] Step five, according to the depth values of the gold finger layers at each measuring point obtained in step four, control the probe to continue fishing on the basis of the depth values of the gold finger layers at each measuring point, and finally form the inner layer stepped gold finger.

[0010] Further, the first preset depth in step two is less than 5 mil from the gold finger layer.

[0011] Further, the spacing of each gold finger layer measuring point in the blind slot area in step four is 1 mm.

[0012] Further, in step five, the probe continues to fish on the basis of the depth values of the gold finger layers at each measuring point by 0.1 mil.

[0013] Further, the surface of the PCB in step one is designed as a full-conducting copper surface.

[0014] Correspondingly, a PCB is provided with an inner layer stepped gold finger, which is prepared by the above-mentioned stepped gold finger PCB milling and fishing method.

[0015] The present application has the following beneficial effects:

[0016] The present application adopts a one-time pressing and fishing method to fish out the stepped gold finger, cancels the original pressing process which requires high-temperature adhesive tape to be pasted on the inner layer substrate of the PCB first, can improve the residual adhesive problem of the one-time pressing and pasting adhesive tape method, can be more competitive than the two-time pressing, simplifies the processing procedure of the stepped gold finger, and shortens the processing period and processing cost of the PCB manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the present application;

[0018] Figure 2 is a structural schematic diagram of the present application;

[0019] Figure 3 is a structural schematic diagram of the present application;

[0020] Figure 4 is a structural schematic diagram of the present application;

[0021] Figure 5 Structure diagram of the present application;

[0022] Figure 6 Structure diagram of the present application;

[0023] Figure 7 Structure diagram of the present application.

[0024] Reference signs:

[0025] 1, inner layer stepped gold finger; 2, PCB surface; 3, through hole; 4, inner layer conductive line; 5, first preset depth; 6, fishing needle; 7, conductive line; 8, second measuring point; 9, first measuring point; 10, walking path of fishing needle; 11, second blind fishing position; 12, third measuring point; 13, blind slot area. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0027] The production process flow of the PCB board is as follows: first inner layer pattern - pressing - drilling - electroplating - milling fishing - outer layer pattern - ink - surface treatment - forming;

[0028] The processes in the above flow are the same as the existing PCB board production process flow except for the milling fishing, wherein the milling fishing is characterized in that it comprises the following steps,

[0029] 1. A stepped gold finger PCB board, the first step is to design the inner layer of the gold finger to pull the conductive line 7, which needs to pass through the through hole 3 in the PCB board to make the internal gold finger layer of the PCB board and the surface of the PCB board conductive; the surface of the PCB board is designed as a copper surface, and the blind slot area 13 between the surface layer of the PCB board and the stepped gold finger is designed to be separated from the copper in advance, as shown in the schematic diagram of Figure 1 and Figure 2 ;

[0030] 2. The second step is to connect the first conductive layer of the PCB board to the host machine in the processing program stage, and the fishing needle 6 is used to perform the first blind fishing of the first preset depth 5 of the PCB board, the fishing needle 6 is fished into the first conductive layer, and the depth value of the first blind fishing is set to be about 5 mil smaller than the gold finger layer. The schematic diagram is shown in Figure 3 ;

[0031] 3. After the first blind fishing operation is completed, the fishing needle is withdrawn until the fishing needle is disconnected from the first conductive layer

[0032] 4. Fourth step, connect the PCB surface layer to the main machine, move the needle 6 to detect the depth value of the gold finger layer, the specific method is as follows: in the program for the gold finger area, set the gold finger layer area measurement point at an interval of about 1 mm in advance (the interval of the gold finger layer measurement point can be increased or decreased according to the thickness deviation of the workboard), and the needle is always moved to contact the gold finger layer during operation Figure 4 The first measurement point 9 is marked, and the main machine forms a conductive loop at this time, and the machine records the depth value H1 when the position is turned on. Then the machine controls the needle 6 to separate from the gold finger layer, and the needle is separated from the conductive layer by about 5 mil (this value is set smaller, which can reduce the rising and falling time of the needle, and this value can be adjusted according to the thickness error of the board). Then the needle 6 quickly moves to the other set measurement point corresponding to the gold finger layer which needs to be blindly fished, as shown in the accompanying drawings Figure 4 The second measurement point 8 is marked, and the needle is always moved to contact the gold finger layer at this time to form a conductive loop, and the machine records the depth value H2 when the position is turned on. The depth values of other gold finger layers in the area are measured in the same way and automatically recorded, as shown in the accompanying drawings Figure 4 And the accompanying drawings Figure 5 .

[0033] 5. The fifth step is to move the needle 6, so that the needle 6 moves from the first measurement point 9 to contact the gold finger layer, and the machine forms a conductive loop at this time. At this time, the machine is set to about 0.1 mil (the program sets the walking path 10 of the needle as shown in the accompanying drawings Figure 7 ) according to the program, and walks to the second measurement point 8 position. When the depth value between the first measurement point 9 and the second measurement point 8 is in a linear relationship with the depth value detected in step four for the blind fishing area 13, the compensation depth is fished out. When the depth value from the second measurement point 8 to the third measurement point 12 is in a linear relationship with the depth value detected in step four, the compensation depth is fished out. Other areas are the same, and this blind fishing method can be used to compensate for the fishing of corresponding gold finger areas in real time according to the depth distribution of the gold finger layer in each area, and the second blind fishing is completed, as shown in the accompanying drawings Figure 6 And the accompanying drawings Figure 7 .

[0034] 6. After completing the second blind fishing, the needle is retracted until the needle is disconnected from the second conductive layer

[0035] It is to be understood that the terminology used herein such as first and second, and the like, is only intended to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, in the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application. In the drawings of the present application, the filling patterns are only for distinguishing layers, and do not have any other limitations.

[0036] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A method for milling and drilling stepped gold finger PCB boards, characterized in that, Includes the following steps: Step 1: Set a through hole (3). One end of the through hole (3) is connected to the gold finger layer through the inner conductive line (4), and the other end is connected to the PCB board surface. A blind slot area (13) is set between the gold finger layer and the PCB board surface layer. Step 2: Connect the first conductive layer of the PCB board to the host. The host controls the retrieval needle (6) to retrieve the first preset depth (5) in the blind slot area (13). The first preset depth (5) is located inside the first conductive layer and above the gold finger layer. Step 3: Retract the retrieval needle until it is disconnected from the first conductive layer; Step 4: Connect the PCB surface layer to the host computer and set the spacing between the measurement points of each gold finger layer in the blind slot area (13); when the retrieval needle (6) touches the gold finger layer at the first measurement point (9), a conductive circuit is formed. The host computer records the depth value H1 when the circuit is connected at this position. Then the host computer controls the retrieval needle (6) to detach from the gold finger layer; move the retrieval needle (6) to the second measurement point (8) to retrieve the circuit. When the retrieval needle (6) touches the gold finger layer and forms a conductive circuit, the host computer records the depth value H2 when the circuit is connected at this position again; measure the depth value of the gold finger layer at other measurement points in the blind slot area (13) in the same way and record it automatically. Step 5: Based on the gold finger layer depth values ​​of each measuring point obtained in Step 4, control the retrieval needle (6) to continue retrieval based on the gold finger layer depth values ​​of each measuring point, and finally form the inner layer stepped gold finger (1). In step two, the first preset depth (5) is less than 5 mil from the gold finger layer; The spacing between the measuring points of each gold finger layer in the blind groove area (13) in step four is 1 mm; In step five, the retrieval needle (6) continues to retrieve 0.1 mil further down based on the depth value of the gold finger layer at each measuring point; In step one, the PCB board surface is designed with fully conductive copper.

Images