Method for producing and manufacturing counterbore of PCB (Printed Circuit Board)

Abstract

The invention belongs to the field of PCB (printed circuit board) processing, and particularly relates to a method for producing and manufacturing a counterbore of a PCB. The method comprises the following steps: S1, drilling: drilling a counterbore in the PCB by using a counterbore drill; s2, burr polishing is carried out, specifically, burr polishing is carried out on a countersunk hole of the PCB, and countersunk burrs are removed; s3, drying the film, and forming a temporary protection image on the PCB through a film pasting-exposure-development process; s4, electroplating is conducted, specifically, the counterbore of the PCB is electroplated, and the electroplating process comprises PTH copper deposition, primary copper electroplating and secondary copper electroplating; s5, etching: etching the PCB, and removing the excess copper layer of the counterbore through chemical etching; s6, removing the film, removing the dry film remained after etching, and exposing the copper circuit; by adopting the process method, the production process, the production control and the quality control of the counterbore of the PCB can have a unified operation mode method and a control method, the production and quality problems can be effectively controlled, and the production quality of the counterbore is improved.

Description

Technical Field

[0001] This invention relates to the field of PCB board processing, specifically a method for producing countersunk holes in PCB boards. Background Technology

[0002] At present, all electronic PCB boards are developing and being laid out in a high-precision direction. Making full use of space and making products thin, light and small have become the research and development direction. How to fix the various components on the PCB board with screws without wasting space has become a problem that must be solved. The design of countersunk holes on PCB boards provides a solution for this design.

[0003] However, in the current technology, there is no unified production operation method for countersunk hole products produced by various PCB manufacturers. Furthermore, countersunk holes with different diameters and design requirements may encounter problems during actual production, such as copper contamination inside the hole, no copper inside the hole, burrs, copper chips or slag, copper blistering, small hole size, and insufficient hole depth. These issues can lead to problems such as loose screws and component floating during subsequent PCBA assembly and DT assembly. Therefore, a countersunk hole production method for PCB boards is proposed to address the above problems. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology and solve at least one of the technical problems mentioned in the background art, the present invention proposes a method for manufacturing countersunk holes in PCB boards.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a method for manufacturing countersunk holes in a PCB board, comprising the following steps;

[0006] S1: Drilling, using a countersunk drill to drill countersunk holes on the PCB board;

[0007] S2: Blinder polishing, blister polishing of countersunk holes on PCB boards to remove countersunk blister;

[0008] S3: Dry film, which forms a temporary protective image on the PCB board through the process of film application, exposure and development;

[0009] S4: Electroplating, electroplating of countersunk holes on PCB boards. The electroplating process includes PTH copper plating, electroplating of copper plate one and electroplating of copper plate two.

[0010] S5: Etching, etching the PCB board, removing excess copper layer from the countersunk holes through chemical etching;

[0011] S6: Stripping the film, removing the dry film remaining after etching to expose the copper traces;

[0012] S7: Solder resist screen printing, which involves a process of ink application, pre-baking, film exposure, development, and curing to cover the board surface with solder resist ink to protect the circuitry.

[0013] Preferably, in S2, if the upper and lower diameters of the countersunk hole require copper / tin / gold plating, then after polishing and burring, it is sent to sandblasting and then to a copper plate; if the upper and lower diameters of the countersunk hole do not require copper / tin / gold plating, after the countersunk hole is produced, it is sent to the sandblasting process for burring and polishing and then to the dry film; in the above sandblasting process, the surface of the countersunk hole should be facing downwards for sandblasting.

[0014] Preferably, in S1, the countersunk drill is a four-flute countersunk drill rod that is 0.2 mm larger than the diameter of the countersunk hole.

[0015] Preferably, in S1, the stacking plates are operated at 1PNL / stack or 1SET / stack during drilling.

[0016] Preferably, a foolproof PAD is designed at the countersunk hole position that is 3 mil smaller than the hole diameter on one side. During the drilling process, the foolproof PAD will be eliminated as the hole is drilled.

[0017] Preferably, before the film is exposed, the solder mask blocking points and the exposed film for the surface without countersunk holes are designed with the diameter of the through holes; the surface with countersunk holes are designed according to the diameter of the countersunk holes, so as to prevent ink from seeping into the holes.

[0018] Preferably, in S5, after etching, a random inspection is conducted to check whether the anti-foolproof PAD around the countersunk hole has not been removed. If not, the current continues normally; if it is, rework is required.

[0019] Preferably, the first piece produced by countersunk hole machining undergoes quality inspection and confirmation. The depth is confirmed using a depth gauge or microscope, and the hole diameter is confirmed using CCD or three-dimensional measurement. Only after passing the inspection can mass production begin.

[0020] Preferably, if both the upper and lower diameters of the countersunk hole require copper / tin / gold plating, the first piece should be inspected for bubbling issues in the upper and lower diameters after solder resist sandblasting and PTH copper plating to prevent batch copper plating failure or poor bubbling. If the upper diameter of the countersunk hole does not require copper / tin / gold plating, but the lower diameter does, then the countersunk hole should be drilled after electroplating two copper and tin and before etching to prevent burrs and copper wires / dross at the connection between the upper and lower diameters. If neither the upper nor lower diameter of the countersunk hole requires copper / tin / gold plating, copper plating problems should be avoided during the production of electroplating two copper.

[0021] The advantages of this invention are:

[0022] 1. The present invention adopts the above process method, which can make the production process, production control and quality control of countersunk holes of PCB board unified with the operation method and control method, which can effectively control production and quality problems and improve the production quality of countersunk holes.

[0023] 2. By adding a sandblasting process after the countersunk hole production, this invention can ensure that the copper foil blistering and burr problems of PTH holes and PTH+NPTH countersunk holes are reduced during electroplating, thus ensuring production quality and improving electrical performance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the method of the present invention.

[0026] In the picture: Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Specific implementation examples are given below.

[0029] Please see Figure 1 As shown, a method for manufacturing countersunk holes on a PCB board includes the following steps;

[0030] S1: Drilling, using a countersunk drill to drill countersunk holes on the PCB board;

[0031] S2: Blinder polishing, blister polishing of countersunk holes on PCB boards to remove countersunk blister;

[0032] S3: Dry film, which forms a temporary protective image on the PCB board through the process of film application, exposure and development;

[0033] S4: Electroplating, electroplating of countersunk holes on PCB boards. The electroplating process includes PTH copper plating, electroplating of copper plate one and electroplating of copper plate two.

[0034] S5: Etching, etching the PCB board, removing excess copper layer from the countersunk holes through chemical etching;

[0035] S6: Stripping the film, removing the dry film remaining after etching to expose the copper traces;

[0036] S7: Solder resist screen printing, which involves a process of ink application, pre-baking, film exposure, development, and curing to cover the board surface with solder resist ink to protect the circuitry.

[0037] Furthermore, in S2, if the upper and lower diameters of the countersunk hole require copper / tin / gold plating, then after polishing and burring, it is sent to sandblasting and then to a copper plate; if the upper and lower diameters of the countersunk hole do not require copper / tin / gold plating, after the countersunk hole is produced, it is sent to the sandblasting process for burring and polishing and then to the dry film; in the above sandblasting process, the surface of the countersunk hole must be facing down for sandblasting.

[0038] Furthermore, in S1, a four-flute countersunk drill rod with a diameter 0.2 mm larger than that of the countersunk hole is selected.

[0039] Furthermore, in S1, during drilling, the stacked plates are operated at 1PNL / stack or 1SET / stack.

[0040] Furthermore, a foolproof pad 3 mil smaller than the diameter of the hole on each side is designed at the countersunk hole position. During the drilling process, the foolproof pad will be eliminated along with the drilling.

[0041] Furthermore, before film exposure, the solder resist blocking points and exposure film for surfaces without countersunk holes are designed with the aperture size of the through holes; for surfaces with countersunk holes, the design is based on the aperture size of the countersunk holes to prevent ink from seeping into the holes; during ink application, solder resist blocking points are set to block the countersunk holes, preventing ink from entering the holes and affecting the conductivity of the holes or subsequent assembly processes; it can also be used to control the copper layer etching range around the countersunk holes to ensure the dimensional accuracy and electrical performance of the countersunk holes.

[0042] Furthermore, in S5, after etching, a random inspection is conducted to check whether the anti-foolproof PAD around the countersunk hole has not been removed. If not, the flow continues normally; if it has, rework is required. During processing, the presence of unremoved anti-foolproof PAD indicates that the countersunk hole is drilled off-center or the hole diameter is too small. Rework refers to the operation of repairing semi-finished / finished boards with quality defects (such as poor appearance or substandard performance) during the production process and making them conform to the standards through specific processes.

[0043] Furthermore, the first piece produced by countersunk hole machining undergoes quality inspection and confirmation. The depth is confirmed using a depth gauge or microscope, and the hole diameter is confirmed using CCD or 3D measurement. Only after passing the inspection can mass production begin.

[0044] Furthermore, if both the upper and lower diameters of the countersunk hole require copper / tin / gold plating, the first piece must be inspected for bubbling issues after solder resist sandblasting and PTH copper plating to prevent batch copper plating failure or poor bubbling. If the upper diameter of the countersunk hole does not require copper / tin / gold plating, but the lower diameter does, then the countersunk hole drilling must be performed after electroplating two copper and tin and before etching to prevent burrs and copper wires / dross issues at the connection between the upper and lower diameters. If neither the upper nor lower diameter of the countersunk hole requires copper / tin / gold plating, copper plating problems must be avoided during the electroplating of two coppers due to dry film breakage.

[0045] Working principle:

[0046] drilling:

[0047] ①Synchronous Drill Strip Stretching 1. If the product expands or contracts and the drill strip needs to be stretched, all drill strips must be changed synchronously, including countersunk drills; 2. It is recommended to control the depth and diameter tolerances to the upper limit to avoid the depth or diameter being too small or to the lower limit.

[0048] ② Material Usage and Parameter Control 1. According to the instructions in the production work order (MI), select a four-flute countersunk drill bit with a diameter 0.2mm larger than the customer's required countersunk hole diameter (e.g., if the countersunk hole diameter is 5.3mm, then use a 5.5mm drill bit). The parameters and hole limits can be implemented according to the parameters of ordinary large drill bits; 2. When producing countersunk holes, the diameter, depth and angle of the countersunk hole must be measured or cross-sectioned first. Mass production can only begin if there are no abnormalities; 3. Depth and diameter tolerances must be controlled in the factory according to the positive tolerance of the diameter and depth tolerances required by the customer to avoid the phenomenon of drilling holes that are too small or too shallow.

[0049] ③ Add depth control to the data 1. According to the method of adding depth control to the back drill strip data, add a blank line before M25 after the data tool sequence for the countersunk hole drill strip, and input M18Z** (** is the depth requirement); 2. If there are multiple diameter specifications or different depths, add (M18**) before M25 after the tool sequence for each diameter specification or depth in the above manner.

[0050] ④ After starting the machine and entering depth control mode, check the parameters: 1. After positioning is complete and the countersink data is imported, press the F4 key and enter the DEPT command to put the machine into depth control mode; 2. Check the parameters. The depth compensation should not have any values; the depth compensation must be "0".

[0051] ⑤ Countersunk Drill Hole Limit Control 1. The hole limit of countersunk drills must be strictly controlled. They must be replaced when their service life is reached and cannot be reused. 2. If countersunk drills are not replaced in time when their service life is reached, the depth will become shallow due to drill bit wear.

[0052] ⑥ Stacking requirements: 1. When producing countersunk holes, stacking can only be done at 1PNL / stack or 1SET / stack.

[0053] ⑦ Product Direction Confirmation 1. According to the instructions in the production work order MI, confirm whether the countersunk hole production surface is the front or back (C / S side).

[0054] Polishing

[0055] ①Rules for burr removal: 1. If the upper and lower diameters of the countersunk hole have copper / tin / gold plating requirements, the burrs must be removed before the hole is sandblasted and then sent to the copper plating stage to reduce burrs and blistering issues at the connection between the upper and lower diameters; 2. If the upper and lower diameters of the countersunk hole do not have copper / tin / gold plating requirements, the countersunk hole must be sent to the sandblasting process for burr removal after production before being sent to the dry film stage.

[0056] plating

[0057] ① Production Process and Quality 1. If both the upper and lower diameters of the countersunk hole require copper / tin / gold plating, the first piece must be inspected for bubbling issues in the upper and lower diameters after solder resist sandblasting and PTH copper plating to prevent batch copper plating failure or poor bubbling; 2. If the upper diameter of the countersunk hole does not require copper / tin / gold plating, but the lower diameter does, then the countersunk hole drilling must be performed after electroplating two copper and tin, and before etching to remove the film, to prevent burrs and copper wires / dross issues at the connection between the upper and lower diameters; 3. If neither the upper nor lower diameter of the countersunk hole requires copper / tin / gold plating, care must be taken during the production of two copper plates to prevent copper plating problems caused by dry film rupture.

[0058] ② Post-etching anti-foolproof PAD inspection 1. For all products with countersunk hole process, an anti-foolproof PAD 3mil smaller than the hole diameter on one side must be designed at the countersunk hole position. This anti-foolproof PAD will be removed after drilling after the countersunk hole is produced. 2. After etching, IPQC should randomly check whether there is any unremoved anti-foolproof PAD around the countersunk hole. If not, the flow continues normally. If so, it means that the countersunk hole is drilled off-center or the hole diameter is too small, and the drilling should be reworked.

[0059] Weld resistance

[0060] ① Eliminating potential product quality issues: 1. After drilling countersunk holes, burrs and impurities will appear at the connection between the upper and lower hole diameters. Sandblasting is required according to the work order before proceeding to the next process; 2. During sandblasting, the countersunk hole face downwards.

[0061] ② Design of solder resist dots and exposure film 1. For all products with countersunk holes, the solder resist dots and exposure film for the surface without countersunk holes should be designed according to the normal size of the through hole diameter; for the surface with countersunk holes, the corresponding countersunk hole resist dots and exposure film should be made according to the size of the countersunk hole diameter to prevent ink from seeping into the hole. 2. Solder resist tools should be confirmed according to the above design. If the tools are inconsistent, the relevant personnel should notify the engineering department for modification.

[0062] Quality Assurance

[0063] ① First piece confirmation sampling inspection: 1. The first piece of countersunk hole must be confirmed by IPQC. The depth is confirmed by a depth gauge or microscope, and the hole diameter is confirmed by CCD or three-dimensional measurement. Only after passing the inspection can mass production begin; 2. After etching, IPQC needs to randomly inspect whether there is any unremoved anti-foolproof PAD around the countersunk hole. If not, the flow continues normally. If so, it means that the countersunk hole is drilled off-center or the hole diameter is too small. The drilling is notified to be reworked.

[0064] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for manufacturing countersunk holes on a PCB board, characterized in that: Includes the following steps; S1: Drilling, using a countersunk drill to drill countersunk holes on the PCB board; S2: Blinder polishing, blister polishing of countersunk holes on PCB boards to remove countersunk blister; S3: Dry film, which forms a temporary protective image on the PCB board through the process of film application, exposure and development; S4: Electroplating, electroplating of countersunk holes on PCB boards. The electroplating process includes PTH copper plating, electroplating of copper plate one and electroplating of copper plate two. S5: Etching, etching the PCB board, removing excess copper layer from the countersunk holes through chemical etching; S6: Stripping the film, removing the dry film remaining after etching to expose the copper traces; S7: Solder resist screen printing, which involves a process of ink application, pre-baking, film exposure, development, and curing to cover the board surface with solder resist ink to protect the circuitry.

2. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: In S2, if the upper and lower diameters of the countersunk hole require copper / tin / gold plating processes, then after polishing and burring, it will be sandblasted and then exited to a copper plate. If there are no copper / tin / gold plating process requirements for the upper and lower diameters of the countersunk hole, after the countersunk hole is produced, it will be sent to the sandblasting process for deburring and polishing before being sent to the dry film. In the above sandblasting process, the countersunk hole face down during sandblasting.

3. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: In S1, a four-flute countersunk drill rod with a diameter 0.2 mm larger than the countersunk hole diameter is selected.

4. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: In S1, when drilling, the stacked plates are operated at 1PNL / stack or 1SET / stack.

5. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: A foolproof pad is designed at the countersunk hole position that is 3 mil smaller than the hole diameter on one side. During the drilling process, the foolproof pad will be eliminated as the hole is drilled.

6. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: Before film exposure, the solder mask blocking points and exposure film for surfaces without countersunk holes are designed according to the diameter of the through holes; for surfaces with countersunk holes, the design is based on the diameter of the countersunk holes to prevent ink from seeping into the holes.

7. The method for manufacturing countersunk holes on a PCB board according to claim 5, characterized in that: In S5, after etching, spot checks are performed to see if the anti-foolproof PAD around the countersunk hole is not removed. If not, the current continues normally; if it is, rework is required.

8. The method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: The first piece produced after countersunk hole machining undergoes quality inspection. The depth is confirmed using a depth gauge or microscope, and the hole diameter is confirmed using a CCD or 3D measurement. Only after passing the inspection can mass production begin.

9. A method for manufacturing countersunk holes on a PCB board according to claim 1, characterized in that: If both the upper and lower diameters of the countersunk hole require copper / tin / gold plating processes, the first piece should be inspected for bubbling issues in the upper and lower diameters after solder resist sandblasting and PTH copper plating to prevent batches from failing to plating copper or having poor bubbling. If the upper diameter of the countersunk hole does not require copper / tin / gold plating, but the lower diameter does, then the countersunk hole should be drilled after electroplating two copper and tin plates and before etching to remove the film, in order to prevent burrs and copper wires and copper slag at the connection between the upper and lower diameters inside the hole. If neither the upper nor lower diameter of the countersunk hole requires copper / tin / gold plating, copper plating problems must be avoided during the electroplating of double copper.

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