Tin spraying process design and manufacturing method for thick copper plate

Abstract

The invention discloses a thick copper plate tin spraying process design and manufacturing method, and relates to the field of thick copper plate tin spraying, and the method comprises the following steps: firstly, preparing and cutting raw materials, carrying out pretreatment and inner layer manufacturing after the preparation and cutting of the raw materials, and carrying out brownification and lamination along with the completion of the pretreatment and inner layer manufacturing, drilling and slot milling are carried out after brownification and lamination are completed, circuit manufacturing and electroplating are carried out after drilling and slot milling are completed, and etching and outer layer detection are carried out after circuit manufacturing and electroplating are completed. According to the tin spraying process design and manufacturing method of the thick copper plate, during CAM data manufacturing, a side rail area, 5 mm away from a set area, of a pnl is set as a copper-free area, glue shortage and cavities occur after lamination of the copper-free area, in order to prevent glue shortage in the plate, the pnl, 5 mm away from the set area, of the pnl is set as a copper laying area, an edge milling process is added before tin spraying, a frame of the outer edge of the PNL is milled away by 5 mm, and the cavities leak out; a channel is provided for stress release and water vapor discharge, and the problem of board explosion and hole explosion of the circuit board is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of tin-spraying of thick copper plates, in particular to a design and manufacturing method of tin-spraying technology of thick copper plates. Background Art

[0002] The tin-spraying process of thick copper plates is mainly used to improve the performance of copper plates. The tin-spraying process has been widely used in electronics, communications, automobile manufacturing and other industries that require electrical connections and reliability.

[0003] In the prior art, a baking process is added, and the time limit for hot spraying after baking is only 10 minutes. The time limit is too short, difficult to control, and difficult for personnel to operate. After baking, the pre-treatment temperature will be lowered, and the hot spraying requirements cannot be met. After pre-treatment, baking is performed, and hot spraying is performed after baking, which increases manual operation and is difficult to implement.

[0004] In order to overcome the above shortcomings, the Chinese patent of the prior art (publication number CN114206018A) discloses an efficient thick copper plate solder resist printing method, and the ink used in the efficient thick copper plate solder resist printing method is mainly composed of the following quality raw materials: epoxy cyclohexyl methyl methacrylate, amide resin, titanium dioxide, methacryloxypropyl trimethoxysilane, propylene glycol methyl ether acetate, trimethylbenzoylphenylphosphonic acid ethyl ester, the interaction between the substances makes the ink have good curing performance and adhesion, and also has excellent heat resistance and weather resistance, and fast curing speed;

[0005] In order to overcome the above-mentioned shortcomings, a Chinese patent of the prior art (publication number CN112153820A) discloses a method for improving the explosion of thick copper plates during tin spraying, comprising the following steps: gong the PCB board before tin spraying, wherein the copper blocks on the sides of the PCB board are gonged off during the gonging. The copper blocks on the sides of the PCB board are gonged off before baking the board, thereby exposing the substrate of the PCB board. After the sides of the PCB board are freed from the obstruction of the copper blocks, the heat can be better released during tin spraying, thereby effectively preventing the PCB board from exploding during tin spraying;

[0006] Although the existing technology can overcome the above-mentioned deficiencies, there are still other problems in its operation. At present, the industry has an immature tin-spraying process technology for 8 / 9oz thick copper plates, and there are often quality risks of bursting and hole explosion. To prevent hole explosion and bursting, the general method in the industry is to bake before tin-spraying, with a baking temperature of 120-150°C and a baking time of 20-40 minutes for hot spraying. However, it only solves the problem of individual thick copper plates (6 / 7OZ copper thick plates). For 8 / 9oz thick copper plates, bursting and hole explosion problems still frequently occur. Summary of the invention

[0007] The purpose of the present invention is to provide a design and production method for the tin spraying process of thick copper plates, so as to solve the problem raised in the above background technology that the tin spraying process technology for 8 / 9oz thick copper plates in the industry is immature, and there are often quality risks of bursting plates and holes. To prevent holes and bursting plates, the general method in the industry is to bake before tin spraying, with a baking temperature of 120-150°C and a baking time of 20-40 minutes, and perform hot spraying. However, it only solves the problem of individual thick copper plates (6 / 7OZ copper thick plates), and the problem of bursting plates and holes still frequently occurs for 8 / 9oz thick copper plates.

[0008] To achieve the above purpose, the present invention provides the following technical solutions: a method for designing and manufacturing a tin-spraying process for a thick copper plate, comprising S1, raw material preparation and cutting; S2, pretreatment and inner layer production; S3, browning and lamination; S4, drilling and slot milling; S5, circuit production and electroplating; S6, etching and outer layer inspection; S7, solder mask and character printing; S8, shape processing and tin-spraying treatment; S9, testing, inspection and packaging;

[0009] The specific steps include:

[0010] S1. Raw material preparation and cutting

[0011] Cutting: Cut the required 8 / 9OZ thick copper plate from the raw material;

[0012] S2. Pretreatment and inner layer production

[0013] Baking plate: Baking the cut thick copper plate to remove moisture and volatiles in the plate;

[0014] Inner layer circuit: circuit pattern is made on the inner layer of thick copper plate;

[0015] Inner layer etching: Etch away the unnecessary copper parts of the inner layer to form circuit lines;

[0016] Inner layer AOI: Use automatic optical inspection equipment to perform quality inspection on inner layer circuits;

[0017] S3, Browning and Lamination

[0018] Browning: Browning the copper plate surface to enhance the bonding strength between copper and resin;

[0019] Lamination: Laminating multiple layers of circuit boards together to form a multi-layer structure;

[0020] S4, drilling and milling holes

[0021] Drilling and milling slots: Drill the required through holes and slots on the circuit board;

[0022] S5. Circuit production and electroplating

[0023] Copper deposition and board plating: deposit copper layer on the inner wall of drilled holes and slot holes, and copper plate the board surface;

[0024] Outer circuit: Make circuit patterns on the outer layer of the circuit board;

[0025] False positive plating: Plating is performed on the outer circuit to enhance the circuit's conductivity and corrosion resistance;

[0026] S6, Etching and outer layer inspection

[0027] Alkaline etching: Etch away the unnecessary copper parts of the outer layer to form the final circuit line;

[0028] Outer layer AOI: Use automatic optical inspection equipment to perform quality inspection on the outer layer circuit;

[0029] S7, solder mask and character printing

[0030] Solder mask printing: Printing a solder mask layer on the circuit board to protect the circuit lines from corrosion;

[0031] Characters and post-baking: Print character logos on the circuit board and perform post-baking;

[0032] S8, appearance processing and tin spraying

[0033] Add milling edge: mill off a 5mm frame on the outer edge of the PNL, control the milling accuracy and depth, ensure that the cavity leaks out, and provide a channel for stress release and water vapor discharge;

[0034] Lead-free tin spraying: Lead-free tin spraying is performed on the circuit board to enhance the conductivity and solderability of the circuit board;

[0035] Electric milling: Electric milling is performed on the circuit board after tin spraying to remove the excess tin layer;

[0036] S9, Testing, Inspection and Packaging

[0037] Testing: Conduct comprehensive electrical performance and functional tests on circuit boards;

[0038] FQC and Packing: Final quality inspection and packing of the circuit boards.

[0039] Furthermore, in step S1, the quality of the raw materials is checked, and a 8 / 9OZ thick copper plate of the required size and weight is cut from the raw materials using precise cutting equipment, ensuring that the cutting surface is smooth and burr-free, and the cutting accuracy and speed are monitored in real time.

[0040] Furthermore, in step S2, the cut copper plate is baked, and then a circuit pattern is drawn on the inner layer, and etching and AOI inspection are performed. After baking, natural cooling is required, and the accuracy and integrity of the pattern and circuit must be ensured during the drawing and etching process.

[0041] Furthermore, in step S3, the copper plate is subjected to browning treatment, and after the browning film is formed, the multi-layer circuit board is laminated according to the design requirements, and the parameters of the browning liquid and the lamination process are controlled to ensure the quality of the browning film and the close combination of the laminate.

[0042] Furthermore, in step S4, a CNC drilling machine or a laser drilling machine is used to drill the required through holes and slots on the circuit board, and the drilling speed and feed rate are controlled to ensure that the hole diameter, hole depth and hole position accuracy meet the design requirements.

[0043] Furthermore, in step S5, the inner walls of the drilled holes and slots are activated, the copper layer is deposited and copper is plated on the board surface, and then a circuit pattern is drawn on the outer layer and electroplated to ensure the uniformity and density of the copper layer and the electroplating layer, as well as the alignment accuracy of the outer layer circuit and the inner layer circuit.

[0044] Furthermore, in step S6, the unnecessary copper portion of the outer layer is etched away, and then an AOI inspection is performed to ensure that the etching is uniform and meets the design requirements, and the detected defects are recorded and classified.

[0045] Furthermore, in step S7, a solder mask layer and character logos are printed on the circuit board, and then baked and cured to ensure that the uniformity, adhesion and accuracy of the solder mask layer and the characters meet the design requirements.

[0046] Furthermore, in step S8, the outer edge of the circuit board is milled, and a lead-free tin-spraying process is performed after the frame is removed to ensure that the quality of the milled surface and the tin-spraying layer meets the design requirements, and the waste liquid and waste gas are properly handled.

[0047] Furthermore, in step S9, the circuit boards are subjected to comprehensive electrical performance tests and functional tests, final quality checks are performed, and qualified circuit boards are packaged to ensure the accuracy and reliability of the test equipment, analyze and record the test results, and use appropriate packaging materials and tools for packaging.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. When making CAM data, the edge area of ​​the PNL 5mm away from the set area is set as a copper-free area. After lamination, there will be glue shortage and voids in the copper-free area. To prevent glue shortage in the board, the PNL is set as a copper-plated area 5mm away from the set area. Before tin spraying, a "milling edge" process is added to cut off a 5mm frame on the outer edge of the PNL. Voids will leak out, providing a channel for stress release and water vapor discharge, preventing the circuit board from bursting and bursting.

[0050] 2. The process of tin spraying and hot spray baking has been eliminated, so that the process steps can be simplified, the tediousness of the work can be optimized, and the automated step reminders can reduce the manual operation of personnel, which can reduce the tediousness of the work of the staff and save physical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0052] Figure 2 This is a schematic diagram of the pretreatment process of the present invention;

[0053] Figure 3 A schematic diagram of the process flow of the present invention is provided;

[0054] Figure 4 It is a schematic diagram of the subsequent processing flow of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Embodiment 1: Figure 1-Figure 4 The technical solution shown is a method for designing and manufacturing a tin-spraying process for a thick copper plate. In order to solve the problem of easy board explosion after the product is manufactured, the following steps are disclosed: S1, raw material preparation and cutting; S2, pretreatment and inner layer manufacturing; S3, browning and lamination; S4, drilling and milling slots;

[0057] S5, circuit production and electroplating; S6, etching and outer layer inspection; S7, solder mask and character printing; S8, appearance processing and tin spraying; S9, testing, inspection and packaging;

[0058] The specific steps include:

[0059] S1. Raw material preparation and cutting

[0060] Cutting: Cut the required 8 / 9OZ thick copper plate from the raw material;

[0061] S2. Pretreatment and inner layer production

[0062] Baking plate: Baking the cut thick copper plate to remove moisture and volatiles in the plate;

[0063] Inner layer circuit: circuit pattern is made on the inner layer of thick copper plate;

[0064] Inner layer etching: Etch away the unnecessary copper parts of the inner layer to form circuit lines;

[0065] Inner layer AOI: Use automatic optical inspection equipment to perform quality inspection on inner layer circuits;

[0066] S3, Browning and Lamination

[0067] Browning: Browning the surface of the copper plate to enhance the bonding strength between copper and resin;

[0068] Lamination: Laminating multiple layers of circuit boards together to form a multi-layer structure;

[0069] S4, drilling and milling holes

[0070] Drilling and milling slots: Drill the required through holes and slots on the circuit board;

[0071] S5. Circuit production and electroplating

[0072] Copper deposition and board plating: deposit copper layer on the inner wall of drilled holes and slot holes, and copper plate the board surface;

[0073] Outer circuit: Make circuit patterns on the outer layer of the circuit board;

[0074] False positive plating: electroplating is performed on the outer circuit to enhance the circuit's conductivity and corrosion resistance;

[0075] S6, Etching and outer layer inspection

[0076] Alkaline etching: Etch away the unnecessary copper parts of the outer layer to form the final circuit line;

[0077] Outer layer AOI: Use automatic optical inspection equipment to perform quality inspection on the outer layer circuit;

[0078] S7, solder mask and character printing

[0079] Solder mask printing: Printing a solder mask layer on the circuit board to protect the circuit lines from corrosion;

[0080] Characters and post-baking: Print character logos on the circuit board and perform post-baking;

[0081] S8, appearance processing and tin spraying

[0082] Add milling edge: cut off 5mm of the outer edge of the PNL, control the milling accuracy and depth, ensure that the cavity leaks out, and provide a channel for stress release and water vapor discharge;

[0083] Lead-free tin spraying: Lead-free tin spraying is performed on the circuit board to enhance the conductivity and solderability of the circuit board;

[0084] Electric milling: Electric milling is performed on the circuit board after tin spraying to remove the excess tin layer;

[0085] S9, Testing, Inspection and Packaging

[0086] Testing: Conduct comprehensive electrical performance and functional tests on circuit boards;

[0087] FQC and Packing: Final quality inspection and packing of the circuit boards.

[0088] Step S1, check the quality of raw materials, use precise cutting equipment to cut out 8 / 9OZ thick copper plates of required size and weight from raw materials, ensure that the cutting surface is flat and burr-free, and monitor the cutting accuracy and speed in real time, step S2, bake the cut copper plates, then draw the circuit pattern on the inner layer, and perform etching and AOI inspection, and cool naturally after baking. During the drawing and etching process, the accuracy and integrity of the pattern and circuit must be ensured, step S3, brown the copper plates, and after forming the brown film, laminate the multi-layer circuit boards according to the design requirements, control the parameters of the brown liquid and the lamination process, and ensure the quality of the brown film and the close combination of the laminated board, step S4, use a CNC drilling machine or a laser drilling machine to drill the required through holes and slots on the circuit board, control the drilling speed and feed rate, and ensure that the hole diameter, hole depth and hole position accuracy meet the design requirements, step S5, activate the inner walls of the drill holes and slots, deposit the copper layer, copper plate the board surface, and then draw on the outer layer Make a circuit pattern and perform electroplating to ensure the uniformity and density of the copper layer and the electroplating layer, as well as the alignment accuracy of the outer layer circuit and the inner layer circuit. Step S6: Etch and remove the unnecessary copper part of the outer layer, and then perform AOI inspection to ensure that the etching is uniform and meets the design requirements, and record and classify the detected defects. Step S7: Print the solder mask layer and character logo on the circuit board, and bake and cure it to ensure that the uniformity, adhesion and accuracy of the solder mask layer and the characters meet the design requirements. Step S8: Mill the outer edge of the circuit board, remove the frame and perform lead-free tin spraying to ensure that the quality of the milling surface and the tin spraying layer meets the design requirements, and properly handle the waste liquid and waste gas. Step S9: Perform a comprehensive electrical performance test and functional test on the circuit board, conduct a final quality inspection, and package the qualified circuit boards to ensure the accuracy and reliability of the test equipment, analyze and record the test results, and use appropriate packaging materials and tools for packaging;

[0089] When making CAM data, the edge rail area of ​​the PNL 5mm away from the set area is set as a copper-free area. The copper-free area will have glue shortage and voids after lamination. To prevent glue shortage in the board, the PNL is set as a copper-plated area 5mm away from the set area. Before tin spraying, a "milling edge" process is added to cut off a 5mm border on the outer edge of the PNL. Voids will leak out, providing a channel for stress release and water vapor discharge, preventing the circuit board from bursting and bursting.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing and manufacturing a tin-spraying process for a thick copper plate, including S1, raw material preparation and cutting; S2, pretreatment and inner layer production; S3, browning and lamination; S4, drilling and slot milling; S5, circuit production and electroplating; S6, etching and outer layer inspection; S7, solder mask and character printing; S8, shape processing and tin-spraying treatment; S9, testing, inspection and packaging; It is characterized in that The specific steps include: S1. Raw material preparation and cutting Cutting: Cut the required 8 / 9OZ thick copper plate from the raw material; S2. Pretreatment and inner layer production Baking plate: Baking the cut thick copper plate to remove moisture and volatiles in the plate; Inner layer circuit: circuit pattern is made on the inner layer of thick copper plate; Inner layer etching: Etch away the unnecessary copper parts of the inner layer to form circuit lines; Inner layer AOI: Use automatic optical inspection equipment to perform quality inspection on inner layer circuits; S3, Browning and Lamination Browning: Browning the copper plate surface to enhance the bonding strength between copper and resin; Lamination: Laminating multiple layers of circuit boards together to form a multi-layer structure; S4, drilling and milling holes Drilling and milling slots: Drill the required through holes and slots on the circuit board; S5. Circuit production and electroplating Copper deposition and board plating: deposit copper layer on the inner wall of drilled holes and slot holes, and copper plate the board surface; Outer circuit: Make circuit patterns on the outer layer of the circuit board; False positive plating: Plating is performed on the outer circuit to enhance the circuit's conductivity and corrosion resistance; S6, Etching and outer layer inspection Alkaline etching: Etch away the unnecessary copper parts of the outer layer to form the final circuit line; Outer layer AOI: Use automatic optical inspection equipment to perform quality inspection on the outer layer circuit; S7, solder mask and character printing Solder mask printing: Printing a solder mask layer on the circuit board to protect the circuit lines from corrosion; Characters and post-baking: Print character logos on the circuit board and perform post-baking; S8, appearance processing and tin spraying Add milling edge: mill off a 5mm frame on the outer edge of the PNL, control the milling accuracy and depth, ensure that the cavity leaks out, and provide a channel for stress release and water vapor discharge; Lead-free tin spraying: Lead-free tin spraying is performed on the circuit board to enhance the conductivity and solderability of the circuit board; Electric milling: Electric milling is performed on the circuit board after tin spraying to remove the excess tin layer; S9, Testing, Inspection and Packaging Testing: Conduct comprehensive electrical performance and functional tests on circuit boards; FQC and Packing: Final quality inspection and packing of the circuit boards.

2. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S1, the quality of the raw materials is checked, and a 8 / 9OZ thick copper plate of the required size and weight is cut from the raw materials using a precise cutting device, ensuring that the cutting surface is flat and burr-free, and the cutting accuracy and speed are monitored in real time.

3. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S2, the cut copper plate is baked, and then a circuit pattern is drawn on the inner layer, and etching and AOI inspection are performed. After baking, it needs to be cooled naturally. During the drawing and etching process, the accuracy and integrity of the pattern and circuit must be ensured.

4. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In the step S3, the copper plate is subjected to browning treatment. After the browning film is formed, the multi-layer circuit board is laminated according to the design requirements, and the parameters of the browning liquid and the lamination process are controlled to ensure the quality of the browning film and the close combination of the laminate.

5. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S4, a CNC drilling machine or a laser drilling machine is used to drill the required through holes and slots on the circuit board, and the drilling speed and feed rate are controlled to ensure that the hole diameter, hole depth and hole position accuracy meet the design requirements.

6. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S5, the inner walls of the drilled holes and slots are activated, the copper layer is deposited, and copper is plated on the board surface. Then, a circuit pattern is drawn on the outer layer and electroplated to ensure the uniformity and density of the copper layer and the electroplated layer, as well as the alignment accuracy of the outer layer circuit and the inner layer circuit.

7. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S6, the unnecessary copper part of the outer layer is etched away, and then an AOI inspection is performed to ensure that the etching is uniform and meets the design requirements, and the detected defects are recorded and classified.

8. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In the step S7, a solder mask layer and character logos are printed on the circuit board, and then baked and cured to ensure that the uniformity, adhesion and accuracy of the solder mask layer and the characters meet the design requirements.

9. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In the step S8, the outer edge of the circuit board is milled, and a lead-free tin spraying process is performed after the frame is removed to ensure that the quality of the milled surface and the tin spraying layer meets the design requirements, and the waste liquid and waste gas are properly handled.

10. The method for designing and manufacturing a tin-spraying process for a thick copper plate according to claim 1, characterized in that: In step S9, a comprehensive electrical performance test and functional test are performed on the circuit board, a final quality check is performed, and qualified circuit boards are packaged to ensure the accuracy and reliability of the test equipment, analyze and record the test results, and use appropriate packaging materials and tools for packaging.

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