Manufacturing method of environment-friendly flexible circuit board and circuit board thereof

Abstract

The invention discloses a manufacturing method of an environment-friendly flexible circuit board and a circuit board thereof, and the method comprises the steps: 1, carrying out the preshrinking stabilization of a black PET membrane: selecting the black PET membrane, setting the MD direction of the black PET membrane as the long edge direction of a keyboard so as to improve the size stability of a post-processing process, taking 10 pieces after cutting, stacking the 10 pieces into an oven, and carrying out the baking, and reducing the size zooming variation of the post-processing process; step 2, printing conductive copper paste: printing the conductive copper paste on the top of the black PET film, and controlling the thickness of the conductive copper paste to be 0.005-0.030 mm; step 3, drying the copper paste circuit; 4, printing covering layer ink; 5, performing chemical gold process treatment; step 6, punching; and step 7, SMT part punching. Compared with the traditional etching copper foil flexible circuit board technology, the method has the advantages that the PI material of the copper foil substrate is changed into PET, the etching copper foil is changed into printing copper paste, and the covering PI film is changed into printing ink, so that the material consumption and the industrial wastewater discharge are reduced, the energy consumption and the carbon emission are reduced, and the environmental protection requirement is better met.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board technology, and in particular to a method for manufacturing an environmentally friendly flexible circuit board and the circuit board thereof. Background Technology

[0002] The conductive layer of current flexible circuit boards generally uses etched lines. The large-area consumption of materials and the problem of industrial wastewater are the causes of energy consumption and increased carbon dioxide.

[0003] Currently, circuit boards typically use PI material for their cover layers to shield noise. However, this design uses LEDs in a general circuit that only carries current and voltage, so small signals such as noise can be ignored. Therefore, printing ink is used to replace the PI film process for the cover layer, which reduces a lot of processes and avoids curling problems.

[0004] Compared to current circuit boards where the PI (pixel layer) covering the pads is slightly larger due to bonding precision requirements, this design controls the printing precision to ensure the pad openings are less than or equal to the size of the LED device. Currently, some circuit boards use silver paste for the conductive layer, which lacks sufficient strength, hardness, and other mechanical properties in high-frequency vibration environments. After prolonged use, the high conductivity becomes unstable, and silver paste is also expensive.

[0005] Based on the above, this invention designs an environmentally friendly flexible circuit board manufacturing process and its circuit board to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a method for manufacturing an environmentally friendly flexible circuit board and the circuit board thereof. Compared with the traditional copper foil etching flexible circuit board technology, this invention changes the PI material of the copper foil substrate to PET, changes the etched copper foil to printed copper paste, and changes the covering PI film to printed ink, thereby reducing material consumption and industrial wastewater discharge, reducing energy consumption and carbon emissions, and better meeting environmental protection requirements.

[0007] The present invention also provides a method for manufacturing an environmentally friendly flexible circuit board as described above, comprising the following steps:

[0008] Step 1: Pre-shrinking and stabilizing black PET film: Select black PET film and set its MD direction to the long side of the keyboard to improve the dimensional stability of the subsequent process. After cutting, take 10 pieces, stack them, and bake them in the oven to reduce the dimensional scaling changes in the subsequent process.

[0009] Step 2: Print conductive copper paste: Print conductive copper paste on the top of the black PET film, controlling the thickness of the conductive copper paste to be 0.005-0.030mm;

[0010] Step 3: Dry the copper paste circuit: Dry the black PET film with conductive copper paste to ensure the copper paste circuit is completely dry.

[0011] Step 4: Print the overlay ink: Print the overlay ink on top of the dried conductive copper paste;

[0012] Step 5, Electroless Gold Processing: Electroless gold processing is performed on the printed soldering parts to protect the printed copper from oxidation;

[0013] Step 6, punching: Send the product to the punching machine for punching;

[0014] Step 7, SMT assembly: Perform SMT assembly to bond LEDs and resistors together to obtain an environmentally friendly flexible circuit board.

[0015] According to a method for manufacturing an environmentally friendly flexible circuit board provided by the present invention, when printing conductive copper paste, the thickness difference of the conductive copper paste is controlled to be less than 3μm.

[0016] According to the manufacturing method of an environmentally friendly flexible circuit board provided by the present invention, the alignment accuracy is less than 0.03 mm when printing the overlay ink.

[0017] An environmentally friendly flexible circuit board according to the present invention includes: a black PET substrate, conductive copper paste lines printed on the top of the black PET substrate, a cover layer ink covering the top of the conductive copper paste lines, and LEDs and resistors bonded by SMT assembly; the opening size of the cover layer ink in the soldering portion is less than or equal to the size of the LED device.

[0018] According to the present invention, the thickness of the conductive copper paste circuit is 0.005-0.030mm.

[0019] Beneficial effects

[0020] Compared with existing technologies, the present invention provides an environmentally friendly flexible circuit board manufacturing method and circuit board, which, compared with traditional copper foil etched flexible circuit board technology, changes the PI material of the copper foil substrate to PET, changes the etched copper foil to printed copper paste, and changes the covering PI film to printed ink, thereby reducing material consumption and industrial wastewater discharge, reducing energy consumption and carbon emissions, and is more in line with environmental protection requirements.

[0021] Compared with existing technologies, the present invention provides a method for manufacturing an environmentally friendly flexible circuit board and the circuit board thereof. This method uses conductive copper paste instead of silver paste, reducing raw material costs while ensuring performance. Simultaneously, it simplifies the cover layer process, reduces steps, and further lowers production costs. The conductive copper paste has superior mechanical properties such as strength and hardness compared to conductive silver paste, making it suitable for applications requiring resistance to certain forces or high-frequency vibrations, and it exhibits good conductivity stability. The high alignment accuracy of the cover layer ink printing and the reasonable control of the window size in the soldering section reduce the impact of external factors on the circuit and improve the stability of the circuit board.

[0022] Compared with the prior art, the present invention provides a method for manufacturing an environmentally friendly flexible circuit board and the circuit board thereof. By pre-treating the black PET substrate, the method effectively reduces the dimensional scaling changes in the subsequent process, ensures the dimensional accuracy of the circuit board, and facilitates subsequent assembly and use. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0024] Figure 1 This is a side view cross-sectional view of the circuit board at the forming point in the manufacturing method of an environmentally friendly flexible circuit board according to the present invention.

[0025] Figure 2 This is a schematic diagram of the printed copper circuit of an environmentally friendly flexible circuit board according to the present invention.

[0026] Figure 3 This is a schematic diagram of the overprinting ink for an environmentally friendly flexible circuit board according to the present invention. Detailed Implementation

[0027] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0028] Reference Figure 1-3 This invention discloses a method for manufacturing an environmentally friendly flexible circuit board and the circuit board thereof, comprising: selecting a black PET film, with its MD direction set to the long side direction of the keyboard; cutting the black PET film to a size suitable for keyboard use; stacking 10 pieces together; placing them in an oven; and baking them at 80-100℃ for 2-3 hours to complete the substrate pretreatment.

[0029] Conductive copper paste is printed on the top of a pretreated black PET film using screen printing technology. By controlling the printing parameters, the thickness of the copper paste is 0.015 mm, and the thickness difference is controlled to be less than 2 μm.

[0030] Place the PET film printed with copper paste into a drying device and bake it at 120-150℃ for 30-60 minutes until the copper paste lines are completely dry. Use high-precision printing equipment to print a cover layer ink on top of the dried copper paste lines, ensuring a registration accuracy of 0.02mm.

[0031] The exposed copper solder joints are gold-plated, with the gold layer thickness controlled between 0.1-0.3 μm. The treated product is then sent to a punching machine for punching according to the dimensions of the keyboard circuit board. Finally, LEDs and resistors are accurately mounted on the predetermined positions of the circuit board using SMT equipment, completing the fabrication of the environmentally friendly flexible circuit board.

[0032] The environmentally friendly flexible circuit board manufactured in this embodiment has been tested and found to have good dimensional stability. After 3000 hours of use under high-frequency vibration, its conductivity remains stable and meets environmental protection requirements. The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the invention. The scope of protection of the present invention is determined by the appended claims.

[0033] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method of manufacturing an environmentally friendly flexible printed circuit board, characterized by, It comprises the following steps: Step one, black PET film pre-shrinkage stability: select black PET film, set its MD direction as the keyboard long side direction to improve the dimensional stability of the subsequent process, cut the film and then stack 10 pieces into the oven to bake, reduce the size scaling variation of the subsequent process; Step two, print conductive copper paste: print conductive copper paste on the top of black PET film, control the thickness of conductive copper paste to be 0.005-0.030mm; Step three, dry the copper paste circuit: dry the black PET film with conductive copper paste to make the copper paste circuit completely dry; Step four, print the cover layer ink: print the cover layer ink on the top of the dried conductive copper paste; Step five, gold plating process: gold plating process is performed on the printed welding part to protect the printed copper from oxidation; Step six, punching: send the product to the punching machine for punching; Step seven, SMT assembly: SMT assembly is performed to bond the LED and resistor to obtain an environmentally friendly flexible circuit board.

2. The method of claim 1, wherein the soft flexible printed circuit board is manufactured by the steps of: When printing the conductive copper paste, the thickness difference of the conductive copper paste is controlled to be less than 3μm. ​ 3. The method for manufacturing an environmentally friendly flexible circuit board according to claim 1, characterized in that, When printing the cover layer ink, the alignment accuracy is less than 0.03mm.

4. An environmentally friendly flexible printed circuit board manufactured by the method according to any one of claims 1 to 3, wherein It comprises: Black PET substrate, conductive copper paste circuit printed on the top of black PET substrate, cover layer ink covering the top of conductive copper paste circuit, and LED and resistor bonded by SMT assembly; the window size of the cover layer ink at the welding part is less than or equal to the size of the LED device.

5. The environmentally friendly soft PCB according to claim 4, wherein, The thickness of the conductive copper paste circuit is 0.005-0.030mm.

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