Circuit board manufacturing method for reducing surface roughness of carbon film

Abstract

The invention provides a circuit board manufacturing method capable of reducing the surface roughness of a carbon film, which comprises the following steps: pretreatment, preparation of a printing screen, printing, curing and baking, and post-treatment, in the process of preparing the printing screen, a 150-200-mesh screen is adopted, and the ink viscosity is set to be 250-350dpa.s; after the printing procedure is completed, a pre-baking device is arranged before the curing and baking procedure, a conveying platform in the pre-baking device is set to be a high-frequency vibration platform, the pre-baking temperature is set to be 80-120 DEG C, and the pre-baking time is 2-5 minutes; the baking temperature of the curing baking is set to be 150-250 DEG C. The volatilization speed of the diluent is slowed down, the bubble size is reduced, and the number of bubbles is reduced, so that the surface roughness of the carbon film is reduced, and the printing quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board processing, and in particular to a method for manufacturing a circuit board for reducing the surface roughness of a carbon film. Background Art

[0002] The Chinese application publication number is CN 107027240 A, and the application publication date is August 8, 2017. It discloses a method for manufacturing a high-resistance carbon film circuit board, including the following steps: a. designing a screen pattern and making a screen; b. using a scraper to print a conductive metal paste on a PCB board through a screen, and forming a conductive metal circuit after drying; c. using a scraper to print a high-resistance ink on the conductive metal circuit through a screen, and forming a first high-resistance carbon film after drying, and the thickness of the first high-resistance carbon film is 7-9μm; d. laying a screen on the first high-resistance carbon film, using a scraper to print a high-resistance ink on the first high-resistance carbon film through a screen, and forming a second high-resistance carbon film after drying, and the thickness of the second high-resistance carbon film is 7-9μm. The present invention decomposes the original one-time printing and forming process into two printings, so that the carbon distribution is more uniform, and the resistance change rate of the formed product can be reduced. The stability of the high-resistance carbon film is high, and the yield of the product is effectively improved. In the actual production process, the defects of the prior art are: when printing carbon film, it is generally printed on a polyester mesh of 250 to 300 mesh, the ink viscosity varies from 150 to 250 dpa.s, and after printing, it is directly placed in a dryer for drying, or directly placed in a tunnel furnace or oven for drying, and the general baking temperature varies from 150°C to 250°C. This printing method causes the diluent to evaporate quickly and generate bubbles, and the bubbles are large and numerous, such as Figure 1 As shown, the result is that the printed surface will crack, resulting in great roughness. In view of this situation, it is urgent to solve it. Summary of the invention

[0003] In view of the above problems, the present invention provides a circuit board manufacturing method for reducing the surface roughness of the carbon film, slowing down the volatilization rate of the diluent, reducing the bubble size, and reducing the number of bubbles, thereby reducing the surface roughness of the carbon film and improving the printing quality.

[0004] To achieve the above object, the present invention solves the problem through the following technical solutions:

[0005] A method for manufacturing a circuit board for reducing the surface roughness of a carbon film, comprising the following steps: pretreatment→preparing a printing screen→printing→curing and baking→post-treatment, wherein in the printing screen preparation process, a 150-200 mesh screen is used, and the ink viscosity is set to 250-350 dpa.s;

[0006] After the printing process is completed, the pre-baking device is first used before the curing and baking process. The conveying platform in the pre-baking device is set as a high-frequency vibration platform, the pre-baking temperature is set to 80° C. to 120° C., and the pre-baking time is 2 to 5 minutes;

[0007] The curing baking temperature is set to 150°C to 250°C.

[0008] Preferably, the printing screen is a polyester screen, and the printing plate distance is set to 2.5-3.5 mm.

[0009] Preferably, the printing screen is a stainless steel screen, and the printing plate distance is set to 1.5-2.5 mm.

[0010] Preferably, the curing and baking process is set to a distance of 10 to 30 m.

[0011] Preferably, the hardness of the scraper used in the printing process is set to 80° to 90°.

[0012] Preferably, in the printing process, the printing speed of 2-3 mesh is set to 200mm / S-300mm / S.

[0013] Preferably, in the step of preparing the printing screen, the mesh angle of the screen is set to 22.5° to 90°.

[0014] The beneficial effects of the present invention are as follows: after the printing process is completed, the pre-baking equipment is first used before the curing and baking process. The conveying platform in the pre-baking equipment is set as a high-frequency vibration platform. Through the low-temperature heating and vibration before the curing and baking process, the diluent evaporates slowly, and small and few bubbles are generated. After the bubbles burst, the effect on the surface roughness is small, thereby reducing the surface roughness of the carbon film and improving the printing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the prior art.

[0016] Figure 2 It is a schematic diagram of the beneficial effects of the present invention.

[0017] The reference numerals are: circuit board substrate 10 , bubble 11 , carbon element 12 . DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0019] Reference Figure 2As shown, a method for manufacturing a circuit board for reducing the surface roughness of a carbon film comprises the following steps: pretreatment → preparation of a printing screen → printing → curing and baking → post-treatment, in the process of preparing the printing screen, a 150-200 mesh screen is used, the ink opening rate under the screen is increased, the influence of mesh knots on ink aggregation is reduced, and the ink viscosity is set to 250-350 dpa.s; after completing the printing process, the ink is first passed through a pre-baking device before the curing and baking process, the conveying platform in the pre-baking device is set to a high-frequency vibration platform, the pre-baking temperature is set to 80°C-120°C, and the pre-baking time is 2-5 minutes; by low-temperature heating and vibration before the curing and baking process, the diluent inside the ink is slowly volatilized, the surface of the carbon film is heated and leveled, causing the ink to dry on the surface, and then enters the dryer for drying, through such an operation setting, small and few bubbles are generated on the surface of the carbon film, and the bubbles have little effect on the surface roughness after bursting, thereby reducing the surface roughness of the carbon film and improving the printing quality.

[0020] The curing baking temperature is set to 150°C to 250°C.

[0021] Preferably, the printing screen is set to be a polyester screen, and the printing plate distance is set to 2.5-3.5 mm.

[0022] Preferably, the printing screen is set to be a stainless steel screen, and the printing plate distance is set to 1.5-2.5 mm.

[0023] Preferably, the curing and baking process is set to a distance of 10 to 30 m.

[0024] Preferably, the hardness of the scraper used in the printing process is set to 80° to 90°.

[0025] Preferably, in the printing process, the printing speed of 2-3 mesh is set to 200mm / S-300mm / S.

[0026] Preferably, in the process of preparing the printing screen, the mesh angle of the screen is set to 22.5° to 90°.

[0027] The above embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film, comprising the following steps: pretreatment → preparation of a printing screen → printing → curing and baking → post-treatment, characterized in that: In the process of preparing the printing screen, a 150-200 mesh screen is used, and the ink viscosity is set to 250-350 dpa.s; After the printing process is completed, the pre-baking device is first used before the curing and baking process. The conveying platform in the pre-baking device is set as a high-frequency vibration platform, the pre-baking temperature is set to 80° C. to 120° C., and the pre-baking time is 2 to 5 minutes; The curing baking temperature is set to 150°C to 250°C.

2. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: The printing screen is set as a polyester screen, and the printing plate distance is set to 2.5-3.5 mm.

3. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: The printing screen is set as a stainless steel screen, and the printing plate distance is set to 1.5-2.5 mm.

4. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: The curing and baking process is set at a distance of 10 to 30 m.

5. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: The hardness of the scraper used in the printing process is set to 80° to 90°.

6. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: In the printing process, the printing speed of 2-3 mesh is set to 200mm / S-300mm / S.

7. A method for manufacturing a circuit board for reducing the surface roughness of a carbon film according to claim 1, characterized in that: In the step of preparing the printing screen, the mesh angle of the screen is set to 22.5° to 90°.

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