Method for manufacturing thick ink on printed circuit board

Abstract

The invention discloses a method for manufacturing thick ink on a printed circuit board, which comprises the following steps of: 1, putting the circuit board on a conveying line, conveying the circuit board to a first group of coating rollers, and coating a first layer of ink on the surface of the circuit board by the first group of coating rollers; 2, the circuit board coated with the first layer of ink is conveyed to a first baking chamber to be baked; 3, conveying the baked circuit board to a second group of coating rollers, and coating the surface of the first layer of printing ink with a second layer of printing ink by the second group of coating rollers; fourthly, the circuit board coated with the second layer of ink is conveyed to a second baking chamber to be baked; 5, exposing and developing the circuit board; 6, curing the thick ink on the surface of the circuit board to complete the preparation of the thick ink on the surface of the circuit board; wherein the thickness of the first layer of ink is greater than that of the second layer of ink. According to the invention, the printed circuit board is exposed and developed once after being coated with the ink twice, so that the exposure and development precision of the printed circuit board is ensured, and the production efficiency of the circuit board is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board processing, in particular to a method for producing thick ink for a printed circuit board. Background Art

[0002] After the printed circuit board (PCB) is fabricated, solder mask ink is applied to the outer surface of the PCB to protect it from the external environment. When thick ink needs to be applied to the outer surface of the PCB, a single application of the ink will dry only the surface, leaving the interior dry and prone to peeling. This is why a double coating method is often used. The existing double coating method involves first coating the PCB with a first layer of ink, then placing it in a baking chamber for baking, followed by exposure and development. The PCB is then coated a second time using the same coating roller, applying a second layer of ink, baking it in the same baking chamber at the same temperature, and then exposing and developing it a second time. This double exposure and development method has the following disadvantages: 1. It cannot guarantee consistent exposure and development between the first and second layers of ink (i.e., the first and second layers of ink cannot be aligned after exposure and development), affecting the accuracy of exposure and development of the PCB. 2. This method results in low overall production efficiency for the PCB.

[0003] Based on this, the present invention designs a method for making thick ink for printed circuit boards to solve the above problems. Summary of the Invention

[0004] The object of the present invention is to provide a method for making thick ink for a printed circuit board to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for producing thick ink for a printed circuit board comprises the following steps:

[0007] Step 1: Place the circuit board on the conveyor line and convey it to the first set of coating rollers, which apply the first layer of ink to the surface of the circuit board;

[0008] Step 2: After the first layer of ink is applied, the circuit board is conveyed by a conveyor line to a first baking chamber for baking. The baking temperature range is: 85°C-130°C, for example, it can be 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or 130°C, but is not limited to the listed values. Other values not listed in the numerical range are also applicable.

[0009] Step 3: The baked circuit board is transported by the conveyor line to the second set of coating rollers, which apply the second layer of ink to the surface of the circuit board;

[0010] Step 4: After the second layer of ink is applied, the circuit board is conveyed by the conveyor line to the second baking chamber for baking. The baking temperature range is: 70℃-120℃, for example, it can be 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃ or 120℃, but it is not limited to the listed values. Other values not listed in the numerical range are also applicable.

[0011] Step 5: Expose the circuit board and develop the exposed circuit board;

[0012] Step 6: Curing the thick ink on the surface of the circuit board. The baking temperature range is 140°C-180°C, for example, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C or 180°C, but is not limited to the listed values. Other values not listed in the numerical range are also applicable. The thick ink on the surface of the circuit board is completed.

[0013] The thickness of the first ink layer is greater than the thickness of the second ink layer.

[0014] In some optional examples, the thickness of the first layer of ink is 20um-25um, for example, 20um, 21um, 22um, 23um, 24um or 25um.

[0015] In some optional examples, the thickness of the second layer of ink is 15um-20um, for example, 15um, 16um, 17um, 18um, 19um or 20um.

[0016] Preferably, the first group of coating rollers consists of a first pair of coating rollers, a second pair of coating rollers and a third pair of coating rollers, each of which has an upper roller and a lower roller. The upper roller and the lower roller of the first pair of coating rollers, the lower roller of the second pair of coating rollers and the lower roller of the third pair of coating rollers are all coating rollers with smooth surfaces. The upper roller of the second pair of coating rollers and the upper roller of the third pair of coating rollers are coating rollers with grids on their surfaces.

[0017] In some optional examples, the surface of the upper roller of the second pair of coating rollers is provided with a 25-mesh grid, and the surface of the upper roller of the third pair of coating rollers is provided with a 30-mesh grid.

[0018] Preferably, the second group of coating rollers consists of a fourth pair of coating rollers, a fifth pair of coating rollers and a sixth pair of coating rollers, each of which has an upper roller and a lower roller, which are arranged in sequence; the upper roller and the lower roller of the fourth pair of coating rollers, the lower roller of the fifth pair of coating rollers and the lower roller of the sixth pair of coating rollers are all coating rollers with smooth surfaces; the upper roller of the fifth pair of coating rollers and the upper roller of the sixth pair of coating rollers are coating rollers with grids on their surfaces.

[0019] In some optional examples, the surface of the upper roller of the fifth pair of coating rollers is provided with a 35-mesh grid, and the surface of the upper roller of the sixth pair of coating rollers is provided with a 45-mesh grid.

[0020] In some optional examples, the first baking chamber is sequentially provided with a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone, and a seventh temperature zone. The temperature range of the first temperature zone and the seventh temperature zone is 85° C.-105° C., for example, 85° C., 90° C., 95° C., 100° C., or 105° C., but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0021] The temperature range of the second temperature zone and the third temperature zone is 90°C-110°C, for example, 90°C, 95°C, 100°C, 105°C or 110°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable;

[0022] The temperature range of the fourth temperature zone and the fifth temperature zone is 110°C-130°C, for example, 110°C, 115°C, 120°C, 125°C or 130°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable;

[0023] The temperature range of the sixth temperature zone is 100°C-120°C, for example, it can be 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values. Other unlisted values within the numerical range are also applicable.

[0024] In some optional examples, the second baking chamber is provided with an eighth temperature zone, a ninth temperature zone, a tenth temperature zone, an eleventh temperature zone, a twelfth temperature zone, a thirteenth temperature zone, and a fourteenth temperature zone. The temperature range of the eighth temperature zone and the fourteenth temperature zone is 70° C.-90° C., for example, 70° C., 75° C., 80° C., 85° C., or 90° C., but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0025] The temperature range of the ninth temperature zone and the thirteenth temperature zone is 80°C-100°C, for example, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values, and other values not listed within the numerical range are also applicable;

[0026] The temperature range of the tenth temperature zone is 90-110° C., for example, it can be 90° C., 95° C., 100° C., 105° C. or 110° C., but is not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0027] The temperature range of the eleventh temperature zone and the twelfth temperature zone is 100-120°C, for example, it can be 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0028] Compared with the prior art, the present invention has the following advantages: the present invention coats the printed circuit board with ink twice (coating a first layer of ink and a second layer of ink) and then performs exposure and development once, thereby removing the unexposed first and second layers of ink together. Only one exposure and development is required, thereby ensuring the exposure and development accuracy of the printed circuit board and greatly improving the production efficiency of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A process flow chart for producing thick ink for a printed circuit board of the present invention;

[0031] Figure 2 This is a schematic structural diagram of a thick ink production line for printed circuit boards of the present invention;

[0032] Figure 3 This is a schematic diagram of the temperature zone distribution of the first baking chamber of the present invention;

[0033] Figure 4 This is a schematic diagram of the temperature zone distribution of the second baking chamber of the present invention;

[0034] Figure 5 Schematic diagram of the structure of the coating roller with a smooth surface of the present invention;

[0035] Figure 6 This is a schematic structural diagram of a coating roller with a grid on its surface according to the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0037] Example 1

[0038] Reference Figures 1 to 4 As shown, the present invention provides a method for making thick ink for a printed circuit board, comprising the following steps:

[0039] Step 1: Place the circuit board 1 on the conveyor line 2 and convey it to the first set of coating rollers, which apply the first layer of ink to the surface of the circuit board 1;

[0040] Step 2: After the first layer of ink is applied, the circuit board 1 is conveyed by the conveyor line 2 to the first baking chamber 3 for baking. The first baking chamber 3 is provided with a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone and a seventh temperature zone in sequence. The temperature of the first temperature zone and the seventh temperature zone is set to 85°C, the temperature of the second temperature zone and the third temperature zone is set to 90°C, the temperature of the fourth temperature zone and the fifth temperature zone is set to 110°C, and the temperature of the sixth temperature zone is set to 100°C.

[0041] Step 3: The baked circuit board 1 is conveyed by the conveyor line 2 to the second set of coating rollers, which apply a second layer of ink to the surface of the circuit board 1;

[0042] Step 4: After the second layer of ink is applied, the circuit board 1 is conveyed by the conveyor line to the second baking chamber 4 for baking. The second baking chamber 4 is provided with an eighth temperature zone, a ninth temperature zone, a tenth temperature zone, an eleventh temperature zone, a twelfth temperature zone, a thirteenth temperature zone and a fourteenth temperature zone in sequence. The temperature of the eighth temperature zone and the fourteenth temperature zone is set to 70°C, the temperature range of the ninth temperature zone and the thirteenth temperature zone is 80°C, the temperature range of the tenth temperature zone is 90°C, and the temperature range of the eleventh temperature zone and the twelfth temperature zone is 100°C.

[0043] Step 5: Expose the baked circuit board 1 and develop the exposed circuit board 1 to remove the unexposed first layer of ink and the second layer of ink;

[0044] Step 6: Curing the thick ink on the surface of the circuit board 1, with the baking temperature range being 140°C. The thick ink on the surface of the circuit board 1 is completed;

[0045] The thickness of the first layer of ink is greater than that of the second layer of ink. The thickness of the first layer of ink is 20 μm, and the thickness of the second layer of ink is 15 μm.

[0046] Example 2

[0047] Reference Figures 1 to 4 As shown, the present invention provides a method for making thick ink for a printed circuit board, comprising the following steps:

[0048] Step 1: Place the circuit board 1 on the conveyor line 2 and convey it to the first set of coating rollers, which apply the first layer of ink to the surface of the circuit board 1;

[0049] Step 2: After the first layer of ink is applied, the circuit board 1 is conveyed by the conveyor line 2 to the first baking chamber 3 for baking. The first baking chamber 3 is provided with a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone and a seventh temperature zone in sequence. The temperature of the first temperature zone and the seventh temperature zone is set to 95°C, the temperature of the second temperature zone and the third temperature zone is set to 100°C, the temperature of the fourth temperature zone and the fifth temperature zone is set to 120°C, and the temperature of the sixth temperature zone is set to 110°C.

[0050] Step 3: The baked circuit board 1 is conveyed by the conveyor line 2 to the second set of coating rollers, which apply a second layer of ink to the surface of the circuit board 1;

[0051] Step 4: After the second layer of ink is applied, the circuit board 1 is conveyed by the conveyor line to the second baking chamber 4 for baking. The second baking chamber 4 is provided with an eighth temperature zone, a ninth temperature zone, a tenth temperature zone, an eleventh temperature zone, a twelfth temperature zone, a thirteenth temperature zone and a fourteenth temperature zone in sequence. The temperature of the eighth temperature zone and the fourteenth temperature zone is set to 80°C, the temperature range of the ninth temperature zone and the thirteenth temperature zone is 90°C, the temperature range of the tenth temperature zone is 100°C, and the temperature range of the eleventh temperature zone and the twelfth temperature zone is 110°C.

[0052] Step 5: Expose the baked circuit board 1 and develop the exposed circuit board 1 to remove the unexposed first layer of ink and the second layer of ink;

[0053] Step 6: Curing the thick ink on the surface of the circuit board 1, with the baking temperature range being 160°C. The thick ink on the surface of the circuit board 1 is completed;

[0054] The thickness of the first ink layer is greater than that of the second ink layer. The thickness of the first ink layer is 23 μm, and the thickness of the second ink layer is 18 μm.

[0055] Example 3

[0056] Reference Figures 1 to 4 As shown, the present invention provides a method for making thick ink for a printed circuit board, comprising the following steps:

[0057] Step 1: Place the circuit board 1 on the conveyor line 2 and convey it to the first set of coating rollers, which apply the first layer of ink to the surface of the circuit board 1;

[0058] Step 2: After the first layer of ink is applied, the circuit board 1 is conveyed by the conveyor line 2 to the first baking chamber 3 for baking. The first baking chamber 3 is provided with a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone and a seventh temperature zone in sequence. The temperature of the first temperature zone and the seventh temperature zone is set to 105°C, the temperature of the second temperature zone and the third temperature zone is set to 110°C, the temperature of the fourth temperature zone and the fifth temperature zone is set to 130°C, and the temperature of the sixth temperature zone is set to 120°C.

[0059] Step 3: The baked circuit board 1 is conveyed by the conveyor line 2 to the second set of coating rollers, which apply a second layer of ink to the surface of the circuit board 1;

[0060] Step 4: After the second layer of ink is applied, the circuit board 1 is conveyed by the conveyor line to the second baking chamber 4 for baking. The second baking chamber 4 is provided with an eighth temperature zone, a ninth temperature zone, a tenth temperature zone, an eleventh temperature zone, a twelfth temperature zone, a thirteenth temperature zone and a fourteenth temperature zone in sequence. The temperature of the eighth temperature zone and the fourteenth temperature zone is set to 90°C, the temperature range of the ninth temperature zone and the thirteenth temperature zone is 100°C, the temperature range of the tenth temperature zone is 110°C, and the temperature range of the eleventh temperature zone and the twelfth temperature zone is 120°C.

[0061] Step 5: Expose the baked circuit board 1 and develop the exposed circuit board 1 to remove the unexposed first layer of ink and the second layer of ink;

[0062] Step 6: Curing the thick ink on the surface of the circuit board 1, with the baking temperature range being 180°C. The thick ink on the surface of the circuit board 1 is completed;

[0063] Among them, the thickness of the first layer of ink is greater than the thickness of the second layer of ink. The thickness of the first layer of ink is 25um, and the thickness of the second layer of ink is 20um. Since the thickness of the first layer of ink is greater than the thickness of the second layer of ink, the baking temperature of the first baking chamber 3 is generally greater than the baking temperature of the second baking chamber 4.

[0064] In the above embodiments, Figure 2 As shown, the conveyor line 2 is provided with a first set of coating rollers, a first baking chamber 3, a second set of coating rollers and a second baking chamber 4 in sequence. The first set of coating rollers is composed of a first pair of coating rollers 5, a second pair of coating rollers 6 and a third pair of coating rollers 7, each of which has an upper roller and a lower roller. Figure 5 As shown, the upper roller and the lower roller of the first pair of coating rollers 5, the lower roller of the second pair of coating rollers 6 and the lower roller of the third pair of coating rollers 7 are all coating rollers with smooth surfaces; Figure 6 As shown, the upper rollers of the second pair of coating rollers 6 and the upper rollers of the third pair of coating rollers 7 are coating rollers with grids 8 on their surfaces.

[0065] Preferably, the surface of the upper roller of the second pair of coating rollers 6 is provided with a 25-mesh grid, and the surface of the upper roller of the third pair of coating rollers 7 is provided with a 30-mesh grid. Mesh count refers to the number of grid cells. Within the same square, the larger the mesh count, the smaller the grid cells. Conversely, the smaller the mesh count, the larger the grid cells. Therefore, the difference between 25-mesh and 30-mesh is simply the size of the grid cells. The 25-mesh grid is larger than the 30-mesh grid.

[0066] Specifically, if Figure 2 As shown, the second set of coating rollers consists of a fourth pair of coating rollers 9, a fifth pair of coating rollers 10 and a sixth pair of coating rollers 11, each of which has an upper roller and a lower roller. Figure 5 As shown, the upper roller and the lower roller of the fourth pair of coating rollers 9, the lower roller of the fifth pair of coating rollers 10 and the lower roller of the sixth pair of coating rollers 11 are all coating rollers with smooth surfaces; Figure 6 As shown, the upper roller of the fifth pair of coating rollers 10 and the upper roller of the sixth pair of coating rollers 11 are coating rollers with grids 8 on their surfaces.

[0067] Preferably, the upper rollers of the fifth pair of coating rollers 10 have a 35-mesh grid, and the upper rollers of the sixth pair of coating rollers 11 have a 45-mesh grid. Mesh count refers to the number of grid cells. Within the same square, the larger the mesh count, the smaller the grid cells. Conversely, the smaller the mesh count, the larger the grid cells. Therefore, the difference between 35-mesh and 45-mesh grids lies solely in the size of the grid cells. A 35-mesh grid is larger than a 45-mesh grid. The mesh count of the upper rollers of the fifth pair of coating rollers 10 is larger than that of the upper rollers of the third pair of coating rollers 7. This ensures that the ink applied by the third pair of coating rollers 7 to the surface of the circuit board 1 is relatively rough, allowing the second layer of ink to better bond with the first layer and achieve greater stability. The 45-mesh grid on the upper rollers of the sixth pair of coating rollers 11 ensures that the surface smoothness of the second layer of ink is comparable to that of a circuit board coated with only one layer of ink.

[0068] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0069] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for producing thick ink for printed circuit boards, characterized in that: The steps include: Step 1: Place the circuit board on the conveyor line and convey it to the first set of coating rollers, which apply the first layer of ink to the surface of the circuit board; Step 2: After the first layer of ink is applied, the circuit board is transported by the conveyor line to the first baking chamber for baking. The baking temperature range is: 85℃-130℃; Step 3: The baked circuit board is transported by the conveyor line to the second set of coating rollers, which apply the second layer of ink to the surface of the circuit board; Step 4: After the second layer of ink is applied, the circuit board is transported by the conveyor line to the second baking chamber for baking. The baking temperature range is: 70℃-120℃; Step 5: Expose the circuit board and develop the exposed circuit board; Step 6: Curing the thick ink on the surface of the circuit board, the baking temperature range is 140℃-180℃, and the thick ink on the surface of the circuit board is completed; The thickness of the first ink layer is greater than the thickness of the second ink layer.

2. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The thickness of the first layer of ink is 20um-25um.

3. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The thickness of the second layer of ink is 15um-20um.

4. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The first group of coating rollers consists of a first pair of coating rollers, a second pair of coating rollers and a third pair of coating rollers, each of which has an upper roller and a lower roller. The upper roller and lower roller of the first pair of coating rollers, the lower roller of the second pair of coating rollers and the lower roller of the third pair of coating rollers are all coating rollers with smooth surfaces. The upper roller of the second pair of coating rollers and the upper roller of the third pair of coating rollers are coating rollers with grids on their surfaces.

5. The method for producing thick ink for a printed circuit board according to claim 4, characterized in that: The surface of the upper roller of the second pair of coating rollers is provided with a 25-mesh grid, and the surface of the upper roller of the third pair of coating rollers is provided with a 30-mesh grid.

6. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The second group of coating rollers consists of a fourth pair of coating rollers, a fifth pair of coating rollers and a sixth pair of coating rollers, each of which has an upper roller and a lower roller. The upper roller and the lower roller of the fourth pair of coating rollers, the lower roller of the fifth pair of coating rollers and the lower roller of the sixth pair of coating rollers are all coating rollers with smooth surfaces. The upper roller of the fifth pair of coating rollers and the upper roller of the sixth pair of coating rollers are coating rollers with grids on their surfaces.

7. The method for producing thick ink for a printed circuit board according to claim 6, characterized in that: The surface of the upper roller of the fifth pair of coating rollers is provided with a 35-mesh grid, and the surface of the upper roller of the sixth pair of coating rollers is provided with a 45-mesh grid.

8. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The first baking chamber is provided with a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone and a seventh temperature zone in sequence. The temperature range of the first temperature zone and the seventh temperature zone is 85°C-105°C, the temperature range of the second temperature zone and the third temperature zone is 90°C-110°C, the temperature range of the fourth temperature zone and the fifth temperature zone is 110°C-130°C, and the temperature range of the sixth temperature zone is 100°C-120°C.

9. The method for producing thick ink for a printed circuit board according to claim 1, characterized in that: The second baking chamber is provided with an eighth temperature zone, a ninth temperature zone, a tenth temperature zone, an eleventh temperature zone, a twelfth temperature zone, a thirteenth temperature zone and a fourteenth temperature zone. The temperature range of the eighth temperature zone and the fourteenth temperature zone is 70°C-90°C, the temperature range of the ninth temperature zone and the thirteenth temperature zone is 80°C-100°C, the temperature range of the tenth temperature zone is 90-110°C, and the temperature range of the eleventh temperature zone and the twelfth temperature zone is 100-120°C.

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