TW202042995A - Method for improving PCB drilling - Google Patents

Abstract

The invention discloses a method for improving PCB drilling, which comprises the following steps: directly coating at least one side of a PCB with a composite resin material, and curing the PCB to enable the composite resin material on the PCB to form a composite resin layer; drilling the PCB coated with the composite resin layer; and carrying out film stripping on the drilled PCB to remove the composite resin layer on the PCB. The cured PCB coated with the composite resin material can be directly placed and processed on the table of a drilling machine without combining and adhesive tape pasting, so that the operation is simplified, and the efficiency is improved. The thickness of the composite resin material after curing is less than that of the existing cover plate, so that less effective blade length of the drill bit is occupied, chip removing or lamination adding is facilitated, the drilling-in positioning of the drill bit is facilitated, and the processing accuracy is improved.

Description

A method to improve PCB drilling

The invention relates to the field of PCB drilling, and in particular to a method for improving PCB drilling.

The drilling process is an important process in the production and manufacture of printed circuit boards (PCBs for short). The quality of the drilling process directly affects the performance and quality of the PCB, and even affects the overall reliability of electronic devices containing PCBs. Cover plates and backing plates are key auxiliary materials for PCB drilling processing. During drilling processing, they are usually placed on the upper and lower surfaces of the PCB to be drilled, placed on the drilling machine table, and attached with tape around them. The backing plate has the functions of protecting the PCB surface and table top, improving the drilling performance and quality. Commonly used cover plates include aluminum sheet, film-coated aluminum sheet, cold punching board, etc. Commonly used backing boards include wood fiber board, composite wood backing board, UV board, melamine board, phenolic board, lubricating backing board, etc.

When drilling holes for existing PCB boards, it is necessary to combine the cover, backing board and PCB board and attaching tape, which is complicated and low in efficiency; the thickness of the existing cover board is mostly in the range of 0.1-0.5mm, and the backing board has a certain thickness tolerance ( ±0.05-0.15mm), the effective blade length of the drill needle, which will occupy a certain length, affects the drilling chip removal or laminated design.

Therefore, the existing technology needs to be improved and developed.

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for improving PCB drilling, which aims to solve the problem that the prior art needs to rely on a backing plate or a cover plate when drilling a PCB board.

The technical scheme of the present invention is as follows: A method for improving PCB board drilling, which includes the steps: Pre-coating a composite resin material on at least one side of the PCB board, and curing the PCB board, so that the composite resin material coated on the PCB board forms a composite resin layer; Drilling the PCB board coated with the composite resin layer; The PCB board that has undergone the drilling process is stripped, and the composite resin layer coated on the PCB board is removed.

In the method for improving the drilling of a PCB board, the composite resin material includes a main body resin, a photoinitiator, a filler, a modified acrylic acid, and an additive.

The method for improving the drilling of a PCB board, wherein the composite resin material comprises 30-50 parts by weight of the main resin, 3-7 parts of the photoinitiator, 20-40 parts of the filler, and 10-20 parts by weight The modified acrylic acid and 0.5-3 parts of additives.

The method for improving the drilling of a PCB board, wherein the main resin is selected from one of unsaturated polyester, epoxy resin, trifunctional aliphatic urethane acrylate, polyester resin, polyimide resin and phenolic resin Or multiple.

In the method for improving the drilling of a PCB board, the composite resin material further includes an organic amine.

In the method for improving the drilling of a PCB board, the thickness of the composite resin layer is 10-200 μm.

The method for improving the drilling of a PCB board, wherein, under the condition of 50-90°C, an alkaline solution with a concentration of 3-5% is used to remove the film of the PCB board after the drilling process, and the coating is removed. A composite resin layer covering the PCB board.

The method for improving the drilling of a PCB board, wherein the composite resin material comprises 40 parts by weight of A6700, 0.06 parts of SA2290, 0.04 parts of FL2520, 9 parts of FL4350, 2.5 parts of I940, 4.4 parts of I7510, 10 parts of M280, 11.5 parts of FL-OW, 18 parts of FL2630, 0.5 parts of SA312, 2 parts of SA24 and 2 parts of organic amines.

The method for improving the drilling of a PCB board, wherein the composite resin material is coated on at least one side of the PCB board in advance, and the PCB board is cured, so that the composite resin material coated on the PCB board forms a composite resin The steps of the layer include: Pre-coating a first layer of composite resin material on at least one side of the PCB board, and performing a first curing treatment on the first layer of composite resin material; A second layer of composite resin material is coated on the surface of the first layer of composite resin material that has undergone the first curing treatment, and the second layer of composite resin material is subjected to a second curing treatment.

The method for improving the drilling of a PCB board, wherein the surface of the first layer of composite resin material after the first curing treatment is coated with a second layer of composite resin material, and the second layer of composite resin material After the second curing step, it also includes: Cycle in turn, coating the n+1th layer of composite resin material on the surface of the nth layer of composite resin material that has undergone the nth curing treatment, and curing the n+1th layer of composite resin material for the n+1th time Processing to obtain the composite resin layer, n is an integer greater than or equal to 2.

Beneficial effects: The method for improving the drilling of a PCB board provided by the present invention directly coats at least one side of the PCB board with a composite resin material and cures the PCB board, so that the composite resin material coated on the PCB board Forming a composite resin layer; performing drilling processing on the PCB board; performing film removal processing on the PCB board that has been drilled, and removing the composite resin layer coated on the PCB board. The cured PCB board of the coated composite resin material of the present invention can be directly placed on the drilling machine table for processing, which simplifies the combined operation of the cover, the backing board and the PCB board, improves the efficiency, is conducive to the realization of automatic operation, and its coating The thickness of the composite resin material after curing is smaller than that of the existing cover plate, which reduces the occupation of the effective blade length of the drill bit, facilitates chip removal or increases lamination, and also facilitates the positioning of the drill bit in the drill and improves the processing accuracy.

The present invention provides a method for improving the drilling of PCB boards. In order to make the objectives, technical solutions and effects of the present invention clearer and clearer, the present invention will be described in further detail below. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

The embodiment of the present invention provides a method for improving PCB drilling, as shown in FIG. 1, including the steps: Step S100, pre-coating a composite resin material on at least one side of the PCB board, and curing the PCB board, so that the composite resin material coated on the PCB board forms a composite resin layer; Step S200, drilling the PCB board coated with the composite resin layer; In step S300, the PCB board that has undergone the drilling process is stripped, and the composite resin layer coated on the PCB board is removed.

In this embodiment, the surface of the PCB board that can be used to coat the composite resin material refers to the upper surface and the lower surface of the PCB board, and the upper surface and the lower surface of the PCB board refer to the The two faces of the drill pin in vertical contact.

In some embodiments, the upper surface of the PCB board is coated with a composite resin material, and the PCB board is cured, so that the composite resin material coated on the surface of the PCB board forms a composite resin layer; The composite resin layer on the surface faces the drill pin, and a backing plate is laid on the lower surface of the PCB board to drill the PCB board; finally, the drilled PCB board is stripped to remove the coating on the PCB board. The composite resin layer on the surface of the PCB board.

In this embodiment, the composite resin layer coated on the surface of the PCB board can replace the cover plate in the prior art. When the existing PCB board is drilled, it is necessary to combine the cover plate with the PCB board and attach the tape. The operation is complicated, the efficiency is low, and the thickness of the existing cover plate is mostly in the range of 100-500μm, which will occupy the effective blade length of the drill needle of the same thickness, thereby affecting the drilling chip removal or the laminated design; and the upper surface is coated in this embodiment The PCB board with the composite resin layer can be directly placed on the drilling machine table for drilling without an additional cover plate, which simplifies the operation and improves the efficiency, and the cured thickness of the composite resin layer is less than the existing cover The plate reduces the occupancy of the effective blade length of the drill bit, which is beneficial for chip removal or increase the lamination. At the same time, the hardness of the composite resin layer is lower than that of the aluminum sheet, which is also beneficial for the positioning of the drill bit and improves the processing accuracy.

In some embodiments, the thickness of the composite resin layer can be set to different sizes according to different types of PCB boards.

In some specific embodiments, the thickness of the composite resin layer is 10-200 μm. The thickness of the composite resin layer in this embodiment is generally smaller than that of the existing cover plate, thereby reducing the occupation of the effective blade length of the drill bit.

In some embodiments, the lower surface of the PCB board is coated with a composite resin material, and the PCB board is cured, so that the composite resin material coated on the lower surface of the PCB board forms a composite resin layer; The composite resin layer on the surface faces away from the drill pin, and an additional cover is laid on the upper surface of the PCB board to drill the PCB board; finally, the PCB board that has been drilled is stripped and removed A composite resin layer coated on the lower surface of the PCB board.

In this embodiment, the composite resin layer coated on the lower surface of the PCB board can replace the backing board in the prior art. When drilling the existing PCB board, it is also necessary to combine the backing board with the PCB board and attach the tape. Its operation is complicated and low efficiency, and because the existing backing board is usually a rigid structure and its surface is relatively flat, this makes it easy to generate a gap between the deformed or uneven surface of the PCB board and the backing board, resulting in drilling burrs The existing backing plate has certain thickness tolerances, usually within ±0.05-0.15mm. The thickness tolerance of the backing plate will increase the depth design of the drilling backing plate under the drill bit. Generally, The design is 0.4-1.0mm, which occupies the effective blade length of the longer drill pin, which affects chip removal and lamination design. However, the composite resin layer coated on the lower surface of the PCB board in this embodiment can replace the backing board. Since the composite resin layer is directly coated on the surface of the PCB board, the composite resin layer has a high degree of adhesion to the surface of the PCB board. There is no gap between them, so it can effectively improve the drilling burrs and processing performance of the deformed or uneven surface of the PCB board. It also reduces the influence of the thickness tolerance of the backing plate on the drilling depth design and reduces the dependence on the backing plate . In this embodiment, by coating the composite resin layer on the lower surface of the PCB board, the PCB board can be drilled without using additional pads, or without replacing the pads, or replacing high-end pads, etc. The application flexibility of the backing plate is improved, and the cost of the backing plate is also reduced.

In some embodiments, the upper and lower surfaces of the PCB board are coated with a composite resin material, and the PCB board is cured, so that the composite resin material coated on the lower surface of the PCB board forms a composite resin layer; The PCB board is directly drilled; the PCB board that has been drilled is processed to remove the film, and the composite resin layer coated on the lower surface of the PCB board is removed.

In this embodiment, the composite resin layer is prepared on the PCB board and the lower surface. Therefore, when drilling the PCB board, no additional cover and backing board are needed, and the PCB board can be directly Drilling on the table of the drilling machine simplifies the operation and improves the drilling efficiency; it does not require the operation of attaching a combination cover and a backing plate, which is also conducive to automatic operation.

In some embodiments, the composite resin material includes a host resin, a photoinitiator, a filler, a modified acrylic acid, and an additive. In this embodiment, the modified acrylic can enhance the adhesion of the composite resin material and enhance its leveling; by adjusting the ratio of each component in the composite resin material, different hardness, different adhesion and easy film removal can be obtained The composite resin layer.

In some embodiments, the composite resin material includes 30-50 parts by weight of host resin, 3-7 parts of photoinitiator, 20-40 parts of filler, 10-20 parts of modified acrylic, and 0.5 parts by weight. -3 parts of additives. In this embodiment, the composite resin layer formed by the composite resin material can replace the existing commonly used aluminum sheet, film-coated aluminum sheet, cold punched board, etc., and can also replace the existing commonly used wood fiber board and composite wood backing board. , UV board, melamine board, phenolic board and other backing boards.

In some embodiments, the host resin is selected from one or more of unsaturated polyester, epoxy resin, trifunctional aliphatic urethane acrylate, polyester resin, polyimide resin and phenolic resin, but is not limited thereto .

In a specific embodiment, the main resin is trifunctional aliphatic urethane acrylate, and the trifunctional aliphatic urethane acrylate has fast curing speed, relatively flexible film formation, wear resistance, excellent adhesion, good hardness, Good weather resistance and other advantages. Further, because the trifunctional aliphatic urethane acrylate is a special trifunctional polyurethane, and a large number of alkali-soluble polar groups are grafted on its side chain, the trifunctional aliphatic urethane acrylate is formed as the main resin The composite resin layer is easier to remove the film in the lye, which can effectively improve the removal efficiency.

In some embodiments, the composite resin material further includes an organic amine. Preferably, the composite resin material further includes 1-5 parts by weight of organic amine, because organic amine can effectively promote the penetration of lye into the composite resin layer, and the organic amine can also interact with trifunctional aliphatic polyurethane acrylic The ester exerts a synergistic alkali-removing effect. Therefore, by adding an organic amine to the composite resin material, the film removal performance of the composite resin layer in the alkaline solution can be further improved.

In some specific embodiments, the organic amine is selected from ethylamine, propylamine, butylamine, etc., but not limited thereto.

In some embodiments, the photoinitiator is one or two of I940 and I7510, but is not limited thereto. The two photoinitiators provided in this embodiment can cooperate with each other to provide a suitable photocuring wavelength range.

In some embodiments, the filler is one or more of 3000 mesh talc powder, 1500 mesh talc powder and silica powder, but is not limited thereto.

In some embodiments, the modified acrylic acid is selected from one or more of monofunctional acrylic acid, difunctional hydroxyl-modified acrylic acid and trifunctional propoxy-modified acrylic acid. In this embodiment, the modified acrylic acid is mainly used to enhance the adhesion of the composite resin material and enhance its leveling.

In some embodiments, the additive additives are selected from one or more of silicon leveling agents, phosphate esters, active amines, toners, and dispersants, but are not limited thereto.

In a specific embodiment, the composite resin material comprises 40 parts by weight of A6700 (trifunctional aliphatic urethane acrylate), 0.06 parts of SA2290 (macromolecular dispersant), and 0.04 parts of FL2520 (toner ), 9 parts of FL4350 (microsilica powder), 2.5 parts of I940 (photoinitiator), 4.4 parts of I7510 (photoinitiator), 10 parts of M280 (monofunctional acrylic acid), 11.5 parts of FL-OW (3000 mesh) Talc), 18 parts of FL2630 (1500 mesh talcum powder), 0.5 parts of SA312 (silicon leveling agent), 2 parts of SA24 (phosphate esters) and 2 parts of organic amines.

In some embodiments, the step of pre-coating a composite resin material on at least one side of the PCB board and curing the PCB board so that the composite resin material coated on the PCB board forms a composite resin layer specifically includes: Pre-coating a first layer of composite resin material on at least one side of the PCB board, and performing a first curing treatment on the first layer of composite resin material; A second layer of composite resin material is coated on the surface of the first layer of composite resin material that has undergone the first curing treatment, and the second layer of composite resin material is subjected to a second curing treatment.

Due to different types of PCB boards, it is necessary to prepare composite resin layers of different thicknesses on the PCB to meet their drilling requirements. For example, when preparing composite resin layers with a thickness greater than 100μm, it is usually necessary to coat twice or twice The above composite resin material; this embodiment takes twice coating the composite resin material on the PCB board as an example, in order to ensure that the composite resin material coated for the second time can be stably combined with the composite resin material coated for the first time, The composite resin material of the first coating needs to be cured before the second coating.

In some embodiments, in order to ensure that the composite resin material coated for the second time can be stably combined with the composite resin material coated for the first time, and at the same time, to improve the film removal efficiency of the composite resin layer, the second The energy of the secondary curing process needs to be greater than the energy of the first curing process.

In this embodiment, the coating method includes, but is not limited to, roll coating, spray coating, curtain coating, casting coating, silk screen printing and the like.

In some specific embodiments, the energy of the first curing treatment is 500 mj, and the energy of the second curing treatment is 800 mj. In some embodiments, the curing method includes, but is not limited to, thermal curing, light curing, and the like.

In some embodiments, the second layer of composite resin material is coated on the surface of the first layer of composite resin material after the first curing treatment, and the second layer of composite resin material is cured for the second time After the steps include: Cycle in turn, coating the n+1th layer of composite resin material on the surface of the nth layer of composite resin material that has undergone the nth curing treatment, and curing the n+1th layer of composite resin material for the n+1th time Processing to obtain the composite resin layer, n is an integer greater than or equal to 2.

For multiple coatings on the PCB board, there are mainly two situations: one is that the thickness of the one-time coating is insufficient, and multiple coatings are required to ensure the thickness; the other is to sequentially coat different functional layers of resin, such as when approaching The PCB surface is first coated with a layer of resin with good metal adhesion and high hardness, the middle is coated with a resin with good film-forming properties and high strength, and the surface is coated with a resin layer with good water solubility to achieve a multi-layer functional resin design with more optimized performance. For multiple coating processes, in order to ensure the adhesion between the coating layers and the risk of embrittlement after multiple curing, generally the inner resin layer of the coating needs to be controlled to an appropriate degree of curing. Generally, a slight adhesion to the back of the hand is better, and the degree of curing If it is too low, the resin layer will be in a liquid state or have greater adhesion, which is not conducive to subsequent coating operations; if the degree of curing is too high, it will cause insufficient interlayer adhesion and even embrittlement problems caused by multiple curing.

In some specific embodiments, when it is necessary to achieve the required thickness of the composite resin layer through more than two coatings, the composite resin material needs to be cured once after each coating, and the last time it is cured The processing energy should be 100% fully cured energy to achieve the formation of a stable composite resin layer.

In some embodiments, the stripping method of the composite resin layer can be selected according to the formula and equipment conditions. In this embodiment, it is better to use a concentration of 3-5% under the condition of 50-90°C. The alkaline syrup removes the film on the drilled PCB board, and removes the composite resin layer coated on the PCB board.

Specifically, the thicker the coated composite resin layer, the harsher the stripping conditions and the longer the stripping time. There are strict requirements for the concentration, temperature, time and other parameters of the resin layer to be removed. If the concentration of the drug is too high, the temperature is too high, or the time is too long, it is easy to cause different degrees of microetching or oxidation on the copper foil of the PCB board. Abnormalities, even affecting the quality of the hole in the later process after drilling, and also put forward higher requirements for the temperature resistance or corrosion resistance of the equipment, which needs to be based on the fading performance of the composite resin layer, the film thickness, and the formula of the potion. To reasonably set the technological process and related parameter indexes. For thinner films such as less than 90μm, the film removal time can be controlled to be shorter, such as within 200s, it is recommended to use a continuous horizontal washing line for filming, or use the PCB manufacturer's existing production line such as dry film washing horizontal line for filming ; For thicker films, such as 120μm or more, the stripping time can be controlled for a long time, such as 300s or more, it is recommended to use intermittent trough suspension stripping.

In summary, the method provided by the present invention for improving the drilling of a PCB board directly coats at least one side of the PCB board with a composite resin material and cures the PCB board, so that the composite The resin material forms a composite resin layer; then, the composite resin layer of the PCB board is directed toward the drill pin, and the PCB board is drilled; the PCB board that has undergone the drilling treatment is stripped to remove the coating on the Composite resin layer on PCB board. The cured PCB board coated with the composite resin material of the present invention can be directly processed on the drilling machine table without assembly and tape, which simplifies the operation and improves the efficiency, and the cured thickness of the composite resin material coated is smaller than the existing thickness The cover plate reduces the occupation of the effective blade length of the drill bit, facilitates chip removal or increases the stacking, and also facilitates the positioning of the drill bit in the drill and improves the processing accuracy.

It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or changes can be made based on the above descriptions. All these improvements and changes shall fall within the scope of protection of the attached patent application of the present invention. .

S100: steps S200: steps S300: steps

FIG. 1 is a flowchart of a preferred embodiment of a method for improving PCB board drilling in the present invention.

S100: steps

S200: steps

S300: steps

Claims (10)

A method for improving PCB board drilling is characterized in that it comprises the steps: Pre-coating a composite resin material on at least one side of the PCB board, and curing the PCB board so that the composite resin material coated on the PCB board forms a composite resin layer; Drilling the PCB board coated with the composite resin layer; The drilling process is performed on the PCB board to remove the film, and the composite resin layer coated on the PCB board is removed. The method for improving the drilling of a PCB board according to claim 1, wherein the composite resin material includes a main resin, a photoinitiator, a filler, a modified acrylic, and an additive. The method for improving the drilling of a PCB board according to claim 2, wherein the composite resin material comprises 30-50 parts by weight of the main resin, 3-7 parts of the photoinitiator, 20-40 parts of the filler, 10-20 parts of modified acrylic acid and 0.5-3 parts of additives. The method for improving PCB board drilling as described in claim 2 or 3, wherein the main resin is selected from unsaturated polyester, epoxy resin, trifunctional aliphatic urethane acrylate, polyester resin, and polyimide resin And at least one of the group consisting of phenolic resin. The method for improving the drilling of a PCB board according to claim 2 or 3, wherein the composite resin material further includes an organic amine. The method for improving the drilling of a PCB board according to any one of claims 1 to 3, wherein the thickness of the composite resin layer is 10-200 μm. The method for improving the drilling of PCB board as described in claim 1, wherein, under the condition of 50-90°C, an alkaline solution with a concentration of 3-5% is used to remove the PCB board after drilling Processing to remove the composite resin layer coated on the PCB board. The method for improving PCB board drilling as described in claim 1, wherein the composite resin material comprises 40 parts by weight of A6700, 0.06 parts of SA2290, 0.04 parts of FL2520, 9 parts of FL4350, 2.5 parts of I940 , 4.4 parts of I7510, 10 parts of M280, 11.5 parts of FL-OW, 18 parts of FL2630, 0.5 parts of SA312, 2 parts of SA24 and 2 parts of organic amines. The method for improving the drilling of a PCB board as described in claim 1, wherein the composite resin material is pre-coated on at least one side of the PCB board, and the PCB board is cured to make the composite resin coated on the PCB board The steps of forming the composite resin layer by the resin material specifically include: Pre-coating a first layer of composite resin material on at least one side of the PCB board, and performing a first curing treatment on the first layer of composite resin material; A second layer of composite resin material is coated on the surface of the first layer of composite resin material that has undergone the first curing treatment, and the second layer of composite resin material is subjected to a second curing treatment. The method for improving PCB board drilling according to claim 9, wherein the surface of the first layer of composite resin material that has undergone the first curing treatment is coated with a second layer of composite resin material, and the second layer is composited After the resin material undergoes the second curing treatment step, it further includes: In turn, the n+1th layer of composite resin material is coated on the surface of the nth layer of composite resin material that has undergone the nth curing treatment, and the n+1th layer of composite resin material is cured for the n+1th time. To obtain the composite resin layer, n is an integer greater than or equal to 2.

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