An etching method for a bendable resistor

Abstract

This application relates to the field of electronic resistor manufacturing technology. More specifically, it relates to an etching method for bendable resistors. S1: Select stainless steel material, perform high-temperature cleaning on the surface, and use a Dynabrade pen to detect that the stainless steel surface meets the 52# standard; S2: Perform double-sided screen printing on the stainless steel material, use LDI exposure for optical analysis, and develop and form to obtain stainless steel material with a circuit; S3: Spray the etching solution onto the stainless steel material with a circuit through upper and lower spray trays for etching. Among them, adjust the upper and lower spray trays so that the height difference between the upper and lower spray trays is 40 - 60 mm, and set the spraying pressure to 3.5 - 5.0 kg / cm²; S4: Clean the etched stainless steel material to obtain a bendable resistor. Through the above process, the uniformity and precision of etching can be improved, effectively avoiding the common problems of uneven etching and rough edges in traditional etching processes. The manufactured bendable resistor has high resistance value accuracy and good stability, and can meet the high requirements of precision electronic equipment for the performance and reliability of resistors.

Description

Technical Field

[0001] This application relates to the field of electronic resistor manufacturing technology, and more specifically, to an etching method for bendable resistors. Background Art

[0002] Bendable resistors generally refer to those resistors with certain flexibility and bendability, which can adapt to certain deformations without affecting their resistance performance. They have broad application prospects in electronic devices and systems in the fields of flexible electronic devices, space exploration and satellite communication, biomedical devices, robots and automation devices, automobiles, aerospace, and military. In these fields, the devices need to withstand various complex mechanical stresses and environmental changes, and bendable resistors can provide stable electrical performance and reliable connections.

[0003] Among them, the commonly used bendable resistors include stainless steel bendable resistors. The reasons are as follows: Stainless steel bendable resistors can usually provide high resistance accuracy, and the error range is usually within a certain percentage, which can meet the needs of precision electronic devices. At the same time, its resistance changes little during use, has good long-term stability, ensures the continuous reliability of circuit performance, and stainless steel bendable resistors have high mechanical strength, can withstand a certain amount of bending and tensile forces, and ensure the reliability of the resistor during long-term use. Stainless steel bendable resistors are durable, have a long lifespan, can reduce the frequency of replacement and maintenance, and reduce maintenance costs.

[0004] The preparation of stainless steel bendable resistors mainly uses the etching method. The surface of the stainless steel is processed very smoothly by the etching method, and very fine shapes and patterns are processed. This is crucial for bendable resistors that require precise shapes and tiny details. Through the etching method, the resistance accuracy and stability of the resistor can be ensured to meet the requirements of precision electronic devices. However, there are some limitations in traditional etching processes, such as uneven etching and rough edges. Among them, due to improper control of factors such as the concentration, temperature, and etching time of chemical solutions, uneven etching will occur. Improper control of the ratio of the etching solution or the etching time will lead to rough edges. These problems of unevenness and rough edges will affect the resistance accuracy and stability of the resistor, and thus affect the performance and reliability of the resistor.

[0005] To solve the above problems, manufacturers use the method of high-temperature etching to accelerate chemical reactions by increasing the etching temperature. However, this will lead to a decrease in etching uniformity and accuracy, so improvement is needed. Summary of the Invention

[0006] To solve the problems of existing uneven etching, rough edges, and high costs, this application provides an etching method for bendable resistors.

[0007] The present application provides an etching method for bendable resistors, adopting the following technical solutions:

[0008] An etching method for bendable resistors includes the following preparation steps:

[0009] S1. Select stainless steel material, perform high-temperature cleaning on the surface, and use a dyne pen to detect that the stainless steel surface reaches the 52# standard;

[0010] S2. Perform double-sided screen printing on the stainless steel material, conduct optical analysis by LDI exposure, and develop and form to obtain a stainless steel material with a circuit;

[0011] S3. Spray the etching solution onto the stainless steel material with a circuit through upper and lower spray trays for etching. Among them, adjust the upper and lower spray trays so that the height difference between the upper and lower spray trays is 40 - 60 mm, set the spraying pressure to 3.5 - 5.0 kg / cm 2 , and control the temperature within the range of 10 - 20 °C;

[0012] S4. Clean the etched stainless steel material to obtain a bendable resistor.

[0013] By adopting the above technical solutions, the uniformity and precision of etching are improved, effectively avoiding the common problems of uneven etching and rough edges in traditional etching processes. The obtained bendable resistors have high resistance accuracy and good stability, and can meet the high requirements of precision electronic devices for resistor performance and reliability.

[0014] Among them, through high-temperature cleaning of the stainless steel surface and using a dyne pen to detect and reach the 52# standard, the cleanliness and uniformity of the stainless steel surface are ensured, providing a good foundation for the subsequent etching process, and helping to reduce the problem of uneven etching caused by surface contamination or unevenness. Adopting double-sided screen printing and LDI exposure for optical analysis, development and forming can accurately control the shape and size of the circuit pattern, ensure the accuracy and consistency of the circuit pattern during etching, and help to avoid problems such as rough edges and shape distortion.

[0015] By adjusting the height difference (40 - 60 mm) between the upper and lower spray trays, setting the spraying pressure (3.5 - 5.0 kg / cm 2 ), and controlling the temperature (within the range of 10 - 20 °C), the contact mode and reaction rate between the etching solution and the stainless steel material surface can be accurately controlled, which helps to achieve the uniformity and stability of the etching process, and avoids the problems of uneven etching and rough edges caused by improper control of etching solution concentration, temperature or time.

[0016] Preferably, in step S3, oxygen is introduced into the etching solution, and the increase amount of oxygen is 0.8 - 1 m 3 / s.

[0017] By adopting the above technical solutions, the chemical reactions in the etching solution are increased, thereby improving the etching rate. At the same time, by controlling the amount of oxygen introduced, it is possible to ensure that the activity of the etching solution remains consistent throughout the etching process, thereby improving the etching uniformity, optimizing the etching quality, reducing the edge roughness phenomenon, and making the edges of the etched pattern smoother. Preferably, a high-precision gas flowmeter can be used to deliver oxygen to ensure that the oxygen flow rate is precisely controllable.

[0018] Preferably, in step S3, the etching speed is 2.5 - 3.5 m / s.

[0019] By adopting the above technical solutions, at an appropriate etching speed, the etching solution can uniformly contact and react with the stainless steel surface, thereby ensuring the etching uniformity, which helps to improve the resistance value accuracy and stability in the process of preparing the bendable resistor. At the same time, it reduces the production cost and meets the high requirements of precision electronic devices for resistor performance.

[0020] Preferably, the etching solution is prepared from the following raw materials by weight percentage:

[0021] Ferric chloride 20 - 40%

[0022] Hydrochloric acid 4 - 8%

[0023] Ammonium persulfate 1 - 2%

[0024] Ferrous chloride 1 - 3%

[0025] Ethylene glycol monoethyl ether 4 - 8%

[0026] Tartaric acid 1 - 3%

[0027] The balance is water.

[0028] By adopting the above technical solutions, using an etching solution prepared from raw materials with specific weight percentages can significantly improve the etching accuracy and uniformity, optimize the etching speed and surface quality, and improve the stability and service life of the etching solution in the process of preparing the bendable resistor. These effects act together on the resistor preparation process, helping to improve the resistance value accuracy and stability of the resistor.

[0029] Ferric chloride, the main component of the etching solution, has strong oxidizing properties and can undergo redox reactions with metal ions on the stainless steel surface, thereby achieving the etching effect. Hydrochloric acid also adjusts the pH of the etching solution, promoting the etching reaction. Ammonium persulfate accelerates the chemical reactions during the etching process, thereby increasing the etching rate. It also reduces the oxidation reaction between water in the solution and silicon, reducing hydrogen production and promoting a smooth and uniform etching reaction. Ferrous chloride has reducing properties and can react with metal ions generated during the etching process to form the corresponding metal chloride, thereby preventing metal ion accumulation from interfering with the etching process. The addition of ferrous chloride also improves the stability of the etching solution. Ethylene glycol ether and tartaric acid, as additives, can adjust the viscosity and surface tension of the etching solution, thereby improving its fluidity and wettability. This helps the etching solution better penetrate into the tiny gaps on the stainless steel surface, achieving a more refined etching effect.

[0030] Preferably, the ink used for double-sided screen printing in step S2 is prepared by the following method:

[0031] 1) Add maleic rosin resin and modified epoxy acrylic resin into a reaction kettle, heat and stir thoroughly, and continue stirring until all of them become liquid;

[0032] 2) Adding water-based acrylic resin, polyvinyl alcohol, surfactant and distilled water to the above reaction kettle, stirring continuously at a temperature of 45-55°C until all the ingredients are dissolved;

[0033] 3) placing a wetting agent, defoaming agent, nano-metal oxide powder and dispersant into the above reaction kettle and continuously stirring at a temperature of 40-50°C;

[0034] 4) After completion, let it stand and finally filter the material to obtain ink.

[0035] The ink prepared using this technical solution improves the ink's adhesion during double-sided screen printing. The maleic rosin resin and modified epoxy acrylic resin enhance the ink's adhesion, ensuring it resists detachment during etching, facilitating subsequent etching. The addition of water-based acrylic resin and polyvinyl alcohol adjusts the ink's fluidity and viscosity, allowing it to be evenly and smoothly applied to the stainless steel surface during double-sided screen printing. This helps achieve finer, clearer printed patterns and improves the resistor's resistance accuracy and stability.

[0036] The addition of surfactants and dispersants can significantly improve the dispersibility and stability of nano metal oxide powders in the ink. They can reduce the surface tension of the ink, promote the uniform dispersion of nano metal oxide powders in the ink, and prevent particle agglomeration and precipitation. This helps to ensure that the ink can uniformly and consistently etch the stainless steel surface during the etching process, achieving a finer etching effect. The addition of wetting agents can improve the wettability of the ink on the stainless steel surface, making it easier for the ink to be coated on the surface. The addition of defoamers can prevent the ink from generating bubbles during the printing process, which affects the printing effect.

[0037] Preferably, the weight parts of the raw materials used for preparing the ink are as follows:

[0038] Maleic acid rosin resin: 3 - 5 parts

[0039] Modified epoxy acrylate resin: 1 - 2 parts

[0040] Waterborne acrylic resin: 5 - 10 parts

[0041] Polyvinyl alcohol: 5 - 10 parts

[0042] Surfactant: 1 - 2 parts

[0043] Distilled water: 25 - 30 parts

[0044] Wetting agent: 3 - 5 parts

[0045] Defoamer: 1 - 2 parts

[0046] Nano metal oxide powder: 4 - 8 parts

[0047] Dispersant: 2 - 3 parts.

[0048] By adopting the above technical solution and optimizing the dosage of the prepared ink, the ink has a suitable viscosity and fluidity, which is beneficial to improving the adhesion of the ink, ensuring that the ink is not easy to fall off during the etching process, and facilitating subsequent etching.

[0049] Preferably, the fluid viscosity of the modified epoxy acrylate resin at 25°C is 15000 - 25000 mPa·s, and the acid value is less than 3 mgKOH / g.

[0050] By adopting the above technical solution, the fluid viscosity of the modified epoxy acrylate resin at 25°C is within a moderate range, neither too viscous nor too thin, which enables the ink to be uniformly and smoothly coated on the stainless steel surface during the double-sided screen printing process, helps to achieve a finer and clearer pattern printing effect, and improves the resistance value accuracy and stability.

[0051] Preferably, the acid value of the maleic acid rosin resin is 16 - 220 mgKOH / g, and the softening point is 108 - 170°C.

[0052] By adopting the above technical solution, the acid value and softening point of maleic rosin are optimized, further improving the good fluidity and transferability of the ink, and ensuring the clarity and uniformity of the printed matter.

[0053] Preferably, the high-temperature cleaning process in step S1 is as follows:

[0054] Mix 40 - 50 g / L of sulfuric acid, 80 - 100 g / L of citric acid, 30 - 40 g / L of aminosulfonic acid, 100 - 120 g / L of nano-silica, 40 - 50 g / L of polyethylene glycol, 5 - 15 g / L of hydrogen peroxide, and 4 - 5 g / L of dodecylpyridine to obtain a cleaning solution;

[0055] Heat the stainless-steel material to 100 - 120 °C, then immerse the stainless-steel material in the cleaning solution, ultrasonicate for 1 - 2 h, with an ultrasonic frequency of 50 - 60 kHz and a power of 500 - 600 W, and then rinse with clear water and dry.

[0056] By adopting the above technical solution, the surface of the stainless-steel material after high-temperature cleaning treatment is smoother and cleaner, which helps the subsequent etching process to proceed more smoothly. Heating the stainless-steel material to 100 - 120 °C increases the surface temperature of the material, making the chemical components in the cleaning solution more active, accelerating the chemical reaction and physical action, thereby enhancing the cleaning effect. Ultrasonication for 1 - 2 h, with a frequency of 50 - 60 kHz and a power of 500 - 600 W, can generate strong vibrations and cavitation effects. These effects can penetrate the tiny gaps on the stainless-steel surface, shake out the stains hidden therein and disperse them into the cleaning solution.

[0057] In summary, the present application has the following beneficial effects:

[0058] 1. In the present application, through steps such as high-temperature cleaning - double-sided screen printing - LDI exposure for optical analysis - low-temperature spraying of etching solution, the foldable resistor prepared has a smoother surface, finer shape and pattern, and significantly improved resistance value accuracy and stability of the resistor, effectively solving the problems of uneven etching and rough edges in the traditional etching process, thereby improving the performance and reliability of the resistor. Specific Embodiments

[0059] The maleic rosin resin was all purchased from Fengyi Rosin Factory in Guiping City, Guangxi.

[0060] The modified epoxy acrylate resin was all purchased from Shandong Shoucheng Chemical Co., Ltd.

[0061] The waterborne acrylic resin was purchased from Shandong Kepler Biotechnology Co., Ltd., with the model kpl - 63666.

[0062] Preparation Examples

[0063] Preparation Example 1

[0064] An ink for double-sided printing is prepared by the following method:

[0065] 1) Add 30 g of maleic acid rosin resin and 10 g of modified epoxy acrylate resin to a reaction kettle, heat and stir thoroughly, and continue stirring until all become liquid;

[0066] 2) Add 50 g of waterborne acrylic resin, 50 g of polyvinyl alcohol, 10 g of surfactant (coconut glucoside), and 250 g of distilled water, and put them into the above reaction kettle, and continue stirring at a temperature of 45 °C until all are dissolved;

[0067] 3) Put 30 g of wetting agent (sodium stearate), 10 g of defoaming agent (lauric acid), and 40 g of nano metal oxide powder (iron oxide) into the above reaction kettle, and continue stirring at a temperature of 40 °C;

[0068] 4) After completion, let it stand still, and finally filter and discharge to obtain the ink.

[0069] The fluid viscosity of the modified epoxy acrylate resin at 25 °C is 15000 - 25000 mPa·s, and the acid value is less than 3 mgKOH / g.

[0070] The acid value of the maleic acid rosin resin is 16 mgKOH / g, and the softening point is 108 °C.

[0071] The differences between Preparation Examples 2 - 3 and Preparation Example 1 are that the types and dosages of the raw materials for preparing the ink for double-sided printing and the experimental parameters are different, and the specific differences are shown in Table 1:

[0072] Table 1 Types, dosages of raw materials for preparing the ink for double-sided printing in Preparation Examples 1 - 3 and experimental parameters

[0073]

[0074] Preparation Example 4

[0075] An ink for double-sided printing. The difference between this preparation example and Preparation Example 1 is that the nano metal oxide powder is obtained by mixing iron oxide, magnesium oxide, and aluminum oxide in a weight ratio of 5:1:3.

[0076] Preparation Example 5

[0077] An ink for double-sided printing. The difference between this preparation example and Preparation Example 1 is that the nano metal oxide powder is obtained by mixing iron oxide, magnesium oxide, and aluminum oxide in a weight ratio of 5:3:3.

[0078] Preparation Example 6

[0079] An etching solution is prepared by the following method:

[0080] Mix ferric chloride, hydrochloric acid, ammonium persulfate, ferrous chloride, ethylene glycol monoethyl ether, tartaric acid and water evenly to obtain an etching solution.

[0081] The differences between Preparation Examples 7 - 8 and Preparation Example 6 lie in the types and dosages of the raw materials for preparing the etching solution and the experimental parameters. The specific differences are shown in Table 2:

[0082] Table 2 Types, dosages of raw materials and experimental parameters for preparing the ink used in double - sided printing in Preparation Examples 6 - 8

[0083] Types and dosages of experimental raw materials and experimental parameters Preparation Example 6 Preparation Example 7 Preparation Example 8 Ferric chloride (g) 200 300 400 Hydrochloric acid (g) 40 60 80 Ammonium persulfate (g) 10 11 12 Ferrous chloride (g) 10 20 30 Ethylene glycol monoethyl ether (g) 40 60 80 Tartaric acid (g) 10 20 30 Water (g) 690 529 368

[0084] Preparation of Comparative Examples

[0085] Preparation of Comparative Example 1

[0086] An ink for double - sided printing. The difference between this comparative preparation example and Preparation Example 1 is that rosin resin is used instead of maleic rosin resin.

[0087] Hydrogenated rosin resin is purchased from Henan Dazheng Chemical Products Co., Ltd., with the product number 138.

[0088] Preparation of Comparative Example 2

[0089] An ink for double - sided printing. The difference between this comparative preparation example and Preparation Example 1 is that epoxy resin is used instead of modified epoxy acrylate resin.

[0090] Epoxy resin is purchased from Henan Huineng Resin Co., Ltd., with the model E - 51.

[0091] Preparation of Comparative Example 3

[0092] An ink for double - sided printing. The difference between this comparative preparation example and Preparation Example 1 is that silica is used instead of nano - metal oxide powder.

[0093] Examples

[0094] Example 1

[0095] An etching method for a bendable resistor is prepared by the following method:

[0096] S1. Select a stainless - steel material with a thickness of 0.2 mm, perform high - temperature cleaning on the surface, and use a Dynabrade pen to detect that the stainless - steel surface reaches the 52# standard;

[0097] S2. Perform double - sided screen printing on the stainless - steel material, use the ink prepared in Preparation Example 1 for printing, perform optical analysis by LDI exposure, and develop and form to obtain a stainless - steel material with a circuit;

[0098] S3. Spray the etchant in Preparation Example 6 onto the stainless steel material with circuits through the upper and lower spray discs for etching. Among them, adjust the height of the upper spray pipe rack to 60 mm, the height of the lower spray pipe rack to 100 mm, maintain the direct injection height of the chemical solution, and set the spraying pressure to 3.5 kg / cm 2 , control the temperature at 10 °C, set the etching time to 15 minutes, and the etching speed to 2.5 m / s;

[0099] S4. Clean the etched stainless steel material to obtain a bendable resistor.

[0100] The high-temperature cleaning process in Step S1 is as follows:

[0101] Mix 40 g / L of sulfuric acid, 80 g / L of citric acid, 30 g / L of sulfamic acid, 100 g / L of nano-silica, 40 g / L of polyethylene glycol, 5 g / L of hydrogen peroxide, and g / L of dodecylpyridine to obtain a cleaning solution;

[0102] Heat the stainless steel material to 100 - 120 °C, then immerse the stainless steel material in the cleaning solution, perform ultrasonic treatment for 1 - 2 h, the ultrasonic frequency is 50 - 60 kHz, the power is 500 - 600 W, then rinse with clean water and dry.

[0103] The differences between Example 2 - 3 and Example 1 are that the types and dosages of the raw materials for preparing the bendable resistor and the experimental parameters are different. The specific differences are shown in Table 2:

[0104] Table 3 Types, dosages of raw materials and experimental parameters for preparing bendable resistors in Examples 1 - 3

[0105]

[0106]

[0107] Example 4

[0108] An etching method for a bendable resistor. The difference between this example and Example 1 is that the ink comes from Preparation Example 4.

[0109] Example 5

[0110] An etching method for a bendable resistor. The difference between this example and Example 1 is that the ink comes from Preparation Example 5.

[0111] Example 6

[0112] An etching method for a bendable resistor. The difference between this example and Example 1 is that in Step S3, oxygen is introduced into the etchant using a high-precision gas flow meter, and the increased amount of oxygen is 0.8 m 3 / s.

[0113] Example 7

[0114] An etching method for a bendable resistor. The difference between this example and Example 1 is that: in step S3, oxygen is introduced into the etching solution by using a high-precision gas flowmeter, and the increase amount of oxygen is 1m 3 / s.

[0115] Comparative example

[0116] Comparative example 1

[0117] An etching method for a bendable resistor. The difference between this comparative example and Example 1 is that: in step S1, the stainless steel material is directly placed in the cleaning solution for cleaning.

[0118] Comparative example 2

[0119] An etching method for a bendable resistor. The difference between this comparative example and Example 1 is that: the temperature in step S3 is controlled at 30°C.

[0120] Comparative example 3

[0121] An etching method for a bendable resistor. The difference between this comparative example and Example 1 is that: the spraying pressure in step S3 is 2 kg / cm 2 .

[0122] Comparative example 4

[0123] An etching method for a bendable resistor. The difference between this comparative example and Example 1 is that: in step S1, the stainless steel material is directly placed in pure water for cleaning.

[0124] Detection method / Test method

[0125] Observe whether there are burrs or flash: Use a 40-fold magnifying glass to observe the bendable resistors prepared in Examples 1-7 and Comparative examples 1-3, and observe whether there are burrs or flash at the etched places.

[0126] Surface finish: Use a roughness meter to detect the surface finish of the vertical and horizontal cross-sections of the bendable resistors prepared in Examples 1-7 and Comparative examples 1-3.

[0127] Resistance test: Randomly select 4 areas from the bendable resistors prepared in Examples 1-7 and Comparative examples 1-3, use a resistance tester to measure the resistance of each area, and record whether the maximum difference in the measured resistance values of different areas of the same piece of material is only 0.0002 Ω. The experimental data is shown in Table 4:

[0128] Table 4 Experimental data of Examples 1-7 and Comparative examples 1-3

[0129] Example or Comparative Example Whether there are burrs or rough edges Surface finish Resistance test Example 1 None 1.8 0.0002 Example 2 None 1.8 0.00019 Example 3 None 1.8 0.00018 Example 4 None 1.8 0.00011 Example 5 None 1.8 0.00012 Example 6 None 1.8 0.00015 Example 7 None 1.8 0.00016 Comparative Example 1 There are burrs 2.4 Yes Comparative Example 2 There are rough edges 1.8 Yes Comparative Example 3 There are rough edges 1.8 Yes Comparative Example 4 There are burrs 2.8 Yes

[0130] Comparing Example 1 with Comparative Examples 1-4, in Comparative Examples 1-4, burrs and flash were observed during the inspection for burrs or flash; the value in the surface finish test for Comparative Example 1 was 2.4; the resistance errors in the resistance tests for Comparative Examples 1-4 were all greater than 0.0002 Ω, indicating that the foldable resistor prepared by the process in this application can effectively improve the etching uniformity and precision, and reduce the problems of uneven etching and rough edges.

[0131] Comparing Example 1 with Examples 4-5, the resistance error values in the resistance tests for Examples 4-5 were all smaller than that of Example 1, indicating that by using iron oxide, magnesium oxide, and aluminum oxide in specific weight ratios, the etching uniformity and precision can be effectively improved.

[0132] Comparing Example 1 with Examples 6-7, the resistance error values in the resistance tests for Examples 6-7 were all smaller than that of Example 1, indicating that appropriate addition of oxygen is beneficial to improving the etching uniformity and precision.

[0133] This specific embodiment is only an interpretation of this application and does not limit this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. An etching method for a bendable resistor, characterized in that, The method comprises the following preparation steps: S1. Select stainless steel material, perform high temperature cleaning on the surface, and use a dyne pen to test whether the stainless steel surface meets the 52# standard; S2. Double-sided screen printing is performed on the stainless steel material, optical analysis is performed using LDI exposure, and development is performed to obtain a stainless steel material with a circuit; S3. Spray the etching liquid onto the stainless steel material with the circuit through the upper and lower spray plates to perform etching. The upper and lower spray plates are adjusted so that the height difference between the upper and lower spray plates is 40-60 mm, the spray pressure is set to 3.5-5.0 kg / cm², and the temperature is controlled within the range of 10-20°C. S4, cleaning the etched stainless steel material to obtain a bendable resistor; In step S3, oxygen is introduced into the etching solution, and the increased amount of oxygen is 0.8 - 1 m 3 / s; In step S3, the etching speed is 2.5-3.5 m / s; The high temperature cleaning process in step S1 is as follows: Mix 40-50 g / L of sulfuric acid, 80-100 g / L of citric acid, 30-40 g / L of sulfamic acid, 100-120 g / L of nano-silica, 40-50 g / L of polyethylene glycol, 5-15 g / L of hydrogen peroxide, and 4-5 g / L of dodecylpyridine to obtain a cleaning solution; Heat the stainless steel material to 100-120℃, then soak it in the cleaning solution, ultrasonicate it for 1-2 hours, with an ultrasonic frequency of 50-60kHz and a power of 500-600W, then rinse it with clean water and dry it. The ink used for double-sided silk screen printing in step S2 is prepared by the following method: 1) Add maleic rosin resin and modified epoxy acrylic resin into the reactor, heat and stir thoroughly, and continue stirring until all become liquid; 2) Place water-based acrylic resin, polyvinyl alcohol, surfactant, and distilled water into the above-mentioned reactor and continue stirring at 45-55°C until all the ingredients are dissolved; 3) Place the wetting agent, defoaming agent and nano-metal oxide powder into the above reactor and continue stirring at a temperature of 40-50°C; 4) After completion, let it stand and finally filter the material to obtain the ink; The weight parts of the raw materials used to prepare the ink are as follows: 3-5 parts of maleic rosin resin 1-2 parts of modified epoxy acrylic resin 5-10 parts water-based acrylic resin 5-10 parts polyvinyl alcohol 1-2 parts surfactant 25-30 parts distilled water 3-5 parts wetting agent 1-2 parts defoaming agent 4-8 parts of nano-metal oxide powder.

2. The etching method of the bendable resistor according to claim 1, wherein: The modified epoxy acrylic resin has a fluid viscosity of 15000-25000 mPa.s at 25° C. and an acid value of less than 3 mgKOH / g.

3. The etching method of the bendable resistor according to claim 1, characterized in that: The maleic rosin resin has an acid value of 16-220 mgKOH / g and a softening point of 108-170°C.

4. The etching method of the bendable resistor according to claim 1, characterized in that: The nano-metal oxide powder is obtained by mixing iron oxide, magnesium oxide and aluminum oxide in a weight ratio of 5: (1-3):

3.

5. The etching method of the bendable resistor according to claim 1, characterized in that, The etching solution is prepared from the following raw materials in percentage by weight: Ferric chloride 20-40% Hydrochloric acid 4-8% Ammonium persulfate 1-2% Ferrous chloride 1-3% Ethylene glycol ether 4-8% Tartaric acid 1-3% The balance is water.

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