Process for masking of corrosion resistant coating on bearings by dispensing

Abstract

This invention discloses a process for applying adhesive to mask bearings with a corrosion-resistant coating. The process involves demagnetizing the bearing parts, cleaning them before adhesive application, applying a peelable adhesive layer to the surface to be masked using a dispensing machine, forming a continuous masking layer, followed by pre-plating cleaning and activation, and then electroplating to form a corrosion-resistant coating on the unmasked surface. During electroplating, the contact position of the mounting fixture is located in the unmasked area. After electroplating, the parts are sealed and dried, and finally the peelable adhesive is removed, resulting in a bearing with a corrosion-resistant coating that retains the dimensional accuracy and surface quality of the masked surface. This invention is suitable for highly corrosive electroplating conditions, ensuring the stability of the masking on precision working surfaces, balancing the bearing's corrosion resistance and working surface precision, and effectively reducing the manufacturing cost of highly corrosion-resistant bearings.

Description

Technical Field

[0001] This invention relates to the field of bearing surface treatment technology, and more specifically to a process for applying adhesive to mask a corrosion-resistant coating on a bearing. Background Technology

[0002] As the application scenarios of bearings in complex working conditions such as humidity and corrosion continue to expand, improving the corrosion resistance of bearings has become an important research and development direction in this field. Currently, most high corrosion-resistant bearings are made of stainless steel, which results in high overall manufacturing costs and makes it difficult to meet the needs of large-scale, low-cost applications. The solution of using ordinary bearing steel to prepare the substrate and then preparing a corrosion-resistant coating through electroplating can significantly reduce costs while improving corrosion resistance. However, the precision working surfaces of bearings, such as raceways and flanges, have strict requirements for dimensional accuracy and surface quality. Chemical reagents and coating deposition during the electroplating process can easily damage the precision indicators of these working surfaces, thereby affecting the vibration and noise performance and service life of the bearing. Therefore, it is necessary to accurately shield and protect the precision working surfaces before the electroplating process.

[0003] Among existing bearing surface treatment masking technologies, patent document CN115216184A, entitled "Peelable Protective Adhesive for Bearing Phosphating Masking and Preparation Method," discloses a peelable adhesive masking solution. This solution coats the bearing raceway surface with a peelable protective adhesive, meeting the raceway masking requirements under phosphating processes. However, this technical solution is designed for surface treatment processes with mild reaction conditions such as phosphating. The adhesive layer has limited resistance to acid and alkali corrosion and immersion in plating solutions, making it unsuitable for highly corrosive electroplating environments such as zinc-nickel, zinc-chromium, electroless nickel, and black chromium plating. Under electroplating conditions, problems such as adhesive layer swelling, damage, and plating solution penetration easily occur, failing to provide stable and effective masking protection for the precision working surfaces of the bearing. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a process for dispensing and masking corrosion-resistant coatings for bearings. By constructing a full-process dispensing and masking process adapted to highly corrosive electroplating conditions, reliable protection of the precision working surfaces of bearings can be achieved. This process preserves the precision of the working surfaces while preparing the corrosion-resistant coating, thereby reducing the manufacturing cost of bearings.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a process for applying adhesive to mask a corrosion-resistant coating on a bearing, comprising the following steps: Step 1: Demagnetize the machined bearing parts to eliminate residual magnetism on the surface of the bearing parts; Step 2: Clean the demagnetized bearing parts before applying adhesive to remove residual impurities from the bearing surface, including iron filings and grinding fluid. Step 3: Use a dispensing machine to evenly apply the peelable adhesive to the surface of the bearing to be masked, forming a complete and continuous masking adhesive layer; Step 4: Perform pre-plating cleaning and activation treatment on the bearing parts after dispensing to clean and activate the surface of the non-masked areas of the bearing. Step 5: Immerse the bearing parts in the electroplating solution for electroplating treatment to form a corrosion-resistant coating on the unshielded surface of the bearing; during the electroplating process, the contact position of the bearing parts with the hangers is set in the unshielded area. Step Six: Seal and dry the electroplated bearing parts in sequence; Step 7: Remove the peelable adhesive from the bearing surface to be covered to obtain a corrosion-resistant coated bearing that retains the dimensional accuracy and surface quality of the covered surface.

[0006] As a further improvement of the present invention, the bearing surface to be shielded includes the bearing raceway surface and / or the bearing flange surface.

[0007] As a further improvement of the present invention, the pre-plating cleaning and activation treatment in step four is used to remove surface contaminants generated during the dispensing process, and to enhance the adhesion between the non-masked surface and the corrosion-resistant coating through the activation treatment.

[0008] As a further improvement of the present invention, the corrosion-resistant coating in step five is any one of zinc-nickel coating, zinc-chromium coating, electroless nickel coating, and black chromium coating.

[0009] As a further improvement of the present invention, the contact position of the hanger in step five is set in the non-shielded area to avoid damage to the shielding adhesive layer and to prevent uneven coating thickness in the non-shielded area.

[0010] As a further improvement of the present invention, the method for removing the peelable adhesive in step seven is either mechanical automated peeling or manual peeling.

[0011] The beneficial effects of this invention are as follows: By constructing a complete process flow including demagnetization, pre-dispensing cleaning, precision dispensing, pre-electroplating activation, electroplating, sealing and drying, and adhesive removal, a dispensing masking system adapted to the structural characteristics of bearings is built. This system can withstand highly corrosive electroplating environments such as zinc-nickel, zinc-chromium, electroless nickel, and black chromium plating, avoiding problems such as adhesive swelling, damage, and plating solution penetration, thus achieving stable masking of the precision working surface of the bearing. The pre-demagnetization and cleaning processes can improve the adhesion and coating accuracy of the adhesive layer, preventing impurities from affecting the masking and sealing performance. The matching activation and fixture point design can ensure the coating quality, ultimately preparing a qualified corrosion-resistant coating on a common bearing steel substrate, while fully preserving the dimensional accuracy and surface quality of the precision working surface. This replaces stainless steel bearings to reduce costs and can meet the high-precision processing requirements of miniature and thin-walled bearings. By limiting the surface to be masked, the role of cleaning and activation, adapting the coating type, optimizing the fixture points, and selecting the adhesive removal method, the adaptability and masking reliability of the process can be further improved, ensuring the coating quality and the precision of the working surface. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to the given embodiments.

[0013] The process for masking bearings with a corrosion-resistant coating using adhesive dispensing in this embodiment includes the following steps: Step 1: Demagnetize the machined bearing parts to eliminate residual magnetism on the surface of the bearing parts; Step 2: Clean the demagnetized bearing parts before applying adhesive to remove residual impurities from the bearing surface, including iron filings and grinding fluid. Step 3: Use a dispensing machine to evenly apply the peelable adhesive to the surface of the bearing to be masked, forming a complete and continuous masking adhesive layer; Step 4: Perform pre-plating cleaning and activation treatment on bearing part 1 after glue application to clean and activate the surface of the non-masked area of ​​the bearing. Step 5: Place the bearing part 1 into the electroplating solution for electroplating treatment to form a corrosion-resistant coating 4 on the non-shielded surface of the bearing; during the electroplating process, the contact position of the hanger of the bearing part 1 is set in the non-shielded area. Step Six: Seal and dry the electroplated bearing part 1 in sequence; Step 7: Remove the peelable adhesive 2 from the bearing surface to be covered to obtain a corrosion-resistant coated bearing that retains the dimensional accuracy and surface quality of the surface to be covered.

[0014] During the process, the residual magnetism on the surface of the bearing parts is first eliminated by demagnetization to prevent magnetic adsorption of iron filings and impurities that could affect the subsequent bonding and sealing of the adhesive layer. Then, the surface to be masked is cleaned before dispensing to ensure adhesion between the peelable adhesive and the working surface, preventing plating solution from seeping through gaps. A continuous masking adhesive layer is precisely applied using a dispensing machine to adapt to the irregular shape of the bearing's working surface. Before electroplating, the non-plated surface is activated and cleaned to improve the adhesion of the plating layer. During electroplating, the hanger is placed in the non-masked area to prevent damage to the adhesive layer and uneven plating. Finally, after sealing and drying, the adhesive layer is peeled off. This process ensures the corrosion resistance of the plating while preserving the original precision of the working surface. It solves the problems of existing peelable adhesives being unable to adapt to highly corrosive electroplating processes and having insufficient masking stability, achieving a balance between corrosion resistance and working surface precision, and reducing the manufacturing cost of highly corrosion-resistant bearings.

[0015] Furthermore, the surfaces to be shielded on the bearing include the bearing raceway surface and / or the bearing flange surface. This setup allows for targeted shielding of the bearing's core precision working surfaces, precisely protecting critical surfaces that affect bearing operating accuracy and noise performance, while maximizing the coverage of the corrosion-resistant coating. This balances corrosion resistance and operational performance, enhancing the targeted nature and practicality of the process.

[0016] Furthermore, the pre-plating cleaning and activation treatment in step four is used to remove surface contaminants generated during the dispensing process and to improve the adhesion between the unmasked surface and the corrosion-resistant coating. This process can eliminate the impact of contaminants such as excess adhesive and fingerprints on the coating quality during the dispensing process. The activated substrate surface can improve the coating adhesion strength, avoid coating peeling and flaking defects, improve the corrosion resistance life of the coating, and further ensure the electroplating quality and process stability.

[0017] Furthermore, in step five, the corrosion-resistant coating can be any one of zinc-nickel plating, zinc-chromium plating, electroless nickel plating, or black chromium plating. The compatibility of multiple plating systems can meet the needs of bearings with different corrosion levels and application scenarios, expanding the applicability of the process, adapting to corrosion resistance requirements under different working conditions, and improving the universality of the process.

[0018] Furthermore, in step five, the contact point of the hanger is positioned in the unshielded area to prevent damage to the masking adhesive layer and to prevent uneven coating thickness in the unshielded area. By avoiding the masking adhesive layer at the hanger contact point, leakage of the plating solution due to puncture during hanger clamping is prevented. This also avoids thin areas of coating caused by hanger obstruction, ensuring uniform coating thickness in the unshielded area, improving overall corrosion resistance, and further enhancing masking reliability and coating quality.

[0019] Furthermore, in step seven, the adhesive can be removed using either automated mechanical stripping or manual stripping. These multiple stripping methods cater to different production scales. Automated stripping can be used for mass production to improve efficiency, while manual stripping can be used for small batches or irregularly shaped bearings to ensure thorough removal, preventing adhesive residue from affecting the precision of the working surface and improving the process's adaptability to production.

[0020] In summary, this solution employs a complete process chain including demagnetization, pre-cleaning, precision dispensing, activation, electroplating, and sealing removal. Pre-treatment of bearing parts surfaces ensures the adhesion accuracy and sealing of the peelable adhesive, forming a stable masking layer to withstand highly corrosive electroplating environments. Ultimately, a uniform and reliable corrosion-resistant coating is obtained. Peelable adhesive dispensing and masking of precision working surfaces such as bearing raceways and flanges solves the problems of existing peelable adhesives being unable to withstand highly corrosive electroplating environments, having insufficient masking accuracy, and being prone to plating solution penetration. This solution achieves the preparation of a corrosion-resistant coating on a common bearing steel substrate while fully preserving the dimensional accuracy and surface quality of precision working surfaces, effectively reducing the manufacturing cost of highly corrosion-resistant bearings and adapting to the high-precision machining requirements of miniature and thin-walled bearings.

[0021] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A process for applying adhesive to mask a corrosion-resistant plating layer on a bearing, characterized in that, Includes the following steps: Step 1: Demagnetize the machined bearing parts to eliminate residual magnetism on the surface of the bearing parts; Step 2: Clean the demagnetized bearing parts before applying adhesive to remove residual impurities from the bearing surface, including iron filings and grinding fluid. Step 3: Use a dispensing machine to evenly apply the peelable adhesive to the surface of the bearing to be masked, forming a complete and continuous masking adhesive layer; Step 4: Perform pre-plating cleaning and activation treatment on the bearing parts after dispensing to clean and activate the surface of the non-masked areas of the bearing. Step 5: Immerse the bearing parts in the electroplating solution for electroplating treatment to form a corrosion-resistant coating on the unshielded surface of the bearing; during the electroplating process, the contact position of the bearing parts with the hangers is set in the unshielded area. Step Six: Seal and dry the electroplated bearing parts in sequence; Step 7: Remove the peelable adhesive from the bearing surface to be covered to obtain a corrosion-resistant coated bearing that retains the dimensional accuracy and surface quality of the covered surface.

2. The process for applying adhesive to mask the corrosion-resistant coating on bearings according to claim 1, characterized in that: The surfaces of a bearing to be shielded include the bearing raceway surface and / or the bearing flange surface.

3. The process for applying adhesive to mask the corrosion-resistant plating for bearings according to claim 2, characterized in that: Step four, the pre-plating cleaning and activation treatment, is used to remove surface contaminants generated during the dispensing process and to improve the adhesion between the unmasked surface and the corrosion-resistant coating.

4. The process for applying adhesive to mask the corrosion-resistant coating on bearings according to claim 3, characterized in that: In step five, the corrosion-resistant coating can be any one of zinc-nickel coating, zinc-chromium coating, electroless nickel coating, or black chromium coating.

5. The process for applying adhesive to mask the corrosion-resistant plating for bearings according to claim 4, characterized in that: In step five, the contact point of the hanger is set in the unshielded area to avoid damage to the masking adhesive layer and to prevent uneven coating thickness in the unshielded area.

6. The process for applying adhesive to mask the corrosion-resistant plating on bearings according to claim 5, characterized in that: In step seven, the peelable adhesive can be removed by automated mechanical peeling or manual peeling.