Method for improving the problem of glue sticking of a car's rolling wheel

Abstract

This invention relates to the field of automotive manufacturing technology, specifically a method for improving the adhesion problem of automotive edging wheels. A Teflon coating is deposited on the surface of the edging wheel. The Teflon coating process is as follows: S1, Substrate pretreatment: The edging wheel undergoes hard anodizing treatment, forming a 15-20 μm thick porous alumina substrate on the surface of the edging wheel; S2, Coating process: The pretreated edging wheel is vacuum impregnated with a nano-Teflon emulsion, and cured at high temperature to allow the Teflon to fill the pores of the oxide film, forming an ultra-thin continuous anti-stick film on the surface; S3, Final parameters: Surface roughness Ra≤0.8μm, long-term temperature resistance 260℃, coating-substrate adhesion ≥0 grade. Compared with existing technologies, this method solves the edging wheel adhesion problem by modifying the material of the coating on the edging wheel surface to reduce the adhesion of residual adhesive to the edging wheel. The use of a Teflon coating reduces the interfacial adhesion between the folded adhesive and the working surface of the edging wheel, inhibiting residual adhesive adhesion at its source.

Description

Technical Field

[0001] This invention relates to the field of automotive manufacturing technology, and more specifically to a method for improving the problem of adhesive adhesion on automotive hemming wheels. Background Technology

[0002] In current passenger vehicle welding workshops, robotic flexible hemming technology is widely used to replace traditional molding hemming for mass production of opening and closing parts such as doors, hoods, and tailgates. This technology offers advantages such as fast changeover, high flexibility, low equipment investment, and compatibility with multiple vehicle models on the same production line, making it the mainstream process route for OEMs. Before hemming, polyurethane hemming adhesive / sealant is applied to the mating surfaces of the inner and outer panels to improve the vehicle body's sealing, corrosion resistance, and structural strength. During the rolling process, overflow and flying adhesive are prone to occur. The high-viscosity adhesive continuously adheres to the hemming roller, axle, and bracket surfaces. The hemming adhesive cures rapidly at room temperature, and the residual adhesive on the surface of the hemming roller gradually thickens and clumps as production progresses. During rolling, adhesive nodules, adhesive threads, and uneven indentations are formed on the edges of the workpiece, causing hemming wrinkles, gap deviations, and poor appearance. In mass production, the machine needs to be stopped to clean the hemming roller every 20 to 50 pieces; otherwise, the risk of batch scrapping increases sharply.

[0003] However, current technology has the following pain points:

[0004] 1. The cleaning effect of manual glue removal depends entirely on the operator's skill level. Residual glue in the gaps of the rolling wheel and the dead corners of the wheel root cannot be completely removed. The cleaning degree is unstable and it is easy to produce intermittent glue marks and uneven defects. The cost of reworking defective products is high.

[0005] 2. Manually scraping the adhesive with a metal scraper can easily scratch the working surface of the edging wheel. Once scratches are formed on the surface of the edging wheel, the adhesive is more likely to adhere, forming a vicious cycle of "scratching - adhesive accumulation - further scratching". This leads to accelerated wear of the edging wheel, shortened service life, and increased cost of spare parts replacement.

[0006] 3. The hard friction of the scraper block easily causes wear and dimensional deviation on the surface of the rolling roller, resulting in loss of control over the rolling edge clearance accuracy, excessive surface and step differences in batches of workpieces, and affecting the accuracy of subsequent coating and final assembly. (Invention Content)

[0007] To overcome the shortcomings of the prior art, this invention provides a method to improve the adhesion problem of automotive edging wheels. The method solves the adhesion problem by modifying the material of the coating on the surface of the edging wheel to reduce the adhesion of residual adhesive to the edging wheel.

[0008] To achieve the above objectives, a method for improving the adhesion problem of automotive edging wheels is designed, including the edging wheel, characterized in that: a Teflon coating is plated on the surface of the edging wheel, and the process flow for plating the Teflon coating is as follows:

[0009] S1, Substrate pretreatment: Hard anodize the rolling wheel to generate a 15~20μm thick porous alumina substrate on the surface of the rolling wheel.

[0010] S2, Coating process: Vacuum impregnate the pre-treated rolling wheel with nano Teflon emulsion, and cure it at high temperature so that Teflon fills the pores of the oxide film and forms an ultra-thin continuous anti-stick film on the surface.

[0011] S3, final parameters: surface roughness Ra≤0.8μm, long-term temperature resistance 260℃, coating-substrate adhesion ≥0 level.

[0012] The specific process of the coating technology is as follows:

[0013] S2-1, Substrate Inspection: Operators must conduct a comprehensive visual and dimensional re-inspection of the substrate in accordance with the workpiece machining drawings and technical standards for the rolling edge wheel.

[0014] S2-2, Grinding sharp angles: Fine grinding of sharp edges, corners, and cutting edges that exist after the workpiece is processed;

[0015] S2-3, High-temperature degreasing and stress relief: Place the polished roller workpiece into a special high-temperature oven and set the matching temperature to remove stress;

[0016] S2-4, Sandblasting roughening treatment: After degreasing and stress relief, the rolled edge wheel workpiece is placed into a closed sandblasting equipment. Special sand with appropriate particle size is selected, and the sand is driven by high-pressure airflow to impact the overall outer surface of the workpiece and the spraying surface at high speed.

[0017] S2-5, Surface roughness inspection: Operators use a high-precision surface roughness tester to select multiple inspection points at different positions and working surfaces of the rolling wheel workpiece for sampling and full inspection, and record the inspection data;

[0018] S2-6, Sandblasting surface cleaning: A multi-stage cleaning method is adopted. First, a high-pressure clean air source is used to blow the entire workpiece of the rolling wheel in all directions to remove surface dust and loose debris. Then, a dust-free wiping cloth is used with a special cleaning agent to wipe the sprayed surface of the rolling wheel workpiece in detail, focusing on cleaning gaps, corners, grooves and other places where dust easily accumulates.

[0019] S2-7, Preheating and dehumidifying the roller base material: Place the cleaned roller workpiece into the preheating equipment, set the temperature, and keep it warm for a period of time to remove surface moisture from the roller workpiece.

[0020] S2-8, Primer spraying: After the workpiece of the rolling wheel is preheated to the specified temperature and stabilized, it is transferred to the dust-free spraying station for primer spraying.

[0021] S2-9, Intermediate Coating: After the primer has completely pre-dried and cured, clean the dust in the spraying environment and carry out the intermediate coating operation.

[0022] S2-10, topcoat is repeatedly sprayed and sintered multiple times: after a single spraying is completed, it is first leveled at low temperature, and then transferred to a high temperature oven for constant temperature sintering and curing, so that the single-layer topcoat is completely dry and densely formed; after the workpiece of the rolling wheel cools down to room temperature, the next round of topcoat spraying and sintering is carried out again, and the cycle is repeated multiple times.

[0023] S2-11, Finished product appearance inspection: Operators conduct a comprehensive visual inspection of the overall coating of the rolling wheel under a standard light source and strong light environment;

[0024] S2-12, Adhesion test: Sampling inspection using industry standard cross-cut test or pull-out test + full inspection of key batches;

[0025] S2-13, Coating thickness inspection: Using a high-precision digital display thickness gauge, multiple samples are taken at different locations such as the workpiece working surface, corners, curved surfaces, and flat surfaces for inspection, and the film thickness data at each point is recorded;

[0026] S2-14, Electrical spark detection: A dedicated electrical spark leak detector is used. The matching detection voltage is set according to the coating thickness, and the entire coated surface of the roller workpiece is scanned at a uniform speed.

[0027] S2-15, Inner Surface Cleaning: Using dust-free air blowing, special dust-free cloth, and special clean solvent to clean the inner holes, inner walls, gaps, grooves and other hidden places of the roller workpiece, and thoroughly remove residual dust, spray splatter, fine debris, oil and impurities from the process.

[0028] S2-16, Packaging: Packaging and placing the roller roller workpiece.

[0029] The sintering temperature range is 350℃~380℃.

[0030] The temperature range for high-temperature stress relief is 380℃~400℃.

[0031] The roller is one of the following: teardrop edging roller, flat edging roller, conical edging roller, or small edging roller.

[0032] The Teflon coating can also be a DLC (diamond-like carbon) coating.

[0033] Compared with the prior art, the present invention provides a method to improve the problem of adhesive adhesion on automotive hemming wheels. The method solves the problem by modifying the material of the coating on the surface of the hemming wheel to reduce the adhesion of residual adhesive to the hemming wheel. The method uses a Teflon coating to reduce the interfacial adhesion between the folded adhesive and the working surface of the hemming wheel, thereby inhibiting the adhesion of residual adhesive from the source.

[0034] Teflon materials have the following properties:

[0035] 1. Non-stick properties: Teflon (PTFE) has a symmetrical molecular structure, no polar groups, and extremely low surface energy, making it the material with the lowest coefficient of friction among existing solid engineering materials, with a dry coefficient of friction of only 0.04~0.1. Automotive body edge adhesives, PVC sealants, butyl rubber, and other polymeric colloids are all polar substances. According to the principle of "like dissolves like," the interfacial bonding force between polar colloids and non-polar Teflon (PTFE) coatings is extremely weak. During the edge rolling process, the colloid is difficult to wet and adhere to the surface of the edge rolling wheel. Even if a small amount of colloid comes into brief contact, it will not adhere firmly and can be easily removed by slight squeezing or wiping, fundamentally preventing the accumulation of residual adhesive and scaling.

[0036] 2. Wear resistance: The process of rolling the body edge is accompanied by the friction and heat rise of the sheet metal stamping. The curing of the edge adhesive will release trace amounts of chemical additives. Teflon (PTFE) has extremely strong resistance to acids, alkalis and organic solvents and will not be corroded or swollen by the adhesive additives. At the same time, it has a wide temperature range stability and will not soften or become sticky at high temperatures, maintaining its non-stick performance and preventing the adhesive from becoming more sticky due to the temperature rise of the production line. Attached Figure Description

[0037] Figure 1 The main view and sectional view of the teardrop-shaped edge rolling wheel.

[0038] Figure 2 These are the front view and sectional view of the flat hemming wheel.

[0039] Figure 3 These are the front view and sectional view of the tapered rolling wheel.

[0040] Figure 4 The front and side views are of a small edging wheel.

[0041] See Figures 1 to 4 1 is a Teflon coating. Detailed Implementation

[0042] The invention will now be further described with reference to the accompanying drawings.

[0043] Currently, most of the rolling rollers used in the welding of door covers are made of Cr12Mo1V1 material, with chrome plating to enhance their wear resistance. However, because the folding adhesive used in welding has good adhesion to metal, it often results in a certain amount of residual adhesive adhering to the surface of the rolling roller, which affects the subsequent rolling accuracy.

[0044] like Figures 1 to 4 As shown, the present invention focuses on changing the coating material on the surface of the edging wheel, and coating the surface of the edging wheel with a Teflon coating 1 to reduce the adhesion of residual glue to the edging wheel, thus solving the problem of glue adhesion on the edging wheel from the source.

[0045] Teflon (PTFE) coating is used to modify the surface of the crimping head.

[0046] S1, Substrate pretreatment: Hard anodize the rolling wheel to generate a 15~20μm thick porous alumina substrate on the surface of the rolling wheel.

[0047] S2, Coating process: Vacuum impregnate the pre-treated rolling wheel with nano Teflon emulsion, and cure it at high temperature so that Teflon fills the pores of the oxide film and forms an ultra-thin continuous anti-stick film on the surface.

[0048] S3, final parameters: surface roughness Ra≤0.8μm, long-term temperature resistance 260℃, coating-substrate adhesion ≥0 level.

[0049] The specific process of coating is as follows:

[0050] S2-1, Substrate Inspection: Operators must conduct a comprehensive visual and dimensional re-inspection of the substrate in accordance with the workpiece machining drawings and technical standards for the rolling edge wheel.

[0051] S2-2, Grinding sharp angles: Fine grinding of sharp edges, corners, and cutting edges that exist after the workpiece is processed;

[0052] S2-3, High-temperature degreasing and stress relief: Place the polished roller workpiece into a special high-temperature oven and set the matching temperature to remove stress;

[0053] S2-4, Sandblasting roughening treatment: After degreasing and stress relief, the rolled edge wheel workpiece is placed into a closed sandblasting equipment. Special sand with appropriate particle size is selected, and the sand is driven by high-pressure airflow to impact the overall outer surface of the workpiece and the spraying surface at high speed.

[0054] S2-5, Surface roughness inspection: Operators use a high-precision surface roughness tester to select multiple inspection points at different positions and working surfaces of the rolling wheel workpiece for sampling and full inspection, and record the inspection data;

[0055] S2-6, Sandblasting surface cleaning: A multi-stage cleaning method is adopted. First, a high-pressure clean air source is used to blow the entire workpiece of the rolling wheel in all directions to remove surface dust and loose debris. Then, a dust-free wiping cloth is used with a special cleaning agent to wipe the sprayed surface of the rolling wheel workpiece in detail, focusing on cleaning gaps, corners, grooves and other places where dust easily accumulates.

[0056] S2-7, Preheating and dehumidifying the roller base material: Place the cleaned roller workpiece into the preheating equipment, set the temperature, and keep it warm for a period of time to remove surface moisture from the roller workpiece.

[0057] S2-8, Primer spraying: After the workpiece of the rolling wheel is preheated to the specified temperature and stabilized, it is transferred to the dust-free spraying station for primer spraying.

[0058] S2-9, Intermediate Coating: After the primer has completely pre-dried and cured, clean the dust in the spraying environment and carry out the intermediate coating operation.

[0059] S2-10, topcoat is repeatedly sprayed and sintered multiple times: after a single spraying is completed, it is first leveled at low temperature, and then transferred to a high temperature oven for constant temperature sintering and curing, so that the single-layer topcoat is completely dry and densely formed; after the workpiece of the rolling wheel cools down to room temperature, the next round of topcoat spraying and sintering is carried out again, and the cycle is repeated multiple times.

[0060] S2-11, Finished product appearance inspection: Operators conduct a comprehensive visual inspection of the overall coating of the rolling wheel under a standard light source and strong light environment;

[0061] S2-12, Adhesion test: Sampling inspection using industry standard cross-cut test or pull-out test + full inspection of key batches;

[0062] S2-13, Coating thickness inspection: Using a high-precision digital display thickness gauge, multiple samples are taken at different locations such as the workpiece working surface, corners, curved surfaces, and flat surfaces for inspection, and the film thickness data at each point is recorded;

[0063] S2-14, Electrical spark detection: A dedicated electrical spark leak detector is used. The matching detection voltage is set according to the coating thickness, and the entire coated surface of the roller workpiece is scanned at a uniform speed.

[0064] S2-15, Inner Surface Cleaning: Using dust-free air blowing, special dust-free cloth, and special clean solvent to clean the inner holes, inner walls, gaps, grooves and other hidden places of the roller workpiece, and thoroughly remove residual dust, spray splatter, fine debris, oil and impurities from the process.

[0065] S2-16, Packaging: Packaging and placing the roller roller workpiece.

[0066] The sintering temperature range is 350℃~380℃.

[0067] The temperature range for high-temperature stress relief is 380℃~400℃.

[0068] The edging wheel is one of the following: teardrop edging wheel, flat edging wheel, conical edging wheel, and small edging wheel.

[0069] Teflon coating 1 can also be a DLC (diamond-like carbon) coating.

[0070] Teflon materials have the following properties:

[0071] 1. Non-stick properties: Teflon (PTFE) has a symmetrical molecular structure, no polar groups, and extremely low surface energy, making it the material with the lowest coefficient of friction among existing solid engineering materials, with a dry coefficient of friction of only 0.04~0.1. Automotive body edge adhesives, PVC sealants, butyl rubber, and other polymeric colloids are all polar substances. According to the principle of "like dissolves like," the interfacial bonding force between polar colloids and non-polar Teflon (PTFE) coatings is extremely weak. During the edge rolling process, the colloid is difficult to wet and adhere to the surface of the edge rolling wheel. Even if a small amount of colloid comes into brief contact, it will not adhere firmly and can be easily removed by slight squeezing or wiping, fundamentally preventing the accumulation of residual adhesive and scaling.

[0072] 2. Wear resistance: The process of rolling the body edge is accompanied by the friction and heat rise of the sheet metal stamping. The curing of the edge adhesive will release trace amounts of chemical additives. Teflon (PTFE) has extremely strong resistance to acids, alkalis and organic solvents and will not be corroded or swollen by the adhesive additives. At the same time, it has a wide temperature range stability and will not soften or become sticky at high temperatures, maintaining its non-stick performance and preventing the adhesive from becoming more sticky due to the temperature rise of the production line.

[0073] The practical effects of this invention:

[0074] 1. Using a Teflon (PTFE) coating, the body edge adhesive cannot spread and impregnate on the surface of the roller to form a continuous adhesive film, and cannot clump together to form a continuous adhesive film; the time required for cleaning is extended from 1-2 hours to once every 8 hours, reducing the number of unplanned shutdowns per day for a single production line by more than 75%, effectively ensuring the continuous operation of the production line; no scrapers, solvents, or grinding tools are needed, only ordinary dust-free non-woven cloth dry wiping or a small amount of water wiping, which can remove the trace amount of residual adhesive on the surface in one go, and the cleaning time for a single roller is shortened from 10-15 minutes to 1-2 minutes.

[0075] 2. Using Teflon (PTFE) coating, the single coating life of the rolling wheel is stable at 6-8 months, significantly reducing the frequency of rolling wheel disassembly, reassembly, and recoating throughout the year; the cost per workstation covers all costs of rolling wheel procurement, surface spraying, disassembly and assembly labor, downtime capacity loss, and cleaning consumables, directly reducing the annual comprehensive maintenance cost by more than 70%; there is no need to stock up on large quantities of spare rolling wheels, reducing workshop capital occupation and warehousing management workload.

[0076] 3. The use of Teflon (PTFE) coating ensures no residual adhesive buildup on the coating surface, maintaining a smooth and flat working surface for extended periods. During the rolling process, pressure is evenly transmitted to the sheet metal folding area, resulting in stable adhesive distribution due to the pressure exerted by the rolling wheel, preventing localized adhesive squeezing or shortages. Fluctuations in the thickness and width of the adhesive lines on the rolled sheet metal are significantly reduced, significantly improving the stability of the adhesive application process. The overall vehicle rolling appearance and sealing-related defect rate decreases by 0.8 percentage points. This results in substantial annual savings in rework labor, sealant, and rework materials costs, while preventing defective products from flowing into subsequent processes and causing secondary defects in welding and painting. The overall vehicle first-pass yield rate is significantly improved.

Claims

1. A method for improving the adhesion problem of automotive edging wheels, comprising an edging wheel, characterized in that: A Teflon coating is plated on the surface of the rolling wheel (1). The process flow for plating the Teflon coating (1) is as follows: S1, Substrate pretreatment: Hard anodize the rolling wheel to generate a 15~20μm thick porous alumina substrate on the surface of the rolling wheel. S2, Coating process: Vacuum impregnate the pre-treated rolling wheel with nano Teflon emulsion, and cure it at high temperature so that Teflon fills the pores of the oxide film and forms an ultra-thin continuous anti-stick film on the surface. S3, final parameters: surface roughness Ra≤0.8μm, long-term temperature resistance 260℃, coating-substrate adhesion ≥0 level.

2. The method for improving the adhesive adhesion problem of automotive edge rollers according to claim 1, characterized in that: The specific process of the coating technology is as follows: S2-1, Substrate Inspection: Operators must conduct a comprehensive visual and dimensional re-inspection of the substrate in accordance with the workpiece machining drawings and technical standards for the rolling edge wheel. S2-2, Grinding sharp angles: Fine grinding of sharp edges, corners, and cutting edges that exist after the workpiece is processed; S2-3, High-temperature degreasing and stress relief: Place the polished roller workpiece into a special high-temperature oven and set the matching temperature to remove stress; S2-4, Sandblasting roughening treatment: After degreasing and stress relief, the rolled edge wheel workpiece is placed into a closed sandblasting equipment. Special sand with appropriate particle size is selected, and the sand is driven by high-pressure airflow to impact the overall outer surface of the workpiece and the spraying surface at high speed. S2-5, Surface roughness inspection: Operators use a high-precision surface roughness tester to select multiple inspection points at different positions and working surfaces of the rolling wheel workpiece for sampling and full inspection, and record the inspection data; S2-6, Sandblasting surface cleaning: A multi-stage cleaning method is adopted. First, a high-pressure clean air source is used to blow the entire workpiece of the rolling wheel in all directions to remove surface dust and loose debris. Then, a dust-free wiping cloth is used with a special cleaning agent to wipe the sprayed surface of the rolling wheel workpiece in detail, focusing on cleaning gaps, corners, grooves and other places where dust easily accumulates. S2-7, Preheating and dehumidifying the roller base material: Place the cleaned roller workpiece into the preheating equipment, set the temperature, and keep it warm for a period of time to remove surface moisture from the roller workpiece. S2-8, Primer spraying: After the workpiece of the rolling wheel is preheated to the specified temperature and stabilized, it is transferred to the dust-free spraying station for primer spraying. S2-9, Intermediate Coating: After the primer has completely pre-dried and cured, clean the dust in the spraying environment and carry out the intermediate coating operation. S2-10, topcoat is repeatedly sprayed and sintered multiple times: after a single spraying is completed, it is first leveled at low temperature, and then transferred to a high temperature oven for constant temperature sintering and curing, so that the single-layer topcoat is completely dry and densely formed; after the workpiece of the rolling wheel cools down to room temperature, the next round of topcoat spraying and sintering is carried out again, and the cycle is repeated multiple times. S2-11, Finished product appearance inspection: Operators conduct a comprehensive visual inspection of the overall coating of the rolling wheel under a standard light source and strong light environment; S2-12, Adhesion test: Sampling inspection using industry standard cross-cut test or pull-out test + full inspection of key batches; S2-13, Coating thickness inspection: Using a high-precision digital display thickness gauge, multiple samples are taken at different locations such as the workpiece working surface, corners, curved surfaces, and flat surfaces for inspection, and the film thickness data at each point is recorded; S2-14, Electrical spark detection: A dedicated electrical spark leak detector is used. The matching detection voltage is set according to the coating thickness, and the entire coated surface of the roller workpiece is scanned at a uniform speed. S2-15, Inner Surface Cleaning: Using dust-free air blowing, special dust-free cloth, and special clean solvent to clean the inner holes, inner walls, gaps, grooves and other hidden places of the roller workpiece, and thoroughly remove residual dust, spray splatter, fine debris, oil and impurities from the process. S2-16, Packaging: Packaging and placing the roller roller workpiece.

3. The method for improving the adhesive adhesion problem of automotive edge rollers according to claim 2, characterized in that: The sintering temperature range is 350℃~380℃.

4. The method for improving the adhesive adhesion problem of automotive hemming wheels according to claim 2, characterized in that: The temperature range for high-temperature stress relief is 380℃~400℃.

5. The method for improving the adhesive problem of automotive hemming wheels according to claim 1, characterized in that: The roller is one of the following: teardrop edging roller, flat edging roller, conical edging roller, or small edging roller.

6. The method for improving the adhesive problem of automotive hemming wheels according to claim 1, characterized in that: The Teflon coating (1) can also be a DLC diamond-like coating.

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