Concrete measures to reduce body particles on the paint shop site and prevent
HC Surface Treatment Network News: The amount of particulate impurities in the body after painting has always been the main factor affecting the delivery quality and production speed of the paint shop. Brilliance China Coatings Workshop has reduced the amount of particulate impurities in the body by taking various measures. From the initial record in February 2012 to the two years in December 2014, the body particles of the paint have dropped from 80 points to 20 points. 1. Pre-processing quality control A large increase in the number of sub-groove magnets and an increase in cleaning frequency: The A-class car body panels produced by the company are all composed of cold-rolled plates. The application of a large number of cold-rolled sheets places high demands on the ability of pre-treatment to remove oil and remove iron filings. The pretreatment of each tank has a high iron filing content, and the magnetic rod and the iron removal removing device in the filter tank cannot guarantee the quality requirements of the outer surface of the electrophoresis vehicle body. The method of pre-treating each tank (excluding the phosphating tank) and adding the magnetic rod to remove the iron scraps is carried out, and according to the iron scrap content between the tanks, different cleaning frequencies are determined (from 2 hours/time to 8 Hours/times). By this method, the number of particles in the surface of the electrophoresis body has been reduced from 50 to 70 points to less than 30 points. 2. Electrophoresis polishing quality control 2.1 Change the grinding method The electrophoresis polishing method in the workshop has been changed twice in total. The initial grinding method is heavy wet grinding and grinding of the whole vehicle. Because of the large amount of grinding mud and the large amount of ash in the corner gap, the analysis of the body particles after painting by the microscope reveals that after the topcoat About 30% of body defects come from sanding ash. The first operation change was made to change the grinding of the whole vehicle to a small area of ​​defect grinding (the treatment of the electrophoresis body has a hand defect and is polished with the area of ​​one finger belly), and the number of particles after the application is reduced by 20%. However, this method can not accurately grasp the grinding force when dealing with defects, because the finger grinding force is large, it is easy to cause the grinding body to appear after the paint, the visual difference is poor, the electrophoresis particles are omitted, and the electrophoresis body phosphating slag is more Simple point grinding can not handle more phosphating slag defects in the body. Therefore, the second adjustment was made, and the outer surface of the body A area was changed to lightly honing, and the granules that still existed after the grinding were focused on. The grinding method after the second change has the following advantages compared to the previous two grinding methods: 1) Gently pull the sand and there will be no more abrasive ash. 2) The whole vehicle A area is subjected to the grinding, and the electrophoresis defects are rarely missed. 3) When grinding the A area of ​​the whole vehicle, apply 8 or more pieces of water sandpaper to level the sanding, and there will be no finger-printing grinding pit after the paint. 4) After the grinding, the outer surface of the car body is smooth, and most of the fine phosphating slag has been smoothed, and the short-wave of the orange peel of the car body is improved after the paint. 5) Employees' operation saves time and effort, and does not cause eye discomfort when looking for defects carefully. The number of particles after the improvement of the paint by two grinding methods decreased by an average of 10 to 15 points compared with the initial number of particles. 2.2 Improve the quality of cleaning and polishing 2.2.1 Wipe rag high frequency replacement For the 3C1B spraying method adopted by the company, the quality of electrophoretic polishing and cleaning of the car directly affects the quality of the car after the paint, and the effect of electrophoretic grinding and cleaning on the quality of the body after painting is extremely important. Compared with the grinding machine, the interior of the workshop pays more attention to the control of the quality of the cleaning car. After the experiment is verified, each grinding and polishing machine employee will change the body of the 4M to replace the 3M high-performance wiping cloth; the cleaning staff will produce 4 bodies per body. Replace the 3M high-performance wipes once, and fold each rag into 4 folds, and use 20% off each production car. 2.2.2 easy to ignore the area of ​​key wipe The inner and outer surfaces of the vehicle body are wiped without dead angles, and the key areas of the body that are easy to store the ash are: the front cover inner panel by the windshield edge, the instrument panel, the top cover flow tank, the door hinge and the hinge lower threshold horizontal area, the back cover hinge and the hinge Windshield edge. Wiping in the critical area effectively reduces the frequency of post-paint defects at the corners and gaps. At the same time, when cleaning the car, pay attention to the fact that the wiping cloth does not touch the sharp parts such as the body stop, so as to avoid the fiber of the wiping cloth being scraped off and remaining in the body to cause fiber defects after the paint. Editor in charge: Zheng Bijia 2.2.3 Cleaning details Because the bolts for fixing the door hinges in the welding workshop are painted and reused with bolts (Fig. 1), the bolts on the door of the bolts are prone to the problem of falling paint slag after installation, resulting in paint slag falling under the hinges of the front and rear doors A and B. Falling, so when polishing and topcoat cleaning, focus on the hinges, recovery bolts, and A and B columns (see Figure 2). In addition, the four-door tooling installation and disassembly are respectively operated in the welding and assembly workshops. During the operation, the tooling is thrown into the tooling box, and the tooling often bumps. In the production process of the painting workshop, the door is infinite position, and no attention is paid. The free closing of the door is particularly likely to cause defects such as falling paint slag and impurities, so the handling of the door tooling during the polishing, topcoat cleaning, and operation is also a key consideration in cleaning the car. 3. The quality of the top coat is improved (the top coat line is 3C1B spray, no medium paint is polished) 3.1 Robot gun sleeve material replacement In the early stage of production, the top coat robot sleeve is made of anti-static cloth material. It can be recycled after cleaning. The multiple layers of the sleeves of the gun coat sleeves are prone to residual paint residue, which is easy to be caused during replacement, cleaning, drying and transportation. The secondary pollution of the sleeves of the guns (external dust and fibers) causes the formation of defects after the paint, and even if the vacuum cleaner is installed on the sleeve of the robot, the foreign fibers cannot be processed. In response to this problem, the shop changed its material to a plastic sheet. After experimental comparison, the plastic sheet material was free from impurities. After statistical paint, the average body particle size of the car body decreased by 2.5 points. 3.2 Topcoat hand repair area is easy to ignore In the early stage of the workshop, the defects of a large amount of fiber and lacquer in the high-light area of ​​the four door door handles of the paint body are often found in the early stage of the workshop. Especially the high-light area defects on the outer surface of the door tooling are particularly obvious. quality. In a day of production, it was found that a large amount of fiber appeared in the high-light area next to the front and rear door handles on the left side of the car body, which was in sharp contrast with the right side. It was found that the left-handed hand-worked employees of the lacquer were not wearing long-fiber gloves as required and wore their own short purchases. The fiber gloves caused defects. After analysis, it was confirmed that most of the long-term fibers and impurities in the high-light area of ​​the front door came from the arbitrariness of the lacquer-handed employees to open the door. The employees did not wear wet paint during the door-to-door repair process. Frequently, use gloves or sleeves to touch the outer door of the door with a sharper opening to open the door to open the door (Figure 3), causing fiber, paint residue, etc. to remain in the vicinity of the mouth area; and paint, varnish hand Employees will not touch the area because the body has been sprayed with wet paint (the top coat line is 3C1B spray, spray paint, varnish without drying after spraying). 3.3 Tooling factors After the paint, the four-door door frame pedal and the front and rear door frame intersections have a large amount of impurities and a large impurity. About 30% of the body repairing production line needs to be repainted in this area, which affects the production speed and quality of the workshop. Most of the observed impurities are paint slag defects. Due to the door infinity device, the painter closes the door and often takes the trolley door to close the door. The door handle and the door frame stop often have a large impact, causing the work lacquer to smash and the sill area appears after the paint. Large paint residue. In addition, the bolts for fixing the door hinges of the welding shop are painted and reused with bolts (mentioned in 2.2.3). When the door switch is strong, the slag is likely to appear on the thread, causing the door A and B columns to be piled up. Slag impurity defects. 3.4 large area increase of Vaseline It was found that after 24 hours of coating the Vaseline panel in a relatively closed chamber, the particle trapper measured the indoor cleanliness of the particles before and after the placement, and the number of particles of 10 μm and above decreased by about 85%, and the particles of 5 μm or more were removed. The number is reduced by about 75%. According to the results of this experiment, combined with the use of Vaseline, the effective period is long, the viscosity of the impurities is good, and the particles do not pollute the environment again after drying (compared with water). A large amount of Vaseline coating was added in the workshop (the original only the inner wall of the spray booth was coated with Vaseline), and the wall panel of the color selection area, the air shower channel of the spray booth, the side wall of the clean room, and the body of the polishing machine were improved. The lacquer cleaning chamber body is coated with Vaseline, and the Vaseline is replaced by water in the ash water box. The whole area is coated in the water box, and placed in the ground of the color selection area, the ground level of the spray booth, and the furnace. The ground floor has a replacement period of 3 months, which directly and effectively reduces the number of dirty spots on the body after painting. Editor in charge: Zheng Bijia 3.5 High cleanliness guarantee during the process of polishing the car to the topcoat At the front of the paint cleaning station, it was found that before the car body was cleaned, the naked eye often saw the short fibers and impurities falling after the body level appeared, and the body was observed at the end of the sanding. There is an impurity fiber falling behind, which indicates that the fiber impurities are dropped twice in the process of polishing the car to the top paint. After a month of statistics (see Table 1), the joint between the elevator and the workshop in the area is closed in the workshop, and the iron mesh part of the elevator is closed twice and the outlet of the sanding vehicle is connected to the outside. All coated with Vaseline, the number of improved body fibers has dropped from 2.2 fibers to 0.3 fibers. 4. Create a defect template and a defect enlargement picture sample library The interior of the workshop mainly relies on particle trapping instrument and 60~100 times magnifying glass to analyze the defects, and samples and analyzes the fibers, impurities and other substances that may be polluted by the body, and makes the defect pattern into a defect model. status. Defects in the body during actual production are inferred by comparing the defect plate with the state of the defect. As of the deadline, the workshop has sampled 21 samples of various types of fiber samples: including wool balls, anti-static clothes, all kinds of rag wipes, filter cotton, filter bags, gloves, clothes and other cotton-like, polymer-like fibers. Resulting in the collection of body impurities after painting and retaining 39 items: including paint residue, slag, damper impurities, furnace ash, petroleum jelly, welding slag, solder balls, welding wire drawing, phosphating slag, glue mist, basin dry impurities , skid body impurities, electrophoretic polishing ash, electrophoresis agglomeration, shredded paper, PVC agglomeration, etc. The production and retention of defective prototypes and defect-enhanced samples effectively find out the source of the body defects, and the defects caused by the production process can be compared with the sample and the enlarged samples to determine the cause of the defects. 5. Conclusion There are many factors that cause defects in the body after painting. For the painter, careful observation and continuous search for the cause of defects are essential. Record and summarize the defects in the production process according to the defect mode to ensure the improvement of the quality of the body after the paint, and continue to reduce the body defects by adhering to the concept of continuous improvement. Editor in charge: Zheng Bijia ESD shoes, have an electrostatically dissipative conductive shoe sole, popularly known as antistatic shoes (which is not the same, incorrectly). Safety Shoes are classed as ESD safe shoes when the resistance value of the system person-shoe-floor is below 3,5 x 10^7 resp. 35 MOhm according to EN 61340-5-1. Esd Shoe,Esd Safety Shoes,Anti Static Shoes,Esd Boots zhejiang leima shoes ind.co.,ltd , https://www.safetyshoeschina.com