SILVER LAKE WEIGHING Electronic truck scale Painting operation instructions Ⅰ. Scope of application 1. This operation manual is applicable to the spraying operation of truck scale products manufactured by the Scale department. For products with special requirements, the spraying shall be carried out in accordance with the requirements of relevant design documents and process documents. 2. Reference standard: Q/MTCN-2401-97 "General Technical Conditions for Painting of Electronic Scales" 3. The paint appearance inspection and paint type test of various scale products can also refer to the relevant requirements in this manual.2. Surface coating color and coating name of truck scale products Part name instruction remark Spraying method Paint color Paint model and name Scale body Spraying Sea gray B05 S04-63 acrylic polyurethane paint Identificatio n Screen printing Blue 5039 ink Safety line Spraying Medium yellow Y07 S04-63 acrylic polyurethane paint 100mm width along the length of the scale Foundation parts Spraying (brush coating) Black S04-63 acrylic polyurethane paint 1. Apply H06-4 epoxy zinc-rich primer on the "U" beams at the bottom of the truck scale platform; 2. Matching of topcoat and primer: When the topcoat is S04-63 acrylic polyurethane paint, the primer is H06-4 epoxy zinc-rich primer. 3. If there are other color requirements in the product design, the painting shall be carried out according to the technical requirements specified in the drawing.II. Product coating requirements and inspection 1. Appearance requirements: a) Paint film surface grade code and limit of each defect quantity Grade code Defect quantity Defect name ⅡA (External surface that is often observed) ⅡB (Rarely observed External surface) ⅢB (Rarely observed Internal surface) ⅡC (Invisible External surface) Impurities, stains Diameter 1.0mm; Less than 7 points within 30x30cm2 Diameter 1.5mm Less than 7 points within 30x30cm2 Look remark Leaking paint, exposed bottom, wrinkles Not allowed Inconsistent surfaces Not allowed Diameter 3.0mm Less than 1 point within 30x30cm2 Diameter 3.0mm Less than 2 point within 30x30cm2 Look remark sagging Not allowed Diameter 1.5mm Less than 1 point within 30x30cm2 Diameter 3.0mm Less than 1 point within 30x30cm2 Look remark Note: The number of defects may exceed the allowable value of ⅢB, but the coating should be uniform, the coating marks should be consistent, and the defects should not be too obvious when observed under visual time/distance conditions. a) Paint film surface grade of vehicle scale products Ⅱ Ⅱ Ⅱ ⅡB ⅡC Note: All inner surfaces are IIIB a) The coating of basic parts and the bottom of large scale bodies should be flat and uniform in thickness. Insignificant spraying defects such as sagging are allowed, but no paint leakage. b) The comprehensive thickness of the effective paint film must reach between 80m and 120m. c) Register Colour (including screen printing), the boundaries between the two colors should be clear, the edges should be neat, and there should be no color bleeding. 1. 1. Surface inspectiona) Use the "time/distance" inspection method for visual inspection. The time and distance of visual inspection are shown in the following table: Surface Grade IIA IIB or IIIB IIC Visual time/distance 10SEC/ 0.8m 5SEC/0.8m 3SEC/1.0m a) Visual inspection conditions Parts cannot be treated in any clever way to reflect light to highlight defects. Visually inspect the surface of parts without directly reflecting light sources. Do not use a magnifying glass for visual inspection. b) Part surface defects cannot exceed the maximum value of the defect quantity limit specified by the paint film surface grade. c) Each process of spraying work must be inspected. Operation or self-inspection data records must be made according to the "Installation and Debugging Process Flow Card". 2. Performance requirements According to Q/MTCN-2401-97 << Electronic Scale General Technical Conditions for Coating ", in order to meet this standard, wet heat, salt spray and adhesion tests are required, and samples are used as samples for testing or outsourcing testing. The preparation of samples is shown in the appendix. a) Wet heat test According to GB/T1740-79 "Determination of wet heat resistance of paint film", the test duration is 240 hours. b) Salt spray test According to GB/T1771-91 "Determination of neutral salt spray resistance of paints and varnishes", the test duration is 96 hours. c) Adhesion test Adopt the cross-cut method, according to GB/T9286-88 "Coating and varnishing paint film cross-cut test". 3. Requirements for logo painting (screen printing) a) Screen printing must be carried out after the paint film is naturally dried for 12 hours. b) Requirements for screen printing of truck scales: The logo is printed on both sides of the left unit scale platform, and the height and length directions are symmetrically distributed to the two sides with the center line. "Electronic Truck Scale" is printed on one side, and the company name "SILVER LAEK " is printed on the other side.a) 2. Product coating construction specifications b) 1. Preparation of paint c) Mix the color paint evenly, filter the topcoat with a 200-mesh filter, filter the primer with a 100-mesh filter, pour the curing agent in proportion, and stir thoroughly. Then let it stand for 15 to 20 minutes. Mixing ratio: d) S04-63 acrylic polyurethane paint color paint: curing agent = 100:20 e) H06-4 epoxy zinc-rich primer color paint: curing agent = 100:10 f) 2. Pretreatment of spraying surface g) a) All steel surfaces must be rust-free before spraying. h) b) The outer surface of the scale body and larger parts must be shot blasted before painting. The rust removal quality level reaches Sa2 (GB8923-88). That is, there should be no visible grease, dirt, scale, rust, paint coating and other attachments on the steel surface, and any remaining traces should only be slight spots or stripes. i) c) If the interval between shot blasting and primer spraying is long (>12h), re-shot blasting is required. j) d) For small parts that cannot be shot blasted and for scales that have a long interval between shot blasting and primer spraying (>12h) and cannot be shot blasted again, the scum and welding spatter must be scraped off first, and then all or part of the rust must be removed manually with a wire brush. k) e) After spraying the primer, it must be dried naturally for 18 hours before the topcoat can be sprayed. Before spraying the topcoat, check the sprayed surface again, scrape off the debris stuck on the surface, and polish the scraped and uneven areas with iron sandpaper with abrasive particle size of P60 (2#). l) f) Before each spraying operation, sweep the surface with a clean broom and blow off the dust on the surface with compressed air. m) 3. Brushing n) a) According to the size of the brushing surface, select a flat paint brush with a width of 25 to 75. o) b) Before using a new paintbrush, rub the brush head back and forth on the emery cloth several times to make the bristles smooth, and then gently tap the brush head several times to remove the fallen bristles.p) c) When painting, the viscosity of the paint is generally guaranteed to be within 30 to 50 seconds. q) When the brush is dipped in paint, the paint liquid should not exceed half of the length of the bristles. After dipping in paint, gently tap both sides of the brush in the paint bucket so that the paint liquid hits the end of the bristles. r) The order of painting is: difficult first, then easy, inside first, then outside, left first, then right, top first, then bottom, side first, back first. Brush vertically and horizontally, and after brushing a large area evenly, scrape the remaining paint on the paint brush on the side of the paint bucket, use the tip of the paint brush to gently straighten the paint surface along the length direction, and brush off the dripping of the paint liquid. s) After the construction is completed, the paint brush should be properly stored, and the bristles should be hung vertically in the solvent or water, neither letting the bristles be exposed to the liquid surface nor letting the bristles touch the bottom of the container. Just spin dry for the next use. 1) 2. Spraying 2) 1) Spraying is done by air spraying and airless spraying. Under normal circumstances, airless spraying is preferred. 3) 2) When airless spraying is used, the viscosity of the paint is generally guaranteed to be within 25 to 35 seconds. When air spraying is used, the viscosity of the paint is generally guaranteed to be within 18 to 22 seconds. 4) 3) The air pressure supplied to the spray gun is 0.4 to 0.6 MPa; 5) 4) The spraying distance should always be kept consistent, and the distance between the nozzle and the surface of the object 6) Air spraying: 25 to 30 cm 7) Airless spraying: 30 to 40 cm 8) 5) The direction of the sprayed paint flow should be perpendicular to the spraying surface and run at a uniform speed and parallel. If the spray gun is tilted and runs in an arc shape or the speed is variable, uneven film thickness will occur, and defects such as stripes and scars will appear. Spray gun moving speed: 9) Air spraying: 30-60cm/s 10) Airless spraying: 30-120cm/s 11) 6) When spraying, the edge of each spray width should overlap 1/3-1/2 on the previously sprayed edge, and keep the overlap width unchanged.12) 7) When spraying, since only epoxy zinc-rich primer is sprayed on the bottom of the truck scale body, the effective paint film thickness is required to be 60-80um. For the rest of the scale body, the primer is epoxy zinc-rich primer, the effective paint film thickness is 40-60um, and the topcoat is acrylic polyurethane paint, the effective paint film thickness is 40-60um. For scales without primer spraying, the effective paint film thickness is 50-60um. 13) 8) Spraying equipment 14) Air spraying: Suction spray gun PQ-2 flat nozzle type 15) Airless spraying: Airless spraying equipment GPQ9C type 16) Nozzle: Column rotary type 14B20 type (or 13C20), 14B30 type (or 13C30); Nozzle selection rules: 14B30 type for large horizontal surfaces, 14B20 type for small horizontal surfaces and vertical surfaces. Generally, appropriate types of nozzles are selected according to different types of paint and different planes. 17) 9) Key points for operating airless spraying equipment 18) a) Connect the compressed air pipe to the equipment air pipe, adjust the valve on the equipment so that the pressure on the pressure gauge is displayed between 0.4 and 0.6Mpa, and start the empty pump. Then immerse the paint absorber in the filtered paint. When the pump sucks in paint, the gun trigger can be closed. After the paint pressure rises to the specified pressure, check whether there is any leakage at the joints and hoses. If normal, the nozzle can be installed for painting. 19) b) When stopping work, the paint in the pipeline does not need to be completely released. Just turn off the air source, pull the gun to release part of the paint, reduce the pressure in the pipeline, and immerse the nozzle head in the solvent to prevent the residual paint in the nozzle from drying and affecting the next spraying. 20) c) During the painting process, when impurities in the paint block the small hole of the nozzle, rotate the nozzle plunger 180 degrees and intermittently pull the gun until the blockage is eliminated. Do not use a sharp needle to pick the hair at the nozzle to avoid affecting the spraying quality. 21) d) After painting, first turn off the air source, open the valve, and release the paint. Immerse the paint absorber in the solvent, inhale the solvent and circulate it to clean it. Finally, remove the nozzle, clean it, and immerse it in the solvent for storage. 22) 10) When the operator needs to stand on the spraying surface during the spraying process, he needs to remove the garbage on the soles of his shoes before going up tothe spraying surface, and then put on protective shoe covers to prevent contamination of the coating and affect the quality of the paint film. 23) 3. Drying 24) 1) Only a completely dried and cured paint film can have excellent mechanical strength, adhesion, hardness and resistance to various media. Commonly used drying methods are natural drying and oven drying. 25) 2) Drying temperature and drying time of commonly used paint types: (Note: All drying times refer to insulation time), S04-63 acrylic polyurethane paint: 90~100℃ 30 minutes 26) 3) The paint film needs to be dried before entering the oven, generally standing at room temperature for 10 to 20 minutes. After entering the oven, it slowly rises from low temperature to the specified temperature, then keeps warm, and finally cools to room temperature with the furnace before proceeding to the next process. 27) 4) If the primer is not sprayed, the wet spray method can be used, spraying in two or three times. If H06-4 epoxy zinc-rich primer is sprayed, S04-63 acrylic polyurethane paint can be sprayed after 18 hours. 28) 29) 5) After the surface of S04-63 acrylic polyurethane paint is dry, the same paint can be sprayed. 30) 6) The product should be moved as little as possible when it is dry. When hoisting, use special hoists and pay attention to the protection of the paint film to prevent scratches on the surface. 31) 7) All products must be stacked after they are completely dry. Each section of the scale body is separated by special corners or sleepers. 32) 4. Other precautions 33) 1) When painting, the places that should not be painted must be covered with butter and other coverings before painting. Specific locations include the nameplate of the truck scale, the sensors of the truck scale that have been installed, the exposed threaded holes, cables and other objects. 34) 2) After the paint is dry, all coverings must be removed and the butter on the outer surface must be wiped clean. Except for the threaded holes. 35) 3) After the scale is shipped and loaded onto the vehicle, check the appearance of the paint film again. If there are scratches or other defects, repaint in time.36) 4) After painting, clean the workplace in time to ensure the cleanliness of the site, and seal the remaining paint and place it in a dedicated location. 37) 5) Before the paint is dry (including primer), do not step on the paint surface or proceed to the next process, or even ship it. 38) If the paint surface is scratched and abraded due to transportation and other reasons, and the damaged area is small, wait until the paint is completely dry, then sand the damaged area with sandpaper to make it smooth, and then repaint the area. If the damaged area is large, wait until the paint is completely dry, then sand the damaged area with sandpaper to make it smooth, and then spray paint the entire surface.。 Ⅱ. Truck scale coating Sandblasting and derusting → dedusting→Drying scale body→ Spray H06-4 zinc-rich primer on the bottom of scale → turn over the scale body and andderusting → spray H06-4 zinc-rich primer all over the scale body→ Natural drying 18 hours→spray all over the scale body s04-63 acrylic polyurethane paint→Natural 0.25 hour→Spray S04-63 acrylic polyurethane paint (medium yellow Y07) along the 150mm on both sides of the scale body→natural drying 12 hours Foundation parts coating Sandblasting and derusting → dedusting→All base parts are sprayed with S04-63 acrylic polyurethane paint→Keep in oven at 90 degrees for 30 minutes and cool to room temperature 4. Preparation steps of paint samples 1. Cut 6 steel plates into 15 pieces per sample and 100mm×50mm in size after shot blasting, and remove burrs with a file. 2. Place the steel plate on a flat plate. Clean the surface of the steel plate with compressed air or a clean brush. 3. Filter the paint topcoat with a 200-mesh filter and the primer with a 100-mesh filter. 4. Mix the filtered main agent and curing agent according to the ratio of the tested paint. Stir evenly during mixing, mix thoroughly, and let stand for 15 to 20 minutes. 5. Spray the cleaned steel plate (airless). The spraying should be uniform and complete, without defects such as bottom exposure and sagging. 6. The steel plate must be completed within 4 hours from shot blasting to spraying primer. 7. Spraying steps and requirements: 1) Primer: Spraying effective thickness 35 to 40μm. 2) Topcoat: 18 hours after the primer is sprayed. The effective spraying thickness is 50-60μm 3) After the topcoat is completely dry for 48 hours, apply a coat of varnish around the sample and on the back. 4) When spraying the primer and topcoat, fill in the relevant data in the "Paint Sample Spraying Record Sheet".