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Uncover the myth of repair and coating of Lamborghini plastic parts

the widespread use of plastic parts in cars is of great significance to the development of the automotive industry. It can not only reduce the weight of cars, save energy, and make cars safer and more comfortable, but also be more resistant to atmospheric corrosion and gasoline than metal, which is easy to be processed and formed and reduce production costs. Especially for sports cars, it is more important. Now let's uncover the plastic parts of Lamborghini aventador

Lamborghini aventador as one of the highlights of the 2011 Geneva auto show, Lamborghini has launched a new flagship, a new generation of "Daniel" - aventador (transliterated as "iventado") with 700 horsepower. A prominent feature of the car is that the whole car adopts a large number of carbon fiber reinforced materials (CFRP) technology, especially the all carbon fiber composite single shell body. This flagship Lamborghini supercar has a futuristic style. The cabin is completely made of carbon fiber and equipped with a hard shell structure. Its bearing structure is a "single shell" design, which can function as a single component in structure, so as to make full use of the super rigidity of carbon fiber reinforced materials

with the rapid development of technology, plastic long-term cooperative coating is now receiving more and more attention from automobile manufacturers. When automobile plastic parts are damaged or the coating is aged due to accidents in use, it is necessary to repair and paint them. Next, let's explain the repair and coating technology of plastic parts of automobile body from three aspects: mechanical damage repair, surface treatment before painting and paint spraying process operation

1 damage repair of automotive plastic parts

1.1 damage of plastic parts and adhesive

1.1.1 damage of plastic parts generally speaking, damage to the paint surface of plastic parts will always affect the part body, causing corresponding damage, such as scratch, crack, scratch, tear, puncture, etc. In order to repair the damaged paint surface, the plastic parts must be repaired first to make it meet the requirements of spraying finish paint. For the repair of the above damage, the chemical adhesive bonding method is usually used

1.1.2 binders there are two kinds of binders commonly used: one is the binder based on epoxy resin or carbamate acetyl and mixed with hardener; The other is a binder with polyester as the matrix and hardener. In recent years, cyanoacrylate, known as super glue, has been gradually used in the bonding of plastics because of its novel characteristics

1.2 damage repair of plastic parts

1.2.1 repair of scratches and cracks of plastic parts. Scratches and cracks of plastic parts are usually repaired with adhesives, and the repair process is as follows:

① clean the parts to be repaired with water and plastic cleaner, and remove wax and degrease the bonding surface

② before using the adhesive, the plastic parts should be heated to about 20 ℃

③ spray the catalyst to the crack side, and then apply the adhesive on the side

④ align the two sides of the scratch or crack according to the original position, press it quickly, and a good bonding effect can be obtained after about 1min. Finally, the bonding part should have a hardening time of 3 ~ 12h to achieve the maximum bonding strength

1.2.2 repair of scratch, tear and puncture of plastic parts the process of repairing scratch, tear and puncture is roughly as follows:

① soak the solvent with the function of removing paraffin, grease and silicone resin on a clean rag, thoroughly remove the dirt at the damaged part, and then wipe it clean

② grind the 6 ~ 10mm wide edge of the scratch hole into an inclined plane to facilitate bonding, and grinding a rough surface is conducive to bonding

③ use a fine grinding wheel to cut off the paint on the edge of the repair part, so that the paint on the surface about 3cm near the hole edge is completely removed, and then carry out necessary cleaning treatment

④ carry out flame treatment on the hole edge to improve the bonding performance. Use the blowtorch flame to move continuously at the slope until the slope is slightly brown

⑤ clean the back of the repair part with silicone and wax remover, and then stick aluminum foil with strong adhesive and moisture-proof tape to completely cover the hole

⑥ prepare the bonding material according to the instructions

most adhesives are installed in two tubes respectively. Extrude the same amount of bonding materials on a metal plate or wood board respectively, stir them fully, mix them evenly, and wait for use

⑧ the second time 1 is that an enterprise enters the graphene industry, or an enterprise cooperates with graphene related enterprises and research institutions to fill the repaired part with the adhesive, and then scrape it flat and reshape it with a scraper. After drying, use 80 # sandpaper to trim a rough outline around, and then use 180 # and 240 # sandpaper to polish the surface. If there are irregularities or pinholes, fill them with fillers

⑨ carry out the final fine grinding with 320 # sandpaper, clean the repair part after grinding, and be ready to apply the finishing coat

2 surface treatment of automotive plastic parts before spraying

generally, plastics are divided into hard plastics (rigid plastics) and soft plastics (semi-rigid plastics). Some plastic spare parts provided by automobile manufacturers have been primed, while others have not been primed. For the latter, special plastic primer, primer sealant or vinyl varnish or paint should be used to improve the adhesion of the paint layer

2.1 surface treatment of hard plastic parts

① for new parts, the surface must be wiped with a clean cloth dipped in alcohol

② thoroughly clean the surface with wax and grease remover

③ polish the exposed glass fibers. When grinding by hand, use 220 # or 280 # sandpaper; When grinding with a grinder, use 80 # ~ 120 # sandpaper

④ wipe the surface again with a clean cloth

⑤ if there are welds and air pockets that need to be filled, apply a layer of body filler on the whole surface, grind and clean after drying, and finally apply a protective layer or two layers of epoxy chromate paint

⑥ according to the instructions on the package, apply the putty on the surface, polish it with fine sandpaper after drying, blow off the dust with compressed air, and wipe it clean with sticky rags

⑦ apply finish paint

2.2 surface treatment of soft plastic parts the treatment methods for soft plastic parts without primer are as follows:

① use a cloth soaked in water to dip in wax, degrease and desilication detergent to clean the whole surface and wipe it dry

② polish the scratch and the surface repaired with filler with 320 × sandpaper, blow off the dust, and wipe it clean with adhesive rag

③ prepare and apply 4 layers of moderately dry soft putty

④ let the surface dry for at least 1H, and then polish it with 400 × sandpaper to remove all gloss and prepare for finishing coat

2.3 surface treatment of polypropylene plastic parts when painting polypropylene plastic parts, a special primer should be used. Polypropylene plastic is very hard, and the top coat can be painted after the traditional internal resin paint is used. The surface treatment process is as follows:

① clean the surface with wax removal and silicon removal detergent

② according to the packaging instructions, apply a thin layer of polypropylene primer coating, and let the primer dry quickly for 1 ~ 10min

③ during rapid drying, apply a layer of traditional internal resin topcoat and let the topcoat dry before installing this part

3 spraying of automotive plastic parts

topcoat process operation the paint used on the plastic surface must have two basic conditions:

good adhesion and the paint cannot excessively dissolve the plastic surface. For automotive coatings, interior parts focus on solvent resistance, and the use of coatings is more complex, including many varieties, which are mainly considered according to the requirements of the substrate; The exterior ornaments focus on water resistance, stone impact resistance, weather resistance and decoration. Most hard plastics do not need to be primed, and the finish coat can adhere well to their surface; A "flexible agent" needs to be added to the paint layer of semi-rigid (flexible) plastics, which can make the paint layer have a certain deformation ability when the matrix expands without falling off or cracking. For the spraying of plastic parts, it is best to use a set of supporting materials provided by the manufacturer, such as flexibility agent, finish paint, internal coating material, diluent and diluent

3.1 spraying of hard plastic parts

3.1.1 spraying of internal hard plastic parts hard plastic (such as ABS) parts generally do not need to be sprayed with primer and putty; The color of the finish paint of internal plastic parts is determined by the adjustment number on the body coding plate, and its finish paint is mainly acrylic paint. All large paint factories provide users with such a high-end table of interior paint drawings, including the supply number, name, gloss coefficient and adjustment number of interior paint. The painting method of internal hard plastic parts is as follows:

① clean the surface of plastic parts with solvent

② spray general internal acrylic paint according to the adjustment number

③ dry the paint layer according to the specified time, and then install it on the vehicle

3.1.2 spraying of external hard plastic parts

external hard plastic parts generally do not need to be sprayed with primer, but some manufacturers suggest spraying a layer of primer first and then the top coat. In either case, the method of spraying the top coat is the same:

① thoroughly clean the surface of parts with cleaning agent

② spray the top coat with appropriate color

③ install the parts on the vehicle after the paint surface is completely dry

④ before painting the glass fiber parts, the putty should be applied first, and then the finish paint should be sprayed according to the method of spraying the body steel plate. Before local repair of hard plastic parts that have previously been sprayed with aeroplastic film compound, a layer of adhesion promoter should be sprayed first. During operation, use 400 × wet sandpaper to polish the damaged parts, and then apply primer, adhesion aid and finish paint

3.2 spraying of elastic plastic parts

most elastic (semi-rigid) plastic parts need to add elastic agent in the paint layer to prevent the paint surface from cracking during deformation. The paint surface added with elastic agent is called elastic paint layer, and its spraying method is as follows:

① thoroughly polish the whole surface with 400 # sandpaper, and clean the whole surface with detergent

② according to the regulations of the manufacturer, mix the primer, elastic agent and solvent together. When mixing, mix the primer and elastic agent first, and then add an appropriate amount of solvent according to the temperature of the workshop

③ adjust the spray gun pressure to the specified value and spray sufficient double-layer wet coating to completely cover the surface

④ dry the primer for 30 ~ 60min, and then spray the bright layer. After drying, install it on the vehicle for use

3.3 spraying examples of plastic parts take the spraying of polypropylene bumper as an example. When painting this plastic part, because this plastic is very hard, a special primer - internal polypropylene paint should be sprayed first, and then the finish paint can be sprayed. The specific spraying process is as follows:

① clean the surface with solvent

② according to the requirements of the manufacturer, spray diluted and evenly mixed polypropylene primer, dry for 1 ~ 2H, and then spray finish paint

③ spray acrylic enamel with appropriate proportion (including hardener) and dry it for 8h to ensure that the paint layer hardens (because it is a hard plastic part, there is no elastomer in the finish coat)

④ when using the primer plus bright paint layer, the primer should be sprayed first, then the acrylic paint should be sprayed after drying, and then the bright paint layer should be sprayed after drying for 15 ~ 30min

⑤ re spraying process of damaged polypropylene bumper