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Laptop plastic parts as well as the development and application of coatings and coating
On April 1, 1974, Intel unveiled its individual user oriented microprocessor after 8080, the personal computer gradually began to enter in the office and home. With the unprecedented development of Internet technology and multimedia technology with a large number of applications, nowadays, computer has been completely change our life. Computer from a small size lab machine to desktop LCD computer now, laptops and the most popular, lightweight laptops, color also is multifarious, especially laptop computers and laptops, like clothing or a car, every year there are different popular colour pattern to attract the attention of consumers.
Laptop (small laptops) shell material for plastic, metal, two main types:
(1) plastic categories: low cost, easy to manufacture, mainly by the molding mould injection molding. Used in laptop computers and laptops plastic ABS, ABS + PC, PC, PP, NYLON, composite materials, etc.Plastic substrate and spraying coating is still the mainstream. This paper mainly introduces the portable computer plastic coating and its coating.
1 plastic material properties
Common plastic material properties:
ABS, acrylic, butadiene and styrene polymerization. General ABS resin composition: A is 25% ~ 30%, and B is 25% ~ 30%, S is 50% ~ 40%, the proportion of 1.07 ~ 1.15. Its characteristics are as follows:
Opaque, uneven; Not high heat resistance, good processability, Meet the thermal deformation temperature of 60 ~ 120 ℃, the general has long been at above 90 ℃ ambient temperature deformation; Have stronger physical properties; Weather resistance is poor, not resistant to uv rays, reduce impact long exposure in the sun; Solvent will melt, but better resistant to acid and alcohol resistance; Combustion would produce peculiar smell; Good electrical properties; High surface gloss. ABS surface can spray paint, printing, vacuum coating and painting, the most suitable for 3 c products.
PP (polypropylene), specific gravity of 0.9 ~ 0.91. Have stronger physical properties, abrasion resistance is good, has certain heat resistance; Has a certain impact resistance at room temperature and low temperature (below 5 ℃) under the poor impact resistance; Electric property, good water resistance and chemical resistance; Combustion will produce the smell of the oil, gelling and printing operations more difficult; Good heat resistance, in the absence of under the action of external force, can use for a long time under 150 ℃, but around 165 ℃ will melt; Bad cold resistance, weather resistance, high rigidity, fire burn.2. Plastic appearance defects and repair
2.1 plastic cosmetic defects2.2 the coating repair
On incoming material of plastic components of the plastic coating factory, appearance quality checks for defective plastic components for rejection or allowed to repair. After the general method of repair is mainly fine sandpaper, darned defects of fixed-point spray or more comprehensive gush a few primer/finish. Commonly used repair method is as follows:
(1). Sanding: the defective plastic, such as fusion line for sanding with high mesh sanding paper or water.
(2) annealing: for there was stress annealing treatment of plastic parts in advance, in order to avoid the spraying or after baking plastic cracking.
(3) deflashing: with box cutters and rolled rod to remove the plastic burrs.
(4) the filling gun: the flawed, point injection in advance or after the spraying and again point injection.
(5) bite base: in weak solvent or change the suitable material.
(6) painting: by repainting increase film thickness and covering power to cover plastic appearance defects in itself.
In fact, according to the author experience, through the after repair of coating factory improve the defects of plastic components, its efficiency is not high, should be from the front to do something about the plastic molding stage.
3. Laptop plastic component coating and characteristics
Now in the market more than normal laptop computers and laptops paint is 1 ~ 2 two-component PU paint, or monocomponent acrylic color lacquer + 1 out of 1 UV light paint such a process is given priority to. Also use only spray 1 more small component of monocomponent acrylic paint technology, portable computer plastic base internal coating conductive plastic paint. Shall be for the use of two-component PU paint majority. Two-component PU paint can be subdivided into general paint, metal paint, varnish coat and elastic softness coating + paint (primer), etc., in the introduction of UV light curing coatings with elastic soft feeling coatings.
4. Portable computer plastic coating and SOP
4.1 small laptop shell plastic accessories (such as push button/power button/lamp pins, etc.) is generally not spray primer coating, spray only one line of monocomponent acrylic paint or two-component PU paint. Using artificial painting or reciprocating mechanical spraying.
The coating process is as follows:
Substrate processing to use IPA (isopropyl alcohol) spray cleaning - > one-component two-component PU acrylic paint or paint to dry (60 ℃, 30 min) - quality control - forced drying (above 60 ℃, 120 min) and the packing.
4.2 laptop shell plastic main parts (such as base/screen frame/frame cover/base, etc.) mainly used for laptop shell plastic main parts coating two-component polyurethane coatings, three kinds of softness coatings and uv-curable coatings, less using single-component acrylic coating. Here in uv curing coatings and elastic softness coating coating process as an example, the process is shown in figure 1 and figure 2.
UV light curing coating basic requirements: (1) clean type job shop, has closed spray (including oven and UV light curing oven); (2) the constant temperature and humidity, especially UV spray; (3) UV spray exhaust extraction system is better, or curing film easy generation sand point, dander, orange peel, flow adjustment, it contains air bubbles, etc. General UV topcoat painting very hard, if there is a sand point or dander, for defective parts polishing wax; Spray or rework after heavy, but the effect is not ideal. Generally small plastic spray paint, especially after spray UV lacquer film flawed simply discarded.
4.3 spraying standard operating procedure (SOP)
Laptops in real quantity antenatal spray paint factory, the engineering department engineers will first try to spray paint line actual small paint spray and try. If the computer company RD/ID (industrial design engineer) coatings are used for several times
A small paint trial cannot meet the requirements of color, appearance, and computer company internal coating physicochemical performance specification standard, stationary computer company RD may replace other coating or change this laptop using coating design specification parameters. The engineering department engineers after small try paint and spray, get actual operation parameters; Combined with paint of the coating product technical data provided by the laptop computer company, coating design and the quality specification to start design for spraying standard operating procedure (SOP), spray paint production standards as the basis. Laptop shell cover (Top) SOP.
5. Spraying equipment
For 3 c products OEM spraying plant powder spraying and painting two points, also have a spray and spray powder in the same factory but in different spraying line.
6. conclusion
Laptops use plastic coating is environmental protection, waterborne, solvent-free uv-curable coatings in the direction of development. Laptop computer market in the face of fierce competition, the upstream laptop design development engineers also stir all his brains on the shell material, appearance, function, color great pains. In addition to plastic material, other materials are also constantly updated. Plastic coating development engineer also to continuous innovation, to meet the requirements of users.