Introduce common problems of vacuum coating equipment process
Vacuum aluminum coating machine is to heat and melt aluminum metal to evaporate in a vacuum state, and aluminum atoms are condensed on the surface of polymer materials to form an extremely thin aluminum layer. Vacuum aluminum plating requires the substrate surface to be smooth, flat, and uniform in thickness; the stiffness and coefficient of friction are appropriate; the surface tension is greater than 38Dyn/Cm2; the thermal performance is good, and it can withstand the heat radiation and condensation heat of the evaporation source; the moisture content of the substrate Less than 0.1%. Commonly used aluminized substrates are polyester (PET), polypropylene (PP), polyamide (PA), polyethylene (PE), polyvinyl chloride (PVC) and other films. What are the common problems with the aluminum plating process of vacuum coating equipment?
1. Holes appear in the film during aluminum plating
①The aluminum material in the evaporation boat is too full. Solution: reduce the aluminum delivery speed; increase the evaporation boat current.
② There is a short circuit between the evaporation boats in the vacuum chamber. Solution: Eliminate the short circuit.
③Splash of impurities in the vacuum chamber
2. The film stretches during aluminum plating
① The tension of the substrate is too high. Solution: Adjust the tension control system for unwinding and winding to appropriately reduce the tension.
②The cooling system works abnormally. Solution: Check the cooling system and eliminate the fault.
3. Brown streaks appear on the surface of the film
① Low vacuum. Solution: Clean the aluminum feeding, evaporation device, cooling system, unwinding, winding device and guide roller in the vacuum chamber; check the vacuum system; reduce the environmental humidity.
②The film releases gas. Solution: pre-dry the film; extend the vacuum time.
③ Excessive spraying of aluminum. Solution: increase vehicle speed; reduce evaporation boat current; reduce aluminum delivery speed.
④ There are impurities in the evaporation boat. Solution: Clean the evaporation boat and heat shielding plate.
⑤The evaporation boat is aging. Solution: Replace the evaporation boat.
Process requirements of vacuum coating equipment: the vacuum degree should not be less than 103PA to avoid brown streaks or uneven thickness of the aluminum layer; control the system tension and turn on the cooling system to avoid stretching and deformation of the film when heated; accurately control the winding speed (280 ～320m/min), aluminum delivery speed (0.4～0.7m/min? 2mm aluminum wire) and evaporation boat heating current to obtain the aluminum layer thickness required by the product (100～300A°); it can be coated on the film in advance A certain amount of primer, fully dried, and then vacuum-plated aluminum can improve the bonding force between the aluminum layer and the film. Then, a certain amount of protective resin is coated on the aluminum film to prevent the aluminum layer from oxidizing and deteriorating. The aluminum-plated film formed by this process is resistant to friction and not easily deteriorated.
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