The vacuum aluminum plating process is carried out in a vacuum state, and the metal aluminum is heated and fused to the transpiration. The aluminum atoms are condensed on the surface of the polymer material to form a thin aluminum layer. Vacuum aluminum plating requires the substrate with smooth, flat and uniform surface; hardness and coefficient of friction are appropriate; has good thermal performance. The commonly used aluminum plating substrates include polyester, polypropylene, polyamide, polyethylene, polyvinyl chloride and other thin films. The common problems in the process of aluminum plating:
1. The cause and solution of hole in the surface of aluminized thin film.
(1) The aluminum in the evaporation boat is too full.
Solution: Reduce the speed of aluminum; improve the evaporation boat current.
(2) There is a short circuit between the evaporation boats in the vacuum chamber.
(3) There are impurities in the vacuum chamber.
Solution: Clean the inner wall of the vacuum chamber, aluminum evaporating device, cooling drum, unwinding, coiling device and guide roller.
2. The causes and solutions of tensile phenomena on the surface of aluminized thin films
(1) The substrate tension is too large.
Solution: Adjust unwinding, coiling tension control system, appropriate to reduce tension.
(2) The cooling system is malfunctioning.
Solution: Check the cooling system and troubleshoot.
(3) The evaporation boat temperature is too high.
Solution: Reduce evaporation boat heating current, increase speed.
3. The causes and solutions of brown striation on the surface of aluminized thin film.
(1) Low vacuum.
Solution: Clean the aluminum feeding and evaporation device, cooling system, unwinding, coiling device and guide roller in the vacuum chamber.
(2) Film releasing gas.
Solution: Thin film pre-drying and extending the vacuum time.
(3) Aluminizing too much.
Solution: Increase the speed, reduce the evaporation boat current, reduce the aluminum feeding speed.
(4) There are impurities in the evaporation boat.
Solution: Clean evaporation boat and heat shield plate.
(5) Evaporation boat aging.
Solution: Replace the evaporation boat.