Common problems of vacuum coating equipment process

Vacuum coating machine vacuum aluminum plating is to heat and melt aluminum metal to evaporate in a vacuum state, and aluminum atoms condense on the surface of polymer materials to form a very thin aluminum layer. Vacuum aluminizing requires the surface of the substrate to be smooth, flat and uniform in thickness; the stiffness and friction coefficient are appropriate; the surface tension is greater than 38Dyn/Cm2; below 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 in the aluminum plating process of vacuum coating equipment? 1. There are holes in the film during aluminum plating

reason:

①The aluminum material in the evaporation boat is too full. Solution: reduce the speed of aluminum feeding; increase the current of the evaporation boat.

② There is a short circuit between the evaporation boats in the vacuum chamber. Solution: Eliminate short circuits.

③Splash of impurities in the vacuum chamber

2. The film is stretched when aluminized

 reason:

①The tension of the substrate is too high. Solution: Adjust the tension control system of unwinding and coiling, and reduce the tension appropriately.

②The cooling system is not working properly. Solution: Check the cooling system and troubleshoot.

3. Brown streaks appear on the surface of the film

 reason:

①Low degree of vacuum Solution: Clean the aluminum feeding, evaporation device, cooling system, unwinding, coiling device and guide roller in the vacuum chamber; check the vacuum pumping system; reduce the ambient humidity.

②The film releases gas. Solution: pre-dry the film; prolong the vacuuming time.

③ Too much aluminum spray. Solution: increase the speed; reduce the current of the evaporation boat; reduce the speed of aluminum feeding.

④There are impurities in the evaporation boat. Solution: Clean the evaporation boat and heat shield.

⑤ The evaporation boat is aging. Solution: replace the evaporation boat.

 Process requirements of vacuum coating machine: the vacuum degree should not be lower than 103PA, so as to avoid brown stripes or uneven thickness of the aluminum layer; control the tension of the system, turn on the cooling system, and avoid stretching and deformation of the film when heated; accurately control the coiling speed (280～ 320m/min), aluminum feeding speed (0.4~0.7m/min? 2mm aluminum wire) and evaporation boat heating current to obtain the aluminum layer thickness (100~300A°) required by the product; it can be pre-coated on the film to a certain extent Dry primer and fully dry, and then vacuum aluminum plating can improve the bonding force between aluminum layer and film. Then, a certain amount of protective resin is coated on the aluminum film to prevent oxidation and deterioration of the aluminum layer. The aluminized film formed by this process is resistant to friction and is not easy to deteriorate.