Normal Working Conditions and Maintenance Methods for Vacuum Coating equipment

I. Normal working conditions of vacuum coating equipment

• Ambient temperature: 10~30℃

• Relative humidity: no more than 70%

• Cooling water inlet temperature: not higher than 25℃

• Cooling water quality: city tap water or water of comparable quality

• Supply voltage: 380V, three-phase 50Hz or 220V, single-phase 50Hz (as required by the appliances used), voltage fluctuation range 342~399V or 198V~231V, frequency fluctuation range 49~51Hz

• The pressure, temperature and consumption of compressed air, liquid nitrogen, hot and cold water required for the equipment should be stated in the product instruction manual.

• The environment around the equipment is neat and clean, with no dust or gases that could cause corrosion on the surface of electrical and other metal parts or cause electrical conductivity between metals.

In addition, the laboratory or workshop where the vacuum coating equipment is located should be kept clean and hygienic. The floor should be terrazzo or wooden painted and dust-free. To prevent the pollution of the laboratory environment by the gases discharged during the work of the mechanical pump, an exhaust pipe (metal or rubber pipe) can be installed above the exhaust port of the pump to discharge the gases outside.

II. Repair and maintenance methods for vacuum coating equipment

1. Vacuum coating equipment should be cleaned once every 200 coating procedures or more.

Method: repeatedly scrub the inner wall of the vacuum chamber with a saturated solution of caustic soda (NaOH), (note that human skin should not come into direct contact with the caustic soda solution to avoid burns) in order to make the film material aluminium (AL) plated on react with NaOH, the film layer will fall off after the reaction and hydrogen will be released. The vacuum chamber is then cleaned with water and the dirt inside the fine extraction valve is cleaned with a cloth dampened with petrol.

2. When a rough pump (slide valve pump, rotary vane pump) has been in continuous operation for one month (halved during the rainy season), it needs to be replaced with new oil.

Method: Unscrew the oil drain bolt, drain the old oil, then start the pump for a few seconds so that the old oil is completely discharged from the pump. Screw back the oil drain bolt and add new oil to the rated amount (observed by oil sight glass). When using continuously for more than half a year, open the oil cover when changing the oil and wipe the dirt inside the tank with a cloth.

3. Before restarting the machine, pay attention to leak detection.

Diffusion pump more than 6 months of continuous use, pumping speed has become significantly slower, or improper operation, filling into the atmosphere, remove the joint water pipe, remove the electric furnace plate, the first level of nozzle screw out, first with gasoline will be pump cavity and pump gallbladder clean once, then wash again with washing powder to water, and then clean thoroughly with water, after the water evaporates dry, install the pump gallbladder, add new diffusion pump oil, and put back into the body, connect the water pipe, install the electric furnace plate, then you can restart. Then you can restart the machine. Before restarting the machine, pay attention to the leak detection work.

Method: Start the maintenance pump, close the door and after a few minutes, observe whether the vacuum level in the diffusion pump section reaches 6 x 10 Pa, otherwise carry out a leak test. Check whether the coupling is fitted with sealing rubber rings or crushed seals. Exclude the hidden danger of air leakage before heating, otherwise the diffusion pump oil will burn the ring and the vacuum coating equipment cannot enter the working state.