What about the oil return from diffusion pump? If the vacuum gauge is not damaged, the oil return is generally not needed to be repaired. The main purpose is to clean the oil of diffusion pump in vacuum chamber. It's better to use gasoline to wipe the vacuum chamber wall all over again, and then wipe it with alcohol again. Oil must be clean is the most important, if there is oil in the room, there will be white film plating, film quality is very poor and other phenomena, not because of the damage of electroplating equipment, but because of oil in the vacuum chamber.

The frequent oil return of diffusion pump may be caused by the following problems:

1. The cooling water is blocked or the water pressure is not enough, which leads to the decrease of cooling capacity, the upper part of diffusion pump becomes hot, and the oil vapor cannot be liquefied well. The solution is to connect the inlet pipe of diffusion pump with 4MPa air source to blow out the scale, and connect the outlet pipe with 4MPa air source. If the scale is much and firm, dilute hydrochloric acid can be passed through. Or replace the diffusion pump.

2. If the heating temperature is too high, because the power of the diffusion pump heater is inconsistent with the rated power, too high, resulting in a large amount of steam, which can cause oil return, which can be solved by replacing the electric furnace wire.

3. If the oil filling quantity is too high, the steam circulation will be slow and the steam will be trapped when it is compressed to the lower level, which will cause oil return. The control of oil filling amount according to the information provided by the manufacturer can be avoided.

4. Oil oxidation, diffusion pump oil oxidation, viscosity and steam flow are affected, can not reach the injection speed, naturally return to the vacuum chamber. Remove the diffusion pump, take out the pump core, clean it with 120 ᦇ gasoline, and then polish it. Polish off the carbon deposit and black oxide layer. Clean and dry it with 120 ᦇ gasoline again. Then install it. Pour the diffusion pump oil or silicone oil and heat it for several times before it can be put into operation. Prevent contamination of workpiece.

5. If the service time of diffusion pump is more than 8-10 years, or in harsh environment, it can be replaced. Improve work efficiency and maintenance cost.