It may be metal friction, which is generally caused by the lack of oil in the bearing, so it is necessary to disassemble the bearing and add the appropriate amount of grease; It may also be the sound made when the ball rotates, which is usually caused by dry grease or lack of oil. Appropriate amount of oil can be added; It may also be the sound produced by the irregular movement of the ball in the bearing, the damage of the ball in the bearing or the long-term non-use of the motor, and the grease is dry, which also needs oiling. Cleaning of the surfaces of various parts of the range hood: Wipe the surfaces of the range hood with a soft cloth and neutral detergent, and be careful not to use strong corrosive detergent to prevent damage to stainless steel panels and other components. Cleaning the oil box The cleaning of the oil box can be prepared in advance: stick a layer of cling film on the box or put a small plastic bag to ensure that the plastic film or plastic bag completely covers the inner surface of the box and can hold the adsorbed waste oil. Then, the oil storage box is pumped every once in a while for replacement, which is basically clean. Clean the oil net. Slowly remove the oil net with a screwdriver, and put the removed oil net in warm water of neutral detergent for 5- 10 minutes. Then use a soft plastic brush to clean the dirt in the pores of the filter screen, and then dry it with a dry rag. If the oil on the oil net is thick, you can also gently scrape off some oil with thin bamboo pieces before cleaning. Fan blade cleaning The cleaning of the fan blades of the range hood can be sprayed with cleaning liquid such as oil fume net. After a few minutes, the oil fume net and the dissolved oil are sucked away by the fan, and then cleaned with a rag. In addition, you can carefully remove the fan blades, soak them in hot water mixed with homemade detergent and vinegar for about 15 minutes, and then scrub them with a rag.