Because the heater made of cast aluminum heating ring has the advantages of long life, good thermal insulation performance, strong mechanical properties, corrosion resistance and anti-magnetic field. Therefore, cast aluminum heating coils are widely used in plastic machinery, molds, cable machinery, alloy die-casting machines, pipes, chemicals, rubber, petroleum and other equipment. The following describes the precautions for the lower cast aluminum heating ring. 1. The working voltage must not exceed 10% of the rated value; the relative humidity of the air is not greater than 95%, and there is no explosive or corrosive gas. 2. The wiring part is placed outside the heating layer and insulation layer, and the shell should be effectively grounded; avoid contact with corrosive, explosive media, and moisture; the lead wire should be able to withstand the temperature and heating load of the wiring part for a long time, and the wiring screws should be tightened when tightened. Avoid using too much force. 3. The metal casting heater should be placed in a dry place. If the insulation resistance is lower than 1MΩ for a long period of time, it can be baked in an oven at about 200 degrees Celsius for 5-6 hours to return to normal. Or reduce the voltage and heat up until the insulation resistance is restored. 4. The metal casting heater should be well positioned and fixed. The effective heating area must be closely attached to the heated body. Empty burning is strictly prohibited. When dust or pollutants are found on the surface, it should be cleaned and reused in time to avoid heat dissipation and shorten the service life. 5. Magnesium oxide powder at the outlet end of the electric heating tube, to avoid the infiltration of pollutants and moisture in the place of use, to prevent leakage accidents.