IF frequencies due to the high aluminum furnace , the molten aluminum of high frequency vibration , combined with the own characteristics of aluminum , which is particularly strong penetrating , so the lining is critical. A special furnace lining for aluminum furnaces should be used . Generally, a good furnace lining can use more than 300 heats. When aluminum is melted, the eddy current generated is large. In the early stage of melting, due to the irregular distribution of the charge, the power supply is subjected to a strong impact, and the thyristor is easily burned out. Therefore, when manufacturing the intermediate frequency power supply, the impact resistance should be considered.