In the 1960s, with the development of battery manufacturing technology, battery powered tools without power cords using nickel cadmium batteries emerged. But at that time, due to high prices, development was slow. By the mid to late 1970s, due to the decrease in battery prices and shortened charging times, this type of electric tool was widely used in Europe, America, and Japan. Electric tools initially used cast iron as the casing, but later switched to aluminum alloy as the casing. In the 1960s, thermoplastic engineering plastics were applied to electric tools and achieved dual insulation, ensuring the safety of electric tools. Due to the development of electronic technology, electronic speed control electric tools also emerged in the 1960s. This type of electric tool utilizes components such as thyristors to form an electronic circuit, which adjusts the speed of the switch button according to the depth at which it is pressed. This allows the electric tool to choose different speeds based on the different processed objects (such as materials, drilling diameter, etc.) during use.