After using the variable step programming method, taking the single-layer pass as an example, the calculation amount and the number of cycles of the node are significantly reduced, and the calculation amount of the calculation of the specific form layer node (roughing) finishing is also reduced by the same proportion. Although the calculation method of the relationship between the change rate and the step size used above is an approximate calculation method, the control method for the step size is simple, and is suitable for the operation of the numerical control lathe system, and the effect of improving the calculation efficiency is also obvious, if the minimum step is to be performed. The length is set slightly smaller than the conventional step size, and the processing precision is enough to meet the requirements. By this method, in the calculation variable step size, the complicated function calculation can be skipped, which helps the first-line technician to use the simplified Calculation method programming and processing. For the numerical control equipment whose calculation function is not very powerful, the variable step size method is used to improve the efficiency and precision of the numerical control system. There are mainly kinds of anti-freezing forms commonly used in domestic wells: air heaters or hot blast stoves are used to heat the wells, and special fans are used to send hot air to the wellheads. For the fan heating mode, special air heating rooms, fan rooms and air supply tunnels are required. The air heater is used to heat part of the well air, and then the cold and hot air are simultaneously sucked into the wellbore by the mine ventilation negative pressure, and the hot and cold air is mixed at the wellhead to achieve the anti-freeze requirement of the wellbore. For the fanless heating mode, an air heating room is required. And the wellhead room sealing requirements are higher. In this way, there are shortcomings such as large land occupation, large investment and energy consumption, complicated management and easy freezing of the initial wellbore; and due to the change of the mine lifting system, the wellhead room is often provided with lifting holes to make the heat loss more serious. After determining the main problems, the anti-freezing scheme of the new wellbore was studied: removing the air heating chamber, and installing a new type of heat-dissipating pipe around the wellhead to directly mix the hot and cold air entering the well at the wellhead, and effectively avoiding the hot air floating by using the mine ventilation negative pressure, saving Investment, reduce floor space and improve thermal efficiency. Bimetallic Single Screw and Barrel ZHOUSHAN HUARUI MACHINERY MANUFACTURING CO., LTD. , https://www.huaruiscrew.com