In recent years, ANITISHI milling machine said that with the rapid development of energy, metallurgy, construction machinery and other industries, many key components in these industries tend to be large and complex, and the precision required for each processing surface is also very high. This requires the development of metal cutting machine tools to focus on heavy-duty machine tools with large torque, large stroke and high precision. CNC floor-type milling and boring machine is a general-purpose machine for machining large parts and components. It is widely used in energy, metallurgy, engineering machinery and other industries. The pillow constitutes a cantilevered moving part. Heavy-duty CNC floor-type milling and boring machine refers to a floor-type milling and boring machine with a spindle diameter of not less than 160mm, a ram stroke of not less than 1200mm, and a spindle stroke of not less than 1200mm (that is, a large-stroke ram) of not less than 1000mm. However, when the large stroke ram is extended, it will cause bending deformation due to its own weight, thus affecting the accuracy of the machine tool. Therefore, the problem of deformation compensation for the large stroke ram is the main difficulty in the manufacturing technology of floor milling and boring machines.
At present, the main compensation methods for solving the protrusion deformation of the ram include: 1. Use the prestressed deflection processing method to realize the deflection compensation, and use the numerical control processing method to remove the deformation part of the ram in advance, so that the ram is in a flat position when the ram is extended. Straight state, this method can produce a certain compensation effect, but the processing and assembly requirements of the ram are relatively high; 2. The method of ram deflection compensation is realized by the CNC system of the machine tool. This method uses the numerical control system to automatically detect the deflection of the ram, through The corresponding displacement of the Y-axis is controlled to achieve compensation, but it only compensates the deflection of the ram, and the bending deformation of the ram is not considered; 3. The electro-hydraulic proportional control method is used to compensate the lower head of the ram, although a certain degree of compensation has been achieved. Compensation effect, but the electro-hydraulic proportional control needs to accurately grasp the deformation function of the ram at each stage, and there is often a large deviation for the fast-moving ram; 4. The hydraulic gravity center eccentric compensation method is used, which is installed before and after the headstock. A counterweight is used to balance the head down of the ram caused by the change of the center of gravity of the headstock. This method is simple to operate, but the head down of the ram caused by the gravity of the ram itself is not completely solved. If the deflection of the ram cannot be solved well, when the main shaft is extended, the bending deformation of the ram will undoubtedly magnify the suspension of the main shaft, thus affecting the straightness of the main shaft movement. Therefore, the heavy-duty CNC floor-type milling and boring machine needs a simple and practical mechanism to realize the automatic compensation of the deformation of the large-stroke ram.