霸刀分享-哪些因素会影响铣床的加工精度？
设备相关因素：首先，数控铣床设备本体的精度很关键。要是机床本身的材料、导轨等达不到数控系统的控制要求，会严重影响零件加工精度。还有，数控机床的性能稳定性、刚性以及能否承受加工过程中的机械振动等，也都会对产品质量产生影响。另外，现在不少数控铣床使用三相异步电机带动滚珠丝杠传输动力，运转时轴承间有空隙，还可能因振动产生形变，加剧零件生产误差，而且加工不同零件时承受的力不同，轴承空隙大小有差异，也会影响零件精度。
刀具相关因素：刀具补偿和刀具路径设置不当也会影响加工精度。由于铣床自身尺寸有限，需要设定刀具补偿值，让系统根据机床大小调节坐标位移以达到程序尺寸要求。设定刀具轨迹时，要考虑刀具大小避免过切。刀具半径补偿有B型刀补和C型刀补两类，B型刀补在加工工件边角时用圆弧过渡，会造成工件锐角磨损和刀具加速磨损，C型刀补采用刀偏计算，能自动求出角度交叉，是很多数控系统常用类型。
工件装夹因素：加工前要保证工件夹装稳定，不然受外力作用产生位移和震动，会影响加工准确性。但实际生产中，因夹持位置、重力和支撑物等因素，工件实际位置可能无法达到预期位置，比如夹紧不当造成的错位，所以要合理设置夹紧位置，尽量接近工件加工位置和硬度高的位置，减少加工震动对工件定位的影响。
温度因素：现在铣床的主轴是核心部分，主轴产生的热量会直接影响其旋转和工件加工精度，特别是转速高时，更容易导致加工误差。同时，系统发热包括切削发热和摩擦发热，虽然大部分热量由切削液和切屑吸收，但少量积累到刀具和工件上，也会对加工精度有影响。而且很多数控铣床缺乏辅助散热措施，加工时相关轴承部位摩擦生热，与刀具和毛坯摩擦产生的热量叠加，使毛坯温度上升，若热量不能及时散发，零件会产生形变，影响加工精度。
铣削参数因素：在零件铣削加工过程中，刀具的旋转速度、吃刀深度、进给量、铣削速度等要素都是很重要的参数。如果这些参数设置不合理，就会在加工过程中产生误差，无法保证加工零件的精度或者表面粗糙度等。
What factors can affect the machining accuracy of a milling machine?
Equipment-related factors: Firstly, the precision of the CNC milling machine itself is very crucial. If the materials and guide rails of the machine tool itself do not meet the control requirements of the numerical control system, it will seriously affect the processing accuracy of the parts. Moreover, the performance stability, rigidity and ability to withstand mechanical vibrations during the processing of CNC machine tools will also have an impact on product quality. In addition, nowadays many CNC milling machines use three-phase asynchronous motors to drive ball screws to transmit power. During operation, there are gaps between the bearings, which may also cause deformation due to vibration, intensifying the production errors of parts. Moreover, different parts are subjected to different forces during processing, and the size of the bearing gaps varies, which also affects the precision of the parts.
Tool-related factors: Improper tool compensation and tool path setting can also affect machining accuracy. Due to the limited size of the milling machine itself, it is necessary to set the tool compensation value, allowing the system to adjust the coordinate displacement according to the size of the machine tool to meet the program size requirements. When setting the tool path, the size of the tool should be taken into consideration to avoid overcutting. Tool radius compensation can be classified into two types: B-type tool compensation and C-type tool compensation. When processing the edges and corners of workpieces, B-type tool compensation uses arc transitions, which can cause acute Angle wear of the workpiece and accelerated tool wear. C-type tool compensation uses tool offset calculation and can automatically calculate the Angle cross. It is a commonly used type in many numerical control systems.
Workpiece clamping factors: Before processing, it is necessary to ensure that the workpiece is clamped stably. Otherwise, displacement and vibration caused by external forces will affect the processing accuracy. However, in actual production, due to factors such as clamping position, gravity and support objects, the actual position of the workpiece may not reach the expected position, such as misalignment caused by improper clamping. Therefore, the clamping position should be reasonably set, as close as possible to the processing position of the workpiece and the position with high hardness, to reduce the impact of processing vibration on the positioning of the workpiece.
Temperature factor: Currently, the spindle of a milling machine is the core component. The heat generated by the spindle directly affects its rotation and the processing accuracy of the workpiece. Especially when the rotational speed is high, it is more likely to cause processing errors. Meanwhile, the system heat generation includes cutting heat and friction heat. Although most of the heat is absorbed by the cutting fluid and chips, a small amount accumulates on the tool and workpiece, which can also affect the machining accuracy. Moreover, many CNC milling machines lack auxiliary heat dissipation measures. During processing, the friction at the relevant bearing parts generates heat, which accumulates with the heat produced by the friction between the cutting tool and the blank, causing the temperature of the blank to rise. If the heat cannot be dissipated in time, the parts will deform, affecting the processing accuracy.
Milling parameter factors: During the milling process of parts, elements such as the rotational speed of the tool, the depth of cut, the feed rate, and the milling speed are all very important parameters. If these parameters are not set reasonably, errors will occur during the processing, and the accuracy or surface roughness of the processed parts cannot be guaranteed.