The feed drive systems are key elements of CNC machines. Almost everything depends on them: positioning accuracy, speeds of working motions, accelerations and smooth motions. Nowadays such drives have to meet very high standards.
Professional solutions require applying servo drives, and for less demanding applications, step motors are sufficient. We can offer both types of feed drives. The main difference between these drives is the position feedback. In the case of step motors all machine movements consist of a large number of single steps generated by the interpolator. Each step, depending on the drive ratio and the amount of microsteps, is from 0005 to 0.1mm. Drives of this type have a very simple structure, which results in a relatively low price. A certain disadvantage is the lack of the measurement of position, and in certain difficult circumstances (overloading) the coordinates may be lost (lost steps), which may cause damage to the processed workpiece or the tool.
Servo drives are devoid of such shortcomings. Their work consists in constant striving to achieve zero deviation, i.e. the difference between the value set and the value measured. The head position is constantly read by the incremental encoders, which can measure the position of the head with the accuracy coming up to 0.001mm. On the basis of this information, the control system controls the motor so that the error is zero. When the load increases, the engine increases the power to prevent arising the deviation of the position, and in the case of exceeding a certain load, the system stops the machine and informs the operator about the need for intervention.
Zobacz, jak powstają najszybsze maszyny CNC w Polsce