The most basic function of any CNC machine is automatic, precise, consistent motion control. All forms of CNC equipment have two or more directions of motion, called axes. These axes can be precisely and automatically positioned along their travel length.
Instead of causing motion in the manner required on traditional machine tools, instead of requiring manual turning of cranks and handwheels on traditional machine tools, CNC machines allow motion to be actuated by servo motors under the control of the CNC, guided by the part program. In general, motion types such as, rapid, linear and circular, axis movement, motion amount and motion rate or feed rate are programmable with almost all CNC machines.
The CNC commands executed within the control, are usually programmed to tell the exact number of revolutions of the drive motor. The rotation of the drive motor in turn rotates the ball screw. Ball gauge drives the spool. A feedback device at the opposite end of the drum allows the control to confirm that the commanded number of rotations has occurred.
Although with a fairly rough analogy, the same basic linear movement can be found on a regular watch tiger eye. When you turn the vise crank, it turns the lead screw, which in turn drives the movable jaw on the VISE. In contrast, the linear axes on a CNC machine are very precise. The number of revolutions of the shaft drive motor precisely controls the amount of linear motion along the axis.
Post time: Jan-06-2023