Differing approaches to motion in CNC machines
Depending on the nature of the machine itself, the motion system can vary based on the rigidity requirements of the toolhead. Very frequently, a compromise is struck between speed and rigidity (or stiffness) so that cheaper or more readily available components may be used. The most common of these tradeoffs is allowing X- and Y-axis motion to be driven by belts while the Z-axis motion operates using a leadscrew. Other designs use leadscrews throughout.
The following figure shows one of my four 3018 machines:
Figure 1.2 – A 3018 machine (see Figure 2.1 for an annotated close-up picture)
In the preceding figure, note the controller on the right. This picture was taken just prior to calibration. This is a machine that can be purchased online as a kit. It is made from some off-the-shelf parts (8020 aluminum extrusions, 8-mm steel rods, stepper motors (which are used for motion), leadscrews, and an engraving...
