The electronics of a CNC machine, as explained in another section, it is not difficult to understand. It is, in fact, a simply set of components that must be sized on the power of the motors and the size of the CNC machine. At its' simplest configuration it consists of:
- a power supply;
- an electronic interface to control the stepper motors (unipolar or bipolar);
- the motors
To this basic configuration could be added, but not strictly necessary, controls that can facilitate the use or improve the machine:
- breakout boards to protect the parallel port of the PC or to trigger the level of the signals coming from the same port
- limit sensors to prevent the machine to reach its physical limits
- positioning sensors for the axis 'Z'
- automatic start and stop controls for the vacuum cleaner or for other appoarates (router,coolant injectors etc.)
- variable speed control for both DC and AC routers
- joysticks, pads ......
Regarding the Motors, consider that most modern motors are hybrid motors (6-8 wires); they can be set both in unipolar or bipolar configuration. Without to be too theoretical, internet is full of theory about, the difference between the use of bipolar and unipolar controllers may be summarized by the fact that for a given power bipolar motors have more torque, higher speed and less vibration even if they require a more complex electronic circuitry. Later on we'll see how to correctly connect all aspects of the system.
Sometimes we use the word 'hobby' regarding motorizations and controller for our cnc machines. Honestly speaking this is not completely true: a simple recent stepper motor at 1A, connected to a screw of 1mm pitch, generated a pressure of 80kg: a lot, trust me. Generally the word hobby has been used to intend motorization below 3 amperes/phase of current. This is generally considered a limit for many integrated (translator+drive) ics dedicated to drive stepper motors.
