Amperage – a measure of electrical energy flowing through appliance at any given time (current), i.e. Watts = Amps x Volts (WAV) or Amps = Watts/Volts

Ball Nut – Ball bearing assembly through which the ball screw is threaded.

Ball Screw - a mechanical linear actuator that translates rotational motion to linear motion.

Bearings - a device to allow constrained relative motion between two or more parts, typically rotation or linear movement.

Canned cycle - A sequence of machine operations initiated by a single G code. Canned cycles act as shorthand that simplify the programming.

Closed loop – uses feedback from the encoder to monitor the output of motors, and also has the ability to correct errors in position, velocity, acceleration, and fault the system if the error is too large. Think of it as GPS for servos.

CNC – Computed Numeric Control

Controller – the machine’s control system, consisting of a mainboard and transformer, draws power from the inverter, and is usually enclosed in a box located on the side supports of the table, or inside the gantry on smaller machines. It receives conditioned signals from a PC and interprets those signals into mechanical motion via the servos.

Encoder – a device that converts the angular position of a shaft or axle to an analog or digital code.

Inverter - an electrical device that converts direct current (DC) to alternating current (AC). It may be single phase or 3 phase, and powers the machine’s systems and motors.

G-Code - The standard machine-tool language. Check out the G-code page, along with the reference and examples pages for more information.

Home/Limit Switch – A normally-closed switch. When the servo contacts the switch, it opens the switch and motion stops.

Linear motion device – converts controlled rotary motion into linear motion with help of a controller.

Open Loop – controller-to-motor communication is one-way, works like following a treasure map (2 steps north, 3 steps west, etc.).

Three Phase power - three circuit conductors carry three alternating currents (of the same frequency) which reach their instantaneous peak values at different times.

PWM – Pulse Width Modulation - binary information is communicated by varying pulse duration (width).

Ramping - The process of controlling the pulse frequency to accelerate or decelerate a stepper motor.

Servo - A motor that is typically a DC brushed type with an optical encoder attached to it. Servos have magnets on the shaft which allow combinations and sequences of electro-magnetic fields to precisely control the rotation of the shaft, while the resulting positional information is fed back to the controller by the encoder.

Spindle - Provides the rotational force to the cutting tool or bit (it’s the routers cutting motor).

Stepper – constant-power motors that can divide a full rotation into a large number of steps. Stepper motors draw excess current regardless of the load, dissipated as heat. For more information, see the Stepper motor page.

Touchpad - used to find the top surface height of the job material.

Torque - the tendency of a force to rotate an object about an axis. With electric motors, torque decreases as RPMs increase.