The earliest numerical control machines date to the 1940s when motors were first employed to control the movement of pre-existing tools. As technologies advanced, the mechanisms were enhanced with analog computers, and ultimately with digital computers, which led to the rise of CNC machining.

The vast majority of today’s CNC arsenals are completely electronic. Some of the more common CNC-operated processes include ultrasonic welding, hole-punching and laser cutting. The most frequently used machines in CNC systems include the following:

CNC Mills

CNC mills are capable of running on programs comprised of number- and letter-based prompts, which guide pieces across various distances. The programming employed for a mill machine could be based on either G-code or some unique language developed by a manufacturing team. Basic mills consist of a three-axis system (X, Y and Z), though most newer mills can accommodate three additional axes.

Lathes

In lathe machines, pieces are cut in a circular direction with indexable tools. With CNC technology, the cuts employed by lathes are carried out with precision and high velocity. CNC lathes are used to produce complex designs that wouldn’t be possible on manually run versions of the machine. Overall, the control functions of CNC-run mills and lathes are similar. As with the former, lathes can be directed by G-code or unique proprietary code. However, most CNC lathes consist of two axes — X and Z.

Electric Discharge Machines

Electric-discharge machining (EDM) — alternately referred to as die sinking and spark machining — is a process that molds work pieces into particular shapes with electrical sparks. With EDM, current discharges occur between two electrodes, and this removes sections of a given work piece.

When the space between the electrodes becomes smaller, the electric field becomes more intense and thus stronger than the dielectric. This makes it possible for a current to pass between the two electrodes. Consequently, portions of a work piece are removed by each electrode. Subtypes of EDM include:

Wire EDM, whereby spark erosion is used to remove portions from an electronically conductive material.

Sinker EDM, where an electrode and work piece are soaked in dielectric fluid for the purpose of piece formation.

In a process known as flushing, debris from each finished work piece is carried away by a liquid dielectric, which appears once the current between the two electrodes has stopped and is meant to eliminate any further electric charges.