Laser Cutting, Glossary | Frequently Asked Questions

Laser Cutting Glossary

Accuracy and Repeatability: Accuracy is the ability of the machine to locate to a fixed mechanical position and manufacture parts to a specified tolerance in a controlled production environment. Repeatability is the capability of the machine to maintain tolerance from part to part.
Dross: Dross is recast molten metal at the back or bottom of a laser cut metal part. Dross is controlled by manipulation of cut parameters like assist gas pressure (the gas jet blowing co-axially with the laser beam during the cutting process.)
Class I Safety: Laser safety is regulated in the United States by the FDA. Class I is classified as the safest configuration for a laser system. The Class I rating requires such safety features as a fully enclosed system that cannot allow a laser beam to escape and redundant interlocks on doors that turn off power to the laser if a machine door is opened during the cutting process.
Class IV Safety: This is an open machine, so safety equipment must be used in the laser hazard area.
CO₂ Laser: Gas lasers that use carbon dioxide as the lasing medium. CO₂ lasers are offered in either sealed or flowing gas configurations. Sealed CO₂ lasers are generally under 500 watts and are less expensive to operate.
Edge Quality: The level of quality the edge of a part has when immediately removed from the machine. When BEAM talks about thickness of material we can cut, we are talking about what we can cut with excellent edge quality that will generally require little or no additional polishing, sanding, or deburring.
Engraving: To carve or etch a design or letters into a material. The laser engraving process can be either Vector (line following) or Raster (scanning with the laser turning on or off to create an image).
Flying Optics: The part being cut remains stationary while the laser beam is directed by mirrors to a gantry that moves at high speed over the part.
Gantry: A mount for the laser consisting of a bridge-like frame designed to move along a set of tracks over an XY table.
Galvo based laser system: Galvo systems direct a laser beam by a fast moving mirror (similar to a signal mirror reflecting sunlight). Galvo laser systems are generally suited to cutting thin materials in a relatively small field. Thicker materials will tend to burn and have non-vertical cut edge. Because these mirrors and the servo motors that drive them are very tiny, they have very little mass and can be moved at high speeds and stopped very quickly.
Gas-assist: Assist gas is a gas jet blown coaxially with the laser beam to assist and improve the results of the laser cutting process. The type of gas will depend on the application, but the most commonly used gasses are Air, Nitrogen and Oxygen. Assist gas works by either increasing or decreasing the vaporization effect of the laser energy and conveying the waste gas and molten material down and out of the cut.
Gimbal: A contrivance, consisting of a ring or base on an axis, that permits an object mounted in or on it to tilt freely in any direction, in effect suspending the object so that it will remain horizontal even when its support is tipped.
HAZ – Heat Affected Zone: The Heat Affected Zone is the cut edge of the part and that area of and into the part that has been chemically or cosmetically affected by the concentrated heat of the laser cutting process. An important goal in laser process development is to find cut parameters to minimize the Heat Affected Zone.
Kerf: The width of a groove or cut made by a cutting tool.
Linear encoder: Linear encoders are optically read high precision “rulers”. Beam Dynamics uses linear encoders on the Ya, Yb and X axes in closed loop with servo motors to ensure high precision that doesn’t wear out over time.
Precision: The ability of a measurement to be consistently reproduced.
Rotary encoder: An encoder is an electrical mechanical device that can monitor motion or position. A typical encoder uses optical sensors to provide a series of pulses that can be translated into motion, position, or direction. Rotary encoders are based in the actual motor, and use pulses to determine its position.
Servo motor: A Servo is a small device that has an output shaft. This shaft can be positioned to specific angular positions by sending the servo a coded signal. As long as the coded signal exists on the input line, the servo will maintain the angular position of the shaft. As the coded signal changes, the angular position of the shaft changes.
Throughput: The number of quality finished parts produced per hour. Generally throughput consists of cut speed, acceleration and other process parameters.
YAG Laser: Solid-state lasers that use the element Neodymium (Nd) diffused in a crystal of Yttrium-Aluminum-Garnet (YAG) as the lasing medium.