Words on the spec sheet.

Average power is a laser's output averaged over time, in watts (W), and is the rated power in names such as '20 W marker' or '1500 W welder'. For a pulsed laser it equals pulse energy multiplied by repetition rate.

Average power sets throughput, but two pulsed lasers with the same watts can perform very differently, so compare pulse energy, pulse width and peak power as well.

Beam quality (M², 'M-squared') is a number that compares a laser beam with an ideal Gaussian beam, which has M² = 1. The closer M² is to 1, the smaller the spot the beam can be focused to.

Common 20 W fiber marking sources are specified at M² below about 1.5, while multimode kilowatt welding and cleaning sources have higher values, so compare M² only between sources of the same type.

A CO2 laser is a gas laser that emits infrared light at 10.6 µm. Wood, acrylic, leather, textiles, paper, glass and stone absorb this wavelength well, so CO2 machines engrave and cut non-metals but cannot mark bare metal.

Steel absorbs only about 11% of 10.6 µm light, so bare metal is marked with a fiber laser; a CO2 laser can still mark painted or coated metal.

A continuous-wave (CW) laser emits a steady beam at constant power instead of pulses. Handheld laser welders and heavy-duty laser cleaners use CW fiber lasers, typically at 1000–3000 W.

CW sources cost less per watt than pulsed sources, but in cleaning they heat the part more and can melt or darken the surface.

A fiber laser is a laser whose light is generated inside an optical fiber doped with a rare-earth element, usually ytterbium, and emitted as invisible near-infrared light at about 1064–1080 nm. It is the standard source for marking, cleaning, welding and cutting metal.

Metals absorb this wavelength far better than a CO2 laser's: steel absorbs about 33% at 1.06 µm but only about 11% at 10.6 µm.

Fluence is the laser energy delivered per unit area, usually in joules per square centimetre (J/cm²). It equals pulse energy divided by spot area: 1 mJ on a 50 µm spot is about 50 J/cm².

Cleaning and marking work only when fluence is above the ablation threshold of the layer you want to remove and below the damage threshold of the material underneath.

A MOPA (master oscillator power amplifier) fiber laser is a pulsed laser in which a seed source shapes the pulses and an amplifier boosts them. Its pulse width, often adjustable from a few to several hundred nanoseconds, can be set separately from repetition rate.

Choose MOPA for colour marks on stainless steel, black marks on anodized aluminium, cleaner marks on plastics and gentle cleaning of moulds; for plain codes on steel, Q-switched is enough.

An Nd:YAG laser is a solid-state laser that uses a neodymium-doped yttrium aluminium garnet crystal and emits at 1064 nm. Flashlamp-pumped Nd:YAG lasers are the established source in jewelry laser welders.

The flashlamp is a wear part and the crystal needs deionized cooling water, so ask for the lamp price and the service routine before you buy.

Peak power is the highest power reached during a laser pulse, roughly pulse energy divided by pulse width. A 1 mJ pulse lasting 100 ns peaks at about 10 kW, far above the laser's average power.

Peak power decides whether a pulse can melt or remove material at all, which matters most on reflective metals such as copper, silver and aluminium.

Pulse energy is the energy carried by one laser pulse, measured in millijoules (mJ) or joules (J). It equals average power divided by repetition rate: 20 W at 20 kHz gives 1 mJ per pulse.

Jewelry welders are often sold on maximum joules, but ask for peak power, pulse length and average power too, because maximum energy and maximum pulse rate cannot be used together.

Pulse width (pulse duration) is the length of one laser pulse, measured in nanoseconds (ns) for marking and cleaning lasers and in milliseconds (ms) for jewelry and spot welders. Shorter pulses leave less time for heat to spread into the part.

Q-switched sources have a fixed pulse width, while MOPA sources let you change it, which controls colour marking and the heat put into a part during cleaning.

A Q-switched fiber laser is a pulsed laser that stores energy and releases it in short, intense pulses of fixed width, about 100 ns on common marking sources. A typical 20 W source delivers up to about 1 mJ per pulse.

It is the lower-cost choice for serial numbers, logos, 2D codes and engraving on steel and aluminium, but unlike a MOPA laser it cannot change its pulse width.

A QCW (quasi-continuous-wave) fiber laser fires long pulses, from about 0.05 to 50 ms, with peak power up to about 10 times its average power. It is used for spot and seam welding of small parts and in jewelry welders.

Compared with a flashlamp Nd:YAG laser it has no lamp to replace and higher efficiency; IPG quotes wall-plug efficiency above 30% for its QCW lasers.

Repetition rate (pulse frequency) is the number of pulses a laser fires per second, usually given in kilohertz (kHz). At the same average power, a higher rate gives more pulses with less energy in each.

A common 20 W Q-switched marking source runs at about 20–60 kHz, while MOPA sources reach into the megahertz range.

Spot size is the diameter of the focused laser beam on the work surface. A smaller spot gives finer detail and higher power density; galvo fiber markers typically focus to a few tens of micrometres.

Spot size grows with lens focal length: in one optics maker's 1064 nm lens series it rises from 26 µm with a 160 mm lens to 50 µm with a 420 mm lens.

A UV laser is a marking laser that emits ultraviolet light at 355 nm, made by frequency-tripling a 1064 nm infrared laser. Its short wavelength focuses to a fine spot and marks plastics, glass and PCBs with little heat.

UV marking sources are usually 3–15 W and cost more per watt; choose one for white or flame-retardant plastics, glass, very small codes and heat-sensitive parts.

The ablation threshold is the minimum fluence, in J/cm², at which a laser pulse starts to remove material from a surface. Each coating, oxide and base metal has its own threshold, which also depends on wavelength and pulse width.

Laser cleaning works in the window between the coating's ablation threshold and the base material's damage threshold, so test settings on your own part before production.

Laser cleaning is the removal of rust, paint, oxide, oil or other layers from a surface with a laser beam that ablates or vaporises the layer while an extractor captures the fume. It uses no blasting media, chemicals or water.

Pulsed cleaners (typically 20–500 W) keep delicate surfaces intact, while continuous-wave cleaners (typically 1000–3000 W) cost less per watt and suit heavy rust on thick steel.

Sa 2½ is the 'very thorough blast-cleaning' grade in ISO 8501-1: viewed without magnification, the steel is free of visible oil, grease, dirt, mill scale, rust, paint and foreign matter, and remaining traces show only as slight stains in spots or stripes.

ISO 8501-1 was written for blast cleaning, so check a laser supplier's 'Sa 2.5' claim against the standard's photographs on your own part; AMPP SP21511-1 (2024) now covers pulsed laser ablation of steel.

Conduction welding is the laser welding mode in which the beam melts only the surface and heat spreads into the metal by conduction, giving shallow, wide, smooth welds. TWI places it below a power density of about 10⁵ W/cm².

It suits thin sheet, visible cosmetic seams and small parts; between conduction and keyhole welding lies a transition range that shifts with spot size and travel speed.

Fit-up is how closely the parts of a joint meet before welding, and gap tolerance is the largest gap a process can still weld. Without filler wire or wobble, a laser butt joint needs a gap below about 10% of sheet thickness (TWI).

On 2 mm sheet that is about 0.2 mm; wobble raises it to about 0.4–0.6 mm and filler wire to about 2 mm, so accurate cutting, bending and clamping pay off.

A handheld laser welder is a fiber laser welding machine in which the operator guides a light torch connected to the laser source by a fiber cable. Typical power is 1000–3000 W, and 1000–1500 W covers most sheet metal up to about 3 mm.

Most units now include beam wobble and accept a wire feeder, and some swap nozzles to clean and cut as well, sold as 3-in-1 or 4-in-1 machines.

The heat-affected zone (HAZ) is the band of base metal next to a weld or cut that did not melt but whose structure and properties were changed by heat. A narrower HAZ usually means less distortion and discolouration.

Laser welding usually leaves a narrower HAZ than TIG or MIG because heat input is low, although filler wire and slow travel widen it.

Keyhole welding is the laser welding mode in which a power density above about 10⁶ W/cm² vaporises a narrow channel through the metal, giving deep, narrow welds with low heat input. Handheld fiber laser welders usually work in this mode.

A keyhole weld is fast and low in distortion but tolerates only small gaps, so fit-up and clamping matter more than in arc welding.

Shielding gas is the gas, usually argon or nitrogen, blown over the weld pool to keep out air and reduce oxidation and porosity. Laser welding needs it just as TIG and MIG welding do.

Practice differs by maker: Lincoln Electric's presets use nitrogen for steels and argon for aluminium, while Han's Laser lists argon for steels, so follow your supplier's welding procedure.

A wire feeder is a unit that pushes filler wire, commonly 0.8–1.6 mm in diameter, into the laser weld pool to add metal. Filler wire bridges gaps, builds fillet welds and lets the same laser fill thicker joints.

With wire, TWI puts gap tolerance at about 100% of sheet thickness on steel up to 6 mm; buy a feeder if you weld fillets, aluminium, uneven gaps or steel over about 3 mm.

Wobble welding is laser welding in which the head moves the focused beam in a small, fast pattern, such as a circle or a line, across the joint. It widens the bead and helps the weld pool bridge small gaps.

TWI puts gap tolerance at about 20–30% of sheet thickness with wobble against about 10% without, and handheld heads typically offer wobble widths up to about 5 mm.

Annealing marking is a laser marking method that heats stainless steel or titanium just enough to grow a thin oxide film, giving a dark or coloured mark without removing material. The surface stays smooth, so it suits medical and food equipment.

Colour marks come from oxide films roughly 0.3–0.8 µm thick and change with alloy, surface finish and focus, so fix settings per part; MOPA sources make the colours easier to control.

Black marking is a high-contrast black laser mark on metal, most often stainless steel or anodized aluminium, made without engraving into the surface. It is usually produced with a MOPA fiber laser using short pulses and closely spaced lines.

Anodized layers vary between suppliers, so test black marks on parts from your own anodizer before you order a machine.

Deep engraving is laser marking that removes metal layer by layer, over many passes, to cut a recess you can see and feel. It is used where a surface mark would wear off or be painted over.

Time grows with depth and area, and higher average power and pulse energy speed it up, so ask for a timed test at the depth you need before choosing between 50, 100 and 200 W.

EZCAD is laser marking software from Beijing JCZ Technology that drives galvo markers through JCZ control cards: EZCAD2 runs with LMC cards and EZCAD3 with DLC cards. It is widely used on Chinese-built fiber, UV and CO2 galvo markers.

Ask which EZCAD version and control card a marker ships with; LightBurn Pro can also drive EZCAD2 and EZCAD3-type galvo controllers.

An F-theta lens is the flat-field focusing lens fitted below a galvo scanner, keeping the spot in focus on a flat plane across the whole marking field. Its focal length sets field size and spot size: a 160 mm lens gives about 110 × 110 mm.

Galvo markers usually take interchangeable lenses, so ask which lens is fitted as standard and what other sizes cost for larger or smaller parts.

A galvo scanner (galvanometer scanner) is a head with motor-driven mirrors that steer the laser beam at high speed, so the beam moves while the head stays still. Laser markers use it to draw the mark, and handheld cleaning heads use it to sweep the beam.

For parts larger than one marking field, the galvo is combined with a rotary axis, an XY table or several marking positions.

LightBurn is paid laser design and control software for Windows and macOS that sends jobs directly to many controllers: Ruida, Trocen and TopWisdom DSP controllers on CO2 machines, GRBL-type boards, and EZCAD-type galvo controllers.

LightBurn Core covers GCode (GRBL) machines and LightBurn Pro adds DSP and galvo controllers, so check which licence your machine needs.

Marking field size is the largest area a galvo laser can mark without moving the part or the head, set by the F-theta lens. In one 1064 nm series, a 100 mm lens gives 70 × 70 mm and a 420 mm lens 300 × 300 mm.

Pick the smallest field that covers your mark: a larger field needs a longer lens, which gives a larger spot and lower power density, so marking gets slower or shallower.

RF and glass tubes are the two common CO2 laser sources: a glass tube is water-cooled and excited by DC high voltage, while an RF tube is a sealed metal tube excited by radio frequency. RF tubes cost much more but give finer engraving detail.

Sellers typically quote a few thousand hours of life for glass tubes and 10,000 hours or more for RF tubes, which can be refilled, so get the tube warranty terms in writing.

A Ruida controller is a DSP motion controller from Shenzhen RuiDa Technology that runs the motion, laser power and control panel of many CO2 laser engraving and cutting machines. Models such as the RDC6445 work with RDWorks or LightBurn software.

Check the controller model on any CO2 machine quote, because a supported Ruida board lets you use LightBurn instead of the supplied RDWorks software.

UV-curable ink is printing ink that stays liquid until ultraviolet light from a lamp beside the print heads cures it into a solid film. Because it cures as it lands, it can print on glass, tile, metal and wood as well as painted walls.

Uncured ink contains acrylates that can cause skin allergies, so operators need nitrile gloves and ventilation, and uncured waste is typically handled as hazardous waste.

A wall printer (vertical or direct-to-wall mural printer) is an inkjet printer that stands in front of a wall and prints an image directly onto it, moving the print heads up and down a mast while the machine steps sideways.

It works best on smooth, clean, light-coloured indoor walls; deep texture and brick joints leave gaps, so ask for a timed test print on your typical surface.

Assist gas is the gas blown through the cutting nozzle with the laser beam to clear molten material from the cut. Oxygen speeds cutting of carbon steel, nitrogen gives clean, oxide-free edges on stainless steel and aluminium, and compressed air suits low-cost thin-sheet work.

Oxygen leaves an oxide layer on the edge that can make paint peel, so many shops cut parts for painting with nitrogen; include gas cost per hour in your running costs.

Kerf is the width of material removed by a cut. On fiber-laser-cut steel it is typically a few tenths of a millimetre, and it widens with thickness and when oxygen is the assist gas.

Cutting software applies kerf compensation, offsetting the tool path by half the kerf so parts come out at the drawn size.

Piercing is the first step of a laser cut, when the beam burns a hole through the sheet before the cutting path starts. Pierce time grows with thickness and adds up on parts with many holes.

When comparing quotes for thick plate, ask for pierce time as well as cutting speed, since both count in the cycle time.

A Class 4 laser is the highest hazard class in IEC 60825-1, above the Class 3B limit of 0.5 W for continuous output. Its direct beam and even diffuse reflections can injure eyes and skin, and it can start fires.

Every handheld laser cleaner and welder is Class 4, while a fully enclosed machine with interlocks, such as a cabinet marker, can be rated Class 1 even though the laser inside is Class 4.

EN 207 is the European standard for laser protective eyewear used against full-power beams; filters are marked with wavelength, mode (D continuous, I long pulse, R Q-switched, M mode-locked) and a level from LB1 to LB10. EN 208 covers alignment eyewear for visible beams.

EN 208 alignment glasses are not for full-power work, and a fiber laser at about 1070 nm needs EN 207 eyewear rated for each mode it uses.

Fume extraction is local exhaust ventilation that captures the smoke, metal fume and fine dust produced at the beam and passes it through filters. Laser cleaning, welding, cutting and marking all produce fume that needs it.

The coating decides the risk: zinc, lead, chromate primers and plastics give the most harmful fume, and used filters from lead or chromate work are hazardous waste.

A laser controlled area (LCA) is a space where access and protection are controlled because laser exposure can exceed safe limits. It uses laser-rated walls or screens, interlocked doors, warning signs, and entry only for trained people wearing the right eyewear.

For site work on bridges, ships or buildings, the laser safety officer sets the boundary with laser-rated screens and signs, and nobody without protection may enter.

The nominal ocular hazard distance (NOHD) is the distance along the beam from a laser beyond which the beam no longer exceeds the maximum permissible exposure (MPE) for the eye. Closer than the NOHD, looking into the beam can injure the eye.

At handheld welding powers IPG says eye damage is possible up to hundreds of feet away, so the laser safety officer calculates the hazard zone for each laser and site.

Optical density (OD) is the measure of how strongly a laser filter blocks light at a given wavelength. Each OD step cuts transmission by 10 times, so OD 7 lets through one ten-millionth of the beam.

OD is valid only at the wavelengths printed on the eyewear; for 1070 nm handheld welding IPG recommends OD 7 or higher, but the required value comes from a hazard calculation.

CE marking is the manufacturer's declaration that a product meets EU law. Laser machines placed on the EU market need it under the Machinery Directive 2006/42/EC, and from 20 January 2027 under the Machinery Regulation (EU) 2023/1230.

Ask for the manufacturer's EU Declaration of Conformity for your exact model; a test-lab 'CE certificate' does not replace it.

A chiller is a refrigerated water-cooling unit that pumps water at a set temperature through the laser source and optics to remove heat. Fiber laser chillers often have two circuits: a colder one for the source and a warmer one for the head optics.

Keep the water above the room's dew point to avoid condensation on the optics, protect it from freezing with antifreeze, and drain it before shipping.

Duty cycle is the share of time a machine can run at its rated output without overheating, given as a percentage of a set period. Arc welders usually state it over 10 minutes: 60% means 6 minutes on and 4 minutes off.

For laser welders and cleaners, ask for the duty cycle at full power and at your highest workshop temperature, especially on air-cooled units.

An FDA laser product report is the document a manufacturer files with FDA's Center for Devices and Radiological Health (CDRH) to show that a laser product meets 21 CFR 1040.10 and 1040.11 before it is sold in or imported into the US.

CDRH replies with an accession number, which confirms receipt of the report, not approval; FDA advises filing at least one month before import.

HS code 8456.11 is the Harmonized System subheading for machine tools that work material by removing it with a laser, such as laser cutting and engraving machines. Laser welding machines usually fall under heading 8515, and some laser markers have been classified under 9013.

Your customs authority decides the code, so agree it with your broker before shipment and ask for a binding ruling if the duty difference matters.

Incoterms are the International Chamber of Commerce rules that define, in a sale contract, who arranges and pays for transport, insurance and customs clearance, and where risk passes to the buyer. Incoterms 2020 has 11 rules, including EXW, FOB, CIF and DDP.

Under EXW you collect at the factory, under FOB the seller loads your ship, CIF adds sea freight and insurance to your port, and DDP adds delivery and import duties; always name the place, such as 'FOB Shanghai'.

A laser source maker builds the module that generates the beam inside a laser machine. Raycus (Wuhan), JPT and Max Photonics (both Shenzhen) are Chinese fiber laser makers widely used in Chinese-built machines; IPG Photonics is a US-headquartered maker.

Compare source models, not brands: ask for the exact model, power, pulse range and serial number, and whether the source warranty comes from the source maker or the machine builder.