Lasers - everything you need to know before purchasing
Buying the wrong laser for your needs can lead to wasted money and time
LASER DEFINITION
'Laser' is an acronym, formed from the initial letters of the phrase 'Light Amplification by Stimulated Emission of Radiation'.
The laser light beam is a very narrow (less than 2mm wide) concentrated powerful beam of parallel polarised light particles (photons) of the same particular electromagnetic frequency as each other (monochromatic) that carries enough energy through air to heat, melt, and sinter metal and other materials predominantly whilst most of the material item remains at room temperature except for the exact location being lasered.
Lasers can cut through materials, or be controlled to cut partway through, thereby creating an etched engraving upon the surface to a particular depth. This is most readily visible on smooth or coloured surfaces, leaving a roughened or discoloured engraving to contrast with the original unetched material.
SIDEBAR
This document uses some British English based spelling, such as fibre for fiber, and aluminium for aluminum. These are not spelling mistakes.
LASER TYPES
There are three type of laser tools, in order of cost (based upon output laser power and capabilities) are: 1. Solid State Blue (Visible) 'Diode' (5-40W), 2. Gaseous State long-wave Infrared (IR) 'CO2' (30-80W), 3. 'Fibre Optic' short-wave Ultraviolet (UV) (1W->100kW).
The differences are the laser technology type and frequencies being used, which affects the laser power available and materials suitable for lasering.
FIRE PREVENTION
Lasers cut and engrave by applying a concentrated focussed energy beam that heats, burns and sinters through the materials that it encounters. This process necessarily creates smoke and fumes — of the material being lasered — which needs to be handled (extracted and filtered to outside). Also, be aware that if the material being lasered is combustible (like natural fibre or plastic products) great care must be taken to limit the heating of the material to less than its combustible temperature, OR IT WILL CATCH FIRE (and damage the laser tool itself)!
MACHINE PROTECTION
A metal (usually aluminium) base plate (catch tray on some models) is required to prevent overshot or cut-through laser from damaging the work-table the laser machine rests upon. A tall honeycomb metal lattice layer is also necessary above the base plate to catch and minimise reflections from the laser striking the base plate. Cheaper Diode-based laser machines don't include these items, so will need to be purchased separately and additionally to the laser machine.
CO2 models require a water cooling system to keep the CO2 High Voltage (HV) discharge tube cool during operation. At a minimum this consists of a separate bucket or open container of distilled water, a submersible water pump, and connected — flexible tubing and return hosing — with the laser machine. Higher power models also require a separate refrigerated cooling system for the cooling water, usually provided in a separate but interconnected module. Some larger cabinet models have this incorporated with the cabinet.
The water pump is often provided with power from the laser machine, so that it can control the water pump operation. The refrigerated module will require its own separate mains power outlet (preferably on a separate power circuit so that it will keep operating should the power to the laser machine fail whilst being operated, for whatever reason).
PERSONAL PROTECTION
Operating Laser equipment requires the wearing of suitably rated safety glasses and shielding that match the laser frequency and penetration power (depth). WARNING: Laser light can instantly damage skin, eyes and sight.
Some models provide a minimal level safety glasses, or an overly dark pair. Better looking appropriately graded safety glasses will need to be purchased separately to the laser machine.
Laser-proof shielding needs to surround the machine to protect the room and people in it from stray laser reflections during laser operations. This can come in the form of an enclosed box with a hinged-lid for access, often containing one or more fixed viewing panes of laser-proof glass or polycarbonate for protection of viewers. Cheaper Diode-based laser machines don't include these items, so will need to be purchased separately and additionally to the laser machine.
Laser cut materials can be quite hot after being lasered and so could cause burns if inadvertently touched. Heat proof (leather rawhide) gloves must be worn when handling recently lasered material that may retain heat. Also not provided by any laser machine manufacturer.
More expensive and more powerful laser machines that come in their own cabinet, either desktop or free-standing, have a built-in shielding and lid with safety switch, such that the machine won't operate until the lid is closed.
CO2 models contain a CO2 High Voltage (HV) discharge tube which emits EMF and laser beam radiation during operation, and so is enclosed within its own compartment within the laser machine cabinet, usually at the top rear, with its own hinged lid. This compartment lid MUST remain closed whilstsoever the laser machine is energised (power ON) to negate the risk of coming into contact with the CO2 tube high voltage (electric shock) or emitted radiation (skin and eye damage/burns).
EXHAUST VENTILATION
All laser operations produce smoke and fumes from the lasering of materials, which needs to be collected and extracted away from indoors and people. Although some models and portable covers may include a built-in exhaust fan, most are inadequate to pump air more than a couple of metres at best. Accordingly, unless you're using a top-of-the-range cabinet model, you will need to install a separate exhaust system (fan and ducting) capable to the task. A simple exhaust fan in the window, wall or ceiling will not suffice, as the fumes have already been released to the room (where people work and breathe). This will also need to be purchased separately and additionally to the laser machine. It will need to be fitted and installed at your own expense. And it will need to be powered as well, with an accessible control switch.
ADDITIONAL EQUIPMENT
Air cooling:
Laser cutting requires job air cooling (so called air-assist) to minimise scorching and burning, which is provided by an external air pump connected by flexible tubing to the laser cutting head, designed to direct the air flow onto the cutting area. Larger enclosed desktop and cabinet laser machines have a built-in job air pump and installed tubing to the laser head. Cheaper Diode-based laser machines don't include these items, so will need to be purchased separately and additionally to the laser machine.
Computer Control Software:
The laser machine computer numerical control (CNC) is provided by an external computer software that controls the laser machine somewhat like a ink-based moving-head printer driver, using custom laser software and vector based images. Images can be created by the laser software, or imported from external graphics packages such as SVG or PDF layered image files.
No laser machine manufacturers provide the computer, the computer's operating system software, nor graphic design software, so these will all need to be provided separately and additionally to the laser machine.
Computer software to operate the laser is available either as free open-source 'LaserGRBL' or purchased 'Lightburn'. Larger and more powerful laser manufacturers produce their own custom operating software, and include it with the machine purchase. Cheaper Diode-based laser machines don't include this item.
The laser software will have to be matched to the laser machine make and model, and customised to instruct the machine to operate appropriately. Machine manufacturers supply online download driver files for each model and computer OS, which interface between the laser design software and the laser machinery equipment.
Rotary roller stand attachment:
The standard 2D laser engraver is only suitable for flat materials and sheets. Separately available for some (more expensive and powerful) laser machines is a motorised rotary roller, wheel, or chuck attachment, for engraving/cutting curved cylindrical or tubular materials (baseball bats, rolling pins, mugs, drinking glasses, bottles, tubing, etc), not spherical materials (balls, domes). Rotary roller stands are normally not provided with the laser machine as standard, except with larger professional cabinet type machines.
This roller device sits unmoving on the laser bed base, with a pair of parallel rollers, wheels, or a chuck to support and slowly rotate the curved surface material item being lasered. This effectively maintains a constant distance between the job material and the laser, allowing the laser to remain focussed at the same depth as the job rotates beneath it for progressive engraving.
Laser roller stands are connected electrically to the laser machine control board by a dedicated wired socket which drives the roller in synchronous rotation with the laser progression. This socket is not normally available on cheaper low cost/power lasers. Best compatible with 50W and up machines that provide an appropriate motor control dedicated accessory socket. Before purchasing a roller stand device, check your laser machine's full specifications in its product description to see if it's compatible, and has the appropriate sized and rated socket, as this also varies between manufacturers and models.
The roller effectively performs as the Y-axis (close/far) in the laser machine, whilst it maintains the X-axis (left/right) using the normal machine X-axis across its arm. The machines Y-axis is not used during roller engraving operations.
MATERIALS
Lasers — depending upon their frequency — can cut and etch (engrave) stiff paper, cardboard, timbers, textiles, leather, rubber, plastics, plexiglass, acrylics, nylon, mylar, polyethylenes, silicone, ceramics, glass, stones and less highly reflective metals such as aluminium and steel alloys. The cut depth total thickness depends upon the laser power. Highly reflective metals such as copper and brass, silver and gold alloys cannot commonly be used due to their heat conductivity and reflectivity, and require the strongest fibre lasers. Likewise, PVC, teflon or other halogen producing substances when burnt should never be used due to their fume high toxicity.
Working with transparent Glass and Acrylics:
Note that clear transparent glass and acrylics cannot be cut by diode laser as they transmit the Diode-based laser light frequency (InGaN 445nm), and so must be cut by longer wave CO2 (Nd-YAG 10640nm). Diode lasers can however, cut coloured opaque glass and acrylics. Again, the cut depth thickness depends upon the laser power. Thin untempered glass tableware is unsuitable to lasering, as it is liable to cracking by localised heat stress from the laser beam.
Working with Timbers:
Solid timber materials, and composite timber plywoods can both be lasered, however will produce a lot of smoke and carbon fumes, as they are both the result of the flameless burning of wood (majorly consisting of carbon fibres).
Be aware that cutting timber leaves a carbon residue behind on the honeycomb laser bed that will require some dedicated cleaning to remove, before it deposits enough soot to provide another fire hazard on its own.
LASER OPERATIONS
The two variable factors in laser cutting or engraving are the laser power level and laser movement speed. The longer a laser beam operates in the one spot on the material, the hotter it will become. Thus a lower power setting can linger longer, and a higher power setting must move quicker, to achieve the same heat level. An over concentration of heat can quickly burn and damage the work material, often remaining visible as scorching. The trick is to achieve the balance settings of the two variable factors such that the material is cut cleanly without any scorching.
CUTTING POWER
The power of a laser determines the cutting speed and thickness.
Diode lasers typically have the lowest cutting speeds around 8mm/second for a few millimeters thickness of materials like plastics, leather and thin metals.
However, higher power industrial rated diode lasers of 1kW or more can reach up to 50mm/second cutting speed for stainless steel up to 6mm thick and aluminum up to 8mm, but with lower quality (definition) than either fibre or CO2 lasers.
CO2 lasers produce high power densities for fast cutting of wood, plastics, and other non-metals. Industrial CO2 lasers of 3kW and above can achieve higher cutting speeds up to around 83mm/second for stainless steel 12mm thick and a whopping 125mm aluminium. CO2 lasers have lower beam quality (definition) than fibre lasers, so cannot produce the very fine precise cuts possible that fibre lasers can achieve.
Industrial fibre lasers provide the highest cutting speeds up to 416mm/second for stainless steel over 25mm and aluminum over 30mm thick. Their high precision and narrow cut kerf enable high-speed cutting of most metal alloys with little dross or wasted material. Fibre lasers are the preferred choice where high throughput and part precision are most important.
POWER EFFICIENCY
Laser beam creation equipment and machines are overall highly inefficient users of electricity, with Diode lasers being 30-60%, CO2 lasers being 10-15%, and fibre-optic lasers varying greatly from 30-60% depending upon the initial light source frequency. The inefficiency is due to most of the electrical energy being converted to heat, and requiring dissipation to prevent self destruction of the laser generation equipment from over-heating during operation.
There is also electrical energy consumed for non-laser generation purposes, such as movement systems (motors and motor control), ventilation systems (air assist job cooling fans, smoke and fume exhaust fan), cooling systems (water/refrigeration and pump), and cabinet control equipment (sensors, control microprocessor board, communications, display/alarm panel, and internal lighting on some cabinet models).
And of course, there's the actual power consumption of the laser generation, which can vary from 1-100,000 Watts, depending upon the laser type, frequency, and the operating power setting currently in use at the time of measurement.
When overall measured at the wall plug, this is commonly referred to as the wall-plug efficiency, as the total of all machine component efficiencies. Even a small desktop laser machine can require a dedicated 20 Amp power socket. Installed stand alone cabinet laser machines require much greater current usage.
CONSUMABLES
materials for engraving/cutting
masking tape or plastic posts for material positioning retainment
For CO2 machines:
- paper masking tape for laser beam alignment
- dimming paper for laser beam focus and position testing
- distilled water for corrosion-reduced cooling system operation
NOTES
Printers, Lasers, and Papers:
Note the physical difference between an 'office-based laser-printer' (that applies coloured or black toner to relatively thin document paper), and a 'workshop-based laser engraver/cutting machine' (that burns away surfaces and cuts holes in multiple type materials).
Subsequently please note the distinct differences between these different types of laser papers: 'laser (printer) paper', 'laser engraving/marking (transfer) paper', dark 'laser dimming paper', and 'paper suitable for laser engraving'.
- 'laser (printer) paper' is normal computer-based printer paper that has been specially manufactured and treated to display clear sharp toner images from a laser printer. It is not the same as ink-jet paper, picture (photo) paper, nor plain printer paper.
- 'laser marking paper' is a coloured film transfer set (fixed) by the heat from the laser — not an engraving — onto a glass or ceramic smooth surface. It is apparently waterproof and hard-wearing, but note it is not permanent like an actual engraving of the glass or ceramic material.
- 'laser dimming paper' — curious 'English as a Second Language' (ESL) misunderstood meaning of the word 'dimming' — is designed to function as laser beam reactive test result paper, which originates as a dark (black or grey) coloured paper that permanently lightens upon exposure to laser beam penetration. (By 'dimming', I think the ESL intent was to describe the change in 'darkness' when dark brightens to light, by inverting the proper directional meaning of 'dim' from being the change where light dims (changes 'light' intensity) to dark, and misappropriating it in the opposite directional meaning as being the change where dark dims (changes 'dark' intensity) to light, instead of using 'lightens' or 'brightens', which more properly would describe it as lightening or brightening paper?)
- 'paper suitable for laser engraving' is thicker than normal printer or writing type paper, so that a partial thickness (depth) amount of it can be engraved — lasered away without burning or cutting a hole all the way through the paper material. Multi-layer multi-coloured paper demonstrates this process extremely well. This material includes card and board — anything above 200gsm or so — and solid (not corrugated) cardboard.
Identifying online engraving materials:
Note when selecting materials online for engraving/cutting, such as for making rubber stamps, that the Chinese online sales sites appear to name both rubber and silicone materials as "rubber". The apparent difference is the silicone variety "rubber" is marketed as 'smoke free' rubber, rather than accurately as silicone. Both materials produce smoke, however rubber is more pronounced and pungent. Synthetic rubber materials, like neoprene or rubber containing chlorine, should be avoided because they release toxic and corrosive gases during the cutting process. Lasers can cut both materials, but they handle differently (silicone is softer and less hard wearing than actual rubber). The CO2 laser is the most suitable laser cutter for cutting rubber and silicone.
Note also that the engraving cut depth may require different laser settings for the different materials (as I don't know that both rubber and silicone behave the exact same way as each other when being lasered).
Note a detailed discussion at https://baisonlaser.com/blog/laser-cutting-rubber-and-silicone/
SCHEDULED MAINTENANCE REQUIREMENT
Checking cooling water condition and supply
Testing water-cooling pump operation
Checking air-assist operation
Cleaning/replacing air filters
Cleaning cutting bed and exhaust fan blades
Cleaning machine surfaces
Cleaning mirrors and lenses
Checking cabinet and frame sturdiness/rigidity (particularly if screwed)
Testing and realigning laser beam path
Testing laser beam focus on dimming paper
Testing machine work area proportion box on dimming paper
Checking and lubricating all moving parts and rail wheels
Checking travel end stops operation
Checking open lid/s safety shutoff
Checking external exhaust system operation
Completing maintenance/safety records
UNSCHEDULED REPAIR MAINTENANCE
Checking computer software for status/error messages
Checking for laser head/bed travel obstacles
Checking for laser output at head bed
Checking mains power supply availability
Checking for unplugged/loose cables or piping
Checking for onboard blown fuses
Checking cooling water operation
Checking for rails/belt tension
CONDITIONS OF USE
You should always seek your own independent professional advice when selecting an expensive purchase such as a laser machine and accessories.
Use at your own risk. This document was prepared in 2024 as a general guide for AustralianJewelleryServices.com.au and is provided online in good faith as-is without guarantees or warranty of any kind, given or implied. It is intended to help prevent you from making a possible purchasing mistake when selecting a laser machine.