A beginners guide to using Laser cutters.

Welcome to the next instalment of Making for Beginners where this time we move away from 3D Printing to similar but different technology – Laser Cutters and Engravers. In this set of articles, we will be looking at: what Laser Cutters and Engravers are (I will refer to all of them as just Laser Cutters for this article); where they came from; what they are used for; the Emblaser II we will be using; suitable materials and safety around and when using this technology. In the following article next month, we will look at the software, actually cutting something and some troubleshooting.

Let’s start with what is the difference between a Laser Cutter and a Laser Engraver. The answer may surprise you – absolutely NOTHING. They are actually one in the same, it is just the actual application that is different. Cutting is physically separating material into more than one piece typically with a sharp tool. Engraving is the action of cutting or carving material from the surface of an object. In the case of a Laser Cutter or Engraver, the “knife” is the Laser Beam and the depth of the cut determines if it Engraves or Cuts. Typically, an Engraving is made with reduced power, and a Cut is made with Full power. Some specific machines are set up for specific jobs like engraving bracelets or cups and mugs, while some are set up more generically and can cut or engrave other objects. So, since there is basically no difference, we will just refer all these types of machines as Laser Cutters.

We still don’t actually know what a Laser Cutter is! So, let’s define a Laser Cutter as a machine that operates in 2D (usually), similar to a Computer Numerically Controlled (CNC) device (like a Milling Machine or a Blueprint Plotter), where the Cutting Head (or Plotting Pen) has been replaced with a Laser device that is capable of variable power output that in turn cuts or engraves into material as directed by the machine and software program. All3dp.com defines:

“Essentially, laser cutting is a fabrication process that uses a thin, focused, laser beam to cut and etch materials into custom designs, patterns, and shapes as specified by a designer.”

Lasers

Strictly speaking, the word Laser is an Acronym. An Acronym is a word made up of the first letters of words that describe something, like TWAIN (Technology Without An Interesting Name). In the case of Lasers, LASER stands for Light Amplification by the Stimulated Emission of Radiation. The word Laser has come to mean the Acronym AND the name of the technology or device.

The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. Townes and Schawlow had previously invented the MASER (Microwave Amplification by the Stimulated Emission of Radiation) which is used as a precision time-keeping devices in atomic clocks and as amplifiers for microwaves in radio telescopes. Townes, Nikolay Basov and Alexander Prokhorov were awarded the 1964 Nobel Prize in Physics for theoretical work leading to the maser. Maiman extended the theoretical work of Townes and Schawlow and built the first working Laser. History becomes a little messy at that time as Townes argued that he had done the research and had, therefore “invented” the Laser as well as the Maser. Townes had failed to solve the engineering to actually create a working device that Maiman had done. The lawsuits over patents lasted for years until Maiman was granted the rights as the inventor of the first working device.

Lasers basically have five parts:

1. The Gain Medium
2. The Energy Pump
3. The High Reflector (basically a 100% mirror)
4. The Output Coupler (basically 99.99% mirror)
5. The Laser Beam

Early Lasers used gas or materials like Rubies as their Gain Medium. When Energy is “pumped” into the Gain Medium it excites the electrons in the material; they climb to a higher energy level, release a photon of energy and drop back down energy levels. As this continues, more and more photons are released at very specific energy levels that correspond to light a specific frequency or “colour”.

These photons reflect back and forth between the mirrors. As more and more energy is pumped into the Medium, the photons interact with each other in a way that intensifies the light in the Laser tube.

Because the mirror on one end is not a 100% mirror, some of this light “leaks” through the mirror into the environment. The light that leaks through is very intense and at a very specific frequency. The intensity of this light means it has a great deal of energy, and since this energy is normally focused into a beam, a great deal of energy can be concentrated in a very small area. This energy literally melts or burns through material if the material cannot shed the excess heat quickly enough.

The light is so intense that, when focused correctly, it can be aimed at reflectors placed on the Moon by the Apollo Astronauts and the precise distance from the earth to the moon can be measured.

There are many different types of Lasers that are used for many different applications, from research to manufacturing to weapons. No, there is no actual Death Star weapon (yet), but Laser weapons are actually deployed on some US Warships and have been for two years. Laser Targeting has been around for decades.

Shown here is a prototype called ATHENA from Lockheed Martin.

Information can be found here: https://www.lockheedmartin.com/en-us/capabilities/directed-energy/laser-weapon-systems.html

In terms of manufacturing, most Laser Cutters are heavy duty and used for precision cutting of metals and heavy materials and use traditional Lasers. Powerful Lasers can cut through substantial thickness of metal plate and are used when more accuracy is needed than a Plasma Cutter. Lower power Lasers are used in the clothes manufacturing industry for rapid precision cutting of fabrics.

The type of Laser we are actually interested in is one of two types commonly used in Laser Cutters. A common Laser used is called a CO2 Laser (aka a Carbon Dioxide Laser) and is an older technology commonly found in Desktop Laser Cutters. The more modern device is a Solid-State Laser. Laser Diodes have been around for a while. Most people have seen Laser Pointers for assisting with presentations or annoying cats. Laser Pointers are powerful enough to permanently blind someone if shone in their eyes but are not sufficiently powerful enough to cut most materials. Laser Pointers are normally a Laser Diode, but the one used for cutting is much more powerful.

Laser Cutters for small Manufacturers and Makers have been around for a few years now, but it hasn’t really been until lately that they have become cheap enough for Desktop models to be affordable. The main reasons behind the drop in price is that many of the components used in Laser Cutters are also used in other CNC technologies such as 3D Printing and Document Plotters. Since the underlying technology is nearly identical, the number of useful devices has exploded. The key advance in Laser Cutters has been the much more compact and powerful Laser Diodes. The technologies are so similar in fact that some manufacturers are beginning to sell units with 3D Print, Laser Etching and CNC Milling built into the same unit. This one shown here is being sold by Jaycar right now.

Exactly when these technologies were invented is sometimes hard to nail down. Automated machines using Numerical Control have been around since the Industrial Revolution about the early 1800s. Computers were added in the 1940s-50s to create CNC. Applications have been mechanised since then, initially with cutting materials or commonly plotting Blueprints. The underlying technology is the 2D and later 3D part, the application comes with the machine head (Pen, Laser, plastic extruder, Mill Cutter or Drills).

Emblaser II

The particular Laser Cutter available to me at the local Library and the one we will use in this article is the Emblaser II from Darkly Labs. Darkly Labs is the Melbourne based company who designs and manufactures the Emblaser range of laser cutters and engravers. It has been operating for about 8-9 years. Information about Darkly Labs can be found here: https://darklylabs.com/about/

IMAGE CREDIT: Darkly Labs

The Emblaser II is a Laser Cutter that uses a Solid-State Diode Laser system that is equivalent in power to a CO2 Laser Cutter machine of 15-20 Watts. I have only been using it in 2D cutting and engraving, but I was surprised to learn that this particular machine is actually capable of cutting in the third dimension to a limited extent. I will be doing my own investigation on this soon to find out what that means now that I know about it.

The specifications of this machine are shown on the table here:

Dimensions
External Dimensions	540 x 720 x 200mm
Material Capacity	500 x 300 x 50mm
Optics
Focus	Factory pre-focused
Laser Unit Type	"Solid-State Diode" Equivalent to 15-20Watt CO2 Laser
Classification	Class I

The external dimensions seem to make it big and clunky, but it is a nice-looking unit with a very generous material capacity.

As stated, the Laser is a Solid-State type and 15-20W is considered quite good for a desktop machine. Some units go up to 120W but are obviously much more expensive.

Class 1 Lasers are the safest available provided they are used correctly. Misused they ARE dangerous.

The Software is the popular LightBurn package and we will look at it next article.

Camera is useful to some but I have not yet learned how to get the most out of it.

Wi-Fi and USB means it can be used stand-alone.

Fume extraction – REALLY important. We will discuss this shortly.

Internal lighting – it is a big box and it gets dark in there.

The cost of the Emblaser II is not cheap as it is designed for the Education market and so has to meet some very strict standards. When the Incoming and Outgoing air-filtration and air-extraction units are added, the Emblaser II System sells for about $5000. Now, before you choke on your coffee – it is designed for school use. That means it must jump through all kinds of realistic and unrealistic hoops to get the nod from people who don’t know anything about the technology and must be convinced it is ultra-safe. It also passes the strict rules that the library has in order for the public to use it. If you are looking for something a bit cheaper, a quick search found some basic units starting from $150 on Banggood. I am sure with some sharp-eyed Google goggles and a bit more research, something more in the home use range can be found.

Safety and Laser Cutters

One of the big reasons some Laser Cutters are so expensive is that they come with a whole bunch of safety stuff. A basic unit will literally be a frame with the tracking assembly and electronics to drive the cutting head and the Laser and little else. This comes under the umbrella of a Class 1 Laser Device, which if you remember “are the safest available provided they are used correctly”. I am just wondering if something that is NOT secured to the desk, that is light enough to be picked up in one hand and has no safety cut-out when it is operating so it could be picked up and waved around while the Laser is cutting is truly a Class 1 device. It might be when used correctly but it will still burn a hole in the wall. Interestingly the Laser Scanner at the local supermarket is a Class 2 device, as are most Laser pointers.

Probably THE biggest safety issue is the amount of energy directed into a tiny space is what makes the Laser actually cut. It does so by literally heating up the material until it becomes a plasma and it dissipates in the atmosphere. The Laser has no memory, and so provided the beam is focused enough it will cut through just about anything if it is left pointing at the same place for long enough.

When it comes to Laser Cutter safety, there are really only a small number of things to remember, but they are all VERY important.

1. Never leave the Laser Cutter unattended while operating
2. Keep a close eye on the cutting operation for problems
3. Keep the lid closed when the unit is operating unless the laser is OFF
4. Know where the Fire Extinguisher and Fire Blanket are kept
5. Keep the cutting area clean
6. Only use APPROVED or TESTED materials

Laser Cutting is safe, in most instances, when best practice is followed. Best Practice is fine in most circumstances but sometimes you will enter a grey area and a little experimenting is needed to get the settings correct. These can be tricky or at worse dangerous. During our class, we wanted to cut out a small dinosaur model from the Internet. We had a small fire start after we scaled the model down for a quick cut. If the model had been normal size, then this would not have been an issue. Scaling the model wasn’t the problem, cutting in a single pass was the problem. There was just too much energy directed to a small area and the material caught on fire. Had we not been watching it, the fire may have caught properly before the laser cut out.

Fires are not the only problem. Lining up the material for cutting; unexpected errors in the GCode; material being too small. These kinds of issues can affect the best planned cut on the machine. You don’t have to watch it like a Hawk but you do need to at least be in the same room and look occasionally. I had one cut fail because a cable accidentally got caught in the driving belts. I had never cut a piece in the extreme top right of the machine, so I didn’t know that the cable could get caught. Now I know.

The lid of many Laser Cutters is coloured to help reduce stray light escaping and causing problems. It also helps contain any smoke or vapours from the cut. Some Laser Cutters have a safety cut out that when the lid is open, the Laser will not fire. Much of the time you can do a cold run to check the position of the material before you do the cut. You should be able to see this through the lid unless it is totally enclosed. The Emblaser II actually has a camera inside so you can see what is happening. It is safer to leave the lid closed unless you are loading or unloading material to be cut.

I have already said we have had a small fire when in class, but we had a fire when the Silicone Matting actually caught fire also. This set off a Fire Alarm and an OHS report had to be put in. I always thought that Silicone Matting was fire resistant. Upon checking, I discovered that this particular Silicone Matting WAS Fire Resistant, but there was more than enough excess heat from the Laser Cutter to make it burst into flame. Always know where to find a Fire Extinguisher and Fire Blanket.

Use the CORRECT Fire Extinguisher!

As mentioned, you should keep the lid closed to allow the fume extraction to work. Laser Cutters do literally burn or vaporise the material they cut. These fumes can be nasty even with approved materials. In addition, the last thing you want is tiny or microscopic particles flying around the room you are living or working in. They can cause breathing difficulties at least and at worse, nasty cancers. Good quality Laser Cutters have not only Fume Extraction, but also Filters to make sure the air going in doesn’t contain anything that may turn ugly when cooked, and the fumes being sucked out don’t have ugly by-products either. It is NOT a good idea to set up a Laser Cutter in small enclosed areas. Good ventilation and good fume disposal are a must. Apart from the fact that these fumes can be not very nice to us carbon-based life-forms, all those fumes and smoke can also kludge up the optics and affect the cut of the Laser.

It is a basic workplace mantra – keep the work area clean. This works the same for Laser Cutters. Not all materials are created equal. You might need a slow, high-powered cut on the light metal you are trying to engrave, but the loose shavings of wood or plastic you didn’t clean up properly from the last few cuts will quite happily vaporise or erupt into flame. Laser Cutters are safe – when used correctly!

Materials

I am saving the last of the safety tips for a whole section of its own, and I need to talk about different materials and their use with Laser Cutters anyway. In theory, you cut or engrave just about anything on a Laser Cutter, but there are definitely some materials you want to avoid. In most cases of this, the material on its own is not a big issue. The issue arises when you start heating it up.

Darkly Labs, like many Laser Cutter manufacturers, provides both materials and a file of recommended settings to cut various materials with their machine that are known to be safe.

These files often recommend tracking speeds and power levels to various operations the machine can do, e.g. cutting 3mm plywood or 2mm laser film; Leather/Suede 4mm; Cork 6mm. All of these materials have different properties, but the recommended settings should handle them ok in a reasonable cutting time and be safe to apply.

The table shown here is a brief description of safe materials. The Darkly Labs website has a more extensive list that includes hard woods like Jarrah, Denim, Anodised Aluminium and Stainless Steel, some Plastics, Oak and Maple, Bamboo, Balsa and MDF. The web link for this can be found at:

https://darklylabs.com/emblaser2/

Material	Max Thickness	Notes	Warnings
Wood	6mm	-	Avoid Oily Woods
Plywood	6mm	Contains Glue	May not cut well
Card/Paper	4mm	Cuts Nicely	-
Cardboard	4mm	Cuts Nicely	Possible fire hazard
Cork	6mm	Cuts Nicely	Avoid thick cork
Cloth/Felt	3mm	All cut well	Not Plastic coated
Leather/Suede	4mm	Leather hard to cut	Real Leather ONLY
Magnetic Sheets	2mm	Cuts beautifully	-
Laser Film	2mm	Cuts Nicely	Check for PVC

Hardware

3D Cutting & Engraving, fully software controlled.

Camera for material alignment.

Wifi & USB Connectivity

Fume Extraction, built-in.

Internal Workspace Lighting

Accessories

Fume Filtration System

Air-Assist System

This list is only the approved materials list that Darkly Labs has actually tested with the Emblaser II. It isn’t the ONLY material you can use. There are many other materials that could be used in a Laser Cutter BUT – research them BEFORE cutting them!

Some materials contain some fairly dangerous substances after being exposed and broken down by a Laser. Many types of Plastic contain Chlorine and this can be a breakdown product. Since Chlorine was one of the poison gases used in World War One, flooding your work area with quantities of this gas can be LETHAL! There are many other potentially nasty laser by-products in other materials. The only way to safely work them out is Research, Test, Check, Repeat.

Some intersting publications on Lasers and Chlorine can be found here:

https://www.instructables.com/Checking-Laser-Cutter-Materials-for-Chlorine-Beils/

https://www.thekoshertonystark.com/could-your-laser-cutter-kill-you-test-for-chlorine-gas/

In a nutshell, whatever you want to cut in your Laser Cutter – Research FIRST, Cut SECOND.

Obviously, the list I have given you and the list Darkly provides isn’t exhaustive, but it is a great starting place. In my research, I found a Laser Head replacement with the equivalent of a 120W CO2 Laser that would cut through 12mm of Pine. That’s not just a piece of wood – that’s a hefty piece of building material. That particular Laser Head would cut that plank in ONE PASS. Since Lasers are precision, it might be possible to cut thicker timber in several passes.

This seems like a good place to stop for this edition of Making for Beginners. In the next article, I will talk a little more about materials and what you can actually do with them. I will introduce the LightBurn software commonly used to control many Laser Cutters. I will demonstrate some of the things you can do on the machine. I will also talk about where you can get free projects. Finally, I will actually put together a fun project from scratch.

NEXT MONTH: LASER MATERIALS & SOFTWARE