Materials for laser cutting

Hobarts Materials for Laser Cutting Article

 

Although we’ve touched on some of the types of materials that can and can’t be cut with laser cutters in previous blog posts, we thought it was about time that we took a deeper dive. In this post, we’ll be looking at the qualities of the materials that can be laser cut, and which materials definitely shouldn’t be anywhere near your laser cutter. 

Laser cutting is preferred to manual methods where increased accuracy and high quality finishes are required. Laser cutting is accurate to just over a nanometre, (which is one billionth of a metre) and lenses are able to focus the laser to within just 0.03 of a millimetre. 

In addition to the incredible accuracy, laser cutting can offer significant advantages over manual methods. It is fast, and can produce the same results time after time, with little operator input required. Not only that, but laser cutters are versatile, and can produce a range of finishes, including etching and engraving, which means that laser cutter owners can provide additional services to customers. 

 

Metals 

Reflective metals such as copper, brass, bronze, silver, and gold are highly reflective in their solid states, which can make them challenging to cut with lasers. The type of laser cutter you are using is important – since some types of lasers simply aren’t powerful enough to cut metals – but you’ll also need to consider cut speed, focus position, power setting, as well as gas pressure, if you’re using a gas to assist your work.

 

Hobarts Metal materials for laser cutting

 

Stainless steel

Stainless steel is frequently used in houses, particularly in kitchens and bathrooms – but there are actually more than 250 different types of stainless steel. It is so widely used because it is strong and durable, resists corrosion, and is also easy to work with, since it can be welded quickly.

Since stainless steel is super-strong, it needs more intensive treatment to cut accurately and to produce high quality finishes. That means that people with laser cutters at home are unlikely to be able to cut stainless steel – either at all, or with anywhere near the type of finish a more powerful laser cutter can achieve. 

However, with the right type of laser cutter, stainless steel can be cut when it is up to 30 mm thick, and cutting with lasers produces a smooth and polished finish without any further work required. 

 

Mild steel 

Mild steel is used almost everywhere – it is pretty versatile, inexpensive, and easy to work with. It is frequently used in construction due to the fact it can’t be damaged by insects, and resists fire and types of rot and erosion that other materials are affected by. Mild steel is also found in machinery, in kitchenware, for outdoor piping, and for creating fencing and gates, since it is much more durable, particularly when it is galvanised.

When you’re going to be working with mild steel, it is essential to store it correctly. Any rust that has started to form during storage will affect the quality of the cut, and paint or markings should be removed before the cut is started. Once the cut has been completed, it is recommended that mild steel is treated or powder coated to prevent rust forming. When cutting mild steel with lasers, best results are achieved with sheets that are thinner than 20 mm. 

 

Corten steel 

Most frequently seen in outdoor building works, at first glance Corten steel (sometimes referred to as ‘weathered steel’) appears to be rusted – but the oxidisation (rusted) effect that appears after a few months of exposure actually helps to protect the metal, and prevents further damage. The best-known example we know of is the Angel of the North sculpture at Gateshead, but it is frequently used in smaller projects in the outdoors where a rustic and aged look is appropriate, such as planters for gardens. 

As with other types of metal, the thinner the sheet of Corten steel, the more accurate the finish. 

 

Hobarts Corten steel, aluminium, copper, brass and other metals for laser cutting

 

Aluminium 

We all know that aluminium is used for drinks cans, but there are an incredible array of other uses – and it is used almost everywhere. The fact that it is much lighter than other metals, yet is still extraordinarily strong means it is used in aircraft and car production, while the superior thermal efficiency means it is used in construction, particularly in windows and doors. 

Since aluminium is light-reflective and heat-conductive, it can be hard to work with using a laser cutter, but it can be cut using gas laser cutters. 

 

Copper

Copper is a great conductor of heat and electricity, so is often used for wiring, piping, and tubing in homes and buildings. That’s not the only place it is used though – it is also used in alloy form in jewellery, in the medical industry (since superbug MRSA cannot survive on copper surfaces) and in machinery.

Copper can be a challenging material to cut using a laser cutter, since it has a low absorption of infrared laser light, and is highly reflective. That means that cut speed needs to be much slower, with enough dwell time to create the pierce hole. There are other issues that need to be taken into consideration, especially when it comes to the focus position, power settings and the cutting gas required.

 

Brass 

Brass is an alloy metal made up of copper and zinc, and is easily shaped – but retains strength after it has been formed. Due to this strength, there are many uses for brass. Door handles benefit from the antimicrobial properties of the copper in the mix, but it is also used for mechanical applications and tools, which have a much longer life than tools made from other metals. 

Similar to copper, brass can be a difficult material to work with on a laser cutter. The reflectivity, and low absorption of infrared laser light is an issue, and so as with copper, cut speed should be slower, and the focus position, power settings and the cutting gas should be carefully assessed to achieve the best results. 

 

Hobarts brass and other metal materials for laser cutting

 

Non-metallic materials

It goes without saying that there are plenty of materials that can be cut with laser cutters that aren’t metal. Laser cutters can produce some amazing effects on non-metallic materials – as long as you have the right type of laser cutter, of course. 

When you’re cutting non-metallic materials, you should also be sure to store them, and prepare them correctly before you put them in the machine for laser cutting. Removing any adhesive, plastic coating and so on is essential for keeping your machine safe from accidental melting or burning.

 

Woods

Woods have been used extensively in manufacturing and for countless uses since the dawn of time – so it stands to reason that once laser cutters became available that woods would be subjected to the laser. 

It is possible to laser cut many types of woods, but you do need to be careful when cutting with lasers. Woods that are oily, or have a lot of resin are more prone to burning – so be sure to watch the laser carefully, to ensure you don’t end up with wood smoke in your machine that will damage the optics. 

When cutting wood with a laser cutter, the best results will be achieved if it is thinner than 20 mm. Low density wood can be cut when it is between 5 mm to 10 mm, but denser woods will look better under 5 mm.  

 

Plywood and composite woods

Plywood is made from multiple layers of thin wood veneer, which are then sealed together with glue at high temperature to make different thicknesses of strong and flexible sheet material. The strength of composite woods means they are widely used for making furniture, as well as being used extensively in building work due to the fact they tend not to warp or crack when there are changes to atmospheric moisture levels. 

It is possible to laser cut plywood and composite woods with a laser cutter, but since they usually contain glue, you’ll want to keep an eye on the machine while you’re cutting in case it catches fire or smokes excessively. The finish may not be quite as good as with solid woods, and plywood may need between three and seven passes with the laser to cut, with a higher power. 

 

Hobarts Plywood and Composite Wood materials for laser cutting

 

Medium-Density Fibreboard and engineered woods

Medium-density fibreboard (commonly referred to as MDF) and other types of engineered woods are usually used for products that are to be used indoors, since they aren’t good at resisting moisture. They’re available without any coating, but are most often seen with a finely sanded surface or decorative veneer, particularly when used for furniture. 

MDF and engineered woods can be cut with lasers, but there does tend to be charring when they are cut. Where veneers have been applied, care should be taken since adhesives can cause burning or melting. The power intensity may need to be higher, and two and five passes may be required to complete the cut.

 

Plastics 

Acrylic, Lucite, Plexiglas and PMMA all cut really well with laser cutters, and results in a wonderfully polished edge on the completed cut. With plastics, different influencing factors may impact on the final finish – from the brand and type of plastic that is being used, the power, frequency and speed of the laser, and the setup of the laser cutter. 

If the plastics that have been laser cut are to be joined to other materials, it should be considered that the heat from the laser can cause stress to the plastic and cause microcracks to form. This may impact on the effectiveness of the join. 

 

Paper and cardboard

All types of paper and card stock are able to be cut to an exceptionally high quality with laser cutters, and the task can be completed pretty quickly, even with lower powered laser cutters. That’s why large numbers of businesses are using laser cutters to create bespoke paper products such as wedding invitations. 

When it comes to cardboard and carton materials, care needs to be taken since there is the risk of fire – which of course means you need to keep an eye on the cut to avoid potential damage to your machine. As with other materials, the thinner the cardboard, the more accurate the results. 

 

Hobarts paper and cardboard materials for laser cutting

 

Cork

It is possible to cut cork, with best results usually obtained from working with thinner cork sheets. Thicker cork can be engraved with good results, and there are some good reasons to cut cork with a laser cutter, including less chipping and breakage, and only low power is required for high quality results. 

When working with man-made cork, be careful – there may be glue or other chemicals that release gases when cut. Results from cutting man-made cork may vary, so be sure to test first.

 

Fabrics

Most types of fabric are suitable for cutting with the right type of laser cutter. Cloth, felt, hemp and cotton can all be cut, and intricate designs can be cut that give the effect of lace when the cut is finished. Since natural fabrics don’t melt on the edges, they will still fray, as with manual cutting methods. Only low power is required for cutting fabrics, or for laser marking on materials.  

Although most fabrics can be cut well on laser cutters, use caution when you’re cutting materials that may be plastic coated, impregnated with plastic or that are made from PVC. These materials are likely to catch fire, or release gases that can damage your lungs, and your machine. 

 

Leather and suede

It is possible to cut leather and suede with a laser cutter, although it can be hard to cut with lower powered machines. The thinner the material, the easier it is to cut with your laser cutter. Since there is natural variance in leather, having some to test on before starting the cut is always a good plan. 

Be sure that your material is natural leather, since faux leather, ‘pleather’ and imitation leathers are typically made from PVC. These artificial leathers release toxic gases when they are cut that won’t only damage the lungs, they will cause severe damage to the inside of your laser cutter too.

 

Hobarts leather suede materials for laser cutting

 

Materials that can be etched 

There are a number of materials that don’t do well with being cut with a laser cutter, some are able to be etched or engraved with a laser cutter. 

Glass and ceramic tiles can be etched using your laser cutter, however if you’re etching on bottles or glasses, there may be distortion – and of course, you’ll need to be sure the glass isn’t going to roll around on the cutting bed.  

Anodised aluminium can be etched, as can painted and coated metals – the finish will be vaporised, which can produce some interesting effects. 

Some types of rock can be etched too, such as marble, granite, soapstone, and onyx. When they have been etched, the finish looks textured, with inner levels being revealed by the etching, depending on how deep the etching is. 

 

Which materials can never be cut with laser cutters? 

While laser cutters can produce some fabulous finishes and effects on a lot of different materials, there are some items that definitely shouldn’t be near your laser cutter – for various reasons. Laser cutters aren’t cheap to replace (at least, quality ones aren’t) and if you’re using it for business, you definitely don’t want it out of action. Some of these materials melt, cause your machine to corrode or can ruin the cutting bed. 

It isn’t just damage to your laser cutter that you want to avoid – some of these materials will cause severe health problems for you and your staff. With this in mind, don’t ever cut any of these materials with your laser cutter.

 

PVC, vinyl, and artificial leathers 

These types of materials release chlorine gas when cut. Chlorine gas is incredibly irritating to the lungs, and in high concentrations it can be fatal in less than 30 minutes – which is why it was used as a chemical weapon in World War 1. This gas can cause huge problems for your machine too: optics can be irreparably damaged by chlorine gas, metal parts of the machine can suffer corrosion, and the control system can be impacted too. 

 

Hobarts PVC and vinyl materials for laser cutting

 

Thick polycarbonate 

Although polycarbonates are extensively used because they’re strong (around 250 times stronger than glass and up to 30 times stronger than acrylics) and can be moulded and thermoformed, unfortunately thick polycarbonates aren’t ideal for your laser cutter. They are likely to catch fire, and when they burn they give off long thin trails of soot that can damage your machine pretty badly – and isn’t going to do you or your staff much good either. 

 

ABS 

This material is super strong and most commonly found in toy boxes in the form of Lego. While there’s definite appeal in trying to use your laser cutter to produce a unique Lego design, it isn’t good for you or your laser cutter. Because ABS doesn’t vaporise, it just leaves a mess on the cutting bed of your machine, and is also prone to catching fire – which isn’t ideal either. Most importantly though, when it is cut it releases poisonous hydrogen cyanide – and that’s before we consider if it has any fibres or resins in it that could cause other issues. 

 

HDPE (milk bottle plastic) 

High-density polyethylene is really popular because it is lightweight, but is really strong, impact resistant and resists mould – which is why it is used so frequently. Unfortunately, it is really unsuited to cutting with a laser cutter, since it is prone to catching fire and melting.  

 

Polystyrene foam  

Polystyrene foam is often used in packaging, insulation and in car seats. Although it is commonly used, it definitely shouldn’t be anywhere near your laser cutter, since it catches fire and burns very quickly. Not only is there risk of fire spreading, but once the fire is extinguished, it will leave melted deposits on your cutting bed – as well as damage to the optics that might occur as a result of the smoke from the fire.  

 

Polypropylene foam 

Commonly used for applications such as insulation, buoyancy, and packaging, just like polystyrene foam, polypropylene foam will catch fire quickly – and as it burns, it drips, and the drips will continue burning. Once the fire is out, those drips of material set really hard, which means that the cutting bed of the machine can be completely ruined.  

 

Epoxy 

Epoxy is frequently used for coating, laminating and infusing wood and carbon for waterproofing and to increase strength and durability. Be sure not to use it inside your laser cutter, since not only will it create an absolute mess when it burns, it also releases poisonous fumes. Even if you’re using an exhaust system to get rid of fumes, you don’t want the risk of fire – so steer clear of cutting materials with epoxy in your laser cutter. 

 

Fibreglass

Fibreglass is used in all kinds of settings, from making bathtubs, to aircraft, boats, roofing – there’s loads of ways it can be used. It is made up of two materials that simply don’t work well in laser cutters: glass, and epoxy resin. Not only is there the potential for damage to the optics of your laser cutter, but it’ll also release the same poisonous gases that we mentioned above, with the potential to catch fire too. 

 

Coated carbon fibre 

Most often used in car manufacturing and the aviation industry, we mentioned above how thin carbon fibre mat can be cut by laser cutters despite the risk of the material fraying. Coated versions though, should definitely not be in your laser cutter, due to the toxicity of the fumes that are released when it is cut.

 

Hobarts fibreglass and carbon fibre materials for laser cutting

 

Foodstuffs 

While in theory, cutting food in a laser cutter is possible with just the risk of fire to be concerned about, it becomes less appealing when you think of the amount of, and types of materials that you and your team have cut in there. With so many materials that are toxic when consumed, even if you’ve cleaned the machine really well, it is best to avoid it – especially if you want to avoid food residue affecting cuts in the future. If cutting food using lasers is something you’re considering doing within your business, then you really need a dedicated laser cutter. 

 

Materials with sticky glue backing 

It can be tempting to cut materials that have sticky glue backing, since in theory, you would be able to get some really cool effects that can then be easily applied elsewhere. But adhesive isn’t good for your laser cutter – when the laser is applied, the glue vaporises, which can coat the lens – and then it will coat, heat, and (before long) crack the lens. Unless you’re ready to stump up for a new lens, don’t risk it. 

 

Which types of lasers can cut different types of materials? 

Now we’ve covered the materials that should definitely never be cut with a laser cutter, it is important to remember that not all types of laser cutters are suited for cutting all types of materials. Before you put a material into your laser cutter and set it going, you should check you’re going to get the best results – not just because you’re risking damage to your machine, but also because you don’t want to waste your time and materials.  

 

CO2 lasers

CO2 lasers create their beams using a carbon dioxide gas mixture that has been electrically stimulated. The beam that is created has a wavelength of up to 10.6 micrometres, and is efficient for cutting – with high quality results. Gas laser cutters are widely used for non-metallic materials, including:

Wood Fabrics
Paper Food Products
Acrylic Plastics Plants
Leather Glass

 

Fibre lasers

Fibre lasers create a beam using a seed laser that is then amplified through glass fibres that have been supplied with energy from pump diodes. Fibre lasers have a very small focal diameter, which results in a much, much more intense beam than gas lasers with the same power. Fibre lasers are exceptionally versatile, and can cut many more types of materials than gas laser cutters with the same amount of power. They’re preferred by many companies due to their longevity – they have a working life of around 25,000 hours and tend not to require as much maintenance as other types of laser cutters (when used correctly, of course).

Most commonly used for cutting thin materials, materials that can be cut with fibre lasers include:

Metals Wood
Alloys Plastic
Non Metals Glass

 

Crystal lasers 

Crystal lasers are solid state lasers, and create beams with a wavelength similar to fibre lasers – around 1.064 micrometres. Businesses that buy crystal lasers use them carefully, and ensure that their use is budgeted for carefully, since the pump diodes need to be replaced before 15,000 laser hours. These parts aren’t cheap to replace either, and the crystal has a much shorter life than fibre lasers.

nd:YAG and nd:YVO are the most common types of crystal lasers. Their names stand for ‘neodymium-doped yttrium aluminium garnet’ and ‘neodymium-doped yttrium ortho-vanadate’ respectively – which is why they are usually shortened to their acronyms, or referred to as crystal lasers. Materials that can be cut with crystal lasers include: 

Coated and non-coated metals

Non metallic materials including plastics 

Some types of ceramics can be cut and marked (in certain circumstances – use caution)

 

Types of laser cutting techniques

Laser cutters don’t behave like a saw – there are several different types of techniques that can be used with different types of material. The laser intensity impacts the thickness of the material that can be cut, while the focal length of the laser lens affects the quality of the cut. 

Vaporisation cutting directs the laser on the point that the material is to be cut, and as the material is heated, it boils, which creates a small hole (the ‘keyhole’). As the hole increases, the material starts to break down around it. Vaporisation cutting tends to be used with materials that don’t melt – woods, carbon, and thermoset plastics.

Melt and blow (also known as fusion cutting) is where the laser heats the material until it is molten, and pressurised gas is used to blow the molten material out of the cutting area. Since the material needs to melt, this technique is usually used for cutting metals.

Thermal stress cracking (also known as fracture controlled cutting) is where a hot, high powered laser is applied to brittle materials to encourage cracking, with the crack then directed to where it needs to go. This method is usually used with glass and thin metals that are sensitive to thermal fracture.

Reactive cutting (also known as burning stabilized laser gas cutting) is similar to oxygen torch cutting, using a laser beam for the ignition. This method is usually applied to carbon steel that is over 1mm thick, and sometimes with steel plates to minimise the laser power required. 

 

Sourcing your materials 

When it comes to finding the materials you want for laser cutting, there are a world of possibilities. You might be working with materials that you’ve accumulated over time, but when it is time to buy your next batch of supplies, check out our range of sheet materials. We’ve got sheet acrylic, anodised aluminium, laminate, polypropylene, rubber, and wood, as well as laserable packs that are ideal for beginners to get started with. If you’re looking for polished acrylic, we have a choice of 20 mm and 25 mm clear cast acrylic blocks that are ideal for creating bespoke award tombstones, and we have classic award tombstones available that contain digital prints. If you’re looking for other materials, get in touch – we may be able to source them for you.  

 

Final thoughts

Laser cutters can be used to produce high quality cuts and effects on many different types of materials. However, not all laser cutters can be used with all types of materials, so it is important to check before you start cutting to avoid damage to your machine, and to you. As always, put safety first. Make sure there is sufficient ventilation, and that you are nearby when the cut is taking place, to avoid any potential accidents.