Tips for laser cutting and etching different materials

 
If you’re just getting started with laser cutting, there’s a lot to get your head around, and there are many different things to consider when you’re working with different materials. Even when you’ve been using your laser cutter for a while, if you have decided to start playing with some new materials or techniques that you’ve not done before, you might be on the lookout for some tips and tricks before you start experimenting.

Experimenting with whichever laser cutter you have available is undoubtedly the best way to discover the techniques that you need – but you have to be clued up before you get going, so we’ve rounded up some tips and tricks when you’re working with different materials in this post. 

Woods

There are a number of issues that can occur when lasering wood – whether natural wood or manufactured wood – and this is why we recommend testing out your methods using offcuts before you get started for real. Because each piece of wood will have different qualities (different moisture content, the age of the wood, and so on) you can’t guarantee that one piece of pine will behave in exactly the same way that the last did.

Ignition – when you’re laser cutting, the risk of fire is small, but it is still there. Keeping air assist on can help with this, but it is definitely advisable to have safety products available. If you’re cutting small pieces that create minor flares, then a spray bottle might be all you need to put the flames out, but be sure to have fire extinguishers, and fire blankets to hand, just in case.

Surface scorch – also known as charring, this is where the cut is completely clean but the laser has left a mark on the surface. In order to help avoid charring, low-tack paper based tape may be applied to both sides of the wood to mask the marking that can be created by the laser. When you remove the tape after the cut, the wood should be clean of any marks.

Edge burn – this is where the surface has burned too much, and the edge is not clean. This is commonly a problem when the power has been set too high. If you’re encountering edge burn, lower the power, and rather than trying to complete the cut in one go, do additional passes with the laser to cut all the way through.

Incomplete cuts – these can occur if you’re working with a lower power. This isn’t necessarily a huge issue, more frustrating, but as we’ve already mentioned, understanding the material you’re working with can help prevent this being a problem. Of course, an incomplete cut is relatively easily remedied with another pass with the laser, or if you’re doing a number of similar cuts, then using a higher power – as long as the higher power doesn’t cause edge burn.
Wood is one of the oldest materials on the planet to work with, and although there are tried and tested methods of creating the effects that you might want from it, laser cutting offers the ability to achieve completely different effects from those manual methods. When working with hard woods such as oak, ash, beech, and maple, it can be tricky to create intricate patterns and so on with manual tools, so the laser cutter opens up the potential for different results.

When you’re choosing natural wood to cut with your laser cutter, it is often better to work with wood that is relatively new from the mill due to the tendency that natural wood has to warp and twist over time. Cutting warped wood can cause the laser beam to become unfocused, and you may not get the result you need.

When you’re cutting woods, each layer that is cut is being vaporised. Keep that in mind, and keep your fume extraction on a high setting when you’re cutting natural wood, as those fumes and particles can interrupt the beam and cause issues, which can reduce the efficiency of the cut, and cause further charring to occur.

If you’re making decisions about whether to seal or finish the wood prior to laser cutting, then it is well worth doing test cuts first, as different effects may be achieved. If the wood is to receive further processing after you have completed the cut, then you might not need to be too concerned about any charring as it is likely to be removed during those processes, whereas pre-sealing the wood may require different cut speeds to minimise charring.  

Finally, whether you’re working with natural wood or manufactured pieces, be aware of sap content in the wood, and in the case of manufactured woods, be aware that with the different types of adhesives used, you may see different results. Both natural saps and manufactured adhesives can be melted by the laser, and unfortunately, when they become liquid, can drip onto the cutting bed, then setting and leaving hard deposits behind. To avoid this being an issue, you may want to cover the cutting bed before you start the cut – low tack, paper masking tape may be all you need. 

Paper and cardboard

Paper and cardboard is a great material to play with when you’re getting to grips with laser engraving and cutting techniques, and there are so many different types of effects that you can achieve. Different levels of engraving, scratching, perforations, and filigree effects as well as cutting around the outer edges of the piece are all possible – as well as plenty more effects that can be achieved. However, there are so many different varieties of paper and cardboard that knowing the thickness, as well as what the paper is made up of is the first step in guiding how you set your laser cutter up.

The main issue that many new laser cutter users encounter is with burning and scorch marks. You’re most at risk of this if you’re cutting at high speed, so turn down the speed. Even at slower speeds, your laser is going to create the effects that you want much more quickly than manual methods such as using craft knives, so don’t rush. Your laser cutter can remove layers from paper and cardboard easily, you can use very low power too.

Like wood, you’ll essentially be evaporating the material when you’re cutting or engraving on paper or card, so be sure to use your gas assist and fume extraction. This will help to remove the smoke (remember, that smoke is actually vaporised material) and prevent it causing damage, or having an impact on the cut.

When you are working with paper, adjusting the resolution can help you to create different effects. If you’re simply cutting the paper, you can work at 1000 DPI, while if you’re engraving a detailed image, or using your laser to engrave a photo onto paper or cardboard, you can reduce the DPI to between 250 and 350 DPI. This will ensure that the points the laser makes don’t overlap, and so that the image looks as it should.

There are so many different effects to create using paper and cardboard in your laser that we could probably write a whole post about it (look out for one of those in the future!). Cutting detailed patterns is just the start, there are engraving effects and more, which is where so many wedding businesses use their laser cutter. All those different effects can be applied to different types of paper and cardboard to create completely unique designs. For example, if you’re looking to create a light and dark engraving effect with your laser cutter, you can do this relatively easily if the paper or cardboard has two different coloured layers – but your design might look great with paper that is the same colour all the way though.

For more information about cutting paper based materials, click here.

Leather and suede

Leather and suede can be cut with your laser cutter, and similar to wood and paper, as the material is cut, it is vaporised, so keep your air assist and fume extraction on. You can create incredibly intricate patterns in leather with your laser cutter, quickly taking leather items such as shoes, wallets, and belts from boring too brilliant.

There are some incredible effects that can be achieved with laser engraving on leather and suede too. Because it is durable and flexible, it can stand up to different amounts of power and speeds from the laser, and you can create very different effects when you’re working with leather and suede. If you’re starting a business with your laser cutter, then there’s a lot to be said for working with leather.

Using your laser cutter for engraving onto leather means that you can personalise items like purses and wallets, watch straps, and handbags. You’ll see the best effects from lighter shades of leather, but if you’re using leathers that have been dyed different colours, you can get some incredible effects where the lower layers haven’t absorbed the dye.

When you’ve finished cutting, or engraving the leather, use a product that will help you get the effect that you want – whether that’s a high shine, or a matte finish. There are plenty of products commercially available, but if you’re doing a one-off project or you’re experimenting, you can use hand cream, sun lotion or even just olive oil – basically, anything that would nourish the skin of humans is likely to be good for leather too. As always, test on an offcut before you go all-in on a piece you love.

An important point to note though: Although you might think that you’re doing better for the animals by using faux leather, pleather, or leather-look materials, do not use fake leathers in your laser cutter. They release chlorine gas when they are cut, which is an irritant to the lungs, and can be deadly within just 30 minutes, as well as damaging for your laser cutter. Definitely not worth the risk. 

Cork

Cork can be used for a variety of projects, and is a low-cost, yet durable option for creating items such as coasters, notebook covers, and pinboards – great, simple pieces that you can start a business with. As a natural material, cork behaves in a similar way to wood and leather, with the laser cutter removing layers of material.

Because it is a relatively soft material, you don’t need high power, so if you’re engraving on cork, then you can work at around 90% speed, between 40% and 60% power. Depending on the density of the cork matting you’re working with, you can produce similar effects to wood, leather, and cardboard.

As with wood, when you’re cutting cork, there can be charring, or residues can be left around the edges – which isn’t ideal if you want a clean finish. Reducing the frequency of the laser can help reduce the problem of charring, but where charring occurs, there is often smoke too, so if you’re cutting a lot of cork, be sure to keep on top of maintaining your laser. Cleaning the lenses will help minimise charring, as well as using your gas assist and extraction to help remove those smoky particles that will contribute to dirty lenses. 

Plastics 

Plastics such as acrylic, Lucite, plexiglass and PMMA all cut really well with laser cutters, and are great for getting an incredibly polished edge without the use of additional products or techniques. As with all other materials though, there are a number of factors that can have an effect on the final cut.

The type of plastic is the first thing to consider – as there are some types of plastic that shouldn’t be cut with your laser. Polycarbonate, ABS (Lego plastic), high-density polyethylene (milk bottle plastic), both polypropylene and polystyrene foams, as well as plastics that contain carbon fibres for strength should be kept well away from the cutting bed of your laser cutter. We’ll talk more about the different reasons for not cutting these materials in a moment, but for the most part, it is to do with keeping both your laser cutter safe, and your lungs safe.

As with other types of materials, the quality of the cut or engrave job will very much depend upon the speed and the power used. If you need to cut a lot, and quickly, then you can use a high speed, but this typically won’t result in such a high polish finish. Edges of acrylics usually look better when the cut has been completed with a slower speed – but if you need to cut a lot of pieces, then you may need to balance the quality of the finish with the quantity that you can complete. You can get much more information about laser techniques with plastics from Universal Laser Systems here.

Polished acrylic blocks are often used as simple trophies for awards, usually with the winner’s name engraved on the front – they look much more expensive than they actually are! There are a number of different techniques for engraving onto acrylic blocks, and the desired final effect may need to be changed. Where thinner acrylic blocks are being used for engraving, and the text is being etched onto the reverse of the block to be read from the front, you may need to mirror the text (and graphics!) to ensure that the details are displayed correctly. 

Glass

Cutting glass, and mirrors can be tricky, since there is a certain amount of reflection that occurs, and in general, it is safe to say that a hobby laser cutter won’t get great results when cutting glass – but there can be exceptions to the rule, so it can be worth a go. Laser engraving and etching are the most commonly used techniques when using a laser cutter with glass, but because the laser doesn’t vaporise glass in the same way that it does with natural materials, you have to work carefully to avoid the micro cracks becoming actual cracks.

Before you get started though, there are several things you’ll need to think about when you’re considering cutting glass with your laser.

The type of glass – different types will have different properties (e.g. Pyrex or toughened glass may stand up to more than fine crystal!) and the glass may become weaker as a result of being cut, and even etched, which can make cracking or shattering much more likely.

The thickness of the glass – like most materials, thicker glass is harder to cut, and multiple passes with the laser may cause weakness or breaking before the cut is complete.

Safety considerations – it should go without saying that when you’re working with glass, mirrors, and any other type of material that is easily broken, if a breakage does occur as a result of the laser, be particularly careful when clearing up and disposing of the broken pieces. In addition, you’ll need to ensure that you’re using the appropriate filtration system, too vent any tiny pieces away safely.

If you’re working with a glass tumbler, or another curved piece of glass, it can be even harder to get the effect that you want – and different thicknesses in the glass can cause cracking.

To avoid micro cracks in the glass turning into larger cracks and material flaking away, you can try techniques that involve using the laser through damp newspaper, or applying washing up liquid to the surface of the glass. These techniques act like a heat sink, reducing thermal overload – however they can reduce the efficiency of the cut, so be aware that they might not behave as you expect.

You can find much more information about working with glass and ceramics from Universal Laser Systems.

Textiles and fabrics

We have talked about how the fashion industry are using laser cutters and 3D printers to create new and interesting effects, and if you have a laser cutter then that translates to huge potential to create some of those for yourself. Laser cutting fabric is useful as it creates a seared edge that means the fabric is much less likely to unravel, and as with other materials, you can create a really intricate design that would take incredible skill to cut, or to create using manual methods.

One of the problems that many users encounter when they are laser engraving, or cutting on fabric is the risk of burning. The key with successful laser cutting and engraving on fabrics is often to use high speed, with low power, which means that only the thinnest of layers can be removed from the top of the fabric, enabling you to get the right type of effect. As with paper, you may also need to play with reducing the DPI that you’re engraving with, since a lower resolution can help to ensure that the laser doesn’t burn right through the fabric.

Ideally, if you’re using engraving techniques with fabrics, you’ll have a fabric with a tight-knit thread. Some fabrics can be cut with your laser, but that engraving techniques don’t work quite as well with, such as terry cloth (the looped cotton that towels and traditional nappies are usually made from) and plush fabrics. You’ll also find that looser knit fabrics are much more likely to be scorched when using laser engraving techniques – and so as with almost every type of material that you might want to use your laser cutter to cut or engrave with, it is well worth carrying out tests before you go ahead to create the final project, because there can be differences between types. You might have used one type of cotton fabric in the past, but if you’re working with one that is a different thickness, thread count or weight, you may need to adjust your settings to achieve the effect you want.

The great thing about cutting fabrics with a laser cutter is that most fabrics are safe to put in your laser cutter – with the main exceptions to the rule being PVC, vinyl, and artificial leathers. We keep mentioning it, but do not use PVC, vinyl, and artificial leathers in your laser cutter. They release chlorine gas when they are cut with a laser, which is problematic for both your laser cutter, and the lungs of anyone who is in the area – it can be fatal in less than 30 minutes in high concentrations.

Materials to avoid cutting or etching

Whether your laser cutter is brand new and you’re just getting started with it as a brand new hobby for the new year, or your laser cutter is at the centre of your business and you’ve been cutting and etching for a while, you’ll want it working perfectly, all of the time. With that in mind, there are some materials that you should never, ever be placing in your laser cutter. We’ve spoken about these materials on the blog before – particularly in our ways to completely ruin your laser cutter post, and our materials for laser cutting post – but since these are so important to be aware of, we’ll do a quick run-through here.

Wherever we mention the possibility of materials that shouldn’t be cut catching fire, you’ll also be risking damage to the optics on your laser cutter, as well as the damage that the smoke can cause to your lungs – and the potential damage to the wider area too.

PVC, vinyl, and artificial leathers should never be in your laser cutter, since they release chlorine gas when they are cut. That’s a problem both for your health (it is an irritant to the lungs, and can be fatal in just half an hour) and your machine, since chlorine gas can damage optics, cause corrosion on metal parts, and cause problems for the control system too.

Thick polycarbonate can catch fire when cut, and burn with long, thin trails of soot that can damage both your lungs, and your laser cutter.

ABS (most often seen in the form of Lego) releases toxic hydrogen cyanide, is prone to catching fire, and leaves a huge mess in your machine.

HDPE (milk bottle type plastic) often catches fire when cut with a laser cutter, and can melt onto the cutting bed of your machine.

Polystyrene foam can catch fire and burn quickly, and leaves melted sediments on the cutting bed of your machine.

Polypropylene foam burns quickly, with drips of the material that keep burning. When extinguished, those drips set solidly, leaving the cutting bed of your machine irreparably damaged.

Epoxy is another material that can burn easily, and releases poisonous fumes.

Fibreglass can damage the optics, as well as releasing poisonous fumes, and catching fire, since it contains epoxy.

Coated carbon fibre can release yet more toxic fumes when cut.

Materials with sticky glue backing can ruin your optics when the glue is vaporised, coating, heating, and cracking the lens.

Foodstuffs potentially could be cut with your laser with ‘just’ the risk of fire and smoke damage (which is still significant, when you consider the potential damage to the lens, and any grease drips and so on) the cross-contamination from materials you’ve already cut can cause a huge health issue – so don’t do it. If you’re going to be laser cutting foods, you really need one for that specific purpose.

A quick note about laser cutting metals

Although crystal laser cutters (nd:YVO – aka neodymium-doped yttrium ortho-vanadate and nd:YAG – aka neodymium-doped yttrium aluminium garnet) can cut metals, they’re costly. For the most part, gas, and fibre laser cutters (and in general, at-home laser cutters) generally should not be used to cut metals. That’s due to the reflectivity of most metals. If you’re unsure, always check the guidelines from the manufacturer before you decide to get started.

Don’t forget the importance of maintenance

We’ve spoken about it regularly, because it has such an impact on the performance and effects that you can achieve – keep on top of maintaining your laser cutter. Debris from previous cutting jobs can cause additional smoking, as well as increasing the risk of accidental fire, so sweep out any remaining materials after each job, and at the end of the day, check the lens. Weekly, check the air filter and replace parts in accordance with manufacturer guidelines.

To keep your laser cutter in perfect running order, annual servicing is a must. If you don’t have the skills or time to complete this, then why not arrange for one of our engineers to visit your location? Our staff are trained to the highest possible level, and carry out a comprehensive 100 point check that helps to minimise the chances of your laser cutter malfunctioning. It is well worth the investment in a maintenance plan for your business too, since things do sometimes break, even with perfect maintenance. Should the worst happen and your laser cutter break down, you’ll also get emergency call-outs included – meaning you’ll be back up and running much quicker than if you didn’t have that cover. Since pricing starts at just £250 for a year’s cover, it is a small price to pay to keep your business up and running. Find out more about our service plans here. 

Final thoughts

Although there is a lot of different hints, tips, and tricks to using a laser cutter, the key is to experiment, really getting to know your machine, as well as learning about the types of materials that you’re going to work with on a regular basis. If you’re in the beginner stage – either with a new laser cutter, or you’ve just started working with a new material, then order one of our laserable packs. With a number of different materials, you’ll quickly get a good idea of what works and what doesn’t, pretty quickly – so you’ll be much better prepared when you’re using new materials.