Customers often ask if I can laser cut or laser engrave an item or material and sometimes it takes a bit of research to answer the question. The short list is that a CO2 laser cannot cut or mark metal, and any plastics with Chlorine are not safe. Paper, wood, acrylics (Plexiglas) and leather can all be laser cut and laser engraved, glass can be engraved. Some plastics make a huge mess in the laser and others, especially those containing chlorine are not safe. Finally there is a list of items that you shouldn’t laser engrave such as food items. Food items can be contaminated by residue from the previous materials used in the laser. Pumpkin Pie lasers very nicely which is great as a display piece but not for the dinner table.
I have a CO2 laser from Epilog which does a great job for typical engraving jobs. I often ask customers to send me a sample of the material to be laser engraved or laser cut so that I can test it and determine the option settings for this material. The customer can then see exactly what the laser engraving or laser cutting will look like with their material.
Plates for trophies, awards and plaques are specially prepared with a coating that reacts with the laser beam. The most common example are black trophy plates that engrave gold or silver – the laser removes the black finish to expose the metal underneath. A CO2 laser cannot mark metal directly so many engraving materials are coated so you can see the mark. Anodized aluminum is a great example – it engraves beautifully! For stainless steel items a coating called Cermark is applied that turns into a black ceramic coating where the laser hits it, and the rest washes off with water.
A CO2 laser will cut and engrave wood. Each species of wood is a bit different in how it reacts to a laser, and different pieces of the same species will behave differently. When engraved, some woods darken giving good contrast, other woods have a very light mark. Cutting wood often leaves a charred edge with a residue near the cut line. Charring and residue while engraving can be removed with a light sanding or by applying a mask before putting in the laser. For thicker pieces, cutting using traditional woodworking methods is more practical before engraving. For example, I would not try to cut out a cutting board with the laser but the laser will do an excellent job of engraving it.
I find I can cut Baltic Birch plywood up to about 1/4 inch on my laser. I can get Baltic Birch as thin as 1/64 inch, which is about the same as thick paper.
Lasers do a great job on acrylic plastics – cutting and engraving. The laser when cutting gives a flame polished edge. Engraving looks great on it’s own, or colour filled with acrylic paints for added effect. Most laser engraving sheet materials for plaques and signage are based on acrylic materials. When edge lit with LED lights the engraving on acrylic signs really stand out. I can get acrylic in various thicknesses and colours, including glow in the dark and florescent colours.
Lasers can engrave glass, but it can be tricky to get high quality results. Sometimes less expensive glass engraves better than more expensive types. For example I would not recommend using a laser on an optical crystal glass award. For a high quality result on glass or crystal I prefer to sandcarve the item.
A laser can engrave many kinds of rubber and cut thinner sheets. I make rubber stamps from a special low odour laserable sheet rubber which is engraved first then cut to size. You can also engrave a hockey puck, but so far I have not found a low odour puck.
Lasers do a great job at cutting paper. With a nice card stock a laser can produce very intricate designs for such things as wedding invitations or cut outs for scrap booking.
Leather items can be laser engraved if they are flat. The laser removes the top layer of the leather leaving the raw leather exposed. Colour and contrast depend on the type of leather, the finish and how it was treated.
Stuff that shouldn’t be lasered
You should not laser any plastic with chlorine, for example PVC or vinyl or polycarbonate. The heat from the laser releases poisonous gases from the material. What is not harmful to people is harmful to the machine.
There are several great charts of materials out there of what can and can’t be lasered – I use this list from ATX Hackerspace for example.