Laser cutting paper and fabric: card, felt, denim and cork without fires
are explained briefly when you hover over or tap them.
Paper, card and fabrics are thin and easily flammable. Even a weak laser cuts through them effortlessly, and that is exactly the trap: with settings for wood, the material catches fire immediately. What counts here is low power, high speed, good fixing and a watchful eye on the machine.
Overview
| Material | Engraving | Cutting | What to watch out for |
|---|---|---|---|
| Paper | possible, very sensitive | very good | burns quickly, blows away in an airflow |
| Card, greyboard | good | good | edges turn brown |
| Corrugated board | limited | good | embers in the air channels |
| Wool felt | good | good | smells like hair, edges darken slightly |
| Craft felt made of polyester | poor | good, edges melt | plastic fumes, clarify the fibre beforehand |
| Cotton | possible | good | edges brownish, little fraying |
| Denim | good for lightening effects | good | check stretch content and prints |
| Cork | very good, dark | good | burns and smoulders, mind the binder |
Paper and card
Paper is the most sensitive material in this article. For cuts in copy paper or photo card, a fraction of the power is enough on any diode laser. Fine paper cuts, greetings cards and patterns for stencils are typical projects.
To get a clean result:
- Low power, high speed: Two fast passes are better than one slow one. Slow speed burns the edges and burns through small tabs.
- Fixing: Paper curls from the heat and is lifted by the airflow. Magnets or pins on the honeycomb bed hold it flat. Without fixing, the sheet shifts in the middle of the job.
- Low air assist: A weak airflow prevents flames. Full air blows the paper away or makes small parts fly around.
- Focus: Paper is thin, so the focus has to sit exactly on the surface. A spacer included in the box helps.
Card and greyboard behave similarly but need more energy. The cut edges almost always turn brown. For architectural models and packaging prototypes this is usually not a problem.
Corrugated board has air channels between the outer layers. Sparks can lodge there and keep smouldering without you seeing anything on the outside. After the job, therefore, check the parts and do not throw them straight into a box with other offcuts.
Felt and fabrics
With fabrics, the fibre decides.
- Natural fibres such as wool, cotton and linen char easily at the edge. The cut is clean and hardly frays.
- Synthetic fibres such as polyester melt at the edge. This seals the cut edge, but it is hard and can feel scratchy. The fumes are plastic fumes and need good extraction.
- Coated fabrics such as oilcloth, tarpaulins or fabrics with a plastic print are critical. Many of them contain PVC. That does not belong in the laser.
Craft felt from the craft shop usually consists of polyester or acrylic fibres. Real wool felt is more expensive, smells like burnt hair when lasered and gives nicer edges.
Denim is a special case. With low power and high speed, the laser lightens the indigo dye without cutting through the fabric. This is how patterns and lettering on pockets and jackets are made. Stretch denim often contains elastane, which reacts differently from cotton. Test on a hidden spot or on an offcut. Avoid prints and coatings.
Lay fabrics out taut and free of creases. Waves change the focus, and loose corners flutter into the beam in the airflow.
Cork
Cork engraves very nicely, dark and even. Coasters, pinboards and notebook covers made of cork are popular projects. Cork does burn well, though, and keeps smouldering. Pressed boards made of cork granules contain binders. If in doubt, ask which one, and do without boards with an unknown coating.
Starting values
The values are a rough guide for a first test grid. Paper and fabric already react strongly to small changes, so start at the lower end.
| Task | 5 to 10 W diode | 20 W diode | 40 W diode | 40 to 55 W CO₂ |
|---|---|---|---|---|
| Paper 80 to 160 g/m², cutting | 20 to 40 %, 100 to 200 mm/s | 10 to 25 %, 200 to 400 mm/s | 5 to 15 %, 300 to 500 mm/s | 8 to 15 %, 200 to 400 mm/s |
| Card 1 mm, cutting | 60 to 100 %, 20 to 50 mm/s | 50 to 80 %, 50 to 100 mm/s | 30 to 60 %, 100 to 200 mm/s | 20 to 40 %, 50 to 150 mm/s |
| Felt 3 mm, cutting | 80 to 100 %, 10 to 20 mm/s | 60 to 90 %, 20 to 40 mm/s | 40 to 70 %, 40 to 80 mm/s | 25 to 45 %, 30 to 80 mm/s |
| Denim, lightening | 15 to 30 %, 200 to 400 mm/s | 10 to 20 %, 300 to 500 mm/s | 5 to 15 %, 400 to 600 mm/s | 8 to 15 %, 300 to 500 mm/s |
| Cork, engraving | 20 to 40 %, 150 to 300 mm/s | 15 to 30 %, 250 to 400 mm/s | 10 to 25 %, 300 to 500 mm/s | 10 to 20 %, 300 to 500 mm/s |
Many diode lasers have a threshold at very low power below which the diode does not fire cleanly. If 5 % does nothing at all, use a little more power and more speed to compensate. How a test grid is set up is explained in Material test, and the meaning of the individual values in Laser parameters.
Fire risk
With no other material is the fire risk as high as here. A few firm rules:
- Never laser unattended. A flame in paper becomes large in seconds.
- Keep a fire extinguisher within reach. A CO₂ extinguisher does less damage to the machine than powder.
- Keep the honeycomb bed clean. Paper scraps and lint collect under the workpiece and catch fire on the next job. Empty the catch area regularly.
- Air assist on, but low. It keeps the flame small without blowing the material away. More on this in Air assist.
- Check after the job. Embers in corrugated board, cork and felt sometimes only show up minutes later.
What does not belong in the laser is explained in Prohibited materials.
Continue with: Material test and Air assist.