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Laser Cutting Fabric and Felt: Power, Speed, and Air Assist Guide
For thin quilting cotton on a 20W diode laser (xTool S1 20W), cut at 90% power, 238 mm/s (14,280 mm/min), 1 pass, with maximum air assist — the go-fast approach seals edges and prevents flare-up. For 3mm craft felt on a 20W machine, use 80% power, 700 mm/min, 1 pass, with air assist off (airflow lifts felt off the bed). Always pin fabric flat and never leave it unattended. Settings from SewingMachineFun.com and Bonny Creations; last verified 2026-06-28 — lasertinkerer.com
"Quilting cotton on a 20W diode: 90% power, 238 mm/s, 1 pass, maximum air assist. 3mm craft felt: 80%, 700 mm/min, air assist off. Go fast on fabric — slow speeds char and ignite."
- Go-fast principle: for thin cotton (80–100gsm), use 90% power at 238 mm/s (14,280 mm/min) with maximum air assist — opposite of wood settings
- No air assist for felt: airflow lifts 3mm felt off the honeycomb bed and ruins the cut; pin flat and cut dry
- Natural fibres are safer than synthetics: cotton, linen, and wool felt produce low-hazard fumes; polyester/acrylic felt produces stronger fumes — use a fume extractor
- PVC check is mandatory: some cheap felt and metallic fabric contains PVC — never laser unless explicitly labeled PVC-free
- Always monitor fabric cutting — fabric ignites faster than any other common laser material
Fire and fume safety: fabric is the highest fire-risk material
What you can laser cut
Synthetic felt and fabric: verify before cutting
Acrylic felt, polyester felt, and synthetic blends are cut regularly by hobbyists, but require active ventilation or a fume extractor. The melted-sealed edge is actually a benefit — it won't fray. Two things to check before cutting any synthetic:
- Is it PVC-free? Some cheap craft felts, metallic fabrics, and glitter felts contain PVC fibres or coatings. Cut a tiny corner in a well-ventilated spot and sniff — a sharp, acrid chemical smell (not just "burning plastic") indicates possible chlorine compounds. Do not proceed.
- Is it labelled? Look for: "100% polyester," "100% acrylic," or "100% wool." Generic "felt" with no composition label is suspect.
| Material | Fume level | What it smells like | Minimum ventilation |
|---|---|---|---|
| Cotton / linen | Low | Singed paper / caramel | Open window or fan |
| Wool felt | Low–medium | Burned hair — strong and persistent | Open window + fan, or fume extractor |
| Acrylic / polyester felt | Medium | Burning plastic, sharp | Fume extractor or outdoor use |
| PVC-containing fabric | Extreme — BANNED | Sharp acrid / chemical — stop immediately | Do not laser under any circumstances |
Eye protection: OD7+ 450nm laser safety glasses are required any time the lid is open. Get a pair below — fabric cutting with an open-frame laser is particularly risky due to the unpredictable material movement.
- OD7+ 450nm laser safety glasses — essential for open-frame lasers
- Honeycomb laser cutting bed — best surface for holding fabric flat while allowing cut pieces to drop through
- Laser fume extractor — particularly important for synthetic felt
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What power and speed cuts cotton fabric on a 20W diode laser?
Cotton cutting on a diode laser uses the go-fast principle: high power combined with very high speed prevents heat from dwelling in one spot long enough to char or ignite the fabric. The two settings below reflect two different approaches and cotton weights — use the one that matches your machine type and fabric weight. Both are starting points; test on a scrap first.
SewingMachineFun.com — quilting cotton. Range: 85–95% power, 200–280 mm/s. Maximum air assist is essential at this speed to prevent flare-up.
Bonny Creations — heavier cotton canvas. Range: 70–85% power, 400–600 mm/min. Slower speed for thicker material; edge will be charred darker. Watch for flare-up.
| Fabric weight | Operation | Laser class | Power | Speed (mm/min) | Speed (mm/s) | Passes | Air assist | Confidence | Source |
|---|---|---|---|---|---|---|---|---|---|
| Thin / quilting (~80gsm) | Cut | 20W optical | 90% | 14,280 | 238 | 1 | Maximum | medium | community SewingMachineFun.com, xTool S1 20W |
| Canvas / medium (~200gsm) | Cut | 20W optical | 78% | 450 | 7.5 | 1 | Yes | medium | community Bonny Creations, xTool D1 Pro 20W |
| Thin / quilting (~80gsm) | Engrave | 20W optical | 22–35% | 7,000 | 117 | 1 | Off | medium | community Bonny Creations, xTool D1 Pro 20W, 254 DPI |
What power and speed cuts craft felt on a 20W diode laser?
Craft felt (a 20–35% wool / rayon blend) is one of the most satisfying materials to laser cut — single clean pass, no fraying, and the charred edge seals beautifully. The trick is no air assist: felt is light enough that airflow blows the sheet off the honeycomb bed, ruining the cut. Pin it down (blue tape around the edges or honeycomb pins) and cut dry.
Bonny Creations — wool/rayon blend felt. Range: 75–85% power, 600–800 mm/min. Wool felt cuts cleaner than synthetic. No air assist — use tape or honeycomb pins to secure.
Estimated — unverified. LTEI-derived from the 20W anchor. Confirm with a test grid before production use. Range estimate: 90–100%, 400–500 mm/min, 1–2 passes.
| Material | Operation | Laser class | Power | Speed (mm/min) | Speed (mm/s) | Passes | Air assist | Confidence | Source |
|---|---|---|---|---|---|---|---|---|---|
| Craft felt 3mm (wool/rayon) | Cut | 20W optical | 80% | 700 | 11.7 | 1 | Off | medium | community Bonny Creations, xTool D1 Pro 20W |
| Craft felt 3mm (wool/rayon) | Cut | 10W optical | 100% | 450 | 7.5 | 1–2 | Off | low — estimated | derived LTEI calc. from 20W anchor — estimated, unverified, confirm with a test grid |
| Craft felt 3mm (wool/rayon) | Engrave | 20W optical | 30–35% | 2,000 | 33 | 1 | Off | medium | community Bonny Creations, xTool D1 Pro 20W, 254 DPI |
| Acrylic felt 3mm (synthetic) | Cut | 20W optical | 50% | 4,500 | 75 | 1 | Yes (moderate) | medium, single source | community Bonny Creations, xTool D1 Pro 20W — confirm PVC-free before cutting |
Energy map: craft felt cutting (20W, 3mm)
The map shows energy density (power ÷ speed) across the cutting envelope for 3mm craft felt on a 20W optical diode laser. The ringed cell (80% / 700 mm/min) is the community anchor. Cells to the upper-right char the felt; cells to the lower-left fail to cut through cleanly.
Technique tips: pinning, backing, and dialling in
How to hold fabric flat on the laser bed
Fabric is the most challenging material to hold flat — it's flexible, lightweight, and sensitive to airflow. Three methods work well:
- Honeycomb bed with push-pins: the most reliable method. The hex holes let cut pieces drop through cleanly, and the pins grip the fabric edges. Works for most fabrics. Best for felt.
- Blue painter's tape: tape the fabric corners and edges to a flat board or the laser bed. Fast to set up. Works well for cotton quilting fabric.
- Freezer paper or iron-on stabiliser: iron the fabric to freezer paper (wax side down) — this adds rigidity and eliminates lifting entirely. The paper peels off cleanly afterwards. Essential for very thin or slippery fabric (organza, chiffon).
What to expect from the cut edge
- Cotton (fast pass): slightly sealed tan/brown edge. The faster you run, the lighter the edge. Not a clean white edge — a diode laser always leaves some discolouration on cotton.
- Cotton canvas (slow pass): charred dark brown edge. Mask the fabric with transfer tape before cutting if you need a cleaner appearance, then peel the tape after.
- Wool felt: crisp sealed edge, dark at the cut line, clean face. Often preferred over scissors for detailed shapes — the sealed edge doesn't fray at all.
- Acrylic felt: melted sealed edge — slightly plasticky looking but will not fray. Cut shapes hold their form well.
When a cut is incomplete
If the laser fails to cut all the way through, resist the urge to slow down significantly — slower passes on fabric tend to char more. Instead, try:
- A second pass at the same settings (for felt)
- Increasing power by 5–10% and running again
- Checking focus — fabric is very sensitive to a 0.5mm focus error, especially if it is not perfectly flat
- For felt: ensure the sheet is pinned down (a lifting edge will move out of focus mid-cut)
Run a test square first
Always cut a 30×30mm test square before your full design. Confirm the cut goes all the way through, the edge looks acceptable, and nothing catches fire. Adjust before committing to a production run. The material test grid generator can create a power/speed test matrix for you — download and run it before your first fabric job.
Frequently asked questions about laser cutting fabric
Should I use air assist when laser cutting fabric?
It depends on the material. For thin cotton and canvas: yes, maximum air assist to prevent flare-up. For craft felt: NO — airflow lifts felt off the bed. For acrylic felt: moderate air assist is fine. The rule is: heavier material that won't move = air assist on; lightweight material that can blow = pin it down and air assist off.
Why are fabric laser settings so much faster than wood settings?
Fabric fibres vaporise almost instantly — they need far less energy per mm than wood. Slow settings cause heat to dwell in one spot, charring or igniting the fabric. High speed at high power gives the same cut energy in a fraction of the time, keeping the work zone cool. This "go-fast" principle is the opposite of wood cutting intuition.
Can I laser cut polyester or acrylic felt?
Yes, but verify it is PVC-free first. Acrylic/polyester felt cuts with a melted sealed edge. Fumes are stronger than wool — use a fume extractor. The safety check: if the product label does not confirm PVC-free, cut a tiny corner outdoors and smell — a sharp chemical/bleach odour means possible PVC. Do not proceed if you smell that.
How do I stop fabric from moving during cutting?
Three reliable methods: (1) Honeycomb bed with push-pins — the best option for most fabrics. (2) Blue painter's tape around the edges. (3) Iron the fabric to freezer paper (wax side down) — adds rigidity and peels off cleanly after. For felt specifically, tape is often enough since you're running with no air assist anyway.
What fabrics can I absolutely not laser cut?
Never laser: any fabric containing PVC (some cheap felts, vinyl-coated fabrics, faux leather, metallic fabric); fabric with metallic foil laminate; carbon-fibre reinforced fabric; fabrics with unknown synthetic composition (test first). Safe natural choices: cotton, linen, wool, silk. Safe synthetics (with ventilation): confirmed PVC-free polyester felt, acrylic felt, nylon.
Related settings and guides
Leather cutting settings
Vegetable-tanned leather — similar flat material, similar pinning challenges. See the chrome-tanned ban.
Paper and cardstock cutting
The same go-fast principle applies to paper: high speed prevents charring on thin sheet materials.
EVA foam cutting
Another no-air-assist material — EVA foam blows off the bed just like felt.
Material test grid generator
Generate a power/speed test matrix SVG or G-code for your machine and material. Run before your first fabric job.