What are good laser settings for 3 mm plywood?

TwoTrees cuts 3 mm plywood at 200–300 mm/min and 100 % on a 5.5 W diode and at 700 mm/min on its 10 W TS3 — roughly 0.9–1.7 J/mm in one pass. AtomStack’s 5 W P1 cuts 3 mm basswood at 120 mm/min and 40 % (1 J/mm). Glue changes this a lot, so test.

Why won’t my laser cut through plywood?

Often the glue or a hidden knot. Exterior plywood usually uses phenolic glue, which one long-time laser user found takes at least four times the power of urea glue, and voids or knots inside the core stop a cut you cannot see. Choose plywood sold for lasers and test each batch.

Is laser cutting plywood safe?

It is widely done, with care. Some plywood glues release formaldehyde and some are not laser-compatible, so use plywood sold for lasers, run proper extraction and stay with the machine — wood can flare up.

What is the difference between basswood and basswood plywood for lasers?

Solid basswood has no glue lines, so it cuts evenly but warps and is costly in wide sheets. Basswood plywood is cheaper and flatter, but the glue between the plies adds resistance. AtomStack’s tables say only “Basswood”, so they do not tell you which they tested.

Material · wood sheet

Laser settings for plywood and basswood

Plywood is thin wood glued in layers, and the laser has to get through the glue too. The same thickness can cut cleanly or stop dead at a glue line, depending on which glue the mill used.

Safety first

Before you start With care

Plywood is a caution material: some glues release formaldehyde and some are not laser-compatible at all. Choose plywood sold for lasers and ventilate well (what not to laser cut). Interior glues cut more easily, but most are urea-formaldehyde, so they still need extraction.
Wood burns. Keep air assist on, keep the bed clear of scraps, and never leave the machine while it runs.
MDF is a different board with more glue binder; it chars heavily and some universities ban formaldehyde-based MDF.

Moving cross-section

What the beam does

Switch the material or laser and watch the same beam give a different result.

Interior gluePhenolic (exterior)Hidden knot

Blue diode ≈ 450 nm

Wood plies
Urea / melamine glue line
Kerf through every ply

Urea or melamine glue lines vaporise with the wood, so the kerf goes straight through every ply.

Cross-section, not to scale.

Laser types

Which laser can process it

These are this material’s rows from our diode vs CO2 vs fiber matrix. (full matrix)

Blue diodeCuts & engraves

CO2Cuts & engraves

FiberNot suited

Not suited: it scorches wood rather than marking it cleanly.

Maker values

Maker settings on one scale

Every value is a starting point published by the maker, and the maker is the source; none of them were tested by us. Machines differ in optical power, so power % and speed are converted to the energy the beam puts into each millimetre of line (J/mm). Tap a point or a table row to see the original row, the math and a link that fills in the converter.

J/mm = optical W × power % × passes ÷ speed (mm/s) · J/mm² = J/mm ÷ line interval (mm)

This is the same formula as the converter. Between lasers of the same type, similar J/mm gives a similar burn. Cutting energy rises steeply with thickness, so compare rows of similar thickness.

AtomStack’s rows say “Basswood” without saying solid wood or plywood; we include them because basswood sheet sold for lasers is usually plywood, but the table does not confirm it. TwoTrees’ rows say “Plywood”. Rows with 10 passes at a high speed are the maker’s thick-stock method, not typos. The A40 Pro V2 LightBurn cuts carry S-values where a percentage belongs.

AllEngraveCut

▬ Half of Engrave rows: 0.053–0.0765 J/mm▬ Half of Cut rows: 6.6–16.5 J/mmEngraveCutDiodeCO2Hollow = row that looks like a typoA40 Pro V2 is calculated at 48 W (the table does not say whether it is the 48 W or the 24 W setting).

57 rows
Software	Maker label · thickness	Job	Speed mm/min	Power	Interval	Passes	J/mm
LightBurn	Basswood	Engrave	6,000	70%	0.1	1	0.07	Convert →
LightBurn	Basswood · 6mm	Cut	130	80% ?	—	10	36.9	Convert →
LightBurn	Basswood · 8mm	Cut	700	80%	—	10	6.86	Convert →
LaserGRBL	Basswood	Engrave	6,000	S700	0.1	1	0.07	Convert →
LaserGRBL	Basswood · 6mm	Cut	130	S1000 ?	—	1	4.62	Convert →
LaserGRBL	Basswood · 8mm	Cut	700	S1000	—	10	8.57	Convert →
LightBurn	Basswood	Engrave	20,000	80%	0.1	1	0.048	Convert →
LightBurn	Basswood · 10mm	Cut	700	80%	—	10	13.7	Convert →
LightBurn	Basswood · 9mm	Cut	100	100%	—	1	12	Convert →
LaserGRBL	Basswood	Engrave	20,000	S900	0.1	1	0.054	Convert →
LaserGRBL	Basswood · 12mm	Cut	120	S800	—	1	8	Convert →
LaserGRBL	Basswood · 17mm	Cut	700	S800	—	10	13.7	Convert →
LightBurn	Basswood	Engrave	20,000	80%	0.1	1	0.0576	Convert →
LightBurn	Basswood · 12mm	Cut	120	80%	—	1	9.6	Convert →
LightBurn	Basswood · 17mm	Cut	700	80%	—	10	16.5	Convert →
LaserGRBL	Basswood	Engrave	20,000	S800	0.1	1	0.0576	Convert →
LaserGRBL	Basswood · 12mm	Cut	120	S800	—	1	9.6	Convert →
LaserGRBL	Basswood · 17mm	Cut	700	S800	—	10	16.5	Convert →
LightBurn	Basswood	Engrave	20,000	80%	0.1	1	0.0576	Convert →
LightBurn	Basswood · 12mm	Cut	120	80%	—	1	9.6	Convert →
LightBurn	Basswood · 17mm	Cut	700	80%	—	10	16.5	Convert →
LaserGRBL	Basswood	Engrave	20,000	S800	0.1	1	0.0576	Convert →
LaserGRBL	Basswood · 12mm	Cut	120	S800	—	1	9.6	Convert →
LaserGRBL	Basswood · 17mm	Cut	700	S800	—	10	16.5	Convert →
LightBurn	Basswood	Engrave	10,000	40%	0.09	1	0.115	Convert →
LightBurn	Basswood · 14mm	Cut	600	S800 ?	—	9	34.6	Convert →
LightBurn	Basswood · 11mm	Cut	130	S800 ?	—	1	17.7	Convert →
LaserGRBL	Basswood	Engrave	10,000	40%	0.0909	1	0.115	Convert →
LaserGRBL	Basswood · 14mm	Cut	600	S800	—	9	34.6	Convert →
LaserGRBL	Basswood · 11mm	Cut	130	S800	—	1	17.7	Convert →
LightBurn	Basswood	Engrave	10,000	25%	0.09	1	0.105	Convert →
LightBurn	Basswood · 20	Cut	1,200	90%	—	10	31.5	Convert →
LightBurn	Basswood · 15	Cut	300	90%	—	1	12.6	Convert →
LaserGRBL	Basswood	Engrave	10,000	S250	0.1	1	0.105	Convert →
LaserGRBL	Basswood · 20	Cut	1,200	S900	—	10	31.5	Convert →
LaserGRBL	Basswood · 15	Cut	300	S900	—	1	12.6	Convert →
Bitmap	Basswood	Engrave	18,000	30%	0.1	1	0.055	Convert →
Vector Line	Basswood	Engrave	3,500	6%	—	1	0.0566	Convert →
-	Basswood · 12mm	Cut	200	80%	—	1	13.2	Convert →
-	Basswood · 15mm	Cut	150	100%	—	1	22	Convert →
Bitmap	Basswood	Engrave	9,000	80%	0.08	1	0.0267	Convert →
Vector Line	Basswood	Engrave	1,000	20%	—	1	0.06	Convert →
LightBurn	Basswood · 3mm	Cut	120	40%	—	1	1	Convert →
LightBurn	Basswood · 5mm	Cut	120	80%	—	2	4	Convert →
Bitmap	Basswood	Engrave	20,000	80%	0.1	1	0.048	Convert →
Vector Line	Basswood	Engrave	1,000	8%	—	1	0.096	Convert →
-	Basswood · 6mm	Cut	120	80%	—	1	8	Convert →
-	Basswood · 7mm	Cut	500	80%	—	10	19.2	Convert →
-	Plywood 1 mm · 1mm	Engrave	2,000	30%	—	1	0.0495	Convert →
-	Plywood 1 mm · 1mm	Engrave	6,000	50%	—	1	0.05	Convert →
-	Plywood 1 mm · 1mm	Cut	400–500	100%	—	1	0.733	Convert →
-	Plywood 1 mm · 1mm	Cut	1,000	100%	—	1	0.6	Convert →
-	Plywood 3 mm · 3mm	Cut	200–300	100%	—	1	1.32	Convert →
-	Plywood 3 mm · 3mm	Cut	700	100%	—	1	0.857	Convert →
-	Plywood 5 mm · 5mm	Cut	100	100%	—	2	6.6	Convert →
-	Plywood 5 mm · 5mm	Cut	300	100%	—	1	2	Convert →
-	Plywood 8 mm · 8mm	Cut	150	100%	—	1	4	Convert →

The glue decides the cut

Nervous System, who laser-cut plywood puzzles for years, found that indoor plywood is usually made with urea glue and outdoor plywood with phenolic glue, and that phenolic “takes at least 4 times as much power to cut by laser as urea glue”. Their best sheet used melamine glue with a basswood core. Owners on the LightBurn forum describe the same thing from the other side: a dark glue line the beam melts instead of clearing.

They also point out that a laser “can only cut at one power”: a void or knot inside the core is invisible from the face and stops the cut. That is why a setting that cut one sheet perfectly can leave parts hanging in the next.

Basswood plywood

Basswood (American linden) plywood is the usual hobby laser sheet because the wood is pale, even and soft. Look for sheet sold as laser plywood and ask which glue it uses; interior urea glue cuts more easily than phenolic but still calls for extraction. Thickness in the maker rows runs from 1 mm to 20 mm, but most one-pass diode cuts in the tables stop around 6–12 mm; thicker rows use many fast passes.

Each extra mm needs more energy, so compare rows of similar thickness. The scatter above mixes all thicknesses on purpose, to show how wide the range is.

Prep and finish

General shop practice (no source):

Keep it flat. A warped sheet changes the focus across the bed; weigh or pin the corners.
Mask against smoke. Low-tack masking tape or transfer tape on the face keeps smoke stains off; air assist helps too.
Check the cut before you lift the sheet. Press a part gently: if it does not drop, run another pass with the sheet still in place.
Tidy the edges with light sanding; the charred edge is part of the look on laser-cut plywood.
Fit joints with the kerf & joint-fit calculator.

How to run a plywood test

Test every new batch: glue and core change between sheets and suppliers.
Cut small squares at a fixed power and speed and add passes until they drop out; then try the next speed. For engraving, use LightBurn’s Material Test (LightBurn).
Start from a maker row for a machine like yours, scaled with the power & speed converter, and allow a margin for knots.
If a square stops at the same depth every time, suspect the glue, not the setting.

FAQ

What are good laser settings for 3 mm plywood?: TwoTrees cuts 3 mm plywood at 200–300 mm/min and 100 % on a 5.5 W diode and at 700 mm/min on its 10 W TS3 — roughly 0.9–1.7 J/mm in one pass. AtomStack’s 5 W P1 cuts 3 mm basswood at 120 mm/min and 40 % (1 J/mm). Glue changes this a lot, so test.
Why won’t my laser cut through plywood?: Often the glue or a hidden knot. Exterior plywood usually uses phenolic glue, which one long-time laser user found takes at least four times the power of urea glue, and voids or knots inside the core stop a cut you cannot see. Choose plywood sold for lasers and test each batch.
Is laser cutting plywood safe?: It is widely done, with care. Some plywood glues release formaldehyde and some are not laser-compatible, so use plywood sold for lasers, run proper extraction and stay with the machine — wood can flare up.
What is the difference between basswood and basswood plywood for lasers?: Solid basswood has no glue lines, so it cuts evenly but warps and is costly in wide sheets. Basswood plywood is cheaper and flatter, but the glue between the plies adds resistance. AtomStack’s tables say only “Basswood”, so they do not tell you which they tested.

Sources

Sources for the laser-type verdicts

Last checked 2026-11-01 · Maker values and calculations; we did not process this material ourselves.

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