Acrylic vs plywood vs MDF vs steel: picking a material for laser cutting
Four materials cover the great majority of laser cutting jobs. They cost different amounts, they cut on different machines, and they fail in different ways. Picking the right one before you post saves a round of "have you considered…" from the shops bidding.
| Acrylic | Plywood | MDF | Mild steel | |
|---|---|---|---|---|
| Laser | CO2 | CO2 | CO2 | Fiber |
| Cost, 3 mm-class part (index) | 1.4× | 1× | 0.8× | 2.5× |
| Sheet cost, 24×48 in (USD) | $45–120 | $25–60 | $12–20 | $60–90 (equiv. area) |
| Cut edge | Glossy, polished | Brown, slightly charred | Dark brown, uniform | Clean, small burr |
| Strength | Rigid, brittle | Strong, flexes | Weak across thin sections | Very strong |
| Engraving | Frosted white, crisp | Brown, variable with grain | Brown, very uniform | Marks only (needs fiber marker) |
| Outdoor | Yes (UV stable) | No, unless sealed | No | Yes if coated |
| Typical uses | Signs, displays, awards, keychains, enclosures, model parts | Signs, boxes, furniture parts, decor, puzzles, models | Templates, prototypes, painted decor, jigs | Brackets, panels, enclosures, mounts, outdoor signs |
Acrylic
The default for anything that needs to look finished straight off the machine. The laser melts the edge as it cuts, so you get a glossy, polished edge for free. Cast acrylic engraves to a crisp frosted white; extruded engraves cloudy and cuts with a slightly rougher edge, but is cheaper and more dimensionally consistent. Ask for cast if engraving matters, extruded if the parts need to be within ±0.1 mm across a sheet.
It's rigid, it's UV stable, and it comes in dozens of colors, mirrors and fluorescents. What it isn't is tough: it cracks on impact and it'll craze if it touches the wrong solvent. Don't tap threads into it; use inserts or through-bolts.
Cost: material is 50–100% more than plywood, and 6 mm cuts slowly, so a 6 mm acrylic job is often the most expensive CO2 option on the table. 3 mm is the sweet spot for signs, tags and model parts.
Pick acrylic for: retail signage, awards and plaques, wedding and event pieces, LED edge-lit panels, keychains, enclosure windows, anything that needs to look glassy.
Plywood
Baltic birch is what shops mean when they say plywood: void-free, consistent, cuts cleanly. It's cheap, strong for its weight, takes glue and screws, and the laser-cut edge — a warm brown — is part of the look for a lot of decor and signage.
The variables are grain and glue. Engraving depth and color shift with the grain, so a large engraved area looks mottled unless the shop tunes it. Some cheaper plywood uses glue the laser won't cut through cleanly, leaving a fuzzy edge or flashing; a reputable shop stocks laser-grade sheet. Thickness runs 3, 6, 9 and 12 mm, with 3 and 6 being the everyday sizes. Above 6 mm the edge gets noticeably charred and the cut slows down.
It's not weatherproof. Outdoor plywood signs need sealing and still don't last like acrylic or coated steel.
Pick plywood for: wooden signs, boxes and organizers, furniture and flat-pack parts, puzzles and toys, architectural model bases, anything where a wood look is the point.
MDF
Medium-density fiberboard: compressed wood fiber, no grain, dead flat, and the cheapest sheet you can laser. It engraves beautifully uniform because there's no grain to fight, and it cuts predictably at any angle.
The trade-offs: it's weak across thin sections and snaps rather than flexes, it swells if it gets wet, the cut edge is dark and the dust is unpleasant. It also doesn't take a finish on the edge well without sealing. But if the part is getting painted, or is a template, jig or prototype, none of that matters and you'll save 20–40% against plywood.
Pick MDF for: painted decor, prototypes before committing to plywood or acrylic, stencils and templates, jigs, backer boards, cheap large runs of parts that don't need strength.
Mild steel
The moment a part needs to hold a load, bolt to something, or live outside, you're in fiber-laser territory. Mild steel cuts fast on a fiber laser — a 2 kW machine runs 2 mm at several meters a minute — with a clean, square edge and a small burr on the underside that a shop will knock off with a deburring pass.
It rusts. Untreated mild steel goes orange within weeks indoors and days outside, so budget for powder coating, zinc plating, or paint, or specify stainless (about 2× the cost) or aluminum (lighter, roughly 1.5–2×, and it doesn't rust). Fiber cutting also comes with higher setup fees, $25–40, and higher per-minute rates, so single small parts are relatively expensive; batches are where steel makes sense.
Bending is a separate operation on a press brake. If your bracket has a 90° flange, say so; not every laser shop bends, and the ones that do will quote it as its own line.
Pick steel for: brackets and mounts, machine guards, panels and enclosures, outdoor signage (with coating), anything structural.
The quick decision
- It needs to look glassy or lit → acrylic.
- It needs to look like wood, or be glued and screwed → plywood.
- It's getting painted, or it's a test → MDF.
- It holds weight or lives outside → steel (stainless or aluminum if it can't be coated).
- You're not sure → post it and say so. Shops will suggest, and often a cheaper material than you assumed.
What each option costs per minute and per sheet is on the price guide. When you've picked, or when you'd rather let a shop pick, post the job with the file and let several shops bid.