What Can Laser Cutters Cut? PET, Metal, and More—A Commarker User's Honest Guide

Look, I don't sell lasers. I use them. My job is triaging rush jobs at a small fabrication shop—300+ rush orders over the last six years, including same-day turnarounds for trade show booths. When a client calls with 48 hours to go, I don't have time for maybe. I need to know what works.

Full disclosure: we use Commarker lasers in our shop. This isn't a sales pitch. It's a practical guide from someone who's had to clean up the mess when a laser was used on the wrong material. I'm writing this because most 'what can laser cutters cut' articles skip the parts that cost money: which laser, which plastic, and which deadline. If you're waiting on a deadline, skip to the section that matters most. (Should mention: this is written from a custom-shop perspective, not a materials lab.)

Questions this guide answers:

• What can laser cutters actually cut?
• Can you laser cut PET?
• What materials should never go near a laser?
• What's the difference between CO2, fiber, and UV lasers?
• Can a laser cutter replace a CNC router or plasma cutter?
• Is a handheld laser welder gun worth it?
• How do I know if my laser can cut a certain material?

What can laser cutters actually cut?

Here's the thing: there is no single laser that cuts everything. The machine's wavelength determines what it can handle, and wattage determines how fast and how thick. Wattage affects speed and depth, but not which material family absorbs the beam.

• CO2 lasers (10.6 µm): wood, plywood, MDF, acrylic, cardboard, paper, leather, cork, some fabrics, and certain plastics like PET/PETG. They can mark coated metals, but most shop-level CO2 units won't cut bare metal.
• Fiber/MOPA lasers (1.06 µm): metals, including stainless steel, aluminum, brass, and copper. Great for engraving and marking. Not for wood or acrylic.
• UV lasers (355 nm): thin plastics, PET film, glass, ceramics, PCB materials, and thin metals. The shorter wavelength creates less heat damage, which is why it helps in precision work.

That's not opinion. Those wavelengths are published in laser manufacturers' material compatibility guides. If someone tells you one machine can cut wood, weld steel, and slice PET film cleanly, they're selling you a story.

Can you laser cut PET?

Short answer: yes, but only if you choose the right laser and set your expectations. The search phrase 'laser cut PET' usually means polyethylene terephthalate, not an actual animal. Let's get that out of the way. No animals. Ever.

PET comes in different forms, and each one behaves differently. If a vendor says they can laser cut PET without asking what form, ask follow-up. Film, sheet, or bottle? That changes everything.

• PET film (the thin roll stuff, or rather, what most people call Mylar): This is where the Commarker Omni 1 UV laser became our hero. A UV laser's cold ablation cuts thin film with less melting and char than a CO2 laser. Not ideal for thick jobs, but for 0.005-inch film, it's exactly what we needed.
• PET sheet: A CO2 laser can handle thin sheet if you test speed and power first. Watch out for brown edges and stringy residue.
• PETG: Common in displays and signs. Cuts well on CO2 when you have the right settings.
• PET bottles: Just don't. The curved shape and inconsistent wall thickness make a mess.

In March 2024, 36 hours before a client's trade show, we had a roll of PET labels that wouldn't cut cleanly on our CO2. I almost told the client no. Then we tried the UV laser, and it saved the job. Never expected that. I thought more power meant better cutting. Turns out, for thin heat-sensitive plastic, wavelength matters more than wattage.

Real talk: if you're cutting PET for a living, test your material before every batch. PET suppliers sometimes change formulations without telling anyone.

What materials should you never put in a laser cutter?

PVC and vinyl release chlorine gas that can damage your lens and your lungs. ABS tends to melt and smoke. Polycarbonate scorches and bubbles. Carbon fiber produces nasty dust and fumes. And anything with unknown additives is a gamble.

If you don't know what's in it, don't cut it.

I still kick myself for not asking what type of plastic a client's sheets were. If I'd checked first, I'd have saved a ruined focus lens and a tense afternoon. Now every job form asks for the exact material and safety data sheet.

Also be careful with laserable plastics that look identical but have different additives. The difference between safe and toxic is often a coating you can't see. Oh, and this gets into chemistry territory, which isn't my expertise. I'm not a materials engineer. What I can tell you from an operations perspective: a 15-second check is faster than explaining a missed deadline to a client.

What's the difference between CO2, fiber, and UV lasers?

Wavelength. That's the short answer. Different wavelengths are absorbed by different materials.

A 60W MOPA fiber laser like the Commarker B4-60W is a metal marking and engraving machine. It does that very well. But if you expect it to cut plywood or acrylic, you'll be disappointed—it's not the right tool.

The Commarker Omni 1 UV laser, on the other hand, is built for fine, low-heat jobs. Thin plastics, PCBs, glass, ceramics. It won't replace a CO2 laser for large acrylic signs, and a CO2 won't replace it for cutting PET film without leaving burn marks.

That's why Commarker offers several different machines. It's not an upsell; different wavelengths are genuinely different tools.

So when someone asks which one is best, my answer is always: it depends on what you're cutting. A workshop often needs two or three different lasers, not one magic box.

Can a laser cutter replace a CNC router or plasma cutter?

No. Not even close.

Laser cutters are great for thin, detailed work. A CNC router physically cuts thick wood and composites. A plasma cutter handles thick metal plate. They do different things. If you put thick aluminum into most laser cutters, you'll get a slow, ugly result.

For metal plate thicker than about 3mm, we typically recommend waterjet or plasma. A laser won't be clean or fast.

This gets into tooling territory, which isn't my expertise. What I can tell you from a scheduling perspective: in our shop, we use a CNC router for thick stock and lasers for detail work. They complement each other. Trying to force one machine to do everything causes more rush jobs than it solves.

Is a handheld laser welder gun worth it?

If you do metalwork, yes—if you understand it's a welder, not a cutter. A handheld laser welder gun is for fusing metal, usually stainless steel, carbon steel, aluminum, or copper. It doesn't cut.

We use a Commarker laser welder gun for rush repairs. It doesn't replace our fiber laser or CO2; it fills a different role.

We added that laser welder gun after a client brought in a broken steel frame with a 48-hour deadline. Normally I'd run trials for a week before buying new equipment, but there was no time. The numbers said rent a TIG welder. My gut said buy the gun. I went with my gut, and it paid for itself within two rush jobs.

If you're considering a laser welder gun, check the duty cycle and whether you have a proper shielding gas setup. Cheap setups can be more trouble than they save.

But I should add that our situation was specific: we already had the safety setup and the metalworking skills. If you're starting from zero, a laser welder gun isn't a first tool. It's a specialized addition.

How do I know if my laser can cut a certain material?

Step by step:

1. Confirm the exact material and any coatings. 'Plastic' isn't specific enough.
2. Look up the safety data sheet or a manufacturer compatibility chart.
3. Cut a test piece with low power and slow speed, then adjust.
4. Inspect the edge. Clean and sharp is good. Brown, melted, or charred means change something.
5. Write down the settings that worked.

The surprise wasn't some secret formula. It was that a simple test cut saved us from ruining a full sheet of material. That's the difference between a rush job done right and a rush job done twice.

This process won't tell you if a material is profitable to cut, only if it's possible. Time is money in rush jobs.

This approach worked for us, but our shop mostly does custom short runs. If you're planning high-volume production, laser cutting might not beat die-cutting or waterjet on cost. Your mileage may vary if your volume is completely different.