The xTool S1 40W Laser Module Is Seriously Capable. It’s Still Not a Steel Cutting Machine.

January 3, 2025. I’d just approved the purchase order for the xTool S1 40W laser module, an air assist bundle, and a rotary attachment. Our shop foreman walked by, glanced at the spec sheet, and said, “Finally. A steel cutting machine.”

I almost let it go. Then I realized he meant it.

This article is the conversation I ended up having with him, and honestly, it’s the conversation I should have had with myself before I started researching. If you’ve been searching for xtool-s1 specs or “xtool s1 40 watt module” reviews, I hope it saves you the same mistake.

I’m the person who signs the equipment invoices

Quick background: I handle procurement for a 12-person fabrication and short-run production shop. I’ve managed the equipment and tools budget for about six years—maybe six and a half, I haven’t counted the fiscal periods—and I’ve tracked every invoice in our cost system. I’ve also made at least two purchase mistakes that still sting. That’s why I look at laser specs the same way I look at a supplier quote: total cost of ownership, not just the sticker price.

If you came here because “steel cutting machine” sounded like a good search term for this laser, I don’t blame you. It’s a strong phrase. It’s also the wrong phrase.

The surface problem: 40 watts sounds more capable than it is

On paper, the xTool S1 40W module sounds like a significant step up from a desktop hobby laser. It is. But the word “power” makes people jump to conclusions.

Here’s the trap: if a 10W diode laser can mark coated metal, a 40W diode laser must cut uncoated steel, right? No. The S1 40W module is a diode laser in the blue wavelength range. It is not a fiber laser, and it is not a CO₂ laser. According to xTool’s product documentation (accessed January 21, 2025), the S1 is designed for cutting and engraving wood, acrylic, leather, and certain other materials, and for marking some metals. “Marking” is not “cutting.”

A diode laser can mark a steel surface. That doesn’t make it a steel cutting machine.

That difference sounds tiny. In a workshop, it’s the difference between a finished part and a scrap bin.

The deep cause: laser cutting is about absorption, not just wattage

I used to be confused about this too. When I compared laser modules, I looked at watts and assumed the higher number did everything the lower number did, just better. That’s true for some tools. A more powerful drill still drills holes faster. Lasers don’t behave that way.

They work with the material’s absorption. A beam that cuts through 10mm wood can bounce off bare steel. You can raise the power, but if the wavelength is reflected, you’re just heating the surface unevenly instead of cutting it cleanly. Industrial steel cutting usually relies on fiber lasers or high-power CO₂ systems, not a desktop diode module.

Also, a laser engraver moves a focused beam in tiny repeated passes. That’s perfect for rastering a logo on a coated surface. It’s not the same as pushing a continuous cut through a thick sheet. The software setting that works for 3mm acrylic may do nothing on 3mm steel. I’ve seen people max the power and blame the machine when the real problem was the material and the beam’s interaction, not the settings.

This is where I’ll sound like a fan of change: five years ago, a 40W diode module sitting on your workbench sounded like a dream. Now it exists, and that’s real progress. The fundamentals haven’t changed, though. Watts matter. Wavelength matters more.

The other deep cause: “plastic” isn’t one material

Now let’s deal with the phrase “laser engraver for plastic.” That phrase sends people to machines like the xTool S1, and then the confusion starts.

Plastic is a category, not a material. In December 2024, our shop tested nine plastics on the S1 40W: acrylic, PETG, nylon, Delrin, HDPE, polycarbonate, two grades of ABS, and epoxy resin. Some engraved beautifully. Others filled the shop with smoke and smell. And PVC is a hard no for me—chlorinated plastics can produce corrosive smoke that’s bad for your lungs and the machine.

You don’t learn that from a spec sheet. You learn it from a $40 sheet of the wrong material. I’ve made that mistake, and I don’t recommend it.

What this confusion costs you

This isn’t a vocabulary lecture. Misunderstanding the xTool S1 costs real money.

• Test material and time. We ran 17 test cuts—maybe 18, I’d have to check the log—before accepting that the S1 wasn’t going to cut 2mm steel. That was about $120 in steel and four evenings of operator time.
• Emergency outsourcing. A “quick job” that needed stainless parts hit our desk after the laser was installed. The S1 couldn’t do it, so we sent it to a waterjet shop at three times the internal estimate. The client didn’t care why; they just saw the increase.
• Skipped safety infrastructure. If you think you’re buying a metal cutter, you might not plan for proper ventilation. We allocated about $780 for enclosure and exhaust changes before the S1 arrived. That should be non-negotiable.

The frustrating part is that many “bad laser” reviews are actually “wrong expectations” reviews. The machine works. The reviewer expected a different machine.

How to buy the xTool S1 40W module with clear eyes

If you actually need a steel cutting machine, buy a steel cutting machine. The xTool S1 is not that. If you need a desktop laser that cuts wood and acrylic, engraves leather, works with a rotary bundle for tumblers, and marks certain metals, then the xTool S1 40W module is a solid choice.

In our shop, it earned its place with projects that match its limits: wood signs, leather coasters, anodized aluminum tags, and acrylic ornaments. Those are the kind of projects that show up when you search for “cool laser engraver projects.” They’re also the projects the S1 can actually handle.

Before you order, create the total cost spreadsheet. Laser module. Air assist. Rotary. Ventilation. Honeycomb or slat bed. Test material. Add 15% for consumables you didn’t plan for. When I budgeted this for 2025, the final total was about 40% higher than the module price alone. That’s not a red flag. It’s just reality. Pricing as of January 2025 shifts with bundles and discounts, so verify current rates on xTool’s site before you commit to a number.

And if you’re buying a laser engraver for plastic, be specific. Check xTool’s material guides, test a small sample first, and watch what the smoke does. Your nose will tell you if you got it wrong.

The bottom line

Part of me wishes the S1 could cut steel. Another part is glad it can’t, because if it could, it would be a more expensive machine with a more dangerous setup, and my procurement spreadsheet would look very different.

Buy the xTool S1 40W module if it matches the materials you actually work with. Don’t buy it because an SEO-friendly phrase like “steel cutting machine” made it sound like a replacement for a fiber laser. Those two tools serve different jobs.

Honestly, I’m not sure why some online listings blur that line. My best guess is keyword demand pulled in copywriters who never turned on a laser. The good news is you don’t have to learn the hard way.

This worked for us, but our situation is specific: a 12-person shop with repeat orders, steady materials, and a procurement system that catches mistakes before purchase. If you’re a one-person maker doing art pieces, a lower-power module might be a better first laser. If you’re a metal shop, go straight to fiber. And if you’re in between, the S1 might be exactly right—as long as you know what it is.