The Laser Buyer's Checklist: 7 Things to Verify Before You Sign the PO

I'm a quality compliance manager at Coherent. Most years I review roughly 200 specs and test reports — maybe 220 if you count the internal audits. I've been doing this for four years and I've seen the same purchasing mistakes repeat in every industry, from job shops to semiconductor fabs. Here's the checklist I run through when someone asks me to evaluate a laser system, whether it's ours or a competitor's.

Seven checks. The last one is the one almost everyone skips. We'll get there.

Who This Checklist Is For

If you're buying a laser for cutting, engraving, or welding — in a job shop, in R&D, or on a production line — this applies to you. Maybe you've gotten three quotes already. Maybe you're still deciding between a coherent laser and another brand. This checklist isn't about brand loyalty. It's about verification: making sure the system you pay for is the system that works.

Check 1: Your Own Specification Comes First

"We need a laser for cutting plastic" isn't an application. It's a starting point. Before you look at any supplier datasheet, write down the specifics: material type, thickness, required feed rate, edge quality, thermal damage limits, daily throughput. If you're engraving powder-coated tumblers for a side business, write that down too. The spec for someone engraving 500 Stanley cups a week looks absolutely nothing like the spec for someone doing one-off custom jobs.

These numbers become your acceptance criteria. If a supplier can't demonstrate that their system meets them with your parts, you're done. No exceptions.

Check 2: Wattage Is Less Important Than Beam Quality

Most buyers focus on maximum power and completely miss the M² factor — the number that describes how close a laser beam is to a perfect Gaussian profile. Power tells you how much energy is available. The beam profile tells you how evenly that energy lands on your material. For cutting and engraving, that's what determines edge quality, kerf width, and heat damage.

Ask the supplier for a beam profile at your working distance. Not at the laser output — at the focal point, using the optics you'll actually use in production. If they don't have measured data, or if you want it verified independently, find a coherent laser beam profiler supplier and get it measured. You want raw data, not a marketing chart.

I rejected a spec sheet last month — well, flagged it for review — because the M² value was measured at 20% of rated power. The customer planned to run the system near maximum. Real talk: beam quality degrades as power increases and as optics heat up. Always ask for data measured at your operating point.

Check 3: Laser Safety Costs More Than the Glasses

The question everyone asks is "what's the maximum power I can get?" The question they should ask is "what does the safety setup cost?" For Class 4 lasers — which covers most cutting and engraving systems — you're not just buying one pair of laser glasses. You need eyewear for every person in the room, plus an enclosed, interlocked system with viewing windows rated for the specific wavelength you're using.

IEC 60825-1 defines the safety classifications. It also defines what "Class 4" means: hazardous to eyes even from diffuse reflections. That standard isn't optional. And the safety infrastructure it implies — enclosure, interlocks, HVAC, signage — can add 15 to 25 percent to your total project cost. Budget for it before you get excited about the laser price.

Counterfeit laser safety glasses are a real problem. Verify your supplier's attenuation data. An OD rating printed on a frame means nothing without the test documentation behind it.

Check 4: Match the Laser to the Material — It's Not Universal

This is where things go sideways most often. People buy based on what their friend has, or what a YouTube channel recommends, and then discover the laser can't handle their material.

Take "best plastic for laser cutting." The answer depends entirely on your laser's wavelength:

• Acrylic (PMMA) — cuts beautifully with CO₂ lasers: clean edges, minimal discoloration, near-polished edge quality.
• Polycarbonate — absorbs CO₂ wavelengths poorly. It melts, discolors, and produces rough edges instead of clean cuts.
• Delrin (POM) — cuts well but needs temperature control. Too much heat and it melts locally.
• ABS — workable, but the fumes require proper ventilation, and you'll see brown edge discoloration.
• PVC — don't. Chlorine gas is a non-negotiable safety problem.

Now consider your application from a different angle. If you're engraving stainless steel tumblers — the "laser engraver for Stanley cups" use case — that's a different machine entirely: usually a fiber or MOPA laser, not CO₂. Wavelength determines everything. Verify your material compatibility before you fall in love with a specific system.

Check 5: Test With Your Actual Part, Not a Sample

This is the step that's genuinely hard to skip and genuinely ignored. Spec sheets describe what a laser does in ideal conditions. Your parts are not ideal. Powder-coated stainless tumblers vary in coating thickness from manufacturer to manufacturer, and even batch to batch. A laser that produces a crisp, dark engraving on one brand might come out pale on another.

Send your actual parts — not a "representative sample" from the supplier's library — and ask for a process development trial. Most serious suppliers will do this at no charge, or apply it toward the purchase. If a vendor doesn't want to test your parts, I'd ask why.

Check 6: Calculate Total Cost of Ownership, Not Invoice Price

Let me be direct: I've watched procurement teams choose the lowest quote and double their real costs within a year. That's not a knock on budget suppliers — it's a knock on not calculating the full cost.

"The $500 quote turned into $800 after shipping, setup, and revision fees. The $650 all-inclusive quote was actually cheaper."

I've said that sentence to more buyers than I can count. TCO includes the chiller, the extraction system, optics replacement (they wear out), calibration, installation, training, maintenance visits, and downtime risk. Budget systems often have cheaper spare parts... until you need them quickly, and the shipping alone is $200 for a $40 part.

That said, I should be fair: some premium systems are overpriced for what they deliver. The point isn't "spend more." The point is know what you're spending before you compare quotes.

Itemize every line. Then compare.

Check 7: Vet the Supplier — And Stay Current

You're not buying a box. You're buying a relationship that matters when something breaks at 4:45 PM on a Friday. Ask the supplier direct questions:

• What's the typical response time for support? Local engineers or remote only?
• What's the lead time for replacement parts? Optics? Nozzles? Lenses?
• What does preventive maintenance cost per year?
• What has the company announced recently? Search, for example, for coherent laser news December 2025 — new models and updates can indicate where the company is investing, not to mention parts availability.

I remember when I was on the buying side — before joining Coherent. The spreadsheet said the cheaper vendor was 15 percent less. My gut said their support was thin. The spreadsheet won. The vendor got the PO, and when we had a beam stability issue, it took them 11 days to respond. Lost production time: about $3,000. Maybe $4,000 if you count the rework. I don't have the exact number anymore.

Look, I'm not saying every budget vendor is bad. Some of them are excellent. I'm saying you need evidence of support capability, not just a delivered quote.

Common Mistakes That Keep Appearing

Some final warnings from my review pile:

Over-spec'ing power. A 150W system costs more, consumes more power, and generates more heat than a 60W that meets your needs. Buy the 60W.

Ignoring beam profile drift. The M² at 10W is not the M² at 80W. If you're running near max, ask for data at that point.

Treating safety as an afterthought. The enclosure, interlocks, and eyewear are line items — and they're not optional.

Assuming one laser does everything. The fiber laser that engraves stainless tumblers won't cut acrylic well. The CO₂ laser that cuts acrylic won't weld copper. Be honest about your primary use case.

If you run this checklist on any laser purchase, you'll see better results than the most beautiful spec sheet will give you. That's the whole point: specifications are promises. Verification is the delivery.

Final Thought

Yes, I work at Coherent — I'm proud of the systems we build. Our competitors have good machines too, and some of them genuinely beat us on specific applications. The checklist above is what I use when evaluating any system. If you're considering ours, I hope you hold us to the same standard. Ask for the beam profile data, test your parts, run the TCO exercise. We'll still be here when you're done.