Coherent Laser FAQ: Rofin Legacy, Picosecond Systems, Files, and Gas

I'm the procurement person at a 180-person manufacturing and R&D company. I don't design the laser processes; I buy the systems, the service contracts, and the consumables. After four years of doing this, I've learned that a purchasing decision is only as good as the questions asked before the PO goes out. The questions below are the ones I hear most often when engineers and owners mention Coherent lasers, picosecond systems, laser files, and plasma cutting. Here are the short, practical answers.

Is a Coherent laser a single type of laser?

No. Coherent makes a portfolio of lasers, not one machine. You'll find fiber lasers, CO2 lasers, diode lasers, solid-state lasers, and ultrafast lasers in their lineup. That's a big part of why I like buying from them for certain projects: if the process changes, the company can usually propose a different tool without starting over.

But the brand name doesn't tell you which laser you need. From the outside, a laser is just a box with a beam. The reality is that wavelength, power, pulse duration, beam quality, and spot size are more important than the logo on the side. When someone says 'we need a Coherent laser,' I ask what material, what thickness, and what production rate. The answer is rarely 'just any model.'

What is a Coherent Rofin laser? Is it supported?

Rofin was a German industrial laser company that Coherent acquired in 2016. So when you see 'Coherent Rofin,' you're looking at the industrial laser product lines that came from Rofin, especially CO2 and some solid-state systems. The name stuck because the installed base is huge and plenty of used machines are still running.

If you're buying a used Rofin laser, don't assume it has the same support status as a current Coherent model. Get the serial number and check with Coherent before you sign anything. I've made that mistake on other equipment, and 'looks like a bargain' turned into a $5,800 repair. Support, spare parts, and safety retrofits are part of the real cost. According to Coherent's 2016 announcement, the acquisition was officially complete in that year, but support availability still varies by model age and location.

What can a Coherent picosecond laser do that a standard laser can't?

Picosecond means pulse duration around one trillionth of a second. That's not just a speed upgrade; it changes how the material reacts. With a picosecond laser, energy is delivered so fast that the material transitions from solid to vapor before much heat spreads into the surrounding area. That's why these lasers are used for micromachining, stents, semiconductor packaging, and thin-film patterning. A Coherent picosecond laser in this class is a serious production tool.

The honest part: a picosecond laser is not a general-purpose cutting machine. It's a specialist tool with specialist costs. If you're cutting 3-mm steel or engraving wood signs, a standard fiber or CO2 laser will do the job better and cheaper. I've seen quotes for production-ready picosecond systems in the low six figures, and that's before exhaust, coolant, and laser-safety controls. It only makes sense if your product truly needs that tiny heat-affected zone.

What file format should I use for a laser cutter?

For cutting, you need a vector file. That usually means DXF, SVG, AI, or PDF with real geometric paths, not a high-resolution picture. Raster files like JPG, PNG, and TIFF are fine for engraving, but they're not a laser cutter file in the way most shops mean the term.

A common mistake is sending a JPG and assuming the laser will 'trace' the outline automatically. It can, sometimes. But the result depends on contrast, resolution, and the software's trace settings. If you want repeatable parts, define cut lines and engrave fills on separate layers and use consistent line colors. In many laser programs, red is set as 'cut' and black is 'engrave,' but verify that with the shop. I assumed 'laser-ready' meant ready to run; it turned out to be a 72-dpi PNG. That order needed a full rework.

Can a laser cleaner be used on wood?

Yes, but with more caution than most people expect. Laser cleaning can remove paint, varnish, or surface contamination from wood, but wood isn't a uniform material. Resin pockets, grain direction, and moisture content all change how the beam is absorbed. If the settings are wrong, you'll burn or char the surface instead of cleaning it.

For wood, the best results usually come from a pulsed laser with low pulse energy and high scanning speed. But the window between 'coating is gone' and 'wood is scorched' is narrow. If the goal is a bare, natural wood finish, I'd test on scrap and still consider chemical stripping or abrasive methods for large areas. Also, a laser cleaner is not a toy. According to ANSI Z136.1-2022, this is a Class 4 laser operation, requiring controlled access, eye protection, and often an enclosure. Budget for that before you buy the machine.

Do you need gas for a plasma cutter?

Yes. Plasma cutting works by sending an electric arc through a gas, turning it into plasma, and the gas also blows the molten metal out of the cut. No gas means no plasma. You can't skip it or replace it with 'just electricity.'

What gas depends on material and desired edge quality. Shop air is the most common for mild steel. Nitrogen is often used for stainless and aluminum to reduce oxidation. Oxygen gives faster mild steel cuts but creates an oxide layer that may need secondary cleaning. Check your plasma cutter manual before swapping gases. I've seen an operator use nitrogen on carbon steel because 'it was available,' and the cut quality was terrible. The gas is not a generic consumable; it's part of the process.