Every week, someone lands in my inbox with a version of the same question: "Which Markforged printer do I actually need?" Sometimes it's "FX10 or X7?" Sometimes it's "Onyx or Metal X?" And once—no joke—someone asked me what is the difference between Fraxel and CO2 laser. Honestly, I'm not sure why that query found me. My best guess is the word "laser" plus the word "difference" got us connected. Wrong person for that; I'm not a dermatologist. But I get the spirit: two similar-sounding options, one decision, and nobody explaining the real difference.
I'm an applications engineer who's handled Markforged orders for four years. I've personally made—and documented—seven significant mistakes, totaling roughly $38,000 in wasted budget. Now I maintain our team's purchase checklist so nobody repeats them.
This is the comparison I wish someone had handed me before the first dollar went out. Two lines: the carbon fiber/composite series (Onyx Pro, FX10, X7) and the metal series (Metal X). Three dimensions that matter: material reality, aerospace readiness, and true cost—including the stand you'll forget to budget for.
Dimension 1: Carbon Fiber Is Not "Basically Metal"
My first mistake cost $14,000. I assumed the Onyx Pro, with its continuous carbon fiber reinforcement, could approximate metal parts. It can't. Not even close.
The composite line does one thing extremely well. It prints chopped carbon fiber filament (Onyx) and reinforces it with continuous carbon fiber strands laid down inside the part. The strength-to-weight ratio is genuinely impressive. We use it every day for jigs, fixtures, and brackets for a defense client. But "impressive for a polymer" is not "basically metal." I learned this when a conformal cooling fixture delaminated on day three. The part had to survive continuous contact with a hot mold. The polymer didn't hold up. The metal line would have. Simple.
The Metal X line is a completely different process. It prints bound metal rods, then you debind and sinter them in a furnace. The output is real 17-4 PH stainless steel, copper, or H13 tool steel. After sintering, parts are solid metal—density typically lands around 96-99%. It's not machined from billet, and the surface finish won't win awards, but it's metal. It handles heat, wear, and load in ways composite cannot.
Comparison conclusion: these two lines are not competitors. The composite series exists to replace aluminum tooling and machined plastic prototypes. The metal series exists to replace outsourced metal part lead times. If your part faces heat or sharp contact, composite will let you down. Metal won't.
Dimension 2: "Aerospace-Grade" Is a Material Claim, Not a Part Approval
The search term "markforged aerospace 3d printer" gets a lot of traffic, for good reason. The composite line offers Onyx FR-A, a flame-retardant material designed for aerospace applications. That material designation matters.
But here's the trap: the material being aerospace-grade does not make your part aerospace-certified. Per FTC guidelines (ftc.gov), claims must be truthful and substantiated—and that cuts both ways. If a vendor tells you a printer is "aerospace-ready," ask what exactly that means. In my experience, it usually means the material meets a flammability standard. It does not mean every part coming off the build plate is ready to fly.
I made this exact mistake in September 2023. We printed a cabin mounting bracket with Onyx FR-A, submitted it, and got rejected two weeks later. The print was dimensionally perfect. The paperwork wasn't. The customer required material batch traceability, process logs, and a signed inspection report. I hadn't set up any of that. That rejection cost us $890 in scrap plus a three-week project delay.
Does the metal line avoid this? No. If anything, it's worse. Metal parts need sintering profile documentation, porosity checks, and more rigorous traceability. What the metal line gives you is parts that can't be made in composite—metal brackets, clips, and tooling that survive real operational loads.
The conclusion here surprised me: for early-stage aerospace adoption, the composite line is the faster path. Qualification is more straightforward, and documentation expectations are more established. The metal line is a bigger commitment with more validation infrastructure—but it unlocks parts you simply cannot print in composite.
Dimension 3: The True Cost (And the Stand Story)
Here's where I get on my soapbox. When I evaluate any vendor quote now, my first question is "what's NOT included?" I've learned this the expensive way.
Printer price, materials, software subscription, training, freight, enclosure, and the scrap you'll generate while learning—that last one isn't in any quote, but it's real. The vendor who lists all fees upfront, even if the total looks higher than a competitor's base price, almost always costs less in the end.
Now, the stand. If you're searching for a 3d printer stand for 2 printers, listen. When we added a second composite printer, I bought a cheap shelving unit from a big-box store. Look, I know. It seemed fine. Two printers on two shelves—what could go wrong? The answer, as it turns out, is kinda everything.
What went wrong: the whole unit wobbled. One printer walked halfway off the shelf during a high-vibration infill pattern. I caught it by pure reflex. No equipment was damaged, but my credibility with the team took a hit. That's when we ordered a VMC Tall Boy. It's a metal frame built to hold two printers, with room for filament boxes and a footprint that doesn't play games. It cost more than the shelf. It was worth every dollar. If you're putting two printers together, buy a stand designed for two printers. Don't improvise.
On shipping, understand what things actually cost to move. Mailing a small printed sample to a customer runs $0.73 via USPS First-Class letter rate as of January 2025—verify current pricing at usps.com. Freighting an entire Markforged system plus a Tall Boy is a different universe: liftgate fees, dock scheduling, crating. If a quote doesn't explicitly list freight, ask before you sign.
And here's a moment of honesty: I almost made a six-figure decision on a hunch. Our defense client asked if we could do metal parts in-house. I had two hours to decide whether to commit budget to a Metal X system before the fiscal deadline closed. Normally I'd run a full ROI projection. There was no time. I went with the Metal X based on trust alone. In hindsight, I should have pushed back on the timeline. The machine has paid for itself—but only because our metal part demand turned out to be real. If it hadn't, that would have been a $100,000 mistake.
Which Should You Buy? The Checklist I Now Use
Here's the thing: there is no universal answer, and anyone who gives you one is selling something. It depends on what you're making.
Choose the composite line (Onyx Pro, FX10, X7) if:
- You're making jigs, fixtures, tooling, or rapid prototypes.
- Your parts need high strength-to-weight ratio without metal's thermal demands.
- You want to qualify for aerospace work without building a metallurgy lab.
Choose the metal line (Metal X) if:
- You need real metal end-use parts in-house.
- Outsourced metal part lead times are killing your projects.
- You have floor space for the debinding station and sintering furnace.
And real talk: if your volume is low, skip the printer entirely. A service bureau will be cheaper until your monthly parts count reaches the break-even point. I do not recommend owning either system for less than a handful of parts per month—we've seen clients do that, and the machine becomes an expensive dust collector.
Before you order anything, run this checklist. It's the same one I use now, and in the past 18 months it's caught 47 potential errors before purchase.
- Ask "what's not included?" and get freight, installation, and training in writing.
- Verify the material designation matches your customer's requirements, not just the marketing sheet.
- Plan floor space for the printer AND the stand. Running two printers? Buy a stand built for two—the VMC Tall Boy exists for a reason.
- Budget for scrap. You will waste material. It's tuition.
- Check current pricing on official sources before presenting numbers to anyone.
And if you came here looking for what is the difference between Fraxel and CO2 laser: wrong person, right instinct. Ask a dermatologist. But the general point holds—the difference between two similar-sounding options only matters once you know what you're actually trying to fix. That part, at least, is exactly like 3D printers.