I'm the office administrator for a 42-person manufacturing company. I manage all our printing and tooling purchase orders—roughly $120K a year across 12 vendors. I report to both operations and finance. When I took over purchasing in 2020, I approved a quote because the price was 30% below our usual supplier. They couldn't invoice properly, finance rejected the expense, and I ate $2,400 out of the department budget. So I've learned to compare total cost, not just purchase price.
This comparison is about two Markforged routes I keep being asked to price: the Markforged Onyx One 3D printer and a Markforged metal 3D printer. I'll also include the CNC mill, a .250 reamer, and an automatic tube-cutting laser because the real question isn't which printer has better specs. It's which process gives you the part at a defensible total cost.
The Old Assumption to Unlearn
The '3D printing is only for prototypes' line was true 10 years ago, back when desktop printers were unreliable plastic extruders. That's changed. But the opposite assumption—that 3D printing has replaced machining—is also wrong. The truth is in between, and it depends on the part.
Dimension 1: Total Cost of Getting a Usable Part
In my first year of purchasing, I made the classic specification error: I read a Markforged metal 3D printer review, saw the machine price, and ignored the post-processing line. Cost me a long conversation with my VP. That was the learning moment.
The Markforged Onyx One 3D printer is the simplest economic story. Machine cost is a fraction of a metal system, material is a spool of Onyx, and the workflow ends when the print finishes. No furnace, no solvents, no extra operator. You might add light hand sanding, but you don't need new facility equipment.
A Markforged metal 3D printer is a different budget animal. The reviews that talk about beautiful metal parts usually mention the full chain: print, support removal, wash, debind, sinter. That means more capital, more floor space, and more training. I've seen metal systems priced reasonably, but the total installation cost is what finance asks about.
Now the CNC mill. If you already have one, a simple part is just stock plus a cutting tool. A .250 reamer is a small purchase line item compared to a machine. If you don't have a mill, you're paying a job shop's minimum, which is often $150 to $250. (The shop that quoted me a simple part had a $200 minimum—not that it wasn't fair, it just wasn't cheap.)
Verdict: For low-volume polymer parts, the Onyx One wins on setup cost. For simple metal parts, an existing CNC mill is still cheaper per unit. Metal 3D printing is only cost-competitive when complexity eliminates multiple machining steps.
Dimension 2: Material Reality
According to Markforged's current product documentation (accessed April 2025), the Onyx One prints in Onyx—a nylon matrix filled with chopped carbon fiber. That means it can handle jigs, fixtures, drill guides, and prototype brackets. It cannot handle everything. If a part needs high-torque threads or constant heat exposure, you may need a metal part.
A Markforged metal 3D printer can produce stainless steel and tool steel. That's real metal. Per FTC advertising guidelines, claims about what a printer can do have to be substantiated; but even a substantiated claim doesn't mean the part skips a reaming operation. What Markforged metal 3D printer reviews often skip is that printed metal still needs secondary machining for tight tolerance features. A .250 reamer on a CNC mill gives you a hole that's exactly round and exactly sized. On a printed part, you may need to ream it after printing to hit the same spec. The printer doesn't replace the reamer; it replaces the rough shape.
For tubes, the comparison goes sideways. If your part is a hollow round tube with cut profiles, an automatic tube-cutting laser is usually the right tool. That machine can't make you a solid bracket, but it can cut a tube bundle faster and cleaner than any 3D printer. (Surprise, surprise: the tool that matches the geometry wins.)
Verdict: Onyx One for rigid polymer parts. Metal 3D printing for complex metal parts that can tolerate a secondary operation. CNC mill with a .250 reamer for tight tolerance holes. Automatic tube-cutting laser for hollow profiles.
Dimension 3: Workflow and Skill Required
This is where my office manager bias comes in. The Onyx One is genuinely shop-floor friendly. We placed ours near the maintenance desk. It's quiet enough that nobody complains, an operator removes a part and starts another, and there's no special ventilation or furnace schedule. It can be one person's part, but it doesn't need one full-time person.
A metal 3D printer is not that. The wash/debind/sinter chain creates a mini production line. You need safety data sheets, chemical storage, a sinter furnace, and someone who owns the process. That's not a desk job. I've had engineers forward me Markforged metal 3D printer reviews and imagine a printer spitting out metal overnight. In reality, the overnight print is followed by a multi-day post-processing sequence.
CNC mills are harder still. Knowing what is a CNC mill used for is easy: it removes material from a block using rotating cutting tools. Running it well is not easy. You need toolpaths, speeds, feeds, fixturing, and a machinist who understands that a .250 reamer is not a drill bit. Without that person, a CNC mill is just expensive iron.
Verdict: Onyx One has the lowest skill floor. CNC milling has the highest. Metal 3D printing is in between, but closer to the mill than to an office printer.
Dimension 4: Lead Time and the Speed Myth
Industry is evolving. What was best practice in 2020 may not apply in 2025. But one myth keeps coming back: 3D printing is automatically faster than machining. In my purchasing experience, it depends.
If you need a single fixture clamp tonight, an Onyx One can do that. If you need a custom .250 reamer, even a fast vendor needs a week to grind, coat, and ship. Printing Onyx doesn't solve that because a reamer is a cutting tool, not a printed part.
For metal 3D printing, the speed story is even more complicated. The print might take 20 hours, but the sinter furnace schedule can add two days. A CNC mill can produce the same simple plate in 40 minutes if it's free. But if the design has internal channels or a geometry that needs multiple setups, metal 3D printing can compress a four-week machining schedule into a week.
Verdict: Onyx One is fast for polymer parts. CNC is faster for simple metal parts. Metal 3D printing is fastest when complexity or assembly count is high.
What Should You Buy?
I can't make the decision for you, but here's the checklist I use.
- Buy a Markforged Onyx One 3D printer if you need low-volume jigs, fixtures, prototypes, or replacement polymer parts. It's the lowest-risk Markforged entry point because it's just printer plus material plus software.
- Buy a Markforged metal 3D printer if you have someone who owns the entire process and you've validated a real part list. Don't buy it because the reviews look good; buy it because the ROI per printed part is clear.
- Keep your CNC mill for tight tolerance holes and flat surfaces. A .250 reamer will still beat a printer on tolerance when the setup is right. If someone asks what is a CNC mill used for, tell them: production metal parts that need predictable dimensions.
- Consider an automatic tube-cutting laser if you process a steady volume of round or square tube. In the right workflow, a tubes automatic cutting laser setup is faster than printing and mating tubes by hand. Just don't expect it to make solid brackets.
Final Thoughts
The fundamentals haven't changed. A part has to do its job. A purchase order has to be justified. An invoice has to be clean. But the execution has transformed. By 2025, I can buy a Markforged Onyx One for printed fixtures, a .250 reamer for finishing holes, and a laser-cut tube bundle from a vendor—all without explaining every line item to finance.
Well, maybe with a little explaining. But if you compare the whole workflow, the case gets easier.