A Fabrication Engineer’s Checklist: Choosing Between a Markforged 3D Printer, CNC Machining, and Laser Cutting

I've been handling manufacturing orders for over seven years. In that time, I've personally made—and documented—17 significant mistakes, totaling roughly $28,000 in wasted budget on my watch. This checklist is the result. It's the pre-flight checklist I wish someone had given me in 2017. If you're deciding between a Markforged 3D printer, precision CNC machining, or laser cutting for your next batch of parts, this is for you.

Here's the thing: the industry has changed a lot since 2020. What was best practice then may not apply in 2025. But the fundamentals haven't changed—you still need to define your requirements, evaluate cost honestly, and verify quality before you scale.

Step 1: Write Down the Actual Part Requirements

Start with the non-negotiables:

• Mechanical load: Will the part bear weight? What stress?
• Operating temperature: Most plastics fail above 150°C.
• Tolerances: Are you at ±0.1mm or ±0.01mm?
• Production volume: 5 parts, 50, or 5,000?

Common mistake: Skipping this step. In 2021, I ordered 40 Markforged Onyx One parts for a fixture only to realize the operating temperature exceeded Onyx's rating. That was $1,300 down the drain (I checked the spec sheet afterward—the thermal limit was right there).

Step 2: Evaluate 3D Printing (Markforged Onyx One 3D Printer as Baseline)

The Markforged Onyx One 3D printer is a solid entry point for carbon-fiber-infused nylon parts. It's not a toy; it's an industrial tool. But before you commit:

• Check the design for support structures. Every overhang above 40° needs support. We once printed a complex duct with internal channels—had to cut it open to remove support that fused to the walls. Use the Markforged support settings wisely (note to self: always set support resolution before slicing, not after).
• Verify print orientation. This affects strength about 60% more than infill percentage. Actual number varies, but layer adhesion is the weak link.
• Reach out to Markforged support before your first production run. I didn't, and we wasted a week on a bed-leveling issue that a 10-minute call would've solved. Their support team is actually knowledgeable (I really should've asked earlier).

Step 3: Don't Ignore Precision CNC Machining

3D printing isn't always the right answer. For parts requiring tight tolerances or high thermal resistance, precision CNC machining near Bloomington (or wherever you are) might be the better route. I learned this the hard way: in September 2022, I approved a 3D-printed batch of 50 parts for an assembly jig. The first part failed on installation because the hole tolerance was +0.1 / +0.2mm—way too loose for the pin. The redo through a local CNC shop cost $890 plus a 1-week delay.

Checklist for CNC evaluation:

• What materials are actually in stock? One shop quoted a part in aluminum 6061, but only had 7075; the change affected the part's electrical grounding (odd, but true).
• Get the DXF or STEP file checked before quoting. A missing view in the drawing cost us $450 extra for a re-cut.
• Ask about inspection reports. Some shops offer full CMM reports; others only give you a pencil mark. For critical parts, that's not enough.

Step 4: For 2D Profiles, Consider Laser Cutting

If your design is flat or can be flattened, laser cutting is often faster and cheaper than both 3D printing and milling. For thicker materials, a 3kW fiber laser cutting system with the right settings is a beast. Download the 3kW fiber laser cutting parameters PDF from your tool supplier—don't guess the speed/power. I once ran a 6mm steel sheet with power too high and speed too low; the kerf was 0.5mm wider than spec, scrapping 12 parts.

And before you ask about maintenance—how often to get CO2 laser optics cleaned? For our shop, every 200 working hours or when the cut quality starts deteriorating. The manual says 100 hours, but we found 200 is enough for a clean environment. Your mileage may vary (if your shop is dusty, more frequent is safer).

Step 5: Compare Total Cost—Not Just Unit Price

Here's where the industry has shifted. Five years ago, 3D printing was a premium option. Now, for a Markforged Onyx One part that runs in the background overnight with no operator, the marginal cost is just the material. But don't forget:

• Post-processing time: removing supports, sanding, tapping holes.
• Rejects and redo. Our data over the past 18 months: 3D printed batches had a ~7% reject rate (mostly surfacing and dimensional drifting), CNC batches ~1% if the setup is solid, laser cutting ~2% with minor burrs.
• Machine downtime. A CNC mill that's cutting test coupons isn't making paying work. 3D printers are easier to schedule: you can queue jobs and run unattended.

Unexpected discovery: the "expensive" Markforged material actually saved us money compared to outsourcing CNC for short runs because of zero setup time and no shipping. (Should mention: we're a mid-size B2B with predictable order patterns, so your numbers might differ.)

Step 6: Verify Quality Before Mass Processing

This is the step everyone skips— the "it'll probably be fine" step. Before committing to 100 units, do a first-article inspection. Catch the errors early. I've caught 47 potential errors using this checklist in the past 18 months.

When you review printed parts, laser-cut parts, or machined parts:

• Measure critical features with a caliper or CMM. Don't trust the file, trust the part.
• Check surface finish: Delamination or stringing in 3D prints; burrs on laser edges; tool marks on machined surfaces.
• Validate material properties. Some vendors claim "industrial-grade" but their resin or filament is weak. Per FTC guidelines (ftc.gov), claims must be substantiated. Ask for a material data sheet, not just a marketing page.

Common Mistakes I've Made So You Don't Have To

Overpaying for 3D-printed parts that should've been laser-cut

Flat brackets? Don't print them. A 3mm thick bracket is 20 minutes on a laser cutter vs 3 hours on a printer plus support removal.

Calling the vendor for a rush order when you haven't checked the drawing

We paid a $150 rush fee for a CNC order, then discovered a dimension typo in the drawing, then paid again for the re-run. Lesson: check the drawing twice, then check it again.

Forgetting to factor in support structures

In my first year (2017), I designed a beautiful Onyx bracket with internal screw bosses. The slicer added support material that was nearly impossible to remove, turning a 20-minute part into a 2-hour cleanup. Use a soluble support material if possible, or redesign to reduce overhangs.

Honestly? I Don't Have All the Answers

I've never fully understood why some shops deliver CNC parts in 3 days while others take 3 weeks for the same file. My best guess is it comes down to internal buffer management. If you have insight, I'd love to hear it. Meanwhile, use this checklist, adapt it, and add your own lessons. The industry is evolving—what was best practice in 2020 may not apply in 2025—but a disciplined approach will never go out of style.