Why Your Small-Volume Polymer Parts Should Be 3D Printed

David Davie
2 hours ago
3 min read

CNC machining has been the go-to for low-volume polymer parts for years. It’s precise,

familiar, and—until now—hard to beat under 500 units. But the economics have shifted. Modern polymer 3D printing now delivers functional, production-grade parts faster, cheaper, and with design freedom that mills and lathes can’t touch.

If you’re still machining Delrin brackets, ABS housings, or nylon fixtures in runs of 1–500, you’re overpaying in time and money. Here’s why the switch to polymer 3D printing is a no-brainer today.

1. Lead Time: Days Instead of Weeks

A typical CNC quote for 50 nylon end caps:

CAM programming: 4–6 hours
Fixture design & build: 1–2 days
Shop queue: 5–10 business days
Shipping: 2–3 days

Total: 2–3 weeks

The same part on a Bambu Lab X1E (high-temp FDM) or Formlabs Form 4 (fast resin):

Upload file → auto-orient → hit print
Print time: 8–20 hours (X1E) or 2–6 hours (Form 4)
Support removal / wash & cure: 15–90 minutes
Shipping: 1–2 days

Total: 1–3 days

That’s an 85–95 % reduction in lead time. For prototypes, spare parts, or bridge runs, this speed changes everything.

2. Up-Front Costs Vanish

Cost Element (50-piece run)	CNC Nylon 6/6	3D-Printed Nylon 12-CF	3D-Printed ASA
Tooling / Fixturing	$500–$1,200	$0	$0
Programming	$250–$500	$0	$0
Material waste	35–50 %	<3 %	<2 %
Per-part cost	$22–$38	$11–$17	$7–$13
Total landed cost	$1,600–$3,100	$550–$850	$350–$650

Mid-2025 pricing; actual costs depend on geometry.

No fixtures. No minimums. Need 3 parts instead of 50? The price barely budges.

3. Complexity Is Free

CNC struggles with:

Thin walls (<0.8 mm)
Internal channels
Snap-fits and living hinges
Undercuts and overhangs

Every complex feature adds setups, custom tooling, or assembly steps.

3D printing doesn’t care. Real parts we’ve converted:

Cover with part number, logo & hinge → one print, no additional machining
Sensor mount with conformal airflow channels → no drilling, 18 % lighter
Robotic gripper finger with lattice core → 38% mass reduction, same strength

These designs are either impossible or wildly expensive on a CNC. On a printer, they’re standard.

4. Polymer Performance Is Production-Ready

Today’s engineering filaments and resins outperform machined stock in durability, temperature resistance, and environmental stability:

Material	Key Properties	Typical CNC Equivalent
ASA	UV-stable, impact-resistant, HDT 98 °C, excellent layer adhesion	Machined ABS or ASA
Nylon 12-CF	Low moisture absorption (0.7 %), 140 MPa tensile, chemical resistant	Glass-filled nylon
PPS-CF	240 °C continuous use, flame-retardant (UL94 V-0), low outgassing	Machined PPS or PEEK
Loctite 3843 Resin	High stiffness (2.1 GPa), HDT 63 °C, excellent surface finish, fast print	Machined ABS or PC

Tolerances: ±0.005 in (0.13 mm) standard; ±0.003 in with process control. Surface finish: FDM as-printed Ra 50–100 µin; resin parts <20 µin out of the vat.

These materials now replace 90 %+ of machined polymer applications in small volumes—with zero scrap and full design freedom.

5. Iteration Costs Drop to Pennies

Change a fillet radius?

CNC: Re-program, new fixture, scrap old parts → $300–$800
3D Print: Edit CAD, re-slice, print one new part → $12

One medical device customer cut design cycles from 5 weeks to 3 days. Same part. Same function. Zero delays.

When CNC Still Makes Sense

Quantities >1,000 → injection molding or high-speed machining wins
Optical clarity (e.g., polycarbonate lenses)
Ultra-fine finish (Ra <8 µin) without post-processing

For everything else? Print it.

Start Simple

Find one low-volume polymer part (<6 in / 150 mm, <100 cm³).
Export the STEP file.
Send it to us – we’ll quote 3D print in 24 hours.

In 8 out of 10 cases, the printed part ships before the CNC shop even loads the bar stock.

Start printing performance.

Email your file to quote@massadditive.com or give us a call. We’ll show you the savings in black and white.

Mass Additive – Small runs. Big results.