Functional Prototypes

Real materials.
Real testing.
Real validation.

Production-material prototypes that pass drop tests, survive thermal cycling, and reveal real engineering issues. Not display-only PLA prints — functional ABS injection, aluminum CNC, nylon SLS/MJF. 3–10 day lead times.

Prototype Quote All rapid prototyping

01 · Use cases

When functional prototypes matter.

Not every prototype needs real production materials. These scenarios, however, demand functional parts — and failing to make them functional means catching problems later in the program, when changes are expensive.

Drop & impact testing

Real material behavior under impact. MJF nylon, aluminum CNC, ABS injection — not SLA resin

Thermal cycling

Test assembly through -40 to +85 °C. Material CTE matches production — real fits, real clearances

Drop ship to pilot users

First 50–500 beta users receive parts indistinguishable from production. User feedback before commitment

Regulatory submission

FDA, UL, CE, FCC submission prototypes must represent production design. Material certificates provided

Assembly testing

Real screws into real aluminum threads. Real snap-fit tolerances. Assembly process validation

Vibration & fatigue

Production-material fatigue behavior — SLA prints fail immediately, real parts reveal actual service life

Dimensional validation

Real production tolerance stack-up. GD&T validation against drawing. First-article inspection capability

Crowdfunding fulfillment

Kickstarter backers receive beta units in real materials while production tooling builds

Trade show demos

Investor and conference demos that feel like production — durability through rough handling

02 · Process selection

Matching process to material need.

CNC machining

Metals + engineering plastics

Default for metal prototypes (aluminum, steel, titanium). Also PEEK, Ultem, Delrin, PTFE where those exact materials matter.

MJF 3D printing (HP)

Nylon PA12 · production-grade

Best general-purpose functional plastic prototype process. Nylon PA12 parts behave like injection-molded nylon. Passes drop tests.

SLS 3D printing

Nylon PA12 · PA12-GF

Similar mechanical behavior to MJF. Available in glass-filled variant for structural applications. Slightly rougher surface than MJF.

Rapid injection molding

ABS, PC, PP, Nylon · true production material

Aluminum tool + real injection material for quantities 500+ when true injection behavior matters. 14–21 day lead time.

Vacuum casting

PU mimics of ABS/PC/PP

For 20–50 parts when injection tooling overhead isn't justified. PU mimics production plastic behavior adequately.

Sheet metal prototyping

Aluminum, steel enclosures

Laser cut + bent real sheet metal for enclosure prototypes. EMI shielding, mechanical, thermal all representative.

FAQ

Functional prototype questions.

Functional prototypes are built in real production materials so they behave like production parts — ABS injection plastic, aluminum CNC, steel machined. Display prototypes are usually 3D-printed PLA or PU cast — they look like the final product but don't have production material properties. Functional prototypes pass drop testing, survive thermal cycling, pass regulatory submission, and reveal real engineering issues.

CNC for metal parts, always — there's no 3D printing equivalent for real aluminum or steel mechanical behavior in most cases. CNC for plastic parts when you need specific material properties (PEEK, Ultem, PTFE). 3D printing (SLS or MJF nylon) is excellent for plastic functional prototypes — nylon PA12 parts behave very similarly to injection-molded nylon. MJF HP prints are production-grade for many nylon applications.

SLS and MJF nylon parts pass most drop tests comparable to injection-molded nylon — we've seen MJF PA12 parts survive 1.5m drops intact. SLA resin prints fail drop testing (brittle). FDM ABS prints fail at layer lines. For drop testing, specify SLS or MJF; avoid SLA and FDM.

If the part mates with production parts (screws, bearings, interface features), the mating tolerances matter. Default to ±0.1 mm on mating features, ±0.2–0.5 mm on cosmetic features. For precision mechanical (cam followers, bearing fits), ±0.025 mm on critical. For electrical enclosure parts, ±0.3 mm is usually adequate.

Depends on the regulatory agency and the device class. For FDA 510(k) submission, functional prototypes must be built using the same materials and processes as production (though possibly in lower quantity). UL testing can be performed on functional prototypes if they represent the production design. We provide material certificates and documentation for regulatory submission.

Engineering review: 3–10 parts. Internal testing (drop, thermal, vibration): 5–20 parts (multiple failure modes). Beta user testing: 50–200 parts. Regulatory submission: 10–50 parts typical. We scale the process to quantity — CNC for small batches, 3D printing for medium, rapid injection molding for 500+.

Real materials.Real testing.Real validation.