A working printed prototype creates a powerful illusion of completion. Many hardware teams treat successful SLA or FDM validation as the finish line, then move straight to requesting injection-mold quotes. The reality is more nuanced: additive processes tolerate geometry that steel tools and molten polymer will not.
Printed parts can carry zero draft, abrupt thickness transitions from thin walls into heavy bosses, undercuts that need no side actions, and parting lines placed wherever the designer prefers. Injection molding turns each of those choices into cost, risk, or both. Missing draft leads to scuffing or stuck parts. Thick-to-thin junctions produce sink marks and residual stress. Features that print freely often demand slides, lifters, or complex tooling that inflate both price and lead time.
These mismatches rarely appear during functional testing of a prototype. They surface later—either as red flags in a careful quotation or, worse, as warped, marked, or incomplete first-article parts that force expensive tool modifications and schedule slips.
The stronger approach is to treat the successful print not as a final design but as a functional proof of concept that still requires a deliberate Design for Manufacturability pass. A focused review of draft, wall uniformity, gate feasibility, and ejection strategy before any RFQ is issued converts most of these issues into manageable CAD adjustments rather than late-stage crises.
Early collaboration with someone who understands both additive freedom and production constraints turns a common startup bottleneck into a competitive advantage. If your files are approaching the quote stage, a short confidential discussion can surface the critical points while changes are still inexpensive.