Low volume injection molding cost: what 500 to 10,000 parts actually runs

Those bands assume a US or vetted Asian tool shop, ABS or polypropylene, and a design that has already passed a manufacturability review. A part that has not been reviewed usually comes back with a quote 20 to 40 percent higher, because the shop is pricing the risk of side actions and thick sections you did not intend to have.

The honest break-even for a typical handheld part is somewhere between 400 and 800 units. Below that, printing keeps you flexible. Above it, you are paying a large premium per part for the privilege of not committing to a design.

Undercuts that force side actions or lifters, each adding $800 to $2,500. Wall thickness that varies across the part, which causes sink and needs correction. Cosmetic finishes: a polished or textured A-surface costs more than a machined finish. Tight tolerances applied everywhere instead of only where they matter. Late changes. Cutting steel or aluminum away is cheap; adding it back is a weld and a re-cut.

Run a manufacturability review before you request tooling quotes. Design the parting line yourself instead of letting the tool shop choose it. Use a family tool for two or three small parts that share a material and color. Choose a resin your molder already runs; exotic materials add setup and scrap. Order a single-cavity tool first, then add cavities when demand is proven.

We design the part, run the manufacturability review, source and manage the tool, and sign off on first article samples. If you already have a design and want a second set of eyes before you commit to tooling, our rapid prototyping and DFM review work is usually the cheapest money on the program. See how it plays out on a real product in the QMS2GO voice recorder case study .