What You Are Actually Paying For: A Silicone Mold Cost Breakdown

Quotes for the same LSR part routinely vary by 3x on tooling alone. Sometimes that is margin gamesmanship, but usually it reflects real differences in what is inside the mold. Here is what drives the price, roughly in order of impact.

Steel and cavity count

P20 pre-hardened steel suits compression molds and short runs. For LSR injection, 420SS or S136 stainless with polish-to-A1 surface is standard — corrosion resistance matters because LSR catalysts attack tool steel over time. Each additional cavity adds part-specific cost, but halves unit price. The right question is not "how much per cavity" but "what volume justifies 2 vs 4 cavities".

Cold runner vs hot runner

A cold-runner block (the standard for LSR) keeps material cured only in the mold, eliminating the cured sprue waste of compression transfer. It adds USD 2–6k to tooling but pays back through zero regrind labor and consistent cavity filling. Molds without cold runners should be quoted with waste-percentage visible in the unit price.

The hidden cost of cheap tooling

A bargain mold that flash-es after 50k cycles costs more than the premium mold that runs 500k. Ask two questions before comparing quotes: what is the guaranteed tool life in shots, and who pays for mold maintenance? We warranty LSR molds at 500,000 shots with maintenance included — if a supplier will not commit to a number, that is the number they expect to fail at.