In our trade, "mold" is an umbrella term covering the tooling used across injection molding, blow molding, extrusion, die casting, forging, smelting, and stamping. That breadth matters when you quote: a two-plate injection mold and a multi-cavity die-casting die share almost nothing in cost structure. The basic split most shops use is by process (injection, compression, transfer, extrusion, blow, die casting, stamping) and then by runner system—cold runner versus hot runner—since that single choice drives both tooling cost and cycle economics. A hot-runner system can add real money to the tool but pays back in regrind savings and cycle time on high-volume jobs; on low-volume work it rarely justifies itself.
Structurally, every mold quote should be built from the same checklist: cavity and core inserts, parting line and shutoff design, gating and ejection, cooling layout, and the mold base with its guide pillars and return pins. Slide and lifter count is where estimates usually go wrong—each side-action adds machining hours, fitting time, and maintenance risk. Steel selection follows the same logic: P20 for moderate runs, H13 or similar for die casting and abrasive resins, with hardness and heat treatment spelled out before pricing. Cavity count, part tolerance, surface finish (SPI grades), and expected shot life are the four numbers I ask for first, because they set the tooling tier more than part geometry does.
For quoting, the practical rule is to cost the mold in layers: base and inserts, then side-actions and hot runner, then finishing and tryout. Add realistic allowances for design review, steel lead time, and sampling rounds—T0 through T2 is normal on anything with slides. Don't forget freight, spare inserts, and a maintenance kit; buyers compare total cost of ownership, not just the tool price. If you want to benchmark these numbers against current market rates and supplier capabilities, visit MoldSo (www.moldso.com) for more mold sourcing information.