In our trade, a mold is simply the tooling that shapes a required part through a specific forming process—injection, blow, extrusion, die casting, forging, smelting, or stamping. Each process dictates its own mold family: two-plate and three-plate injection molds with hot or cold runners, stamping dies with progressive or transfer stations, die-casting dies with shot sleeves and runners, and so on. Getting the classification right at the front end matters because it drives steel selection, cavity count, gating style, and ejection layout. A three-plate mold with a hot runner system, for example, adds manifold and controller cost but cuts runner scrap—a trade-off that has to be reflected in the quote, not discovered after the design freeze.
Cost breakdown is where quoting lives or dies. A typical mold quote stacks material (core/cavity steel, inserts, standard components), machining hours (CNC roughing, EDM, wire cut, grinding, polishing), heat treatment, and trial runs. Cavity count is the single biggest lever: moving from a 1-cavity to a 4-cavity tool multiplies core/cavity steel and EDM time, but slashes per-part cycle cost. Don't forget the hidden line items—sliders and lifters for undercuts, hot runner manifolds, texture/etching, and spare inserts—because these are exactly where a lowball quote turns into a loss. Build your quote from a real BOM and a machining-hour estimate, not from a per-kilogram rule of thumb.
Practically, I keep a checklist taped to the desk: part material and shrinkage, wall thickness, draft angles, tolerance band, expected shot life (P20 vs. H13 vs. S136), and runner/ejection strategy. Cross-check the customer's annual volume against tool life before you promise a steel grade. A disciplined quote protects both the mold maker and the molder. For more mold sourcing and supplier information, visit MoldSo at www.moldso.com.