How much does a die casting mold cost?

What makes one die casting die cost more than another?

Die size, the number of cavities, the number of slides and cores, and the precision and finish the drawing demands drive most of the difference. The grade and treatment of the die steel, and whether a separate trim die is included, account for much of the rest.

Size comes first. A larger part needs a larger block of tool steel, a larger die base and more machining and polishing hours, and it has to run on a larger machine, so everything scales together. Cavity count comes next: a two- or four-cavity die costs more to build than a single-cavity die for the same part, but it makes more parts per shot, so the choice is a trade between up-front cost and piece price.

Slides and cores are the hidden multiplier. Any feature that is not in line with the direction the die opens, such as a side hole, an undercut or a boss on a side wall, needs a moving slide or a core pulled by its own mechanism. Each one adds design, machining, fitting and maintenance. Redesigning one side feature so it can be formed in the line of draw, or machined after casting, is often the single largest saving available on a die.

Precision adds cost in less obvious ways. NADCA notes that measurements taken across the parting line are affected by flash, so critical dimensions should sit in one die half (NADCA, parting line). A drawing that puts tight tolerances across the parting line, or asks for precision tolerances on every feature instead of standard ones, forces extra die work or extra machining. The NADCA tolerance guide explains the difference between the standard and precision classes.

Finally, the steel. Die casting dies are made from premium hot-work tool steel, most often H13, because ordinary steel will not survive repeated contact with molten metal. NADCA publishes its own Recommended Procedures for Die Steel, covering steel quality and heat treatment for these dies. A quote that names the steel grade, the quality level and the heat treatment is easier to compare than one that just says “H13”.

How does the die cost turn into a cost per part?

Divide the die cost by the number of good parts it will make over its life, or over your program volume if that is shorter. That amortized figure is what the die adds to each part, and it is why a costly die can still be the cheaper route at volume.

A simple illustration, using round numbers rather than any quote: a die costing $20,000 that makes 100,000 good parts adds $0.20 to each part. If the program needs 300,000 parts and the die wears out before that, a replacement die or a major rework has to be added, and the per-part figure should include it. NADCA lists tooling, including replacement dies as the originals wear, as one of the three parts of die casting processing cost, with the casting operation itself and secondary work such as trimming (NADCA, manufacturing economics).

Two consequences follow for buyers. First, compare dies on amortized cost at your real volume, not on sticker price: a cheaper die with a shorter expected life, or one that needs frequent repair, can cost more per part. Second, ask each supplier what die life they are assuming and what happens when it is reached. If one quote assumes the die lasts the whole program and another assumes a replacement halfway, the two prices are not describing the same thing.

Who owns a die casting die, and does it count toward US customs value?

Ownership is whatever your contract says, so write it down before the die is built. For US imports, tools, dies and molds that the buyer supplies free or at reduced cost are “assists” whose value is added to the customs value of the parts (19 CFR 152.102).

On ownership, general contracting practice is to state in the purchase order or a separate tooling agreement who holds title, who insures the die, who maintains it, how long it will be kept after the last order, and on what terms it can be released or shipped to another source. Ask for the die to be marked or recorded as your property if you are paying for it. None of this is exotic, but without such a clause a buyer can find it hard to move a program without paying for a second die. This page gives general guidance only; have your own counsel review tooling terms.

On customs, the regulation is specific. Under 19 CFR 152.102, “tools, dies, molds, and similar items used in the production of the imported merchandise” count as assists when the buyer supplies them free of charge or at reduced cost, and 19 CFR 152.103 requires the value of an assist to be added to the price, apportioned in a reasonable way (19 CFR 152.103). The same section allows the value to be spread over the first shipment, over the units made up to the first shipment, or over the entire anticipated production, depending on the documentation the importer provides. How a separately invoiced tooling charge should be declared depends on the transaction, so settle it with your customs broker before the first entry.