Metal Forming& Mold Fees

Every custom metal piece starts as either a flat sheet that gets deformed, or a cavity that gets filled. Stamping pushes a blank between a punch and a die; the metal flows into the shape and keeps its thickness. Die-casting injects molten zinc alloy into a closed steel mold; the part takes the shape of the cavity and is ejected when it solidifies.

The choice is usually made by the drawing, not by the price. A design that is essentially a plate with relief — a pin, a badge, a tag — belongs to stamping. A design that is a small sculpture with depth, hollows and curved sides belongs to casting. Trying to force one into the other process is where most avoidable tooling cost comes from.

The consequence for tooling is immediate. A stamping die is a punch-and-die pair that has to survive impact thousands of times without its edge rolling over. A casting mold is a cavity that has to survive heat, pressure and abrasive alloy without its surface eroding. Two different tools, two different failure modes, two different maintenance routines.

Buyers picture a die as one solid block. It is an assembly. A stamping die is a stack of plates: the upper shoe carries the punch, the stripper holds the sheet flat while the punch enters, the die block contains the cavity, and the lower shoe sits on the press bed. Guide pillars keep the two halves aligned to a few hundredths of a millimetre, stroke after stroke.

This is why a small change to the drawing can cost real money. Moving a line by 0.2 mm is a file edit; moving it in hardened steel means re-cutting the cavity, re-making the electrode, and re-fitting the shut-off. The fee follows the steel, not the drawing.

The fee is an engineering job, not a material purchase. Steel is a minority of it. Most of the money is machine hours and skilled handwork, which is why a tool cannot be discounted the way a production run can — there is no material substitution that makes it cheaper without changing what you get.

• Design & CAM programming10–15%

  Turning the artwork into toolpaths, electrode drawings, and a machining plan.

• CNC machining30–40%

  Roughing and finishing the cavity. This is the largest single line in most tooling quotes.

• Electrodes & EDM15–25%

  Burning the detail a cutter cannot reach. Electrodes are consumed, so they are quoted as material.

• Steel & heat treatment10–20%

  The block itself, plus hardening and tempering. Smaller than most buyers expect.

• Fitting & trial shots10–15%

  Matching the shut-off surfaces by hand, then T1 and T2 trials until the part is right.

• Polish & logistics5–10%

  Cavity polishing, marking, and moving a heavy block of steel to where it will live.

Typical split for a small-part tool, not a fixed formula. Shares move with cavity count, relief depth and how much hand-fitting the geometry demands.

This is also where two quotes for the “same” die quietly diverge. One shop runs three EDM passes and fits the shut-off by hand; the other runs one pass and relies on the machine. One hardens the cavity and tempers it; the other skips the step because it adds a week. Both produce a tool that works on the first day. They stop being comparable somewhere in the second year — which is the subject of sections 06 and 07.

A mold fee is a fixed cost. It is paid once, before the first good part exists, and it does not care how many parts follow. The arithmetic is simple: cost per unit equals the tooling divided by the quantity, plus the piece price.

Only the first term moves. Doubling the order halves the tooling share; it does not touch the piece price. That is why the same fee feels enormous on a first sample order and irrelevant on a repeat order ten times the size.

The practical consequence: a tool is expensive only if you never reorder. A program that runs three seasons pays for its tooling several times over, and the second order carries no fee at all. When you compare suppliers, compare the cost of the first order plus the reorders — not the tooling line in isolation.

The two processes are not interchangeable, and the differences are geometric rather than aesthetic. If a design needs a paper-thin edge, it cannot be cast. If it needs a hollow that would trap the part in the mold, it cannot be stamped without extra slides or a redesign.

In practice the decision is made in the first sketch. Flat with relief, sharp edges, fine line work: stamping. Dimensional, thick, curved, with hollows: casting. A design that sits between the two — a thick body with fine engraved detail — usually resolves as casting plus a stamped insert, or as stamping with a simpler silhouette.

Tool life is quoted as a range, never a number, because it depends on what the tool is asked to do. Sheet hardness, relief depth, press condition, lubrication and the maintenance interval all move it. A die that runs thin brass with shallow relief will outlast a die cutting deep relief in stainless by a wide margin — same supplier, same steel.

What matters more than the headline figure is the order in which a tool degrades. Precision does not collapse; it drifts, and it drifts in a predictable sequence.

Two tools can both be described as “a die” and behave completely differently at this stage. One still holds the fine separations after a long run; the other has already rounded them, and the enamel that used to sit in a crisp channel now sits in a soft one. The part still functions. It just no longer matches the sample anyone approved.

A longer tool life is not a promise made at the end of a quotation. It is a set of decisions made before the first cut, most of which are invisible in a photograph of the finished die. These are the five we hold ourselves to, and each one has a specific effect on how slowly the tool loses precision.

The difference shows up as time, not as a specification. The first re-polish comes later. The fine lines in the artwork survive more cycles before they soften. The shut-off stays clean, so parts stop needing de-flashing by hand. And when the tool does need work, replacing an insert restores the geometry instead of accepting a worn cavity.

It also shows up in what we can hand over. Every tool has a record: steel grade, hardness, cavity count, the maintenance interval, and the first-article dimensions measured at T1. Those numbers are what make a claim about tool life checkable rather than rhetorical — for us and for anyone else quoting you.

In most contracts the party that pays for the tool owns it. The complication is that ownership is legal while possession is physical: the tool lives in a factory, on a shelf, in a rack with hundreds of others. What you actually own is a right to have it used, maintained, and — if you leave — handed over.

“Free tooling” is the phrase to slow down on. It usually means one of three things: the fee is amortised into the unit price, so you pay it anyway; the fee is waived only against a volume commitment you may not reach; or the tool is not yours, so it cannot travel with you if you change suppliers. None of these is automatically bad — but each one should be named in the contract rather than discovered later.

Six questions to settle before you pay

1. Is the mold fee one-time, and does it appear as a separate line on the invoice?
2. How many cavities, and is the stamping die single-station or progressive?
3. Which steel grade, and what hardness is the cavity taken to?
4. Are trial shots included, and how many rounds before an extra charge?
5. If the artwork changes, what is re-cut and what has to be rebuilt?
6. Who owns the tool, where is it stored, and what is the reorder minimum?

A supplier who answers all six without hesitation is telling you something about how the tool will be treated in year three. One who deflects is telling you the same thing.