Two buyers send the same part. One wants 3,000 a year, the other 300,000. If the quotes come back with the same tooling route, one of them is being quoted badly - because volume is what decides whether a part is a single-hit job, a progressive die or a transfer press job.
How does part volume change the tooling route?
Volume changes the tooling route because a die is a fixed cost and press time is a variable one. At low volume a single-hit or compound tool is usually right: the tool is cheaper, the press is slower, and the piece price does not matter much because there are few pieces. As volume rises, the arithmetic flips - a progressive die costs more to build but removes operators and runs several parts per stroke, so the extra tool cost is repaid in labour and cycle time. Above that, a transfer press makes sense where the part is too large or too deep for a strip to carry it, and the investment only pays on a long programme. The other input is hits per part: a part needing a draw plus four trims and a pierce carries five times the press time of a single blank, which moves every crossover point.
The three routes, and what each is for
- Single-hit or compound. Lowest tool cost, one operation per press stroke, an operator loading and unloading. Correct for low volume, for parts still in development, and for shapes too large or too deep for a strip.
- Progressive die. The strip carries the part through several stations in one tool. Higher tool cost, fewer operators, high output per stroke. It earns its keep when the annual volume is high and the part is small enough to be carried.
- Transfer press. Separate dies in one press line, with a transfer mechanism moving the part between them. It suits larger or deeper parts that a strip cannot hold, and it needs a long programme to justify the line.
What to give the supplier so the route is chosen properly
- Annual volume and the batch pattern - a steady 200,000 is a different problem from two batches of 100,000 with a year between them.
- The expected programme life, because a die amortised over five years and one amortised over one year are different investments.
- Whether the part may change after the first articles, which argues for the cheapest route that can still make a good part.
- The tolerances that actually matter, since a tight callout can force a route change on its own.
- The material and thickness, because both change how many stations a part needs and therefore the tool cost.
Key point
Volume and hits per part decide the tooling route, not preference. Quote the route against the volume you actually expect - and if the volume is uncertain, say so, because a progressive die built on an optimistic forecast is the most expensive way to be wrong.
Balford builds the tooling for both routes in house and runs them on presses from 25 t to 350 t.
Frequently asked questions
When should a part move from a single-hit die to a progressive die?
When the annual volume is high enough for the extra tool cost to be repaid by fewer operators and more parts per stroke. The crossover depends on hits per part and on labour cost, so it is a calculation rather than a fixed number.
What is the difference between progressive and transfer tooling?
A progressive die carries the part on the strip through several stations in one tool. A transfer press uses separate dies and moves the part between them mechanically, which suits larger or deeper parts that a strip cannot carry.
Does the number of hits per part affect the route?
Yes, directly. A part that needs a draw plus several trims and a pierce uses several times the press time of a single blank, which shifts every volume crossover point and can change which route is cheapest.
What information decides the route?
Annual volume, the batch pattern, the expected programme life, whether the part may change after first articles, the tolerances that actually matter, and the material and thickness. Without volume and hits per part, a supplier can only guess.