Tracking die life and tooling cost in a forging or stamping shop

Stamp a unique number on every die. Punches and impressions get numbers too. Keep one record per number holding the part it makes, the press it runs on, the steel grade and the date it entered service.

Record the purchase cost, or the in-house build cost including steel, heat treatment and wire cut hours, because nothing later can be charged without a starting figure. Capture it on day one.

Progressive dies need station numbers too. A single worn punch at station four should not condemn the whole set, so wear must be traceable to the exact piece that failed.

Die life is measured in hits, not calendar days, because a die can sit idle for a month and then run for three shifts straight. Count strokes from the press counter at the start and end of each run, and write the difference against the die number.

Manual counting breaks down on long shifts. Hammer blows on a forging line are harder still to tally by hand, and a tired operator will round the figure to something that feels right. A cheap sensor on the press, or a counter reading typed into a tablet at changeover, beats anyone’s memory of a night shift.

Record scrap strokes separately. A die that turns out many rejects is wearing differently from one that makes good parts, and the repair history should say why.

Each time a die leaves the press, note why: burrs rising, a cracked insert, flash growing or a punch that galled. Then record the action taken, whether regrind, polish, weld build-up or an insert change, or nothing at all. Doing nothing is an entry too.

Record the stock removed at each regrind. Shear dies and trimming tools lose a little steel every time, and once shut height or clearance cannot be recovered by regrinding, the tool has reached the end.

They are the best evidence you own. They tell the toolroom which sections fail first, and whether a different steel or coating paid back the extra cost of buying it.

Set a stroke target per die. Start with the toolmaker’s estimate, then revise it using your own history after three or four lives, because your steel, lubricant and press speed are not theirs.

Set a warning at around four fifths of the figure so the toolroom can prepare a spare or schedule a rebuild. A mid-order failure stops the press, spoils the batch and delays the dispatch to a customer who was already waiting. Plan the rebuild instead.

A retirement point can also be a quality limit such as burr height, flash thickness or a gauge reading on the first piece off the die. Whichever arrives first wins.

Take the original cost plus all repair costs, subtract any scrap value, divide by the strokes the die delivered and multiply by parts per stroke. That is tooling cost per part.

Add it to job costing. Quotes that omit tooling undercharge the jobs that wear dies fastest, usually the hard steels and deep draws, and they hide which customers are worth keeping.

Start with the five busiest dies. Give them numbers, open their cards and begin counting at the next changeover, and let the rest follow once the first month of records proves useful.