In this guide 6 sections
Track die life by giving each die a number, counting strikes at every run, logging each polish and rework, and setting a retirement rule. Divide the die’s total cost, repairs and polish labour included, by the good parts it forged, and that figure is your die cost per part.
Step one: number every die and its insert
Stamp or engrave a number on each die block and insert, because many shops number only the set and lose track when an insert moves to another set. Number the parts that wear.
Create one record per die with steel grade, hardness after heat treatment, purchase date and cost, then add the part and press.
Photograph the die cavity when new. That reference picture lets the tool room judge washout, heat checking and wear against the original cavity months later, without relying on memory.
Step two: count strikes at every run
The press operator enters the die number and strike count at the end of each run, and your own history matters more than any textbook figure. A hot forging die may take several thousand strikes before it needs attention, so a consistent count at every run matters.
If the press has a stroke counter, read it at the start and end of every run and subtract the two figures. Without a counter, add good parts to rejects. Be consistent.
Keep two counters per die, one cumulative since new and one since the last rework or weld repair, because the tool room needs both.
- Die number and press number
- Strikes at start and end of the run
- Billet heat used on the run
- Operator and shift
Step three: log polish, rework and repair
Every tool room visit is an event. Record the date, the reason, the work done and the time taken, whether the cause was washout, heat checking, a crack at a radius or a worn flash land.
Weld repair and re-sinking a cavity change the die’s remaining life far more than a polish does, so mark them as separate event types in the record.
Add the labour, outside grinding and EDM time. Without those hours, the die cost per part looks lower than the shop actually spent, and a die with heavy rework can look falsely cheap.
- Date and reason for removal
- Work done: polish, weld repair, re-sink or regrind
- Hours and outside vendor cost
- Cavity measurement after the work
Step four: write a retirement rule
Retire a die when a critical dimension reaches a set limit, when a crack passes a set length, or when the rework count hits a ceiling. Choose one rule per die family.
Write the rule on the die record so that the tool room, not the press crew, makes the retirement call. Nobody judges wear well at shift end.
Order the replacement die or insert as soon as the rework count reaches the warning level, so that retirement never leaves a press idle waiting for tooling. Orders should never wait for a die.
Step five: read the cost per part
Add the purchase cost, every repair cost and the polish labour, then divide by the total good parts forged since the die was new. Compare dies on the same part first. Then compare steel grades.
A die that looks cheap at purchase but needs frequent weld repair may cost more per part than a dearer die that runs long between reworks. The numbers settle old arguments between the press crew and the tool room, because both sides read the same strike counts from the same record.
Pick the part with most complaints. Start its die record today.
Die life card
A one page card per die. The top holds die number, part, press, steel grade, hardness and purchase cost, and below it a run table lists date, strikes, heat and operator for every run. A rework table beside it lists date, reason, work done, hours and outside vendor, with a cavity measurement after each repair. The foot holds the retirement rule. Beneath it sits the die cost per part.
Open a blank worksheet to printQuestions owners ask
How many strikes should a die last?
It depends on the part geometry, the forging steel, the die temperature and the lubrication, so only your own records can give a realistic range for each part. A few dies give a first range.
Do cold forging dies need the same tracking?
Yes, because punches and die inserts in cold forging wear and crack too, so count strikes the same way and log every regrind and every replaced insert.
Who should own the die record?
The tool room head owns it. The press crew only enters counts. Rework and retirement decisions stay with the tool room, because its people can measure the cavity while the press crew is busy producing.
Can this work without software?
A paper card works for a few dies. Once you run dozens across several presses, a system that adds counts automatically saves arguments, lost cards and the evening hunt for whoever last wrote down a count.