Budget for a second mould, not a perfect first one.

Problem

The team specified a hardened steel tool for a part whose geometry was still moving. Every design change became a tool change, and a tool change on hardened steel is a welding job.

Context

A five-person team making a water filter housing. First tool quoted at 8,400 USD with a six-week lead time; two revisions took it past four months.

What they did

1. 1.Cut a soft aluminium tool for the same part at roughly a fifth of the cost and a third of the lead time.
2. 2.Ran 400 shots off the aluminium tool and froze the geometry against real parts rather than drawings.
3. 3.Ordered the steel tool only after two consecutive runs needed no change.
4. 4.Kept the aluminium tool as the backup for short colour runs instead of scrapping it.

What to avoid

• •Two of the three geometry changes came from assembly, not from the moulded part, and would not have been caught by more CAD review.
• •The steel tool's quoted lead time did not include the tryout loop, which added three weeks each time.
• •Nobody costed the idle line while the tool was away being modified.

Sources

• Tooling quotes and revision logRafiki Housewares programme notes

Related lessons

• Cut the tool in aluminium before you cut it in steel.→
• Find the step that stopped scaling before you cut the bill of materials.→