Modern single-crystal turbine blade casting (core shift defect)

15-thousandths-inch walls with ceramic-core shift up to 5–10 thou leaving zero wall remaining; 100% CAT-scan inspection at a half-million-dollar machine; <30% scrap rate the production target.

Today the walls are getting down as thin as 15 thousandths of an inch. The problem with going thinner — you've got a ceramic core in the middle while you're growing it — and if you get a little core shift of 5 or 10 thousandths, you've got no wall left. So they inspect these by putting them in a CAT scan machine. For a half million dollars you can buy a CAT scan machine for metals. You put the blade in after casting, get a full three-dimensional image inside and out, just like a CAT scan on your brain. They do 100% CAT scan, measure wall thickness, and hopefully scrap less than 30% of the production.