Geothermal turbine housings, requalified and reshored

Meridian was importing turbine housings on a 22-week lead time, and roughly one housing in nine was rejected at incoming inspection for split-line flatness that had drifted after the customer's own stress relief.

The failure was intermittent, which made it expensive: it was not caught until the housing had already absorbed a full machining cycle and a coating operation.

We instrumented the existing process before proposing a new one. Housings were measured before stress relief, after stress relief, and after machining, which located the movement in the roughing sequence rather than in the furnace.

The routing was rebuilt around a rough-machine, stress-relieve, finish-machine sequence with the split line cut last, and a fixture that constrains the housing on the same three datums through every operation.

Calder Ridge took the weldment and stress relief; Brightwater took finish machining and split-line work; Ostmark built the fixture and the checking gauge. One routing, three plants, one program manager.

Split-line flatness rejections fell from 11.4% to 0.6% across the first 400 housings and have stayed there.

Lead time dropped from 22 weeks to 9, and landed cost fell 14% once rejection and expedited freight were removed from the comparison.

The program has since expanded to include diaphragm carriers and bearing pedestals on the same routing discipline.