The capacity hidden in a valve-testing cycle

Completed direct-mount butterfly-valve units with actuators, staged on the bench.

This entry describes a four-day kaizen in the butterfly-valve cell of a North American manufacturer of HVAC controls. The cell assembles three families of valve-and-actuator unit (direct-mount, linkage, and three-way) and its output was the operation the firm’s growth ran through. The client’s name, the individuals involved, and the product part numbers have been altered or omitted at the client’s request.

Situation. The cell built three families of butterfly-valve-and-actuator unit, one assembler to a unit, and the firm’s growth ran straight through it. Demand was set to rise by nearly two-fifths, and the plan on the table was the obvious one: more assemblers, more floor, a third shift.

Complication. The cell looked full. But the assembly work was not where the time went. Assemblers walked to a bandsaw to cut threaded rod, searched a supermarket of 80-odd part numbers for the next order, and waited on deliveries that missed their slot. At the direct-mount stations they stood and watched a valve test run itself: the automated test took 6 minutes, and the assembler’s hands were needed for 2½ of them. The effort to grow had been aimed at the assembly. The loss was in everything around it.

Question. So the question we put to the shift leads was not how to speed the assembler up. It was this: was the cell actually out of capacity, or was the capacity sitting idle inside that 6-minute test, and out on the walk to the bandsaw?

Resolution. Two more test boxes went on each direct-mount station (the team had them running within a day), so one assembler tended three tests at once instead of watching one. Orders were staged and kitted at the bench, threaded rod pre-cut, the supermarket halved. Direct-mount throughput doubled; walking on the three-way unit fell by more than two-thirds. The cell now meets the growth it was bracing to hire for with the people it already had, and the shift leads run the daily board that holds it.

Direct-mount throughput: Doubled: two additional test boxes per station, in place within a day.
Operator travel, three-way unit: 556 feet → 178 feet. A 68% reduction.
Non-value-added time, three-way unit: Down 59%.
Supermarket: 80-odd part numbers at the cell, reduced by 45%.
Designed capacity: Meets a 38.6% rise in demand with existing staff.
Sustaining: Standard work posted at the cell; the shift leads run the daily-management board.

· · ·