"The HyGain-Telex plan in Lincoln, Nebraska, manufactures antennas. It currently has an U.S. Army contract for Model X32 antennas. The contract requires a production rate of two hundred Model X32s per day. The contract quantity may be changed quarterly."
Manufacture of the X32
Analysis of the manufacture of the X32 concentrates on the base, which is a cylinder 6 inches in diameter and 10 inches high (see diagram on page 2). Manufacturing of the base occurs in several stages.
Step #FunctionTime (min)
1Holes are molded into the base by use of core plugs2.50
2.1A dozen more holes are drilled then half of them are tapped 0.12 to 1.02 2.2The remaining six holes are installed with "helicoils1.82 3Assemble as "birdcage" inside the Lexan base1.78
4Foam the assembly2.61
Concentrating on the drill-and-tap and assembly steps (2.1, 2.2, and 3), drill-and-tap ran one shift while assembly usually ran two shifts.
The total flow distance of the manufacturing of the X32 is 1,296 feet from mold to the final prepping area.
192 ft 144 ft 480 ft 480 ft
The flow-time data is described at "as short as about five days for a few lots, but we are quoting six weeks to markings." A rough average was achieved "by putting pieces of colored tape on a few molded bases from several lots over the space of three weeks. The average flow time, found by noting how long it took for the taped units to get to final prep, was seven weeks. One week of that was the flow time from the start of the drill-and-tap to assembly.
The ratio of actual production lead time (or flow time) to work content time from the start of the drill-and-tap to final prep is as follows:
WIP Inventory =(value for 2000 units unspecified)
Lead Time=21300 to 23100 min (8.8 to 9.6 days)
Work Content =10.35 to 11.25 min...