Schonberger Case

Schonberger Case #1: HyGain-Telex: Analysis for JIT Production

Company Objective

"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 # Function Time (min)

1 Holes are molded into the base by use of core plugs 2.50

2.1 A dozen more holes are drilled then half of them are tapped 0.12 to 1.02

2.2 The remaining six holes are installed with "helicoils 1.82

3 Assemble as "birdcage" inside the Lexan base 1.78

4 Foam the assembly 2.61

5 Paint 1.82

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.

Flow Data

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.

Flow Ratios

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

Potential Rework = 2000 units

Lead time to work content = 2000 : 1

The ratio of actual production lead time for the start of drill-and-tap stage to assembly is as follows:

WIP Inventory = (value for 2000 units unspecified)

Lead Time = 3880 to 5680 min (1.6 to 2.36 days)

Work Content = 1.94 to 2.84 min

Potential Rework = 2000 units

Lead time to work content = 2000 : 1

Note, scheduling released work packets in lot quantities of 2,000. Drilled