Using TOC, Lean, and Six Sigma Tools

A writer at a LinkedIn blog asked a very good question: has anyone used the Theory of Constraints, Lean, and Six Sigma tools together to solve a problem??

This post will be the first in a series reviewing how we utilized a variety of tools to improve throughput and quality in a systematic fashion at Interpoint. In hindsight, we did successfully mix the tools of TOC, Lean, and Six Sigma. What was missing from our application was the lingo. More later on why that may not have mattered.

BACKGROUND

Interpoint was a small, publicly-traded company with a long history serving the defense and aerospace markets. The company designed proprietary DC-DC converters and custom-designed hybrid microcircuits using a customer circuit. The hybrid featured silicon die (FETs, transistors, diodes, etc.) that were mounted on a multi-layer silicone substrate. After die attach, the substrate was epoxied into a metal package. The circuits were joined by electro-mechanical wirebonding, tested, and then sealed and burned-in using MIL-STD 883 criteria.

A good visual of hybrid circuits is here.

A barcoding system was used to track trays of parts. A group of parts, say the 11424-002, would have a work order associated with it and have several trays of parts associated with the assemblies. Manufacturing was done in a clean room with many static prevention tools and processes. Hence the trays were metal.

Our first improvement was to digitally download the barcode into Excel and use this spreadsheet to track product progress. Predicting scheduled completion and the quantity (yield) of a work order was at best an educated guess. We then developed notional durations for each process in manufacturing for each custom product that would normally be manufactured in a given year.

These steps, while an improvement over guesswork, left me wondering what else we could implement to make yields better. My next post will describe how we started down that path.