How to Analyze Process Flow to Achieve Value for Six Sigma
A process in Six Sigma where material and information flow continuously is one that has minimal waste, so one way to identify waste and improve value is to look for disruptions to flow. Here are some indicators of poor flow:
Materials, products, or information being processed or moved in batches
Bottlenecks that choke the flow of a process
Stops and starts in the flow of the process
Uneven pacing of items through the process
Physical movement of items back and forth across a process
Differences or exceptions in the sequence or pacing of items through the process
Staging or prepping of batches of items for a subsequent step
As an example of perfect flow, and thus perfect value, imagine standing in the bakery aisle at the supermarket. As you pick a loaf of bread from the shelf, a freshly baked loaf immediately replaces the one you took. The act of you, the customer, purchasing a loaf of bread automatically signaled the producer to make a new loaf.
Under this theoretical ideal, the customer always gets the freshest loaf possible, the producer carries no wasteful inventory, and no waiting or transportation delays occur. This setup is the imaginary image of a perfectly configured process.
This perfect take one, make one ideal, as it’s sometimes called, stems from a philosophy of single piece production flow. The opposite of single piece flow is batch processing, where multiple items are advanced through process steps together. Unlike single piece flow, batch processing always creates waste.
For example, the first items processed through each step have to wait as the rest of the batch catches up. Batches waiting for the next step create inventory. Changes or mistakes mean an entire batch may have to be scrapped. And so on.
Anything that disrupts single piece production flow always creates waste. You may not see the waste at first, but with careful eyes, you can always find it.
Your goal should be to configure your process so that it is as close to the ideal of take one, make one as possible. That’s the start of your improvement journey. Then every day thereafter, seek to improve your process to be that much closer to the ideal.