What's wrong with batching?

In one of my lean training training classes today we were discussing the concept of batch and queue. I believe the definition was that batch and queue is a mass production concept where many items are produced at one work station, then these items sit in a queue, while they are waiting on the next work station.

Batching behavior leads to many of the seven wastes. First, batching creates over production. Producing items earlier than expected consumes energy, labor, and materials. There is an opportunity cost with early production and the resources consumed and time lost cannot be undone. Once we have over production the flood gates open. Over production leads to inventory, waiting, usually there is transportation. If the items are not used in a timely manner, there can obsolescence. We also have to track the parts, cycle count the parts, light and heat the parts, and insure the parts. None of these activities creates value, but sure increases the cost.

To eliminate batches, the ideal approach is to create 1 item flow. In this environment one piece is moved through workstation after workstation, where value can be added without stopping. Lead times are shortened, quality improves, and wastes that disrupt continuous flow are easily exposed.

If one piece flow is not possible, then pull systems can also help reduce the effects of batch and queue. Working like your local supermarket, small amounts of material are made and as they are removed from the supermarket, a signal goes upstream to replenish the removed items. This system acts to help minimize over production, by only producing what has been consumed.

There are situations where creating a small pitch can help create better flow. That will be a topic for another blog. In most situations, batching can be considered "bad". Leverage one item flow and pull to get closer to just in time processing.

Lean Blessings;

Ron

Ron Bercaw
www.breakthroughhorizons.com