How far can you take lean manufacturing practices before you cross the line of what makes sense economically versus doing what a pure lean implementation tells you that you should be doing?

We have all heard the statement, “You were too close to the forest to see the trees.”  I think at times, in our eagerness to adopt lean manufacturing principles and practices we find ourselves “Too close to lean that we sometimes can’t see what makes sense.”

To illustrate this situation let me tell you about a company that was faced with a similar situation.

The company was a major player in the medical products/device manufacturing industry.  They had adopted a lean philosophy plant wide and had been following lean practices for about 5 years.  They had seen fantastic results as they broke down traditional methods and practices and followed the lean manufacturing principles to a “tee”.

They had done a superb job of connecting their processes in their various value streams and had managers of each area that believed in lean but were having a difficult time understanding how to decide what was right for their next efforts along the path of continuous improvement and lean implementation.

They were trying to achieve a single part flow into a low volume, high variety type of job shop assembly area.  They had established supermarkets for each the components that were required by each value stream.  In their hopes to fully connect the component manufacturing with the component demand in the value stream cells they were contemplating bringing some fabrication equipment into several of the value stream cells to reduce supermarket inventories of certain critical parts and to perhaps better connect the process.

The fabricated parts required multiple machine center resources to complete.  Many issues related to safety, cleanliness and process flow also needed to be considered.  The existing fabrication center was set up in a “U” shaped cell and actually ran very well.   Additionally, the existing fabrication cell supplied component and services to several other value streams within the plant.  After much contemplation and study, the group agreed that bringing the fabrication cell into the assembly areas would be a big mistake.

What came out of this study is that you can actually find better ways of fully connecting the processes in the overall manufacturing operations without actually having to physically locate all associated production tasks in the same cell.  With a little work and thought, the supermarket inventory levels were dropped, the communication of TAKT time demands were better established across the lines of fabrication and assembly, and the customer began to realize immediate benefits of better connecting their processes.