I just finished responding to a post on lean.org where the poster was struggling a bit to justify moving two sequential operations together vs. the proposed simple solution of adding conveyance from one to the other. I thought it would be worth a bit to think that through.
In a previous post “Sticky or Slick”, I admitted struggling a bit myself trying to capture the “lead story” of the Toyota Production System, the one sentence core principle that could guide decisions. I still think it is close to “Structuring the organization and the work environment to harness people’s creativity to save time.
Let’s apply that logic to this situation. Now obviously I have not seen this operation myself, so I have no idea about the work breakdown, the cycle times, the nature of the work elements, so I am going to make up opportunities that illustrate the point.
I believe the key point that gets lost here is that, in 99% of the cases, you are not moving operations closer together. You are moving operators together. You are improving material flow with the purpose of creating better people flow. The TPS is about people. Specifically, it is about organizing the work and the work place so the people can make improvements that save time and make a difference.
operations operators team members who are performing sequential operations are separated in space or time, then although each can work to improve her own individual work, the results don’t pass the “so what?” test. “I reduced my work cycle from 10 minutes to 7 minutes.” So what? Now you are idle for 3 minutes. You still need to be there. And it is usually beyond the technical wherewithal of a shop floor team member to automate himself completely out of a job. Since they cannot reduce cycle time to zero, there is no net difference.
But now you have a problem to solve:
This person is idle (the waste of waiting). What must I do so he has meaningfully work?
Changing the layout is now the obvious countermeasure.
To turn this “problem” into true kaizen, create or improve flow by placing those two operations very close together. Now the magic happens. As each team member works to save time (or as they work as a team), they can also continually re-balance their work so at least one of the two is still loaded close to the takt time. Eventually they reach the point where one of them can perform both operations, freeing up the other. Even if this does not quite happen, by always consolidating the wait time onto one person, that person can take on more tasks assuming they are within reach. If they are not within reach, then move them closer together and facilitate more kaizen. Changing the layout is a countermeasure, not the objective. It is a countermeasure to the problem – the waste of waiting.
The “why” of putting things close together is to give the workers the power to improve their own work and the total flow of the system. The side-benefit of doing this is that you reduce inventory and save time. People’s time, throughput time.
Structure the work and the work place so the people who do the work have the opportunity to improve the system in a meaningful way.
The cycle of kaizen:
- Attack overproduction so other wastes are revealed.
- Convert other forms of waste to the “waste of waiting.”
- Adjust the work balance, and then the physical flow to eliminate the waste of waiting.
If you do it in the other order – attack the waste of waiting first, the only way a team member can remain busy is through overproduction… and overproduction is bad. Very bad.
and.. after a couple of months and several dozen posts I finally added the category “kaizen” for this one. I am not sure why it took so long.