By Jon Miller | Post Date: January 17, 2007 11:27 PM | Comments: 7
This is a question I have most often heard from European engineers, or from people in other countries who are working with extremely high volume light assembly operations, usually following some teaching about just in time production or Standard Work:
"What do you think about the rabbit chase system?"
I don't like the rabbit chase system at all. I would rather have people try the rabbit system, as well as Standard Work in u-cells or straight lines, whichever made sense, and compare the results. But if asked, I will explain that the rabbit chase does not seem Lean to me at all.
The rabbit chase system, first of all, involves each worker doing all operations in a cell from beginning to end, "chasing" each other around and around as they work in the same cell. I don't know where the "rabbit" piece comes from.
The advantages stated for the rabbit chase are that it is easy to add or subtract people from the line to increase output, and that you do not need to balance the line because people self-balance as they develop a pace. In addition, each person could gain a sense of satisfaction from learning how to operate each process.
One of the main reasons that I have seen the rabbit chase performed is that the line speed or takt time for that cell is much too fast to do anything other than race to keep up. In some cases there would be more time waste in hand-offs and than in actual value added work done. But in these cases the design of the equipment and the pacing of work itself needs to be reconsidered, and slowed down through duplication of cells and low cost equipment.
The hand-off approach that is the typical flow line or u-cell involves balancing cycle time between workers, and a clear definition of work sequence. Some raise the issue of timing of the hand-off but this is a non-issue if you allow one piece of Standard WIP.
In the rabbit chase full training needs to be done for entire process for each person, which is a good thing if you can do it, but more practically the u-cell allows you to cross train step by step.
In the rabbit chase each person must check their own quality, or perhaps rely on an end-of-line inspection, while in Standard Work the quality is built-in through in-process checks by the person doing the work as well as verification and feedback by the downstream person upon hand-off.
In the case of the rabbit chase it would seem like there is the possibility of interference between one person and the next, if the speed difference between workers stacked up over time.
Standard Work forces you to document a repeatable work sequence for each person that is based on takt time and while this is not always easy, it is an important discipline and the foundation of kaizen through the removal of variations in cycle time, making the work easier, low cost automation, etc.
No doubt I am understating the benefits of the rabbit chase system, since I have undone far more of them than I have implemented. Feel free to comment in defense of the rabbit chase, as I could use the education.
Whichever way you prefer, do an experiment to try it the other way. If you don't like the results keep trying until you get the results you need. Just don't say "I told you it wouldn't work" and revert back to today's proven method, which you need to think of as the "worst ever". That's kaizen way.Comments are moderated to filter spam and inappropriate content. There may be a delay before your comment is published.