I was with the factory’s kaizen leader, and we were watching an operation toward the end of the assembly line.The takt time of this particular line was on the order of 400 minutes, about one unit a day. The exact takt really doesn’t matter, it was long compared to most.

One of the Team Members needed to pump some grease into a fitting on the vehicle he was building. But his grease bucket was broken. We watched as he wandered up the line until he found a good grease bucket, retrieved it, went back to his own position and continued his work. The entire delay was much less than a minute. No big deal when you compare it to 400+ minutes, right?

Let’s do some math.

There are six positions on this particular line. Each one has two workers, a few have three, for a total of 14.

What if, every day, each worker finds three improvements that each save about 5 seconds. That is a total of 15 seconds per worker, per day. Getting a working grease bucket would certainly be one (maybe two) of those improvements. (Consider that the worker he took it from now doesn’t have to come and get it back!)

That is 14 workers x 15 seconds = 210 seconds a day.

210 seconds x 200 days / year = 42,000 seconds / year.

42,000 seconds / 60 = 700 minutes

700 minutes / the 400 minute takt time = we are close to having a line that works with 12 instead of 14 workers.

What is that grease bucket really worth?

Of course your mileage may vary.

But how often do you pay attention to 5 second delays?

Of course getting the grease bucket is really just simple 5S — making sure the Team Member has the things he needs, where and when he needs them.

So how would 5S apply in this case?

Mainly a good visual control would alert the Team Leader, or any other alert leader, to the fact that the grease bucket is out of place. A good leader will see that and ask a simple question:

**Why?**

And from that simple question comes the whole story, and an improvement opportunity.

But in order to ask “Why?” there must first be recognition that something isn’t right. And this is the power of a *standard*.

Hi Marc,

I stumbled across this article due to a link in the most recent article you wrote.

I was wondering about the line: >> 700 minutes / the 400 minute takt time = we are close to having a line that works with 12 instead of 14 workers.

I thought this means about 2 more items per year (1% increase).

But I fail to undeerstand why this means we can run with 12 instead of 14 workers.

Maybe you can explain to me a little more.

Thank you

Christian

Christian –

Thanks for commenting. That post was written quite a few years ago, and you are making me review the math.

Let me run it backwards…

To calculate the number of people I need on the line I need two numbers:

– The sum of the operator cycle times (the total labor required)

– The rate at which I need to produce trucks (takt time)

Let’s assume that the total labor content was something on the order of 5600 minutes at the start.

If there is 5600 minutes of work to do, and we have 400 minutes to do it, we need:

5600 / 400 = 14 people working together to get it done.

Any amount of labor over about 5400 minutes is going to push me to 14 people with rounding.

Now, by having each and every worker find three ways to save 5 seconds, each and every day, that time savings accumulates day after day, slowly reducing the total labor content.

At the end of a one day, that 5600 minutes of total work is 5596 minutes.

At the end of one (5 day) week, that 5600 minutes of total work is 5583 minutes.

At the end of 120 work days (6 months), the total work is down to 5180 minutes.

5180 / 400 = 13 people working together to get it done.

At the end of 200 days where I have found 210 seconds of time savings each and every day, the total work content is down to 4900 minutes.

4900 / 400 = 12.25 which is within reach of getting down to 12 people.

It is sort of like the effect of compound interest, only with time.

In reality, getting this kind of consistent kaizen is extraordinarily difficult unless there is a focused, skillfully led effort. It requires good coaching, commitment to the target(s) and focus on the long-term objective. It also requires the workers to be vigilant for any issues that come up so they can alert their leaders quickly. The consequence of not having that vigilant escalation process is that the above process reverses, team members start spending time just getting the grease bucket, and time creeps back into the work cycle, forcing you to add people over time.

Mark