The Takt Time for Your Question is 42 Seconds

This discussion prompts a question about Takt Time. I understand that Takt Time is available working time per day (in seconds) divided by customer daily demand (in pieces). Suppose that a work center sets aside 5 minutes for clean up and 5 minutes for a morning meeting. Does the "available time" include these during the shift minutes of non-production or not in the Takt time calculation? If I view these activities as essential ones that I am always going to have, then I may take this time out of the equation. If I view these minutes as opportunities to reduce or eliminate this non-production time through other types of improvement, then I might leave these minutes in the calculation. From a TPS viewpoint is there a Standard on how to treat this time?

Net available time is strictly the time that is available for production. If production is stopped for clean up or meetings, it is not available. Takt time would be set based on the net available time, excluding planned meetings and clean up.

You could build in the 10 minutes as available time and treat these 10 minutes as "losses". Toyota does not do this since you would need to work 10 minutes of overtime each day in order to make your target production output for the shift. You would be paying time and a half for those 10 minutes every day.

The TPS approach to clean up would be to eliminate the need for clean up by making it a natural part of the Standard Work for each process. Every cycle would involve putting things back in their place or putting the trash in a trash bin. For “occasional” clean up or removal of trash the water spider or team leader would be responsible. For extraordinary cleaning, root cause analysis and reoccurrence prevention would occur.

As for meetings, close attention by the team leaders and supervisors to the work being done, as well as constant on-the job training and communication would largely replace it. Good visuals and standards also minimize the need for formal daily start up meetings.

If you treated these 10 minutes an "not available" that would reduce the numerator and make your takt time smaller, speeding up the line and requiring redistribution of operation cycle times. This would most likely require kaizen to rebalance the line at the same staffing, thus improving productivity.

I am trying to implement Takt Time calculation to a product line, and, although I think I understand the concept, I am still missing something big...
We run 2 shifts; including downtime, breaks, the net operating time is around 13hrs/day. Customer requirements are 200/day, so the Takt Time is 3.8min.
The standard time to build a unit is 38.5min.
So the calculation of number of operators required is 38.5/3.8=10 operators.
But looking from an efficiency standpoint, 10 operators put roughly 75hrs of charge time per day, to build 200 units. So the actual time/unit is now 22.5min; that means I would have to be efficient at 160%... Could anybody explain?

Jean Luc,

I think there is no problem with your understanding of takt time. Based on available time of 13 hours/day x 60 min/hour = 780 minutes and customer demand of 200/day, takt time would be 3.8 minutes.

780 min / 200 pieces = 3.8 min/piece

Standard times are mostly useless in my experience.

If 10 operators are charging a combined total 75 hours to build 200 units, they are using 75 hours x 60 min = 450 min to make 200 pieces. Therefore

450 min / 200 pieces = 22.5 min / piece

This is an average. In fact the real total manual cycle time is even smaller. I encourage you to follow the principle of "genchi gembutsu" and go to the factory and see for yourself what is really happening.

My recommendation is to "go to gemba" and actually observe and measure the total manual cycle time it takes to make one piece. Take this new total manual cycle time and divide it by takt time and that is your target manpower.

If the total cycle time is 22.5 minutes and takt time is 3.8 minutes then your manpower calculation is

22.5 min / 3.8 = 5.9 min / piece

So your improvement target is to reduce the cycle time and balance the workload through kaizen so that 5 people can do the work.

Finding the true total manual cycle time will not be a challenge if you know how to read a clock. Your real challenge will be in making sure the 5 people that are freed up from this process can be quickly deployed to another area where they can be productive.

I hope this helps.

Jon

I am a Team Leader over a very high volume line.I understand and agree with takt time. However even with training I am finding it hard to get the team to believe. They complain when I have them follow the standard flow based on takt time. They claim it is tiring running back and forth versus batching about 3-5 pieces at each station thus reducing the walk time. I am at Gemba everyday and many times run on the line. I have had them do a chase line which is as close to one piece as you can get. They would rather stay at a station versus the chase as well. We are getting ready to implement Hiejunka on the line. Doing so will further require adherence to takt time. How can I convince them that takt time will work? I need them to work with it and not against it.

Hi Ben,

Thanks for your question. It's a good one.

First of all, it sounds like you may be breaking the 50 second rule for takt time in manual operations. In short, if the takt time is less than 50 seconds and the team members on your high volume line are having to repeat the same cycle more often than once every 50 seconds, they will fatigue too soon. Quality, productivity, safety will all suffer.

At Toyota they could double the speed of their lines from 60 seconds to 30 seconds and avoid spending billions on new factories, but they don't.

In lighter industries than automotive I've seen takt times as low as 30 seconds that are still a reasonable pace, but whenever possible we encourage longer manual cycle times. In practice this may mean duplicating production lines so that you can slow down your takt time (two lines = takt time that is twice as long, three lines = takt time that is three times as long, etc.) This also greatly improves your flexibility by reducing changeovers and allowing you to design the lines to be less universal. Even so, because it can mean duplicating equipment if you do not have modular equipment already, many firms balk at this.

If you already have a reasonable takt time (above 50 seconds) then it could be that your processes are too far apart, creating a lot of extra back and forth motion that the team members don't like.

If neither of these conditions are true, you may just be dealing with run of the mill resistance to change. Thank your team members for identifying the problems, ask them for ideas on how to make it better, but be clear with them that you will never compromise takt, flow, pull. Stick with it.

We've encountered this situation many times before and found ways to overcome it. Feel free to e-mail me or call our office if you want a more full explanation.

Jon

I have joined an organisation which is considering TAKT as its chosen production method. The product is aircraft structure manufacture and production is broken down into parts of the fuselage, rear fuse, front fuse, fin etc. The products themselves are highly complex which demand high tolerances which can be difficult to consistently achieve, the build rates are relatively low in comparison with many companies (30 to 60 per year), there is constant but low to medium rates of change and due to the nature of the product, the supply chain is making specialist parts in low volumes and consequently supply can be troublesome. I read with interest the experiences of people in regard to TAKT, but I cant find reference to the environment where TAKT is ideal and where it is not applicable, could you advise

John

Hi John,

I have posted a reply here. I hope it is helpful, and that others who read your question can also add their experience.

Jon

I would like to know more production techniques. I am production engg here working in mnc.

Hi Mohan,

You can find more information about production techniques inside the archives of this blog. We have some more information on TPS and Lean at www.gemba.com. Another great resource is www.superfactory.com

I hope that helps.

Jon