Over time I have seen may organisations try and put their interpretation on takt time. Most try to put some form of ‘fudge factor’ into the calculation. This is normally so they can accommodate and ‘efficiency ratio’ or some form of equipment efficiency measure. But why do they do this?
Well most of the time it is because the organisation has completely missed the point of using takt time as a tool. Most understand that takt time is the ‘beat of the customer’, but few really understand that is is also a measure of waste within the process.
It’s also an Abnormality management tool………..
Used properly it is very easy to understand the cost of stoppages, for example, if our production line is planned to run for 40 hours and produce 2400 units (takt time = 60 seconds) but we only produced 2000 units, then we have a loss of 400 units. it is very easy to see we would have to run 400 minutes overtime to catch back. This in turn we can attribute a true cost to. But the reality is that it makes little sense to add cost to the process in this way. So we have to consider another alternative.
Within the Takt time calculation the key phrase is ‘Available time’. It is quite acceptable to include ‘Planned down-time’ into the calculation so long as it is planned ahead of time.
So we could choose to build into the calculation and amount of time for maintenance and TPM activities to that when we run the process during the planned up-time we can measure the success of our TPM and maintenance.
This is why companies like Toyota do not generally run 3 shift operations. They choose to spend time each day working on preventative maintenance so that when the bulk of the manpower is on site, the lines run to pure takt time. That way they can look for not only at the quality of the equipment maintenance, but also look for small incremental losses. The trick is to have a very good capture system and have the infrastructure to put into place good countermeasures.
The moment you add ‘fudge factors’ into the calculation you are sending the message that some inefficiencies are OK and you loose the ability to put pressure on the organisation to find and fix its inherent abnormalities.
So before you try to make up your own takt time rules, think about the message you are sending and is there a way you can organise the operation in a different way to drive people to improve and look for small losses.
The word Takt is derived from the German word for beat. In the case of Lean, this refers to the pace of the process as dictated by the customer. If the customer orders 10, then 10 must be produced, not 9 or 11.
The best way to visualise this is by imagining an orchestra with the conductor at the front. He is the customer. The conductor moves his baton up
and down to indicate the ‘beat’ of the music he requires. The musicians follow this beat, all at the same speed, completely synchronized. If he speeds up, the entire orchestra speeds up with him. As he slows down, so do the musicians.
This is the concept of Takt time. A process should adjust its output based on ‘true’ customer demand and not keep running at its maximum speed.
Takt time can be calculated on virtually every task in a business environment. It can be used in manufacturing e.g. machining parts, drilling holes etc. In administration e.g. processing orders, call centre operations etc or in a production line environment, to pace the line.
When implemented correctly, running a process to Takt time provides many benefits. Just a few of these are:
- Since you produce only what is required by the customer, inventory is reduced
- Since the ‘product’ moves along the process at a given speed, bottlenecks are easily identified.
- Since problem processes are easily identified. repeat issues, like breakdowns, can be understood and fixed.
- Since the process moves at a fixed speed, work is balanced across all operators. If it is not bottlenecks will occur.
A lot of confusion can be generated around Takt time calculations. The simplest way of calculating Takt time is to calculate the Takt time for the output of the process. Work from the perspective of the customer.
In order to calculate Takt time, two pieces of information are required.
- Available Time – this is the shift time minus any breaks, clean up time etc.
- The Average Customer Demand – how many does the customer actually require in a given period.
Work in fixed periods (days or weeks) and apply the following calculation.
A store card company receives 2,100 applications per month. And on average they work 20 days per month.
Workers are paid for 7.5 hours per day. They have two 15 minute coffee breaks per day – which are paid.
So the Takt time is calculated as follows:
From the 7.5 working hours 30 minutes must be deducted (for breaks). 7 hours = 420 minutes
2100 / 20 = 105 applications per day
Therefore the takt time calculation is as follows:
420 minutes = 4 minutes
So if we were processing applications to Takt time, you would expect to see an application being processed every 4 minutes. Running with a Takt time of 4 minutes means that the process is set up to deal with the customer demand as efficiently as possible.
This Is an extract from the book Tools for Success, by Barry Jeffrey and Graham Ross. If you would like to know more why not follow the link www.kaizentrainer.com