Lean Implementation and Measuring Output
In many manufacturing companies, measuring output is not as easy as counting the number of filing cabinets (or the number of cars coming off an assembly line). In a paint or chemical factory, for example, measuring units of 1-litre cans means something completely different than measuring 10-litre cans.
The output in units of the smaller product might be much greater but the larger can will represent more volume output and more value.
Likewise in a machine shop, a unit might be a simple cylindrical bush, while the next unit might be a complex casting with multiple machining operations, followed by painting and assembly.
Sometimes a common unit of measure can be established. Many chemical processes, for example, apply a bulk measure such as litres or kilograms that can be used to measure the flow and control the rate of flow at each production point.
In this case, takt time might convert to a rate expressed in liters or kilograms per hour, and you can level production using that measurement.
In jobbing or small batch production environments we often find that the number of batches or jobs is the key driver of activity. Each batch or job requires materials to be assembled, machinery changed over, and documentation prepared.
Therefore, in those businesses, we often find that the number of batches or jobs is the best measure of output. Naturally, we always try to reduce batch size, but by focusing on managing the flow of jobs or batches, we are much better able to control the flow through the factory than to try to compare apples with oranges when managing unit output.
We, therefore, calculate takt time based on the number of batches or jobs. In the example described above, if we were doing 10 jobs per day, our working time would be 420 minutes per day, and takt time would be 42 minutes per job.
Because all jobs are not the same, you cannot apply takt time as rigorously as you apply it when managing discrete units. Perhaps the most relevant figure is the daily target of 10 jobs.
Setting a target of 10 batches or jobs a day can be immensely valuable in balancing your workload throughout your factory. The aim is to ensure that each process step completed its 10 jobs every day.
Balancing the way you release work to the factory can reduce imbalances in the type of work. For example, not releasing all the time-consuming jobs at once or not releasing all the easy jobs at once, but mixing them to balance the workload.
What is Takt Time / Defination fo Takt time
Takt time Definition is: Available production time/customer demand = takt time
Let’s break this calculation down a little further:
Available production time – Let’s take Example, we assume the electrical Part manufacturer operates an 8-hour shift, 5 days a week. 8 hours x 60 minutes equates to 480 total minutes – but, of course, not all the 480 minutes are “available”. TeaBreak, lunch breaks, material preparation in the morning, and a cleaning time In the evening all take away from the “available” time. So assuming there are 2 x 10-minute tea breaks, 30 minutes for lunch & Additional 20 minutes in total consumed at the start and end of each day, the “available” production time is 410 minutes.
Customer demand – this relates to the number of units the customer requires each day. To keep the maths simple, we will assume this customer designs and sells a range of electrical printers and requires their assembly partner to produce 100 of these a day.
Takt time – if we take our available production time (410 minutes) and divide that by our customer demand (100), the takt time equates to 4.1 minutes or 246 seconds. This means a completed unit must be finished every 246 seconds or there is a danger the electronics manufacturer will not meet their customer’s demand.
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