Why Takt Time is Important, and How to Calculate It


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The term takt time derives from the German word Taktzeit and translates to either "measure," "cycle," or "pulse" time – depending on which source you read. Put simply, takt time refers to the amount of time a manufacturer has per unit to produce enough goods to fulfill customer demand.

Frequently used within lean production lines, takt time is an essential tool in ensuring that goods flow through each build station in the most efficient manner.

So, now you know the basics of takt time, let's explore in more detail how to calculate it. This article will also explain the benefits this tool offers electronics manufacturers and highlight a number of areas that require consideration for anyone looking to implement the tool themselves.

Calculating takt time

A common misconception is that takt time relates to the overall build time – i.e., the number of man-hours put in to building a product. It doesn't – it relates to the time span required to build a product from start to finish to ensure the continual flow of finished products needed to satisfy customer demand. Once takt time has been established, the electronics manufacturer needs to physically separate out the build into individual stages and resource the production line accordingly. 

The basic calculation is: Available production time / customer demand = takt time

Let's break this calculation down a little further:

Available production time - For the purposes of this article, we assume the electronics manufacturer operates an 8-hour shift, five days a week. Eight hours equates to 480 total minutes – but, of course, not all the 480 minutes are "available." Tea and lunch breaks, material preparation in the morning and a clean down at the end of each shift all take away from the "available" time. So, assuming there are two 10-minute tea breaks, 30 minutes for lunch and another 20 minutes in total consumed at the start and end of each day, the "available" production time is in fact 410 minutes.

Customer demand – This relates to the number of units the customer requires each day. To keep the calculations simple, we will assume this customer designs and sells a range of electro-mechanical industrial 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.

The Benefits of Takt Time

Efficiency – Once up and running, takt time is very easy to measure. Electronics manufacturers operating lean production lines will use this tool to ensure as much waste is removed from the process as possible - i.e., minimising the takt time - and monitor performance very closely. The work content within each build stage should be balanced, to ensure the takt time is maintained, and if for any reason operators finish a stage quicker than planned, or struggle to keep up, the engineering teams can then look at ways of rebalancing the production stages.

Visibility – One of the main benefits takt time offers is increased visibility for production line operatives and their supervisors. With each stage broken down the build process becomes very visual. If an operator struggles to keep pace, then production output starts to slow or, in the worst case, stops altogether. While in itself this is not a good thing, the immediacy with which a problem is highlighted to the supervisor is a benefit and allows them to react accordingly.

Considerations

Many lean lines operate Kanban replenishment systems to ensure raw materials are immediately available to production. In order to continually "feed" these lines, the electronics manufacturer must have a stable supply chain in place. Any material shortages or quality issues will immediately slow or stop the line completely so systems and processes must exist away from the production line to minimize the risk.

This can be particularly challenging for electronics manufacturers producing highly complex electro-mechanical products. Often, these consist of a large number of drawn items which, if not manufactured correctly, or if they sit on the edge of tolerances, may not fit as expected. It's recommended, therefore, that separate inspection areas are created for this kind of material so that all incoming materials can be checked against drawing, prior to them being issued out to the line.

Finally, it won't always make sense to break down the entire product into individual build stages - there could be far too many processes. If we take the electro-mechanical industrial printer example there are over 1,000 individual parts that make up one unit. And a large number of these parts are called up within sub-assemblies – like the printed circuit board assembly (PCBA) – so consideration must be given over which build elements are completed out on the line and which are carried out offline.

We hope you have found this article of use and now have a better understanding of takt time, some of the benefits the tool has to offer, and how to calculate it.

This article originally appeared on the JJS Manufacturing blog which can be found here.

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