Toyota Standard Work – Part 1: Production Capacity

Toyota is excellent with their standard work. They use a series of worksheets to simplify the creation of these standards.  These are sometimes also know as the “famous 3 slips”. The first one is a production capacity sheet to define what capacity you have available. The second one is a standard work combination table to define when the operator is doing what. The third one is a standard work layout sheet to help with the layout and arrangement of the machines. While there are many different ways of doing this, I like the Toyota approach. Since this is a larger topic, I’ve broken it into multiple blog posts. Lets start with the Production Capacity sheet.

Why Standard Work?

Question MarkIf there are different ways that things can be done, then some of these must be better than others. The idea of standard work helps employees perform consistently. Please note that any good work standard – or even any good working procedure – needs a lot of input from the people who actually do the work!

The naming of this method and the three sheets that I will show you in this and the next two posts is by no means used consistently across the lean community, and there are many different similar names. At Toyota this is known as Standard Work, which is also the name John Shook uses. However, this may lead to confusion with the more general standardized work or work standards (meaning there is a standard of some kind, but not necessarily this method). Kei Abe called it Man/Machine Balance, but this was not gender neutral and hence was changed to Operator/Machine Balance in the USA. Kiyoshi Suzaki calls them Work Combination Charts, which Michel Baudin shortened to Work Combo. Definitely many thanks to Michel Baudin for letting me know all those many names and their origins.

Where to Use It

The production capacity sheet helps with the calculations of the line capacity, and the standard work layout helps with the line layout. The standardized work combination table defines the working standard of the operator. Each of these address a specific issue in planning and standardization.

Preparations

Warehouse manager writing on clipboardBefore we can start, we need a few pieces of information.

We need to know what the line has to do. The different process steps need to be defined or known. Ideally, we already have a line, but it would also work for a yet-to-be-built line as long as we know the process steps.

We need to know the target speed of the line. How fast should the goods be produced? Key metrics here are the cycle time and the  customer takt (or line takt) (the ratio between the two is the OEE). The resulting metric here is the target cycle time. How fast should each machine be (without breakdowns, delays, and other losses) measured in seconds (or minutes, hours, etc.) per piece?

We need to know the speed of each machine, including the time needed for the operator and the time needed at which a machine can work without the operator as well as . At Toyota, this is usually measured using stopwatches (if the line already exists). Other countries where the unions disagree with stopwatches need to use different methods, usually a system of predetermined motions (e.g., MTM). The key metrics here are the manual work time and the additional machine work time. This is such important data that Toyota has a standard sheet for this purpose, the “Production Capacity Sheet”:

Production Capacity Sheet

The production capacity sheet is an overview with the basic data and some simple calculations regarding the machines in the line. I have created an Excel spreadsheet, based on the Toyota spreadsheet, which also does some simple calculations. Below is the overview of the sheet, but since it is a bit small, let me break this down into pieces:

Production Capacity Sheet Header

The header contains the usual things you find in the headers: The name of the part to be produced, the part number for the software system, a date, a responsible person, and also a plant section. An example is given below. Feel free to modify these as needed in the Excel sheet.

Production Capacity Sheet Process Times

Next we get to the actual data. We list the processes/machines that have to be done. Below is the detail from the data sheet, filled in with example data.

First add the machine names and numbers in sequence, so you know which machines you are talking about. Next add the working times, distinguishing between manual work time and machine-only work time. The spreadsheet will calculate the total time for you.

All machine times would have to be faster than the target cycle time. If a machine is slower than the target cycle time, it won’t have enough capacity to supply the customer. You need a faster machine or a second machine.

Production Capacity Sheet Change Over Times

In the next few columns comes the info on the lot size and changeover time. As you can see below, you add the lot size and the duration of the changeover into the cells. You can also change the duration of a shift in the header below process capacity (here 7 hours).

The Excel sheet will automatically calculate the maximum process capacity based on the manual and machine work times and the changeover time. This capacity is simply calculated as follows:

{ \text{Process Capacity}=\frac{\text{Operating Time}} {\text{Manual Time + Machine Time +}\frac{\text{Change Over Time}} {\text{Lot Size}}}}

Production Capacity Sheet Totals

Finally, you will see a “Total” line at the bottom. Curiously enough, this is only for the total of the manual work times. But, if you think about it, this makes total sense. The total manual work must be less than the takt time, otherwise the line is too slow. Hence, this number is needed. The total for each individual process is in the “Total Time” column already, needed to check if the machines are fast enough. Having a “Total of the Total” is of little use here. Hence, even though it is easy to calculate the totals of the machine time and the total of the totals, you don’t need it, and hence you do not clutter the sheet with unneeded information.

Goodies for Download

During this short series of posts on the Toyota Standard Work approach I have used an Excel spreadsheet. For your convenience here is the spreadsheet as well as a PDF version thereof. Both documents are provided under the Creative Commons CC-BY-SA 4.0 license, meaning you can use them freely, but should give credit to me on AllAboutLean.com.

Now you have the data basis to do the standard work. I will describe the standard work combination table in the next post. Hopefully, this was not too dry for you, and I promise it will all start to make sense in the next post. Until then, stay tuned, and go out and organize your industry!

PS: I learned about this (and many other things) at the highly interesting C2U Lean Leadership Training in Japan and from Michel Baudin.

6 thoughts on “Toyota Standard Work – Part 1: Production Capacity

  1. “Key metrics here are the customer takt (or line takt) and the cycle time (the difference between the two is the OEE).”

    Customer takt is the time you need between two consecutive finished products to fulfill customer demand? And cycle time is the actual time that the machine takes for this? OEE is theoretical output when production is perfect minus all the losses on the machine (e.g. Quality, downtime, rate loss) – so if 20 out of 100 minutes are lost, OEE is 80%?

    Example: If my clients request a new car every 10 minutes, I can produce one ever 5 minutes, but due to some losses I am producing one every 10 minutes only. The difference between takt and cycle time is 0. But my OEE is not zero (and not 100% either). Could you please elaborate?

  2. Hi Koen, your customer takt equals your line takt and is 10 minutes.If your cycle time is 5 minutes, then your OEE is 5min/10min (Cycle time/takt time) = 50%. Half of your time is useful, half are losses. Hope this helps.

  3. Hi Christoph,
    great read, truly enjoying your articles and appreciate the effort that went into them!
    I disagree with the definition of OEE though. To my understanding OEE is measured against ideal cycle time of a machine by evaluating three losses (running slow, defective parts and downtime). The loss you’re describing is over capacity and would result potentially in low OEE due to underutilised equipment.ost likely the business would decide to only run process for a portion of the day and therefore the waste would not necessarily be captured by low OEE but wasted capital having bought a machine with too much capacity. What are your thoughts?
    Kind regards,
    Wolf

  4. Hi Wolf, the OEE is the ratio between the cycle time (which in my definition is the fastest repeatable speed) and the line takt. When planning a line, you may not have the line takt yet, hence you take the customer takt and make a best guess of the OEE of the line to get to the cycle time. Not sure if I understood your comment correctly.

    In any case, Toyota does not have this problem, as they assume customer takt = cycle time, and make up the losses at the end of the day with overtime.

  5. Hi ChristChr,
    takt is commonly defined as the amount of products a customer pulls in a given time span. OEE is not directly connected to it as it is the performance of equipment (or a process) to it’s capacity. Some companies try and match cycle time to take time (customer demand) but this is not a necessity. An example would be a customer demanding 100 pieces per day while our line is capable of making 200. In that case we would most likely stand the line down for half a day to avoid over productio thus running at 100 percent OEE. On the contrary we could run the line all day long and would be running at 50 percent. Utilisation and OEE are measures closely linked in planning but not always a function of each other. While takt time ist the external demand against capacity OEE is the performance of equipment against its (internal), theoretical, maximum capacity.
    Apologies for the convoluted explanation.
    Does this clear things up?
    Kind regards,
    Wolf

  6. Hi Wolf, I think you got the takt upside down. The customer takt is the time span divided by the amount a customer pulls (not the other way around). For this you do not need the OEE. This is the *customer* takt. Similarly the line or machine takt is the time span divided by the amount produced. Ideally, the line takt is about the same as the customer takt (otherwise you will get the problem of low utilization as you described above). The cycle time (fastest repeatable time per part). The OEE is needed to get from the customer or line takt to the *target* cycle time if you want to know how fast your line should be. Does this help?

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