Takt time and Family Product
- February 20, 2010 at 3:47 am #53305
Hi,I have problem finding the right product family and the right Takt time:
-the company is a furniture manufacturer
-the products are made-to-order (highly customized)
-the products mostly go through the same processes
-the processing time variation is very high for different products
anybody has any suggestion?Thank you.0February 20, 2010 at 4:00 pm #189563
With low volume, high variety product lines, it is often helpful to first isolate the variation in by first grouping the products into product families. In your case, since all products use the same process steps/resources, you would likely group based on similar processing times (the elapsed time it takes a unit of work to move through a process). You can use two general rules of thumb here: group those that have PT within 15% of the average and you should see the PT roughly pareto out – 80% of the highly variable PT will be found in about 20% of your product line. Now you have your operations organized into Value Streams (Value Stream = Product Family) and you can calculate and assign Takt Times where appropriate (One Takt per Product Family). This now allows you to plan your staffing levels based on the change in work content (ie changing PT) in the different Value Streams based on degree of customization (Work Content / Takt = # Operators). Just rememeber the goal is to reduce waste, with takt, etc simply being the methods or tools used to achieve this aim. Understand the philosophy first, tools come second. And above all else, first focus on stability in the individual operations, especially in those where external variability (introduced by the customer or supplier) creates real chaos. Takt time is used to synchronize the operations. If you connect operations that are not highly stable (in PT and Throughput), you will create real problems for yourself. Good Luck.0February 20, 2010 at 11:49 pm #189573
Thank you John for your reply, I really appreciate it.
I’m not sure if im getting this right.
what you are suggesting is that i’ll have my product family based on the processing time, and calculate 2 different takt times?how would i be able to calculate the takt time based on processing time?Thank you.0February 21, 2010 at 2:04 am #189574
You group products based on their (1) use of similar resources or process steps (2) their use of them in similar amounts (ie time or processing time). So yes, if your products use the same processing steps but in highly dissimilar amounts, you would want to consider grouping them into separate families. You do this to isolate variation that you can’t readily eliminate. If you just tried to group these products together and run to a given takt, you would find it impossible to establish manageable work flows. And you calculate takt based on Available Work Time / Average Daily Demand Rate. Obviously, the ADDR will differ per product family, so the resulting takt time will differ. So one takt time per product family (aka value stream).
But I digress. If you are early in your lean deployment, I would say ‘slow down’ and focus on stabiliizing processes and understanding them from a Business Process Management perspective (ie Where is cost, time, quality generated in each process). Again, work from the philosophy first – reducing the time it takes to get defect-free products to the customer – tools are simply the way to implement the strategy. Stay simple…map and measure your processes first…know how they work (yield, output, WIP, etc), clearly define internal and external cusotmer/supplier relationships/needs, etc and seek to eliminate variability in quality and output (ie FPY, Exit Rates, etc). Get a good mentor and do some research on the following: BPM, VSM, 5S. These will give you plenty to work with and give you great initial results in establishing stability and flow…..don’t outrun your headlights at this point. Good Luck.
You can do alot with simple BPM0February 22, 2010 at 2:59 am #189582
Thank you again John.I just did not understand the rule of thumb that you mentioned. would you please explain it more clear? I really appreciate it.I don’t have much time to do research on BPM, but I will keep that in mind for my other projects( thanks for the advice).I actually have the current state map of the production line and collected all related data. I’m trying to apply lean for the production line.
do you think that a month would be enough time to finish it?0February 22, 2010 at 9:08 pm #189602
What does that mean “apply lean to a production line”? How are you defining and measuring success for this 30 day lean effort?
0February 22, 2010 at 11:19 pm #189606
The objective is to create continuous flow. Ideally, the product flow continuously all the way through value streams. or basically changing the system from push to pull.
the problem is finding the takt time. and if I calculate 2 takt times based on the processing time, then which one would I use in the pace maker?
what exactly would I have in the supermarkets or FIFO Lines?Thank you.0February 23, 2010 at 5:30 pm #189620
I am unaware of your circumstance or experience, but it appears as if you have bitten off a little much. I would slow down and get someone with experience in lean deployments to help you.
You said you already completed your Current State Value Stream (and Future State I am assuming if you are looking to implement) and collected all the needed data. I would say without having a Product Family Matrix in place with the end items grouped based on similar process steps and processing times, you do not have all the informatoin you need. In addition, in a VSM, you map value streams (aka product families) individually – you can’t map until you have the operation organized into PF. So the problem isnt choosing a takt time. The problem is that you have one map for a group of products that have highly variable PT, meaning you will likely have too much variability in the cell/line to flow the work. Keep in mind, when you connect processes to create flow, the variability in one operation now becomes the variation in all the other operations you connect it to. Now a problem in process A affects processes B, C, D, etc. So highly variable processing times, if not isolated, will make flow problematic.
And if you are working with LVHV (low volume highly variable) products (which is usually the case with variable PT), then a sequenced or stagged pull system might be a better fit for you. Supermarkets are useful when producing HVLV product lines, not LVHV. And what you have in the queue depends on a variety of factors.
And to do all this in 30 days? If you can pull it off, my hat’s off to you.
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