In this video we watch the traditional “mass production” manufacturing technique square off against the lean “one piece flow” methodology. Have a watch to see who wins!
This is my first attempt at making a video like this. I must admit, talking into a camera is much harder than pressing these keys! With this said, you can expect much kaizen to be done as I work to improve my “skills” in this area.
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In my comment, please read, in the 5th paragraph st<sl<su<f (ie, folding is the bottleneck)
Matthieu
Let me apologize for stammering and add some lines I just forgot to write in my first post.
————————
These lines :
“So what about our ten envelopes ?
With a lot size of 10, we have the batch process time : 10f + t1 + 10su+ t2 + 10sl + t3 + 10st
And as for the one piece flow process (if we assume from Eric’s datas that st<sl f) ?
Whereas the batch time formula doesn’t change, the one piece flow becomes… ”
—————-
Should have been
“So what about our ten envelopes ?
With a lot size of 10, we have the overall batch process time : 10f + t1 + 10su+ t2 + 10sl + t3 + 10st
With one piece flow, we have (if we assume from Eric’s datas that st < sl < su f) ?
Whereas the batch time formula doesn’t change, the one piece flow becomes…”
—————–
again sorry. Ron, if you could edit these, I would be grateful.
Matthieu
This is definitely the last one, but not everything i’m writing goes through
Am I so ill ?
With one piece flow, we have (if we assume from Eric’s datas that st < sl < su f)
should have been
With one piece flow we have (if we assume from Eric’s datas that st < sl < su f) : 10f + t1 + su + t2 + sl + t3 + st. Hence OPF clearly outperforms batch processing on that point.
But what if our transfer time (t1) gets bigger than folding (f) ?
Whereas the batch time formula doesn’t change, the one piece flow becomes…”
I’m looking for a place where to hide
Matthieu
Hi Ron, nice video despite the constraints you mention.
Although I passionately sell the idea of one-piece flow to my clients let me play devil’s advocate here. The logical end to this process would be to get the letters to the post office and suppose (for arguments sake) the post office was 10 minutes away. Therefore, delivering 10 letters on the basis of one-piece flow would take 200 minutes. By carrying 10 letters in one trip this can be done in 20 minutes … saving 180 minutes and a lot of gasoline. That’s significantly more than the 1 minute gained in actual production. I know some folks would say we have a balancing problem but there is no way you can cut down the travel time unless you move house next door to the post office and that we all know is not a feasible solution. Alternatively, you could convince the postal department to come to your door and pick up each letter the moment it is ready!! That would be something!!
Regards
Arup
Also a friend of one-piece-flow (as the ultimate solution or north star) I would prefer to do a SMED-approach.
What travels have to take that bring you close to the postoffice or just a post box?
Instead of doing the post deliver action as a single viewed action combine it with some other action (such as shopping, or visiting a customer or something that is regularly occurring) taking the post with you.
That will save another great deal of the time;-))
Best regards
Ralf
PS.: Always have a scope on the broader picture and what isn’t done today probably will lead to the ultimate solution of our problems.
OPF will have the advantage if it reduces the amount of product handling. In the presented scenario, where there was only one person doing the work, the handling was reduced, because the OPF approach eliminated the wasteful steps of adding a folded letter to a WIP pile and then picking it up again to put in an envelop, and then adding the stuffed envelop to a WIP pile only to then pick it up again to seal it, etc.
However, if each step of the process was performed by a different person, I don’t think this handling waste would actually be reduced; it would just be spread across 3 people. Piles of WIP would not accumulate, and lead time would be reduced, but the total effort to produce a finished part would be no less than for the 1-man batch process. Total effort might, in fact, be larger, because instead of moving a pile of WIP once, the “pile” (of 1 part) is moved for each and every part. If increased throughput is needed, might a better scenario be to have each of the 3 people doing all of the steps in parallel rather than each doing one step in series?
Also, I’m curious how you respond to the challenge that there are no economies of scale to be had with OPF? OPF processes are readily scalable via mass parallelization, but only linearly, meaning it takes X times as much effort, time and material (i.e., cost) to produce X times as much product. Done right, batch processes can do X times as much product (at the operation in question, at least) for less than X times the cost. One possible answer to my own question is that there is an often significant investment of time and effort required to develop (and validate) a scaled up batch process.
Finally, the shorter time until the first product is produced is only an advantage if you can release the product as soon as it is produced. If you need to wait until all product is made to release the batch, then this offers no advantage.
(edited for language)
YOU ARE THE ****!
Thank you very much for posting this video. When I first watched it, I was incredulous. I said he’s not doing it right, simulating the sealing and stamping is easier/faster than doing the actual job. I say this with confidence as a person who has to do the exact fold/stuff/seal/stamp routine on 350 pieces a month for my job. So today, I decided to recreate your experiment and timed myself doing 10 pieces in batch operations (the way I normally do this task) and 10 pieces using one piece flow. The result: batching took 4:42, OPF took 3:48.
It’s pretty obvious where the saving comes in – if you have steady process, you can cut the time between handoffs. The time saved between operations is plain to see. The most important lesson it taught me is that “problems can’t hide”. If the process or operator had a problem in the lean method, it would be found straight away and fixed. With mass production, you might need to go back and re-fold everything (say, to get the address in the window if there was one). Great stuff!
Hi ,I am intersted in comments in apparel and other factory on one piece flow and mass production .
Also please send me email about your comments on “Unit Production System”
Great video – thanks!
When I work as a consultant I try to make my customers think in one-piece flow. But I have to admit that I sometimes also try to sell them “batch production” – but just in smaller batches than they work with today.
The reason is that it sometimes leads to more waste to run one-piece flow. Like in an office or a production where a process it too short to justify a transportation for each product. Then I rather talk about frequency of transportation between processes. Where they today hand over products (papers or parts) e.g. every 2nd day (could be much longer!) they now change to e.g. 2 times per day.
I use a self-made example to illustrate one-piece flow at courses etc.
Round 1: 10 workstations. All products = LEGO bricks at workstation 1. Now the operator should assemble 10 “products” running back and forth with parts doing assembly.
Round 2: The LEGO bricks are now placed a 5 workstations with one-piece flow.
Round 2 is 30% faster than round 1.
Approx the same result as you get.
I would like to make a video with my example and share it with you once it is ready.
I was just thinking.. So say I want a solar panel on my roof, is the one-piece processing better for that? I’d place the order with a fitting company, they would then order it from a supplier. The supplier would then build then construct the solar panel, build it, test it and deliver it. Id’ then have it fitted.
Using mass production, would the item be in stock and already tested? Wouldn’t the customer see the item in days rather than the entire time it would take to produce the whole thing from scatch?
In the example you showed, it relies on the fact that a single operator is present. What if for each envelope you folded, you had to wait for the tree to be cut down for the paper by a single person? Batch processing a tree for all the paper is surelt more efficient in this case?
This is very informative, thanks! But as someone who has had to do this exact process of sending out brochures, I have come across a number of issues with OPF.
Your example has 4 steps and it is relatively easy to remember to do all steps. In my situation, I have had anywhere from 6-10 steps (multiple pages to be folded, return label, “please post” stamp) and it gets much more difficult to remember each step. You waste a lot of time going back to check that all 10 steps were completed for each piece.
Additionally, it a lot of cases, you need to match up a specific piece of paper with a specific envelope. For example, an uniquely addressed letter must go in the correct uniquely addressed envelope. If you find a mistake during OPF, you must go back and re-open many envelopes to find the incorrect one, wasting huge amounts of time, not to mention creating a lot of stress.
I like this process and I think this is a very clear way of presenting the Lean methodology …