This article is written by Brad Cairns who is in the cabinet business, but the same lean principles apply across various industries including ours.
If you endeavor to be a lean organization, then one would immediately think “The faster and leaner I can be, the better.” I wouldn’t ever disagree with that statement, but I would caution you. The old adage, “Slow and steady wins the race,” most definitely holds true.
More than likely you have embarked on your lean adventure because you saw a YouTube video, maybe you attended a conference, or perhaps you discovered lean between the pages of some amazing books written on the subject. Regardless of how you heard about lean, I’d be willing to bet some of these terms sound familiar: Kaizen (improvement), Muda (waste), SMED (Single minute exchange of dies), and the holy grail of lean, Single-Piece Flow.
For the purpose of this article, we are going to focus on single-piece flow. I feel like it’s the biggest trap for new, excited lean practitioners. First, let’s define single piece flow. The practice claims that if you make one unit and make it right from start to finish, there will be fewer defects, higher productivity and you will expose the waste. So, for us cabinet makers this is saying if you can build one cabinet from start to finish, it will be faster than the way we are doing it now. Sounds crazy right? Well, believe it or not, it’s true.
Whatever you do, keep reading! If you stop here, run out into your factory and demand to build one cabinet at a time ‘cause Brad said it would be faster, the only guarantee I can give you is that you will be immediately bankrupt.
Traffic jam lesson
Let’s look at an example of single piece flow I witnessed the other day. It was the first time outside of a factory I saw it failing, and it’s a situation we can all relate to. I was sitting in a long line of traffic, as I approached the intersection expecting some sort of accident, there was no such event. It was simply the traffic lights were not working, thus each driver had to treat the traffic light as a four-way stop. This forced us all right into “single-piece flow.” We were processing one car at a time through the intersection. Where typically the lights would handle the cars in big batches and there would not be such a significant delay.
Isn’t this proof that the batches we love so much have the concept of single piece flow beat? Nope. Here is the catch. A true single-piece flow assumes you have eliminated all the waste from the process. In the traffic example, we were forced into single-piece flow, but, we did not remove any of the waste. So, the waste we experience in our batch was applied to every single car, which made it infinitely worse.
In this scenario, we are battling the waste of transportation. Each vehicle has to traverse the entire length of the intersection before the next vehicle can go.
This means we are adding 50 feet of transportation waste to each vehicle, where in the batch processing with traffic lights we can fit three or four cars into the intersection at a time, thus making the process three or four times faster.
If all this holds true, how can the power of single-piece flow prevail? Let’s look at some options. First, scrap the traffic lights and put in a “roundabout.” This would reduce the amount of waiting associated with being stopped at a light when there are no other cars coming, and as soon as there is an opening you can scoot around the intersection. When traffic is heavy, there will still be some waiting to merge and such, but generally there will be better flow than being forced to come to a complete stop.
The next step to achieving single-piece flow in this scenario would be to build a bridge. Then cars could pass each other simultaneously one at a time, no need to stop and batch (traffic light) or slow to merge (roundabout), and we can all picture how much faster bridges would be.
How does this apply back at our factories? Step one is to establish the fundamental belief that single-piece flow is the end goal. However, don’t fall into the trap of doing it too fast. As in the traffic example, if you go to lean too fast, the waste will be insurmountable, and it will feel like the walls are crashing in around you. Your people will be working their fingers to the bone, productivity will tank, further adding to the confusion. We are all working way harder, how could it be getting worse? Take a much slower approach, you will discover limitations all around you. It could be the way orders are released to the shop, software, machines and defiant people!
Remember we are all programmed as batch producers, and a slow gradual shift will be much less painful.
When people are writing and teaching about lean practices, we all tend to speak in infinite terms such as “Eliminate” in the case of waste, “single-piece flow” in the case of production. This can cause a slight misconception and put people into the bad situation of too lean, too fast.
A much safer and more effective approach is to simply benchmark what you are doing now, and focus on a reduction. Let’s say you are releasing cabinets to your saw or router in batches of 60 boxes. Simply put a plan in place to slowly reduce that each week (or month) by 10.
With each reduction you will probably run into something that makes it seem like a bad idea. That’s your golden nugget of opportunity. Each time one of those pops up, work with your team to overcome that obstacle. When the dust settles, reduce it again.
Lean should be a big game of eliminating waste, a fun scavenger hunt.
Make it an enjoyable challenge for your people and watch their jobs become easier, quality go up, your productivity soar as costs go down. Remember, slow and steady wins the race!
Source: Woodworking Network
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in | September 01, 2019