We quite often get calls, or find ourselves in a conversation where somebody is inevitably asking, “What’s the leanest way to lay out my factory”?
This is always a delicate subject because it is important that all machines are located in the right spot based on lean principles, but it’s not that decisive. There isn’t a lean layout, and a not lean layout. We have to remember the essence of lean is continuous improvement, which means everything is changing all the time. Whether we like it or not, that includes our brain, our processes and, yes, our factories. So as you read on and develop a plan for where you’re going to put all of your equipment and workstations, keep in mind rule number one of factory planning is “no monuments.” Check out this youtube video on monuments https://youtu.be/YahEUkJI7Xc
To illustrate this point, at my own factory our maintenance engineer threatened to put our CNC routers on wheels we shuffle the factory around so much. This was officially the fourth time in 12 months that we moved around our entire factory. And I don’t just mean we moved a table saw. I’m talking about complete factory makeover, we moved every single machine, electrical connection & dust pipe, yes, the whole kit and caboodle.
One step at a time
It’s really important to step your way through the process from receiving the material to shipping the product one step at a time. Don’t think about Step 10 while you’re thinking about Step 1. Just think about how do we unload trucks, make that as efficient as possible. Then when we transport raw goods to our machinery, how do we make that distance as short as possible.
If you’re thinking about assembly and packaging at the same time you’re thinking about loading machines, you may skew reality at Step 1 for what you think is going to be good for Step 10.
Here are seven steps that should dramatically improve your layout planning.
Step 1: At the heart of a good factory layout is one pretty easy concept. All we’re trying to do is reduce the distance a component travels from the time the raw material comes in the door, until the time the finished goods leave the building. Inside of that, there are all kinds of concessions needed for people and machines. But this is the ultimate goal. I will quote Henry Ford when it comes to plant layouts, he said “machines should be as close as they can possibly be together, but they ought not to be one inch further away than they have to be."
Step 2: Find a way to get a scale model of your factory and all the machines. This can be as simple as paper and a cork board, or as advanced as 3-D modelling. The moral of the story is use what you’ve got! Some of the best success I’ve had with plant layouts we actually cut out wooden blocks of all the machines so we could move them around like board game pieces. Or scraps of paper on the kitchen table get the job done as well. The only trap here is falling in love with your first idea, make sure you wipe the slate clean and come up with at least three or four possibilities.
A great way to accomplish this is to include your team, giving everyone a voice on the new layout. Try to incorporate one small idea from everybody. This will minimize the pushback from the production staff when you finally make the move.
Step 3: Identify your bottleneck. The reason you need to know your bottleneck is because you have to protect it. Any other station in your factory can go down for a short period of time without affecting throughput, except your bottleneck. So you want to make sure you put a buffer of work before your bottleneck and a “just in case” area after it.
The buffer before the bottle neck should always have a predetermined amount of work. A half a day’s work is really tight, two days’ work would probably be a little too much. How do you determine this relates to deciding how long are you going to need to fix your most likely breakdown. That way, if that bad thing happens, the bottleneck can keep working. And the “just in case” area should be able to hold the same amount of work in the event the bad thing happens after the bottleneck.
Step 4: You’re going to need to have a good idea of statistical fluctuations within your factory. For example: If you’re a cabinet shop (abiding by the 80/20 rule of course) within that 80 percent of your production, what is the fastest thing to build, and what is the slowest thing to build? Then make sure your work buffer between stations will not run out of work based on that calculation. This means if you have two stations working an assembly line, Station 1 ends up with the slow build item, and Station 2 does not run out of work before Station 1 completes that task.
Step 5: You should have a really good idea of how much you want your factory to produce. You can build a lot of assumptions around some pretty reliable averages in the cabinet making world. Here are a few
- 1.8 man hours per cabinet is good, if you’re above four hours, I would consider calling in some outside help.
- Batch sizes between 10 and 15 cabinets usually work out really well.
- 1 CNC can cut between 80 and 120 sheets per day when you're cutting cabinet parts.
- If you’re a kitchen producer, don’t underestimate your finished goods storage. You know as well as I do, contractors are never on time!
Step 6: Try to build in some flexibility with your layout. The only things that really keep a machine in one spot are air, electricity and dust collection. A good idea is to roll up about 10 to15 feet of wire above the machine so if you find you need to move it a bit one way or another, it’s not a big hassle. Your other challenge is always dust collection the snap together pipes are great for this purpose, albeit expensive, so if that’s not in the budget, just get good at cutting pipe.
Step 7: Test your layout before you move anything. Some good measurables are:
- Total linear feet travelled from start to finish
- Total work in progress (WIP)
- Number of people required
- Physical steps of each operator to complete their task
And there’s nothing that says any of these measurements are right or wrong, just try to improve them with every iteration of your layout.
Last but not least, it never hurts to ask a friend or a professional to give it a once over. There’s a good chance you’ve been staring at it for a week and could be blind to some obvious improvements, or at least you can sleep at night knowing somebody else has validated your ideas
PS- There is also one other factor when it comes to layouts, just remember you can’t get everything right the first time! Expect some hiccups and some bumps in the road. Accept that you may have to move a few things that are a real pain in the butt after the fact. So long as you’re expecting this to happen, then it’s not such a daunting task when it does
Now, stop reading, get out into your factory, and just move that thing you’ve been dying to move for three months. FIX WHAT BUGS YOU!
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