Lean Manufacturing in Simple Terms: Reduction of Waste

One of the main objectives of the lean manufacturing process is to reduce the amount of waste that is created in the fabrication flow. It doesn't matter what the product is, if you're wasting raw materials and time while you are filling your customer's order, those are things you will probably never get back. More waste means less efficiency. Less efficiency translates to more costs. More costs means less profit. Well, you get the picture.

It really doesn't matter whether your job is manufacturing tractors, building bicycles, or baking cupcakes, having the right amount of material on hand, and coming up with a method that gets the job done with the least amount of effort in the least amount of time is always to your benefit. A lean manufacturing method is one that recognizes those steps that do not add value to your job, and eliminate them to the greatest possible extent.

Let's talk about some different kinds of waste, and cite some simple examples.

1. Excess production. If you have an order to deliver 24 cupcakes to your customer, you will probably want to make some extra ones, in case one is dropped on the floor while you are icing it. If that extra one keeps you from having only 23, requiring you to start the entire baking process over again, it has been a good thing to have, and should be a part of your plan. But how many extra pieces represent the right amount, and how many extra would be too many? If you discover over time that you only drop a cupcake about once per week, then making three extra with every batch is more insurance than you really need. Cutting back on overbuild with each batch reduces material costs and time for labor, and therefore, would make your process more lean, more efficient. Some of the numbers would change if you were able to sell these stale left-overs to someone down the road, but for the purpose of this discussion, we are assuming that they are thrown in the trash after the customer's order of 24 is filled.

The answer to this problem may be to know the metrics of your process well enough to understand how many extras are the correct quantity. Keeping track of how many you throw away each week may mean more paperwork, but it can pay off in the long run.

2. Queuing problems. When you have a production flow that is based on several people doing specialized tasks, and the flow gets interrupted at some point, the "downstream" workers are basically just standing around. That certainly doesn't fit in a lean manufacturing flow. In our cupcake kitchen, if you have people who just slap on the icing when the cupcakes are finished, and the oven breaks down, or the delivery of flour was late, there is no value added to the product when those workers are standing idle.

The answer to this problem may be to cross-train workers so that there is something else for them to do when there are no cupcakes to ice. Have your "icers" measuring out ingredients for the next batch, and you will be getting something done during their down time.

3. Motion and transport problems. Lean manufacturing is best carried out when the logistical flow of your fabrication is convenient. For example, if you are baking cupcakes in the kitchen, but for some strange reason you store all your sugar in the bedroom closet, you are going to spend a lot of time walking back and forth between the kitchen and the bedroom. Not only that, but with each new trip for sugar, you add the risk of dropping a container, and wasting that much raw material. Okay, this is a wild example, but the lean manufacturing point to be made is that one task in your process should be conveniently located next to where the previous task was performed, and where the following task will be performed.

The answer to this problem may be to lay out your work flow so that it eliminates extra transport, motion, and confusion. You can check this out by tracing out the usual path that is followed moving product from one step to the other. Your "spaghetti chart" can be an indicator that you have extra steps in the flow. Those extra steps do not add value to your product, and should be reduced to make a more economic lay-out.

4. Defective product problems. Almost all manufacturing systems suffer from some weakness that will result in a few substandard end-products. Good lean manufacturing methods require management of those weaknesses, so that the number of reject cupcakes is reduced to the lowest possible number. For example, if you discover that one side of the oven cooks hotter than the other, burning an occasional cupcake on that side, it may be time to get the oven fixed. While the repair may represent an overhead cost that will take awhile to recover, the value over the long haul will likely be worth it. Even if your cupcakes are slightly overcooked, your customer may notice the taste, and then silently decide to take his business to another baker.

The answer to this problem is to make sure your process routinely yields a high quality product. Following a lean manufacturing method will require you to frequently look at your processes and equipment to make sure that everything is working well.

If all of this is a bit overwhelming, and you need to start somewhere on your lean manufacturing focus, begin with the problem of overproduction. This is the most common area where waste is produced, and one of the easier places to trim. Maybe your business isn't cupcakes in the kitchen, but the same lean manufacturing techniques can improve your competitive edge in the marketplace, regardless of what product you make.