Eliminating Waste in Lean Manufacturing
A Value Adding task is one that advances the product. Value must always be understood from the Customer's perspective. Value is “in the eyes of the Customer”. Sometimes, a quick and dirty way to ascertain whether a task is a value-adding task is to ask: Is the customer willing to pay for this? If the answer is no, then it is not a value-adding task.
What is Waste?
Waste is anything that detracts you from advancing the product towards the customer. Waste is work that does not contribute to the product's advancement and does not represent value to the customer.
It is important that you clearly understand that wasteful tasks are normally not a reflection on somebody's skills or attitude. In most cases, waste is a sign of a process that needs improving. So if you find waste in what you do, don't hide it but look for ways to reduce it or eliminate it.
Types of Waste
Waste comes in many forms and you may say “I know it when I see it”. But here is a standard classification of waste, known as “The Seven Forms of Waste”.
Overproduction is to make more than what is needed right now. This is the form of waste associated with building batches of parts. When you build more than is required immediately by the customer you are using resources (people, machines, and materials) that could have been used for another order. There sometimes is no choice but to build a batch, but that should not stop you from calling it what it is, waste. Overproduction is considered by many Lean experts as the worst of the Seven Wastes.
Transportation is the kind of waste that arises from moving the item. When products, parts, or components travel from process to process it is waste because during the transportation there is no physical change in the product, just a location change.
Motion waste also has to do with moving but not what but who. When operators move more than necessary to do the standard work, it is waste. When you have to walk to parts, waste. When you have to walk to get a tool, waste. When operators have to move a lot, that motion is disruptive to the product’s flow.
Waiting is the time you spend waiting for materials, components, a schedule, or anything you need to do your job. Wait time passes, and it is lost forever. No catch-up strategy will work. There are many reasons why wait time happens, but let’s go back to batch building. If you are the customer waiting on the first unit of that batch of 100, Unit One must wait for Unit One hundred. The fact that your order was first does not help you much when your order is included in a batch. If you ever found yourself waiting, it may very well have been because your supplier was working on a batch.
Over-processing is the waste that takes place when more work than necessary is done to a product. Over-processing can also be seen when overly complex parts or components are used, where simple ones will do. If a 4-inch weld seam will do but a 6-inch seam is applied, this may be a case of Over-processing.
Every time you see a pile of product lingering on the factory floor with no one is working on it you are seeing waste. The same goes for large quantities of parts that are ordered and held in stock for months on end. More inventory than what is needed right now, costs money. These costs come in the form of acquisition costs, storage costs, retrieval costs, and obsolescence costs. Inventory that is not moving is not adding value and if it not adding value it is waste.
When a process generates defects, those defects will either have to be corrected or they will go on to become a defective product. Any time defects go undetected they generate waste. This does not mean that we should hire only humans incapable of making mistakes. Mistakes happen, because we are human, even if we try hard not to make them. What is not OK is to let those mistakes go undetected and become defects.When a process generates defects, those defects will either have to be corrected or they will go on to become a defective product. Any time defects go undetected they generate waste. This does not mean that we should hire only humans incapable of making mistakes. Mistakes happen, because we are human, even if we try hard not to make them. What is not OK is to let those mistakes go undetected and become defects.
These are the seven forms of waste commonly known in industry. But I have one more for you to consider.
The waste of Human Potential is the waste that comes from not taking advantage of people’s natural desire to be a part of something good. Everybody wants to be part of the winning team and everyone has something to contribute to make the line, the process, the stage better. There is a lot of power in hundreds or thousands of brains looking for ways to improve the processes they work at. Don't waste this valuable resource!