Lean manufacturing and the ‘Seven deadly wastes’
The principal notion of lean manufacturing is quite simple; continuously working on eliminating waste from the manufacturing process. Lean manufacturing articles like to call this waste the “Seven Deadly Wastes”. Lean manufacturing concepts are techniques, practices and tools for combating waste. Waste is a term for unwanted materials. Everyone has waste including me since every Sunday night I drag garbage and recycling containers to the end of the street. In manufacturing it is a bit different. Waste can be of many forms. The idea is to eliminate everything that does not add value from the perspective of the customer.
The Seven Deadly Wastes are:
Everything needs transportation of some sort. But how do you minimize it in terms of times and distance. Every time a product is moved there is a potential of damage, delay or the product could be lost. It also pertains to transport inside our facility. A couple tips to minimize transport waste include minimizing work-in-process that goes to inventory. Also avoid changing job priorities. Once you setup a job, finish the job before you add another.
Manufacturing product that is either staged and waiting for the next process or is in finished goods is considered non-value added. In other words, it is quantities of product that is above supporting the immediate customer need. Bottom line is if product isn’t sold then it is money tied up into the material which the customer hasn’t bought yet. This is a burden on the company’s cash flow. Some tips for reducing inventory waste include bringing in raw materials only as they are needed. Reduce or eliminate buffers between steps in production.
Movement refers to people and equipment. Anytime an operator is searching for parts or moving equipment around they are not building product and making money. This is why being organized is very important. Because of the small runs we perform at OTTO, tools and components need to be in their place so that operators are spending the minimal time pulling equipment. Also make sure your workstations are sensibly organized. Not just neat and clean but parts and tools in advantageous locations to build with speed and quality. Components should be as close to the operator as possible to limit the reach lengths.
Waiting and Delays
This is the time that work-in-process is waiting for the next step in production. Not only is the product taking up space where damage can occur but if there is a quality issue you will not find out about it until there is a lot of suspect work-in-process. It is also costing the company money because the customer has not paid for it yet. A good tip is line balancing or making sure there are consistent times that are used for each step in production.
Overproduction shows up when processing is inefficient. If quality is poor one would overproduce because they don’t want to setup again in case of rejects. That also means that the setup takes too long. Now there is excess inventory that the company is paying for. Pace production so the rate of manufacturing matches the rate of demand.
This is one of the more difficult wastes to detect and eliminate. Knowing what the customer wants is very important. Precise communication from sales and the customer is key to making sure that over processing is not done. An example of this is individually bagging versus bulk packing. Individually bagging a product for the customer that may use many at the same time is inefficient. The customer has to rip open the bag instead of putting the parts bulk at their workstation. So money is lost on both ends. It costs more for OTTO to individually bag and it costs more to remove each component from the bag from the customer end.
Costs in the system are setup for no scrap. So when a sales person quotes a job to a customer they are assuming everything will run smooth. When there is scrap the salesperson cannot go back and ask for more money because we have rejects. Scrap costs money and time because you have to rebuild and pull new parts to finish the build. Not only that but it shows that your process is out of control. It also makes a company prone to returns and complaints from customers. A good tip is to look at the single most frequent reject and determine why it occurs.
You can be a detective. Look at your shop floor and see if you can identify any of the “Seven Deadly Wastes.” Then ask yourself if you can remove them from your processes.