What Is Waste?
There are 7 wastes of lean manufacturing that are commonly referenced. Before considering these 7 types of waste though, it is important to consider what is meant by the term waste. Waste can be defined as any activity that consumes resources but creates no value for the customer. It is an activity that the customer is not willing to pay for. Within most business processes, the activities that actually create value as perceived by the customer make up a small percentage of the total activities. Reducing the number of these wasteful activities represents a significant opportunity for businesses to improve their performance. Elimination of the 7 wastes of lean can reduce costs, increase profits, improve employee engagement, reduce rework and improve delivery time. The lean process of plan, do check and act is a fundamental part of identifying and then eliminating waste or muda.
Muda. It’s the one word of Japanese you really must know. It sounds awful as it rolls off your tongue and it should, because muda means “waste,” specifically any human activity which absorbs resources but creates no value: mistakes which require rectification, production of items no one wants so that inventories and remaindered goods pile up, processing steps which aren’t actually needed, movement of employees and transport of goods from one place to another without any purpose, groups of people in a downstream activity standing around waiting because an upstream activity has not delivered on time, and goods and services which don’t meet the needs of the customer.
Lean Thinking~ James P. Womack & Daniel T. Jones
The 7 Wastes of Lean Manufacturing
Waiting is perhaps the most obvious of the 7 wastes of lean manufacturing. It is easily identifiable as lost time due to poor flow: parts shortages, bottlenecks, and equipment breakdowns. In an office based environment, this may take the form of slow software loading times or waiting for an important phone call. This is also frustrating for the employees involved, which can lead to reduced morale.
Over production is the most important of the 7 types of waste. It is building more of a product than the customer ordered or wanted. Remembering that waste is anything for which the customer is not willing to pay, it is easy to see why over production is a waste. However over production actually drives all of the other six types of waste as well. The excess product now has to be stored somewhere which means excess motion, transportation and inventory. Also, over production means that if a reject is found, there will be more units that need to be reworked.
Parts that do not comply with the specifications of the customer lead to rework. Worse still they can lead to scrap and the necessary production of new parts. Usually, rejects have to be sent back down the production line again to be put right. This consumes valuable production time. Sometimes a separate rework area is required, which increases labour and duplicates tooling.
This is wasted movement that is made while working. It could take the form of having to walk to another area to collect a tool, part or document. It also covers searching for things in a messy environment. A classic example is sorting through piles of paperwork to find the one form required at that moment to complete the job.
This is work that adds no value for the customer or business. This usually takes the form of over engineering a product: unnecessary features that the customer does not use, but that increase the cost to the business. This could be maintaining paint finish or other tolerances, more tightly than is required by the customer. Another example is building a product that will last for five years when the customer is going to replace it after two.
Excess material, work in process or finished goods. Excess inventory represents cash tied up in the form of material, which is difficult to turn into cash quickly. Inventory also takes up space. It has to be managed, stored and can become obsolete leading to scrap. The quality of inventory can deteriorate over a period of time, especially perishable items such as food or rubber seals.
Unlike excess motion which is wasted movement of people, transportation is excess motion of work in process. This can be at the process level or the value stream level. At the process level, excess transportation can be having machines too far apart so that parts need to be moved on a fork lift truck. At the value stream level, excess transport can be moving finished parts or components between facilities and not consolidating the transport.
How to remember the 7 Wastes of Lean Manufacturing
There is a simple way to remember the 7 wastes of lean manufacturing: simply remember the rather silly acronym WORMPIT!
- Over production
- Motion (Excess)
- Processing (Over)
If you can remember WORMPIT, you can easily use each letter to recall the 7 wastes of lean manufacturing.