Lean manufacturing: The Seven Deadly Wastes
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Manufacturers over the world are adapting the lean manufacturing approach to minimize or eliminate waste and maximize value on their manufacturing processes. Lean manufacturing essentially involves eliminating waste. It takes into account the overburdening on resources and unevenness of the workload to ensure even distribution of work and zero to minimal wastage of time, money and resources-the factors which affect the profitability of a business the most. The overall positive impact of lean manufacturing can be seen on several fronts like productivity, space, delivery, etc.
Lean manufacturing is focused on eliminating these drains of time and money, commonly referred to as the Seven Deadly Wastes.
This type of waste refers to unnecessary movement of finished goods, raw materials, or work-in-process. It can be eliminated by:
- Designing a seamless and sequential flow from raw materials to finished goods
- Ensuring that work-in-process is never placed into inventory
- Maintaining continuity and consistency in assigning job priorities
- Using high precision equipment
Excess products including raw materials, works-in-process, or finished goods which exceed the immediate need is known as inventory waste. It can be reduced by:
- Purchasing raw materials only as and when needed
- Reducing or eliminating buffers between the production steps
This type of waste refers to unnecessary motion or movement of people which does not add value. It can be controlled by:
- Designing smarter and logically organized work areas
- Considering changing equipment arrangement if the original placement requires extra movement of people involved
- Using equipment for higher efficiency such as forklift scales, conveyor scales, etc., to reduce unnecessary motion
When there is work-in-process waiting to move to the next step in production, time is being wasted and no value is being added. This type of waste is described as waiting. To reduce this waste, it would help to look at the time spent from order to shipment and determine the actual amount of time spent on true value-added manufacturing. This waste can be eliminated or reduced by:
- Making processes as seamless as possible so that there are minimal or no buffers in between the production steps
- Incorporating standardized instructions so that a consistency in the method and time required for each production step is maintained
This is one of the most serious forms of waste, as it results in excess inventory which often is used to disguise other inefficiencies and problems in the system. It involves production of something before it is needed. To handle this type of waste:
- Reduce setup times so that the size of the batches can be reduced, and they can be economically manufactured
- Employ a pull system to control the manufacturing capacity
- Adjust production pace so that the rate of manufacturing matches the rate of customer demand
This type of waste is more difficult to detect and eliminate. It is created when there is more processing than is necessary to meet the consumer demands. It can be eliminated by:
- Identifying potential simplifications in the manufacturing process
- Comparing customer requirements with manufacturing specifications to eliminate over-processing
The production which requires rework or is scrap is referred to as defects. Such defects can be handled by:
- Transforming process design to produce less defects
- Making processes smart enough to detect abnormalities so that they can be rectified immediately
- Identifying the single most frequent fault and determine the reason behind its occurrence
- Incorporating a process protocol which brings consistency to the manufacturing method
Kevin Hill heads the marketing efforts at Quality Scales in Byron, Calif.