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Lean Thinking and Methods
What is Lean?
By definition, lean manufacturing is the systematic elimination of waste from all aspects of an organization's operations, where waste is viewed as any use or loss of resources that does not lead directly to creating the product or service a customer wants when they want it. In many industrial processes, such non-value added activity can comprise more than 90 percent of a factory's total activity1. (More information about the types of waste in lean manufacturing.) Lean manufacturing – also known as lean, agile manufacturing, or Just-in-Time production – was originally developed by the Toyota Motor Company in Japan based on concepts pioneered by Henry Ford.
Nationwide, numerous companies of varying size across multiple industry sectors, primarily in manufacturing and service sectors, are implementing lean production, and experts report that the rate of lean adoption is accelerating. Companies generally choose to engage in lean production to boost company profits and competitiveness. These efforts have three primary objectives:
- Reduce production resource requirements and costs;
- Increase customer responsiveness; and
- Improve product quality.
How is Lean Manufacturing Different from Traditional Manufacturing?
Lean involves a fundamental paradigm shift from conventional "batch and queue" mass production to product-aligned "one-piece flow" pull production. Whereas "batch and queue" involves mass production of large lots of products in advance based on potential or predicted customer demands, a "one-piece flow" system rearranges production activities in a way that processing steps of different types are conducted immediately adjacent to each other in a continuous flow.
This shift requires highly controlled processes operated in a well maintained, ordered, and clean environment that incorporates principles of employee-involved, system-wide, continual improvement.
Lean Methods
There are numerous methods that organizations use to implement lean production; the most commonly used methods are listed below. A summary of the environmental implications of each method is also available.
While most of these methods are interrelated and can occur concurrently, most organizations begin by implementing lean techniques in a particular production area or at a "pilot" facility, and then expand use of the methods over time. Companies typically tailor these methods to address their own unique needs and circumstances. In doing so, they may develop their own terminology around the various methods.
Overall Lean Frameworks
Kaizen Rapid Process Improvement Events — Kaizen (Japanese for "to take apart and make good") refers to the continuous, incremental improvement of production activities. It is typically implemented through frequent, structured worker-oriented events that last 3-7 days.
Value Stream Mapping — A process mapping method used to document the current and future states of the information and material flows in a value stream from customer to supplier. Lean practitioners use value-stream maps to identify targets for future process improvement activities (e.g., kaizen events).
Process Improvement Methods
5S — An improvement process involving five steps (Sort, Set in order, Shine, Standardize, and Sustain) to create and maintain a clean, neat, and orderly workplace. Some organizations add a sixth "S" for Safety.
Standard Work & Visual Controls — Standard work represents the best ("least-waste") way to perform a given operation. Visual controls are used to reinforce standardized procedures and to display the status of an activity so every employee can see it and take appropriate action.
Cellular Manufacturing — An approach where manufacturing work centers (cells) have the total capabilities needed to produce an item or group of similar items; contrasts to setting up work centers on the basis of similar equipment or capabilities, in which case items must move among multiple work centers before they are completed.
Just in Time (JIT) / Kanban — Just in time is a production scheduling concept that calls for any item needed at a production operation – whether raw material, finished product, or anything in between – to be produced and available precisely when needed. Kanban (signals) are used to control levels of inventory and work in process.
Total Productive Maintenance (TPM) — An approach to enlist operators in the design, selection, correction, and maintenance of equipment to ensure that every machine or process is always able to perform its required tasks without interrupting or slowing down defect free production.
Six Sigma — A methodology and collection of statistical tools to reduce variation and improve business processes. Six sigma aims at a defect rate of no more than 3.4 defects per million chances.
Advanced Lean Enterprise Methods
Pre-Production Planning (3P) — The lean method for product and/or process design. 3P designs and implements production processes, tools, and equipment that support one-piece flow, are designed for ease of manufacturing, and achieve appropriate cost, quality, and lead time. Also known as Production Preparation Process.
Lean Enterprise Supplier Networks — A set of buyer-supplier relationships where organizations apply lean production concepts across the supply chain to reduce costs, delays, and other wastes.
Footnotes
1. Simon Caulkin. "Waste Not, Want Not." The Observer (September 2002)