Glossary of Lean Manufacturing Terms
Andon board: a visual control device in a production area, such as a lighted overhead display. It communicates the current status of the production system and alerts team members to emerging problems.
Balancing the line: the process of evenly distributing both the quantity and variety of work across available work time, avoiding overburden and underuse of resources. This eliminates bottlenecks and downtime, which translates into shorter flow time.
Cell: an arrangement of people, machines, materials and equipment--with the processing steps placed right next to each other in sequential order--through which parts are processed in a continuous flow. The most common cell layout is a U shape.
Chaku-Chaku: a Japanese word that means “load-load.” It is a method of conducting single-piece flow in which the operator proceeds from machine to machine, taking a part from the previous operation and loading it in the next machine, then taking the part just removed from that machine and loading it in the following machine. Chaku-chaku lines allow different parts of a production process to be completed by one operator, eliminating the need to move around large batches of work-in-progress inventory.
Continuous flow: a concept where items are processed and moved directly from one processing step to the next, one piece at a time. Also referred to as “one piece flow” and “single piece flow.”
Cycle time: the time required to complete one cycle of an operation. If cycle time for every operation in a complete process can be reduced to equal takt time, products can be made in single-piece flow.
Error proofing: a process used to prevent errors from occurring or to immediately point out a defect as it occurs. If defects don’t get passed down an assembly line, throughput and quality improve. See “poka-yoke.”
Feeder lines: a series of special assembly lines that allow assemblers to perform preassembly tasks off the main production line. Performing certain processes off the main production line means fewer parts in the main assembly area, the availability of service-ready components and assemblies in the main production area, improved quality and less lead time to build a product.
Flow: the progressive achievement of tasks along the value stream so that a product proceeds from design to launch, order to delivery, and raw materials into the hands of the customer with no stoppages, scrap or backflows.
Jidoka: one of the two pillars of the Toyota Production System. It provides machines and operators the ability to detect when an abnormal condition has occurred and immediately stop work. Jidoka highlights the causes of problems when they first occur. This leads to improvements in build-in quality by eliminating the root causes of defects.
Just-in-time: the second pillar of the Toyota Production System. It is a system for producing and delivering the right items at the right time in the right amounts. The key elements of just in time are flow, pull, standard work and takt time.
Kaizen: a Japanese word that means “continuous improvement.” It refers to small, incremental improvement of an activity to create more value with less waste. A kaizen event is a highly focused, action-oriented workshop that typically involves a team of five to 15 individuals. It usually lasts three to five days. The goal of a kaizen event is to concentrate on improving one specific process.
Kaizen teian: a Japanese term that means “continuous improvement proposals” or improvement through suggestion. It focuses on participation rate, rather than the value of specific ideas. The emphasis is on encouraging individual operators to continuously make improvements. Kaizen teian suggestions are usually small-scale ideas confined to the operator’s workcell that are easy, cheap and quick to implement.
Kanban: a Japanese word that means “card” or “visible record.” It refers to a small card attached to boxes of parts that regulates pull by signaling upstream production and delivery.
Kitting: a process in which assemblers are supplied with kits--a box of parts, fittings and tools--for each task they perform. This eliminates time-consuming trips from one parts bin, tool crib or supply center to another to get the necessary material.
Lead time: the total time a customer must wait to receive a product after placing an order.
Lean manufacturing: a manufacturing philosophy that shortens the time between the customer order and the product build and shipment by eliminating sources of waste. It attacks waste within a plant or process; waste elimination results in cost reduction.
One-piece flow: the opposite of batch production. Instead of building many products and then holding them in queue for the next step in the process, products go through each step in the process one at a time, without interruption. It improves quality and lowers costs.
3P: the production preparation process is a tool used for designing lean manufacturing environments. It is a highly disciplined, standardized model. 3P results in the development of an improved production process where low waste levels are achieved at low capital cost.
Point of use: a technique that ensures people have exactly what they need to do their job--the right work instructions, parts, tools and equipment--where and when they need them.
Poka-yoke: a Japanese word that refers to a mistake-proofing device or procedure used to prevent a defect during the production process. See “error proofing.”
Pull production: the opposite of push production. It means products are made only when the customer has requested or “pulled” it, and not before. Doing so prevents building products that are not needed.
Right sizing: a process that challenges the complexity of equipment. It examines how equipment fits into an overall vision for how work will flow through the factory. When possible, right sizing favors smaller, dedicated machines rather than large, multipurpose, batch-processing machines.
5S: a lean tool used for workplace organization and standardization. Benefits include prompt problem detection and clear standards. In addition, routine disciplines are established to keep the workplace in order and ensure that materials are in the correct location to maximize productivity. The 5S’s are sifting, sweeping, sorting, sanitizing and sustaining.
Sanitizing: one of the 5S’s used for workplace organization. Sanitizing is the act of cleaning the work area. Dirt is often the root cause of premature equipment wear, safety problems and defects.
Sifting: one of the 5S’s used for workplace organization. Sifting involves screening through unnecessary materials and simplifying the work environment. Sifting is the separating of the essential from the nonessential.
Simulation: a 3D technique used to balance the line. It involves using cardboard, wood and plastic foam to create full-sized equipment mock ups that can be easily moved around to obtain an optimum layout.
Single-piece flow: a process in which products proceed, one complete product at a time, through various operations in design, order-taking and production without interruptions, backflows or scrap.
Six Sigma: a standard of operational excellence used in lean manufacturing environments. It is a process that designs and monitors everyday business activities in ways that minimize waste while increasing customer satisfaction. Six Sigma objectives are directly and quantifiably connected to the objectives of the business.
Sorting: one of the 5S’s used for workplace organization. Sorting involves organizing essential materials. It allows the operator to find materials when needed because they are in the correct location.
Standardized work: a precise description of each work activity specifying cycle time, takt time, the work sequence of specific tasks and the minimum inventory of parts on hand needed to conduct the activity.
Standard work instructions: a lean tool that enables operators to observe the production process with an understanding of how assembly tasks are to be performed. It ensures that the quality level is understood and serves as an excellent training aid. It enables absentee replacement individuals to easily adapt and perform the assembly operation.
Sustaining: one of the 5S’s used for workplace organization. Sustaining is the continuation of sifting, sweeping, sorting and sanitizing. It is the most important and the most difficult, because it addresses the need to perform the 5S’s on an on-going and systematic basis.
Sweeping: one of the 5S’s used for workplace organization. Sweeping involves collecting nonessential goods and removing them from the work area.
Takt time: a reference number that is used to help match the rate of production to the rate of sales. In other words, the rate at which customers require finished units. It is determined by dividing the total available production time per shift by the customer demand rate per shift. “Takt” is a German word for pace or beat.
Toyota Production System (TPS): a system developed by Toyota Motor Corp. to provide best quality, lowest cost, and shortest lead time through the elimination of waste. It is often illustrated as a “house” comprised of two pillars: Just-in-time and Jidoka. TPS is maintained and improved through iterations of standardized work and kaizen.
Value: a capability provided to a customer at the right time at an appropriate price, as defined by the customer.
Value stream: the specific activities required to design, order and provide a product, from concept to launch, order to delivery, and raw materials into the hands of the customer. Whenever there is a product for a customer, there is a value stream. Up to 90 percent of the actions and 99.99 percent of the time along a typical value stream can consume resources, but create no value for customers.
Value stream mapping: the process of directly observing the flows of information and materials as they now occur, summarizing them visually, and then envisioning a future state with much better performance. It raises consciousness of the enormous waste of time, effort and movement that occurs. The relevant actions to be mapped consist of two flows: orders traveling upstream from the customer and products coming downstream from raw materials to the customer.
Visual controls: any devices, such as andon boards, that help operators quickly and accurately gauge production status at a glance. Progress indicators and problem indicators help assemblers see when production is ahead, behind or on schedule. They allow everyone to instantly see the group’s performance and increase the sense of ownership in the area.
Waste: anything that does not contribute to transforming a part to the customer’s needs. There are seven types of manufacturing waste: production over immediate demand; excess work in progress and finished goods inventories; scrap, repairs and rejects; unnecessary motion; excessive processing; wait time; and unnecessary transportation.
Work in process (WIP): items between machines or equipment waiting to be processed.