Lean Manufacturing

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Lean Manufacturing

Lean Manufacturing is the term our country uses to describe the Toyota Production System (TPS).  Thousands of U.S. executives, engineers, and manufacturing technicians have traveled to Japan to visit Toyota to learn how to achieve very high quality while maintaining competitive prices and a very well paid workforce.

Lean Manufacturing involves the following concepts:

andon - a system of flashing lights used to indicate production status in one or more work centers; the number of lights and their possible colors can vary, even by work center within a plant; however, the traditional colors and their meanings are:
green - no problems
yellow - situation requires attention
red - production stopped; attention urgently needed
autonomation - in Toyota parlance, automation with a human touch; English translation of jidoka.

baka-yoke - a manufacturing technique of preventing mistakes (error-proofing) by designing the manufacturing process, equipment, and tools so that an operation literally cannot be performed incorrectly; an attempt to perform incorrectly, as well as being prevented, is usually met with a warning signal of some sort; the term poka-yoke is sometimes referred to as a system where only a warning is provided.

cellular manufacturing - an approach in which 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; the term group technology is sometimes used to distinguish cells that produce a relatively large family [group] of similar items.

cycle time - the normal time to complete an operation on a product. This in NOT the same as takt time, which is the allowable time to produce one product at the rate customers are demanding it.

error-proofing - a manufacturing technique of preventing mistakes (baka-yoke) by designing the manufacturing process, equipment, and tools so that an operation literally cannot be performed incorrectly; an attempt to perform incorrectly, as well as being prevented, is usually met with a warning signal of some sort; the term poka-yoke is sometimes referred to as a system where only a warning is provided.

flexible manufacturing system - an integrated manufacturing capability to produce small numbers of a great variety of items at low unit cost; an FMS is also characterized by low changeover time and rapid response time. 

heijunka - A production scheduling/leveling tool, essentially to distribute kanban cards in an efficient manner.

jidoka - a Japanese word which translates as autonomation; a form of automation in which machinery automatically inspects each item after producing it, ceasing production and notifying humans if a defect is detected; Toyota expands the meaning of jidoka to include the responsibility of all workers to function similarly, i.e. to check every item produced and to make no more if a defect is detected, until the cause of the defect has been identified and corrected.

jishu kanri - self-management, or voluntary participation.

just-in-time - a production scheduling concept that calls for any item needed at a production operation - whether raw material, finished item, or anything in between, to be produced and available precisely when needed, neither a moment earlier nor a moment later.

jutsu - to talk, or ‘the art of’ (i.e., 'leanjutsu: the art of lean production').

kaikaku - A rapid and radical change process, sometimes used as a precursor to kaizen activities.

kaizen - the philosophy of continual improvement, that every process can and should be continually evaluated and improved in terms of time required, resources used, resultant quality, and other aspects relevant to the process.

kanban - a card or sheet used to authorize production or movement of an item; when fully implemented, kanban (the plural is the same as the singular) operates according to the following rules:

  1. All production and movement of parts and material take place only as required by a downstream operation, i.e. all manufacturing and procurement are ultimately driven by the requirements of final assembly or the equivalent.


  2. The specific tool which authorizes production or movement is called a kanban. The word literally means card or sign, but it can legitimately refer to a container or other authorizing device. Kanban have various formats and content as appropriate for their usage; for example, a kanban for a vendor is different than a kanban for an internal machining operation.


  3. The quantity authorized per individual kanban is minimal, ideally one. The number of circulating or available kanban for an item is determined by the demand rate for the item and the time required to produce or acquire more. This number generally is established and remains unchanged unless demand or other circumstances are altered dramatically; in this way inventory is kept under control while production is forced to keep pace with shipment volume. A routine exception to this rule is that managers and workers are continually exhorted to improve their processes and thereby reduce the number of kanban required.

karoshi - death from overwork.

lean manufacturing or lean production - the philosophy of continually reducing waste in all areas and in all forms; an English phrase coined to summarize Japanese manufacturing techniques (specifically, the Toyota Production System).

line balancing - equalizing cycle times [productive capacity, assuming 100% capacity utilization] for relatively small units of the manufacturing process, through proper assignment of workers and machines; ensures smooth production flow.

[Back to Definitions]

mixed-model production - capability to produce a variety of models, that in fact differ in labor and material content, on the same production line; allows for efficient utilization of resources while providing rapid response to marketplace demands.

mizusumashi - the classic 'water spider', who performs a wide range of tasks which allow workers to perform 'value-added' tasks.

mokeru - the Japanese term for the industrial engineering, more properly translated as ‘profit-making I.E.’.

muda (waste) - activities and results to be eliminated; within manufacturing, categories of waste, according to Shigeo Shingo, include:

  1. Excess production and early production
  2. Delays
  3. Movement and transport
  4. Poor process design
  5. Inventory
  6. Inefficient performance of a process
  7. Making defective items

mura - inconsistency

muri - unreasonablness

nagara - smooth production flow, ideally one piece at a time, characterized by synchronization [balancing] of production processes and maximum utilization of available time, including overlapping of operations where practical.

ninjutsu - the art of invisibility (applies to management)

poka-yoke - a means of providing a visual or other signal as to the location or condition of a part characteristic. Often referred to as 'error-proofing', poke-yoke is actually the first step in truly error-proofing a system (see baka-yoke).

pull system - a manufacturing planning system based on communication of actual real-time needs from downstream operations ultimately final assembly or the equivalent - as opposed to a push system which schedules upstream operations according to theoretical downstream results based on a plan which may not be current.

5S - refers to the five words seiri, seiton, seison, seiketsu, shitsuke. These words are shorthand expressions for principles of maintaining an effective, efficient workplace

  • seiri - eliminating everything not required for the work being performed
  • seiton - efficient placement and arrangement of equipment and material
  • seison - tidiness and cleanliness
  • seiketsu - ongoing, standardized, continually improving seiri, seiton, seison
  • shitsuke - discipline with leadership
(Like many concepts, the 5S can be interpreted narrowly or broadly, depending on circumstances of their use.)

seiban - Seiban is the name of a Japanese management practice taken from the Japanese words "sei", which means manufacturing, and "ban", which means number. A Seiban number is assigned to all parts, materials, and purchase orders associated with a particular customer job, or with a project, or anything else. This enables a manufacturer to track everything related with a particular product, project, or customer. It also facilitates setting aside inventory for specific projects or priorities. That makes it great for project and build-to-order manufacturing.

sensei - one who provides information; a teacher, instructor, or rabbi.

setup time - work required to change over a machine or process from one item or operation to the next item or operation; can be divided into two types:

  1. internal: setup work that can be done only when the machine or process is not actively engaged in production; OR
  2. external: setup work that can be done concurrently with the machine or process performing production duties.

saki - a rice wine, preferrably served warmed.

shojinka - continually optimizing the number of workers in a work center to meet the type and volume of demand imposed on the work center; shojinka requires workers trained in multiple disciplines; work center layout, such as U-shaped or circular, that supports a variable number of workers performing the tasks in the layout; the capability to vary the manufacturing process as appropriate to fit the demand profile.

SMED - abbreviation for Single Minute Exchange of Die; literally, changing a die on a forming or stamping machine in a minute or less; broadly, the ability to perform any setup activity in a minute or less of machine or process downtime; the key to doing this is frequently the capability to convert internal setup time to external setup time; variations on SMED include:

sushi - raw fish, particularly good for your health and heart, and available in wide variety.

  1. Single-digit setup: performing a setup activity in a single-digit number of minutes, i.e. fewer than ten.
  2. OTED: One touch exchange of die; literally, changing a die with one physical motion such as pushing a button; broadly, an extremely simple procedure for performing a setup activity.

takt time - takt, is a German term for rhythm. Takt time is the allowable time to produce one product at the rate customers are demanding it. This is NOT the same as cycle time, which is the normal time to complete an operation on a product (which should be less than or equal to takt time).

teian - a proposal, proposition, or suggestion. A teian system can be likened to a system which allows and encourages workers to actively propose process and product improvements.

Toyota - changed from the true form, Toyoda, meaning abundant rice field, by the Toyota marketing department. Toyoda is the family name of the founders of the Toyota Motor Company.

water spider - one who performs a wide range of tasks which allow workers to perform 'value-added' tasks.

WCM - world class manufacturing is the philosophy of being the best, the fastest, and the lowest cost producer of a product or service. It implies the constant improvement of products , processes, and services to remain an industry leader and provide the best choice for customers, regardless of where they are in the process.


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Last updated: April 30, 2002.