Toyota Production System (TPS) Terminology
This reference guide explains some of the special terms used on a daily basis at jobsites at Toyota Motor Manufacturing. It is our hope that this glossary of special terms will be of use to anyone wishing to further their understanding of the Toyota Production System.
Definitions obtained to create this guide are from the following sources and are to be used for educational purposes only:
Toyota Motor Manufacturing, TMMK, Georgetown, 2007 (Toyota Production System Terms)
TPS Glossary, Toyota (Hand Book)
University of Kentucky, Institute of Research for Technology Development, Lean Systems Program(2008-2013©)
A type of visual control that displays the current state of work (i.e., abnormal conditions, work instructions, and job progress information). It is one of the main tools of Jidoka.
Often in the form of an electrical board which lights up to show at a glance the current state of work operations. Andon boards allow speedy corrective action to be taken by supervisors when a problem arises. Besides indicating abnormal situations, some Andons provide work instructions (such as quality checks, change of cutting tools and conveyance of parts) and job progress information.
Continuous Flow Processing
One of the three basic requirements of Just-In-Time. This means eliminating the stagnation of work in and between processes and carrying out one-piece-at-a time production.
The total amount of time required for a worker to complete one cycle of his entire job process, including manual working time and walking time.
A system that modifies preceding production processes to keep a minimum inventory of finished parts, and produce only enough to replace, or fill-up those parts withdrawn by the following process.
The so-called 5Ws and 1 H (who, what, where, when why and how) are used in analyzing production processes. To search for the true cause of problems, instead of asking “why” once, it is repeated five times.
Flexible Manpower Line
This means preparing a production line so that it can meet changing production requirements with any number of workers without lowering productivity.In contrast, a fixed-manpower line is one that always requires a fixed number of workers. No upward or downward adjustment can be made in it to meet changes in production demand.
The four S’s are the corresponding Japanese and English terms of Seiri-Sifting, Seiton-Sorting, Seiso-Sweeping, and Seiketsu-Spick and Span. Collectively they mean the maintenance of an orderly, clean and efficient working environment.Sometimes a fifth S in Japanese is added: Shitsuke indicating worksite discipline.
Increasing the delivery frequency of parts in order to keep the inventory at each process to a minimum. To do this without lowering the load efficiency of vehicles (i.e. without increasing the total runs made by all vehicles) calls for mixed loading.
Means go and see for yourself. Go see the problem. This is the belief that practical experience is valued over theoretical knowledge. You must see the problem to know the problem.*Get your boots on; common phrase used at TMMK.
Goals (with targets) and means for achieving it to address business priorities and to move the organization to a new level of performance; variable from year-to-year; could also be multi-year; and is developed by executive management.
Jidoka along with Just-In-Time, is one of the two main pillars of the Toyota Production System. It refers to the ability of production lines to be stopped in the event of such problems as equipment malfunctions, quality problems or work being late either using machines which have the ability to sense abnormalities or using workers who push a line-stop button. This prevents passing on defects. Reoccurrence prevention becomes simpler as abnormalities become more obvious making it possible to “build in quality at the production process”.At the same time, since defects are prevented automatically, inspectors become unnecessary, which in turn results in significant labor savings.
Management driven kaizen activity where management members identify areas in need of continuous improvement and spread information through the organization to stimulate kaizen activity.
One of the two pillars of the Toyota Production System, Just-In-Time refers to the manufacturing and conveyance of only what is needed, in the amount needed. This enhances efficiency and enables quick responses to change. Just-In-time presupposes Leveled Production (Heijunka) and is build upon the three basic operating principles of the pull system, continuous flow processing and Takt Time.
Muda (non-value added) exist everywhere related to people, material and facilities, or the production set-up itself.Kaizen refers to the series of activities whereby instances of Muda are eliminated one by one at minimal cost, by workers pooling their wisdom and increasing efficiency in a timely manner. Kaizen activities typically empphasize manual work operations rather than equipment. Also, Kaizen is not an activity to be performed by a specialist, but can be – in fact should be – performed by all employees at each job site.
This is a small signboard that is the key control tool for Just-in-Time production.Kanban serves:
Instruction for production and conveyance
A tool for visual control
To check against over production
To detect irregular processing speeds
A tool to perform kaizen
The functional categories of Kanban are:
1-card kanban (referred to as Production Kanban)
2-card kanban (referred to as Withdrawal Kanban)
Part Specific kanban (used for single part family or grouping)
Route Specific kanban (used for mix production)
CONWIP (CONstant Work In Progress)
Partial replacement of manual labor by machines. The savings on labor; however, is not to the extent of saving one unit of manpower.
Heijunka is the overall leveling in the production schedule of the variety and volume of items produced in given time periods. This is a prerequisite for Just-in-Time production.
This means improving work procedures, machinery and equipment to free workers from particular jobs on a production line consisting of one or more workers.
The term used when any plant transport vehicle is loaded with more than one type pf parts.Use of mixed loading makes it possible to increase frequency of delivery without lowering conveyance efficiency, i.e. without increasing the total number of deliveries. This in turn allows the amount of inventory kept at each process to be decreased. It also permits the delivery schedules to be more easily adjusted according to production changes.
Preliminary work to involve other sections/departments in discussion to seek input, information and/or support for a proposal or change (policy, etc.) that would affect them.Also means to “prepare the soil.”
Muda (non-value added)
Muda (non-value added – usually translated as waste) refers to those elements of production that add no value to the product and only raise costs:
- Muda of Over-Production
- Muda of Waiting
- Muda of Conveyance
- Muda in Processing
- Muda in Inventory
- Muda of Motion
- Muda of Correction
Muda of Over Production
Just-In-Time production is an ironclad rule at Toyota and producing anything 1) earlier than needed or 2) in greater volumes than needed (as indicated by kanban or other indicators) results in excess inventory and is known as muda or over production. This muda often hides muda of waiting and muda of motion. It also leads to muda by an increase in the number of conveyance vehicles and pallets. Among the different kinds of muda, muda of over-production is the most serious.
Muda of Waiting
This refers to a situation where a worker who has been working according to a standardized work sequence finds himself unable to process to the next job. This often occurs due to the volume of work being low.
Muda in Conveyance
Conveyance itself is basically muda since it doesn’t add any value to the product: the more conveyance per unit, the more the final product cost. This term refers to any conveyance above the minimum necessary to keep “Juts-In-Time” production operating smoothly – such as temporary unloading, load transfer, removal of small quantities, and movement from one spot to another.
Muda in Processing
Any work or processing that does not add value to the product and advance the production process or contribute to the precision or quality of the processed units is referred to as Muda in Processing.
Muda in Inventory
All of the inventory (materials in-process work and finished products) that derives from the process of production and conveyance.
Muda of Motion
Muda of Motion is any human movement in production that adds no value to the product.
Muda of Correction
This refers to the muda of producing defective items which must be repaired or discarded. Includes the regular processes which tend to make people less aware of the muda involved and therefore impair improvement.
The irregularities that sometimes happen in the production schedule or in the volume of parts or vehicles produced. Instead of remaining at set levels, volume moves temporarily up or down. For workers, it refers to workloads which vary from the standard.
At the jobsite, this means giving too heavy a mental or physical burden to workers on the shop floor. For machinery, muri means trying to have equipment do more than its capability. Muda, mura and muri are known collectively as the 3 M’s.
In Multi-Process Handling, one shop worker will move down a row of machines or equipment arranged in the order of the flow of production processes and will perform all necessary jobs within the Takt-Time.
Multi-Machine Handling means that one shop worker will move along a group of machines or pieces of equipment and operate them to perform multiple jobs by himself.Those machines and equipment are grouped together because of the similarity of processes involved or similarity of the machines used.
In order to conduct one-piece-at-a-time production and multi-process handling, a shop worker must be able to perform many different jobs, operating diverse types of machinery and equipment. To accomplish this Toyota constantly endeavors to improve a worker’s skills so that he can easily perform jobs outside his normal area of assignment following monthly Takt Time changes caused by production volume changes. Such a shop worker is multi-functional worker. (also called Shojinka)Takt-Time changes each month according to changes in the production schedule and with this change the area of assigned jobs changes also. This flexibility would not be possible without multi-function workers.
This refers to the system of production in which only one part or one vehicle at a time is processed or assembled and sent along the production line to following processes.
Of the many operations involved in set-up jobs, this refers to those operations which cannot be carried out without stopping the line or machines.Such operations include the actual changing of dies, cutting tools, jigs, etc.
Off-Line Set Up
Those parts of the set-up operation which can be done without stopping the line or machinery. For example, the work of preparing and putting away dies, cutting tools and jigs.
The time that a machine operates maintenance free as a percentage of the time during which it is switched on. This is equivalent to the reliability of equipment and its maintenance.
The ideal condition is to have 100% operational availability during the time the machine is on to fill a Kanban order.
The general name for standard procedure and conditions of all jobs. Operation standards ensure that standardized work is carried out correctly at each jobsite. The information is available at each jobsite on worksheets, based on diagrams, quality check standards, QC process charts, safety standards, etc., and are aimed at achieving quality, quantity, cost and safety targets. Examples include, operation instruction sheets, quality check sheets, work standards sheets, etc.
These are parts that cannot fit on the racks along the production line or in other storage locations. They end up on the floor or otherwise temporarily stored near by.
This is a tool that informs the shop worker, foreman or supervisor whether work operations are ahead of or behind schedule.
Parts Withdrawal Kanban
This Kanban indicates the timing and quantity for a worker at one process to pick up a new supply of parts from a preceding process.
Also referred to as mistake proofing or error proofing. This refers to the low-cost, highly reliable devices or innovations that either detect abnormal situations before they occur at a production process; or once they occur, will stop the machines or equipment and prevent the production of defective products.
- Those which prevent errors by an operator and those which detect errors by an operator and give a warning
- Those which detect defects in a product and prevent further processing on them.
One of the three basic requirements of Just-In-Time. The pull system refers to the system of manufacturing in which following production processes withdraw from proceeding processes the parts they need, when they need them, in the exact needed amount.
Production Instruction Kanban
This Kanban is used to order the start of production at each production job site.
This is a measure used to evaluate production productivity. It is usually defined as follows:
The above equation can cause problems, depending on how it is interpreted. The actual production should equal the number of units sold. When production and sales figure do not equal, even if apparent efficiency improvements are achieved, costs will not be reduced and overall productivity is considered to be poor.
Production Lead Time
This refers to the time it takes to provide one product from acceptance of order to shipment. It is defined as follows:Production lead time = A + B + CA : from order reception to beginning of work
B: from beginning of work on raw materials to completing product (processing + non-processing time)
C: from completion of first to last piece of one unit of conveyance.
Production Sequence Table
This is a table which shows the production sequence of different models on a mixed-model production line. Based on the ration of the “mix” of different models in the production plan, the order of producing different models follows a Heijunka or leveled pattern.
QC Process Chart
This chart lists the quality control (QC) items – standards, specifications, and characteristics of each process – for building quality in the production processes. It also includes the names of the supervisors and shop workers who are responsible for quality control and the QC methods used.
Set-Up time is divided into three elements as follows:
- Off-Line Set-Up: time during which machine is not stopped
- On-Line Set Up: time during which machine is stopped
- Adjustment time: time after set-up is finished that machine is stopped to obtain necessary quality levels or resolve problems.
Set-Up Time is the time it takes to change over from the production of one product to another, from the instant that the processing of the last component of one type is finished, to the production of the first good sample of the next type of component. It includes all the time needed for changeover of the dies, cutting tools, etc..Set-Up Time = On-Line Set Up Time + Adjustment Time
Sequential Parts Withdrawal
Once the production sequence for products and parts is decided, those products and parts must be picked up from preceding processes according to that sequence.
This is a Production Instruction Kanban used on a lot production line where different parts are processed and time is needed for changing from processing of one item to another. The Signal Kanban is a triangular shape, often referred to a “triangle Kanban.” It is used mainly for jobs related to stamping, die casting, and resin molding processes.
Simultaneous-Start Time Study
This method is used to discover problems on a production line or process. At a given signal, all shop workers start work beginning with the first job (the first job in the standardized work sequence.) When they have finished one cycle of jobs, another signal is given and they start work on the next cycle.
This paper (also known as a build sheet) is attached to a vehicle or product giving instructions concerning the parts to be fitted to the vehicle or attached to the product. The instructions are expressed in codes.The advantage of this paper is that information and the product move along together.
The Toyota Production System organizes all jobs around human motion and creates an efficient production sequence without muda. Work organized in such a way is called standardized work. It is made up of three elements: takt time, working sequence and standard in-process stock.
Standard In-Process Stock
One of the three elements making up standardized work this is the minimum quantity of parts always on-hand for processing in and between sub-processes. It allows the worker to do his job continuously in a set sequence of sub processes, repeating the same operation over and over on the same order.
Supplier Kanban are attached to parts containers coming from suppliers. Their Kanbans are basically used the same way as Withdrawal Kanbans.
Takt-Time is the time which should be taken to produce a component or one vehicle. It is calculated as follows:Takt Time = Total Daily Operating Time/Total Daily Production Requirement*Daily total operating time is figure on the basis of all machinery operating at 100% efficiency during regular working hours.
Takt Time (Actual)
It is desirable that production targets be achieved within regular working hours and the word “Takt-Time” refers to work accomplished within regular hours.When it becomes necessary for operational purposes to calculate Takt Time for other than regular hours, that Takt Time is called “Actual Takt Time.”
Means to critique the status, the proposal and the problems, and not the person.
Toyota Production System
This is the manufacturing system developed by Toyota which pursues optimum streamlining throughout the entire system through the elimination of Muda (non-value added) and aims to build quality in at the manufacturing process while recognizing the principle of cost reduction.It also includes all the accompanying technology necessary to accomplish those aims.The two main sub-systems supporting the Toyota Production System are “Just-In-Time” and “Jidoka.”
The Toyota Way
As told by Atsuhi Niimi, President and CEO, Toyota Motor Manufacturing North America
- Respect people
- Be humble
- Treat dealer and suppliers as partners and listen to what they say
- Never become satisfied with the way things are because there is always an improvement waiting to happen
- Go and see, don’t read about it
- Hold meetings to explore failures and find improvements, not to celebrate success
- Be conservative and consistent
- Be a good corporate citizen
- Focus totally on customer so you can make money by earning their respect
- Be fiercely competitive, because that is the best way to serve the customer
- Reinvest money where you earned it
Value Adding Work (Shigoto)
Shigoto is the Japanese word for “work” or “job”, but at Toyota refers to any process that adds value to the product.
This is when a manager or supervisor can tell at a glance if production activities are proceeding normally or not.Andon and kanban are typical visual control methods.
One of the three elements of standardized work. It is the sequence of operations in a single process that leads a floor worker to produce quality goods in the most efficient way.
Across everywhere. Plant related activities and/or countermeasures that are communicated plant wide and with other company affiliates.
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