A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A-B Control

A system that controls the working relationship between two machines. The system regulates the timing and the amount of work in process passed from machine A to machine B. Three conditions must be met for the proper function of an A-B control.

  • Machine A must be full
  • The exact specified amount to be conveyed to Machine B must be complete and in queue
  • Machine B must be empty

Only when all three conditions are met will the entire system convey.

See Pull

Andon

Is the Japanese word for “lamp.” In a Lean environment an Andon is a system of lights that are triggered by operators when they find an abnormality. In more advanced manufacturing environments, an Andon can be triggered automatically by sensors found in equipment. An Andon may be a red light bulb above a work station. It may also be an array of lights found on a single board that signals a team leader of where an abnormality is found. Furthermore, Andon boards may be equipped with lights indicating specific abnormalities for visual and data collection purposes.

The diagram below shows an andon light turning red when a defect is detected. For more information on andon lights and the different levels of jidoka, please watch the Jidoka Series videos.

Andon

Assembly Line

A system for building or assembling a product though divided and repeated tasks used to progressively complete a product that is generally being conveyed on a line. The advent of the Assembly Line is credited to Henry Ford in 1913. Some sources say that Ford arrived at the idea of a moving assembly line after making a visit to a meat packing factory. He observed a moving disassembly line of beef products with workers individually responsible for removing a specific portion of meat from the carcass. Ford reversed this concept and applied it toward assembling automobiles, which yielded multifold productivity increases per worker.

See Cells

Assembly Line

The diagram above shows workers working on an assembly line.

Automatic Line Stop

A device or system that ensures that a production line stops when an abnormality is detected. In automated lines a “mistake proof” or “poka yoke” device is used to trigger the stop switch when an abnormality is detected. On a manual assembly line, a pull cord or button serves as the lone stopping device.

Autonomation

See Jidoka

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Bottle Neck

A step along the production process that restricts the output of the entire line.

The illustration on the right shows a bottle neck in painting. There is a backup of items after cutting and stenciling is out of work.

Bottle Neck

Batch and Queue

Producing large sums of work in process (batch) and conveying it to the next work station for holding (queuing). This method of production is generally used by mass producers to increase individual machine utilization.

Buffer Stock

See Inventory

Built-in Quality

See Jidoka

Build to Order

The ability to create a production or provide a service from start to finish to a confirmed order without exceeding the amount of time the customer is willing to wait. This disposition allows a provider to deliver the product or service while holding minimal inventory. The ability to Build to Order is a desirable goal for Lean producers.

Bullwhip Effect

See Demand Amplification

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Capacity Linearity

The practice of planning capacity or designing equipment to accommodate small incremental increases in demand rather than large step functions. Ideally, capacity could be immediately added or taken away in the exact increment that demand changes.

Example:

Simplex Improvement has decided to go into manufacturing computer monitors. The demand for last year was 10,000 monitors and the production manager is confident this will be the case for the upcoming year. The owner of Simplex Improvement has the option of designing a single expensive machine capable of producing 10,000 monitors or 10 smaller, less expensive machines capable of producing 1,000 units each. Having studied the concept of capital linearity, she decides to spend the R&D budget to develop the smaller machines much to the dismay of the production manager. It turned out that the demand forecast was incorrect and 11,000 monitors were needed. In this case only an additional smaller machine was needed rather than another large machine capable of producing 10,000 units. As demand changes over time, small increments of machines can be added or subtracted to the system to economically accommodate the system.

Capacity Linearity

The diagram above shows the concept of capacity linearity. The green line on the graph is linear and represents buying smaller, less expensive pieces of equipment to accommodate demand. Whereas, the orange represents buying large, more expensive pieces of equipment. Clearly, to accommodate 11,000 monitors it would be more economical to add a smaller machine capable of producing 1,000 monitors than purchasing a larger more expensive machine capable of producing 10,000 monitors.

Cause and Effect Diagram

See Ishikawa Diagram

Cells

A self contained manufacturing area where all of the needed steps are right next to one another in sequence of completion. Cells are commonly “U” shaped, “L” shaped and linear. Cells are often manned by more than one individual with work sequences that allow for cross quality checks. Each individual within the cell must have specific tasks that allow for balanced pacing and sequencing of production.

Pod (1 person cell)

A pod is a self-contained cell usually organized into a “U” shape. Each worker is responsible for completing a product from start to finish. Pods are used when the entire work content is short and the handoffs associated with an assembly line add too much cost to the product.

Pod Cell

Advantages

  • Cheap to install
  • High volumes of product generated with multiple pods

Disadvantages

  • Longer learning curve than assembly line
  • Single worker controlling quality of entire process
  • Difficult to control speeds of different operators

U-Shaped Cell

An assembly line placed in a “U” shape to minimize walking. Because raw materials and finished goods are in the same area of the “U, ” the entire walking cycle is minimized. The work content in a U-Shaped cell is balanced between the operators. The entire work content of the product is divided so that multiple handoffs occur. In a work cell with 2 operators, 2 or more handoffs should occur to promote successive checks. Standard Work In Process at handoff points and at machines with long cycle time times maintain a level of stability for the cell. Note that equipment should be organized so that operators work inside of the cell. This allows work content to be divided in a manner that allows workers to help each other when necessary. The outside of the “U” shaped cell should be staged for restocking consumable and raw materials to flow inward toward the operators.

Advantages

  • Minimal Walking
  • Successive quality checks between operators
  • Raw materials and finished goods can be conveyed in a single step
  • Shorter learning curve than Pod
  • Smooth production to Takt Time
  • Ability to run with single operator if needed

U Shaped Cell

Disadvantages

  • Loss of line of sight between operators
  • Difficult to implement conveyor belt
  • Larger amounts of floor space needed than Linear Cell

Linear Cell

An assembly line placed in a traditional straight line shape. Work is conveyed manually or automatically to the next station. Operators are only responsible for a small portion of the entire work content. Once the part is conveyed the operator does not handle it again.

Linear Cell

Advantages

  • Fastest learning curve of all cells
  • Conveyor system friendly
  • Minimal floor space required
  • Excellent design for facilities with incoming and outgoing doors on opposing sides
  • Excellent line of site between juxtaposed operators

Disadvantages

  • Poor design for some facilities
  • Operator completes part and does not see final outcome
  • Difficult to run with single operator

L Shaped Cell

An assembly line shaped in the form of an “L.” L Shaped Cells may be used to overcome machinery and space constraints. In many cases a single long piece of equipment is coupled with a smaller secondary machine. If machines are designed with operators on opposing sides then an L Shaped Cell maintains a degree of line of sight.

Advantages

  • Advantageous elements from U shaped Cells and Linear Cells can be combined
  • Less floor space than U shaped Cell needed

L Shaped Cell

Disadvantage

  • Finished product and Raw materials not located side by side
  • Awkward shape may increase material handling time

For more information on different types of cells please watch the Cells Series videos.

Chaku-Chaku

The Japanese term for “load-load.” The concept of designing equipment to allow an operator to transition smoothly between machines in a cell without the task of unloading parts. If the concept is applied thoroughly, the operator in the cell will load a part into a machine and transition that particular part (or previously completed part) into the next machine in a single motion.

Changeover

The act of changing a machine or product line from one product to another. Changeover time is measured from one product's last good run on the line to the next product's first good run on the same line. In general, changeover time is the sum of the cleanup and the setup times.

Continuous Flow

See One Piece Flow

Critical Path

Any task that if delayed, delays the final delivery of a product or service. To evaluate the Critical Path, all tasks must first be coupled with prerequisite tasks. The tasks should then be placed on parallel paths for those items that can be performed at the same time. The emerging longest path is the Critical Path. Delaying any task along this line would delay the delivery of the final product or service.

Example:

The president of Simplex Improvement is taking a rare Saturday off. She has a to-do list. Understanding the importance of recognizing and organizing items around the Critical Path she decides to evaluate what needs to be done.

  • Watch the Georgia Tech football game on tape from Thursday night 3 hours
  • Go for a jog .5 hours
  • Take a shower .5 hours
  • Wash laundry 1 hour
  • Dry laundry 1 hour
  • Eat breakfast .5 hour

Step1: Couple each task with its prerequisite:

  • "Go for jog" is a prerequisite for "Take a shower"
  • "Wash laundry" is a prerequisite for "Dry laundry
Step 2: Identify tasks that can be performed simultaneously:
  • "Watch football", "Eat breakfast," and "Wash/Dry Laundry" can be performed simultaneously.
Place items in parallel paths where possible. The longest emerging path is the critical path.

In the chart, going for a jog, taking a shower and watching football emerges as the longest path, which means that this is the critical path. Delaying any of these tasks will cause a delay to the entire system.

Notice that "Eat Breakfast" and "Wash/Dry Laundry" can shift without affecting the Critical Path.

Cycle Time (Observed Cycle Time)

The amount of time that elapses between the completion of two parts completed on the same line. Cycle time may also be defined as the amount of time it takes for a single operation to complete a single part. Both working definitions are based on shop floor observation. The general term “Cycle Time” should be specified as “Observed Cycle Time”. It is important to note that with all variations of “Cycle Time” definitions, the starting and ending point of each cycle must be exactly the same point to ensure a complete cycle. For more information on cycle time please watch the Cycle Time Series videos.

See Effective Machine Cycle Time

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Demand Amplification (also Bullwhip Effect or Forrester Effect)

The phenomenon of upstream demand increasing as downstream producers begin requesting slightly more goods than are needed. Demand amplification is caused by actual or perceived instability in upstream processes, as well as temporary spikes in demand.

Example:

Simplex Improvement is launching a new line of pies for the upcoming holiday season. It places an order of 50 pie crusts with the local factory. Sensing an increase in demand, the pie crust factory responds by ordering enough flour for 55 pie crusts to replace the 50 that were just ordered. The flour mill in turn orders enough wheat to produce 61 lots of flour to replace those that had just been ordered. The local distributor of wheat notices an abnormally high order for wheat from the flour factor and orders 67 units of wheat to replace those that were just sold to the flour factory.

This example illustrates how a 10% demand amplification factor can compound to a 34% increase in order size in a matter of 3 steps.

After conducting market research, Simplex Improvement decides not to pursue the new pie line. All orders are cancelled and the upstream processes are now holding more inventory than ever based on perceived increases in demand.

Demand Amplification

The diagram on the right illustrates the demand amplification example. An order of 50 pies was aplified to 67 units after just 4 steps.

Downtime

Any production time lost due to planned or unplanned events.

  • Planned downtime includes scheduled breaking, scheduled maintenance, changeovers etc
  • Unplanned downtime includes equipment failure, material outages, absenteeism, mid-run equipment adjustments, etc.

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Effective Machine Cycle Time

The net cycle time which accounts for manual loading and unloading, machine cycle time and changeover time. The Effective Machine Cycle Time provides an accurate view into how long it truly takes for a workstation to complete a part. Machine and Manual Cycle Times must be understood before attempting to calculate Effective Machine Cycle Time.

Machine Cycle Time

The amount of time that it takes a machine to complete an operation on a product. Machine Cycle Time is purely a machine measure. Any operator interaction with the part must be excluded.

Manual Cycle Time

The amount of time that it takes for an operator to complete an operation on a product. When an operator works with a piece of machinery, Manual Cycle Time is generally the loading and unloading time.

Effective Machine Cycle Time / EMCT

The example above shows the different elements that make up effective machine cycle time including: setup time per piece, manual cycle time, and machine cycle time. For more information on effective machine cycle time and how it is calculated please watch the Cycle Time 2 of 2 video.

Example:

Engineers at Simplex Improvement observed a machine producing one monitor in 60 seconds (Machine Cycle Time). This was observed numerous times before being presented to upper management. Having studied Effective Machine Cycle Time a member of upper management asked the engineers to factor in the manual loading time of 10 seconds, the manual unloading time of 10 seconds (Manual Cycle Time) and the changeover time of 120 seconds. The engineers also discovered that this particular line of monitors ran in batches of 20. The effective machine cycle time is the sum of machine cycle time, load time, unload time, and time per piece of setup time. In this case effective machine cycle time was: 60 seconds (Machine Cycle Time) + 10 seconds (load time) + 10 seconds (unload time) + 120 seconds / 20 (setup time per piece) = 86 seconds. In other words, monitors were only being produced one every 86 seconds and not one every 60 seconds.

Efficiency

A metric that measures the ability to meet customer demand while using minimal time and resources.

Efficiency = (Parts demanded by the customer) / (# People / Time)

Apparent Efficiency vs. True Efficiency

Example:

Simplex Improvement has implemented an assembly line for manufacturing medical devices. Initially 10 operators were able to produce the customer required 500 parts per day. After some kaizen activities were performed, the 10 original operators were producing 1,000 parts per day. This gain in Apparent Efficiency actually hurt the company’s financials. A shop floor worker noted the True Efficiency would be to incrementally decrease the workers on the line until 500 units would be produced daily. Her advice was taken and it turned out that 5 workers could produce 500 parts per day.

Case 1: (500 parts demanded by customer) / (10 People / Day) = 50
Case 2: (500 parts demanded by customer) / (5 People / Day) = 100

Error Proofing (also Mistake Proofing also Poka Yoke)

Designing or modifying equipment or processes so that defects cannot occur.

Example:

Diesel fuel with larger nozzles
Man hole covers circular rather than square

The diagram on thr right is an example of error proofing. The ends of the hoses only fit in their respective fixture. Additionally, this is an example of visual control. The hoses are color coded blue for air and red for gas. It would be clear to see if the hoses were mistakenly interchanged. For more on error proofing please watch the Jidoka Series.

Error Proofing/ Poka Yoke

Every Product Every Interval (EPEx)

A measurement of how often all types of products produced within a work station or a production system.

Example:

Simplex Improvement produces products A, B and C. It receives orders in batches of 100 for each of the products. It takes a full day to run each of the products. To avoid multiple setups Simplex Improvement runs A, B and C in order in batches of 100. This takes three days. So Simplex Improvement is running Every Product Every 3 days.

After some setup reduction events, Simplex Improvement found that it could break the batches of 100 into thirds with minimal losses. Now Simplex Improvement runs products A, B and C within a single day. In other words, they are running Every Product Every 1 day.

Lean thinkers strive to run all products within shorter intervals. Running smaller lots more frequently decreases order-to-cash time and reduces the risk of running large defective batches.

The diagram on the right shows a heijunka board. By looking at this board we can tell every part is produced every week. For more information on heijunka boxes and EPEx please watch the Heijunka 2 of 4 video.

EPEx, Every Part Every Interval

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Fill-Up System

A replenishment system in which a work station only makes enough to fill up the exact amount that was consumed by the next work station. A visual indicator such as a line or empty slot serves as the trigger to control replenishment timing and quantity.

First In, First Out (FIFO)

Consuming products in the exact order in which they were received. Consuming products in a strict sequence from “oldest” to “newest” reduces the risk of spoilage. This disciplined approach is the key to pull production as only a sequenced and timely replenishment FIFO system will prevent outages or overproduction.

Practical examples of FIFO include racks with tilted shelves which are loaded from the rear. Painted lanes in the factory floor that are just wide enough for the product to be conveyed without changing the sequence. The product would enter the painted lines from the rear and move forward as product is consumed.

FIFO/First In, First Out

The diagram above shows shapes in a FIFO lane. For more infomation on how FIFO is used in pull systems, please watch the Pull 1 of 2 video.


Fishbone Diagram

See Ishikawa Diagram

Five S

A systematic approach to organization and cleanliness that lays the foundation for other Lean improvements.

Seiri (Sort):

Clearly identify those items that are unneeded and separate them from those that are needed in a given work area. Remove those items that are unneeded. Sorting must be done in a systematic manner with a clearly written sorting criteria dictated by the shop floor. General categories for the outcome of items should also be clearly defined.

Seiton (Simplify):

Create home locations for those items which remain. Items should be placed at point of use and stored in a manner that is ergonomically correct. Tooling should be placed in sequence of usage to detect nonconformance to the process.

Seiso (Systematic Cleaning or Shine):

Clean and inspect all items and equipment in the work cell. Pay special attention to leaks and repair the source of the leak. Also note all lubrication points on the equipment and tooling. Finally make note of any disposable components on the equipment.

Seiketsu (Standardize):

Label, outline and shadow board all tooling and equipment in the area.

Shitsuke (Sustain):

Create daily, weekly, monthly and annual cleaning and maintenance agreements with the operators and maintenance personnel. Most of the lubrication points and the replacement of disposable components should be addressed by the operators. Create a pictorial acceptable conditions agreement that clearly shows what the work area should look like. Create a disposal procedure that outlines how items should be classified and what action should be taken if an unneeded or new item shows up the in work area. Finally, institute a weekly and monthly audit of the work area. Train all operators and supervisors on the audit procedure. Post the results as often as the audit frequency dictates.

Original Definition of 5S

Below are the original definition of the 5S’s according to Hirano’s book: Just In Time Factory Revolution.
  • Seiri - Proper arrangement
    • Sort through then Sort out
    • Sort through what you have, identify what you need, and discard what is unnecessary

  • Seiton - Orderliness
    • Assign a separate location for all essential items
    • Make the space self explanatory so everyone knows what goes where

  • Seiso - Cleanliness
    • Clean equipment, tools, and workplace
    • Keep the workplace spotless at all times

  • Seiketsu - Clean up
    • Maintain equipment and tools
    • Keep the workplace clean

  • Shitsuke - Discipline
    • Stick to the rules scrupulously
    • Make them a habit
Main Points
  1. Proper arrangement Seiri and Seiton must be visual so everyone knows what is where
  2. The 5S must be a companywide program
  3. The 5S are the start in identifying problems and wastes. They must be part of a total improvement program

Five Whys

A method for finding the root cause of an issue by asking “why” consecutive times.

The following is an example from Taiichi Ohno’s book: Toyota Production System

  1. Why did the machine stop?
  2. There was an overload and the fuse blew

  3. Why was there an overload?
  4. The bearing was not sufficiently lubricated

  5. Why was it not lubricated?
  6. The lubrication pump was not pumping sufficiently

  7. Why was it not pumping sufficiently
  8. The shaft of the pump was worn and rattling.

  9. Why was the shaft worn out?
  10. There was no strainer attached and metal scraps got in

Fixed Position Stop System

A production line management system that promotes the correction of production line issues before or at discrete line stoppage points. It is a common misconception that Toyota workers pull andon cords that immediately stop the production line. While this was the case before, the engineers found that most of these stops could have been corrected without a complete line stoppage. Workers began to avoid stopping the line causing quality issues to increase. Stopping the line at ambiguous points also caused a great deal of confusion for operators that were midway through a process. The Fixed Position Stop System remedied all of these issues by allowing a buffer time for minor issues to be corrected, while creating logical stopping points in case of a line stoppage. Workers can now freely pull the andon cord to signal a supervisor without the burden of stopping the entire production line.

Flow Production

See Assembly Line

Four M’s

Man, Material, Method, Machine. Four inputs starting with “M” that are manipulated to produce a product or service. The Four M’s were used on the original Ishikawa diagram for problem solving and root cause analysis. The Four M’s have now grown to Six M’s and currently include Measurement and Mother Nature (Environment).

Man

All personnel involved with producing a product or service. Man defects are those generated by human error or miscalculation.

Material

Raw material and work in process. Materials defects are those that are found when Raw materials arrive out of specification. They are also found during the conversion phase when materials do not behave as planned under acceptable conversion procedures.

Method

The standards or techniques applied to converting raw materials into finished goods. Defects can be generated through poor procedures or by incorrectly following well-written work standards.

Machinery

Shop floor equipment used to convert raw materials to finished goods. Machine defects can occur when machinery is poorly maintained or when used for the wrong application.

Measurement

Gauging, estimating or interpreting information from an output source. Measurement errors occur when operators incorrectly read knobs and analog gauges or make an error when taking any kind of manual measurement.

Mother Nature (Environment)

Environmental factors that affect the production process. Mother Nature defects are those caused by environmental factors that are difficult to control, such as Humidity and Barometric pressure.

See Ishikawa Diagram

Future State Map

See Value Stream Mapping

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Gemba

The shop floor or where value is being added. Gemba is the Japanese word for “actual place.” Lean practitioners should spend significant time in Gemba making true shop floor observations. Value Stream Maps and Standard Work cannot be created unless the Lean practitioner has a deep understanding of the production system which can only be gained by spending time in Gemba.

The diagram below shows the shop floor at Simplex Ski Company. To see the Simplex Ski Company example please watch the Value Stream Mapping Series.

Gemba

Genchi Genbutsu

Is a Japanese term which means “go and see”. The philosophy of Genchi Genbutsu implies that issues should be observed and resolved at Gemba (the actual place).


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Hansei

Is the Japanese term for “self reflection”. Hansei is practiced at all levels of a Lean organization. When an issue occurs all parties involved are expected to reflect on how they contributed to the issue and most importantly, how they can avoid making this same mistake again.


Heijunka

A system for level loading the output of a production line.

The illustration below shows a traditional batched approach for production compared to the lean leveled approach. For more information about heijunka please watch the Heijunka Series videos.

Heijunka

Orders generally arrive in large batches due to volume incentives given to the customer. A Lean practitioner will drive toward producing smaller batch sizes by level loading what is produced. There are many reasons for applying Heijunka to a production line.
  1. Heijunka decreases the lead time. Large batches are broken up, opening capacity for other products to be produced.

  2. Heijunka shortens the order-to-pay time and improves cash flow. Because multiple small batches of varying products are run, a shipment can be made immediately after the batch is complete and payment can be received.

  3. Heijunka decreases the risk of large quantities of defects. Because only small batches are produced, the likelihood of cumulative group of orders being defective is decreased. In the rare case that a small batch is found to be defective by the customer, the financial burden of reproducing it is much less than if the entire large batch was found to be defective.

  4. Heijunka allows for better production flexibility. Large runs tie up equipment and make emergency requests from customers difficult to handle. If only small batches are run, an extra small batch order can be worked into the sequence with minimal disturbance to the production line.

  5. Heijunka smoothes production. Consistent, cyclical production provides a stable environment for production. Less time is needed for scheduling and firefighting.

Heijunka Box

The application of the Heijunka concept generally taking the form of the box or control board. A Heijunka Box serves as the central nervous system for the entire pull system in the facility. The Heijunka Box is used to level the pacing and sequencing of Kanban Cards in reaction to pull from customer demand.

The illustration on the right shows a heijunka board for shape production. Withdrawal kanban cards are located on this board and control the pace and sequence of production. For more information on heijunka and to see more on heijunka boards, please watch the Heijunka 2 of 4 video.

Heijunka Box

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Ishikawa Diagram

A root cause analysis tool used to visually display the causes associated with a certain effect. The original Ishikawa diagram used the Four M’s (Man, Material, Method, Machine) as the main causes. Two additional M’s (Measurement and Mother Nature or Environment) were later added bringing the total to 6M’s.


The illustration on the left shows an iskikawa diagram displaying the 6M’s.
Ishikawa Diagram of Fishbone Diagram

Ideal State Map

See Value Stream Map


Implementation Plan

Is a document that captures all of the kaizen events needed to take a current state value stream map to the future state map. Star bursts from the current state are translated directly to this plan. A typical implementation plan captures 90 days of events.

The diagram below shows an implementation plan that was generated for the Simplex Ski Company red value stream.

Implementation Plan

Inventory

Any goods a facility including, of raw material, work in process and finished products.

1) Buffer Stock

Finished-goods inventory kept on hand to protect the external customer from outages. This amount is carefully calculated based on past data and is rotated to prevent spoilage.

2) Finished Goods

Product that is in its final state and ready to be shipped to an external customer.

3) Raw Materials

Unprocessed stock that has in no way been altered after being received from the supplier.

4) Safety Stock

Inventory used to prevent internal customers from outages. This amount is carefully calculated based on equipment reliability, lead times for replacement and fluctuations in demand.

5) Shipping Stock

Finished goods that are arranged in a manner that is conducive to level pulling. In general, shipping stocks are found on pallets in carefully designed First In First Out (FIFO) lanes that are replenished based on a level pull from the customer. Ideally, the timing is such that the carrier arrives at the exact same time the final pallet enters the FIFO lane.

6) Work In Process

Any inventory that has been altered from its original raw stock form but is not yet a finished good.

Types of Inventory
The diagram above shows the different types of inventory. The number in the diagram corresponds to the numbers listed in the descriptions. For more information on the different types of inventory please watch the Inventory 1 of 2 video.

Inventory Turns

A metric that roughly measures how many times a warehouse completely changes all items in inventory. Inventory turns are generally calculated in one year increments to account for variations in the cost of goods sold stored and fluctuations in volume.

Inventory Turns = Cost of goods sold for 1 year / Average value of inventory on hand during the year.

Example:

Simplex Improvement would like to see if the Lean initiative is paying off. Prior to starting down the Lean journey, the inventory turns were 1. After implementing Lean, it sells monitors for $100 each and sold 50 last year. It also holds 5 on hand in the warehouse at any given time.

Inventory Turns = (50 monitors x $100) / (5 monitors x $100) = 10

Lean organizations strive for high Inventory Turns as this implies lower inventory levels and more favorable cash flow.

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Jidoka (also Autonomation)

Loosely translates to intelligent automation or automation with a human touch. Jidoka is one of two pillars of the House of Lean. The concept of Jidoka was pioneered by Sakichi Toyoda who created a textile loom that would automatically stop when a thread broke. Originally, all textile looms were monitored individually by an operator. Toyoda’s innovation allowed a single worker to monitor many machines. Jidoka is the pillar that addresses quality at the source. There are three main levels of Autonomation.

For more information about the different levels and examples of jidoka please watch the Jidoka Series videos.

Recognition Jidoka

Indication that a defect as been generated. The first step to building in quality at the source is creating machinery that can detect an error. At this level of Autonomation the machine continues to operate. An operator is still required to take action on the piece of machinery to prevent more defects from being generated.

The illustration below is an example of recognition jidoka. When the registration is off, an andon light turns red to notify the operator of the problem. For more discussion on recognition jidoka please watch the Jidoka 1 of 2 video.

Recognition Jidoka

Action Jidoka

Indication that a defect has been generated plus machine reaction. At this level of Autonomation, the machine detects the defect and takes a basic action, such as rejecting a faulty part or stopping operation. A part-time operator is still required to remove defective parts and make corrections to settings to prevent future defects.

The illustration below is an example of action jidoka. When the product is defective it is automatically routed into the waste bin. For more discussion on action jidoka please watch the Jidoka 1 of 2 video.

Action Jidoka

Prevention Jidoka

Indication that a defect is likely to occur plus machine correction. At this level of Autonomation, the machine can detect when aspects of parts are drifting toward a specification limit. The machine makes the necessary adjustments to realign settings to prevent defects from occurring. An operator is rarely needed to monitor the equipment.

The illustration below is an example of prevention jidoka. When the registration approaches the upper or lower spec limit it is automatically adjusted by the machine. For more discussion on prevention jidoka please watch the Jidoka 1 of 2 video.

Prevention Jidoka

Just-In-Time

Receiving or producing what is needed, when it is needed and in the exact amount that is needed. Just In Time is one of two pillars of the House of Lean. This pillar addresses production efficiencies and controls.

For more information about Just-In-Time please watch the Cycle Time, Takt Time, Pull, and Cells Series videos.

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Kaikaku

Kaikaku is the Japanese term for “innovation,” “transformation,” or to “radically change.” Kaikaku implies a complete expulsion of the current system in exchange for a completely new and innovative approach.

Example:

Prior to the mid 1990’s the general process for filing a tax return looked something like this:

  1. Gather tax information
  2. Go to a local library or city hall for a tax form
  3. Fill out tax form
  4. Mail tax forms
  5. Wait four to six weeks for return in the form of a check
  6. Go to the bank and deposit check
  7. Wait two days for check to show up in account
After some enterprising individuals performed a kaikaku to the process it looks something like this:
  1. Gather tax information
  2. Purchase tax return software
  3. Type in tax information
  4. Electronically submit information
  5. Tax return automatically shows up in account in 3 days
Prior to the kaikaku of the process, the lead time for receiving a check could be over six weeks. Post radical change, an individual can enjoy a refund in as little as 3 days.

For more discussion on kaikaku please watch the Perfection 2 of 2 video.



Kaizen

Kaizen is the Japanese word for “improvement” or “to change for the better.” Improvement efforts should first be explored using the Deming Cycle (Plan Do Check Act). If they are determined to be beneficial, then they are instituted as a part of Standard Work. Kaizen breaks down into Process Kaizen and System Kaizen. Both are equally important.

  • Process Kaizen— small incremental improvements made daily.
  • System Kaizen— larger step function improvements which alter an existing system.
For more information on process and system level kaizen please watch the Perfection 1 of 2 video.



Kaizen Event

An improvement workshop (often lasting one week) in which a targeted work area or system of work areas undergo a Lean transformation. A Kaizen Event must be facilitated by an experienced Lean professional and its participants must include all those who work in or are in any way involved with the targeted area. Kaizen Events should be used as a driver to take an organization’s Current State Map a step closer to its Future State Map. The Current State Map should be updated after the Kaizen Event demonstrates to have been successful.

Kaizen Newspaper

A document designed to capture remaining action items after the completion of a Kaizen Event.

The image below shows an example of a kaizen newspaper. Notice how it includes the problem, who is responsible, when the item is due, and the current status. For more information on kaizen please watch the Perfection 1 of 2 video.

Kaizen Newspaper


Kanban System

A production, conveyance and inventory control system that utilized cards or anther visual control system to maintain a level of stability. A Kanban System maintains a level of stability by authorizing the pulling, pacing and sequencing of production. When the rules of a Kanban System are followed, products are be produced in sequence and in the correct amounts.

For more information on different types kanban systems and how to calculate kanban please watch the Pull 2 of 2 video.

Kanban Rules

The working conditions that must be met for a Kanban System to function properly.

  1. Downstream processes only request the exact amount of product specified on the Kanban.

  2. Upstream processes only produce the exact amount of product specified on the Kanban and in the exact sequence in which they were received.

  3. No items can be conveyed or produced without a Kanban

  4. All products must have a correctly corresponding Kanban attached

  5. Defective product is never conveyed

  6. Products in amounts that differ from the amount specified on the Kanban are not conveyed

  7. The amount or number of Kanban is to be reduced slowly over time.
If the demand or lead time is highly variable, a Kanban System cannot be implemented. A general rule to determine high variability is to compare the mean to the standard deviation. If the standard deviation of the demand or lead time is three times or greater than the mean, forecasting should be used instead of a Kanban System.

Kanban Cards

Cards that serve as the primary mode of communication in a Kanban System. There are two main types of Kanban Cards which generally work in tandem. They are Withdrawal and Production.

  • Withdrawal Kanban: Signals which product should be pulled to the subsequent work station.
  • Production Kanban: Signals which product should be produced to fill what was pulled from the previous work station to the subsequent work station.
Production and Withdrawal Kanban Cards

The illustration above shows an example of a production and a withdrawal kanban card. Notice how both cards list the part number, description, previous location,subsequent location, current location, and an image of the part. Also, tthe cards are color coded and fit together like puzzle pieces. This ensures the correct parts are pulled and produced.



Calculating Kanban

Number of Kanban Needed = (Demand x Replenishment Lead Time + Safety Stock) / Package Quantity

Example:

Simplex Improvement is attempting to implement a Kanban System for the electric cords that are needed on the monitors it produces. An engineer has taken a years worth of data and found the average weekly demand is almost always 100 cords. The electric cord supplier has a predictable Lead Time of two weeks. The cords come in bundles of 20. The executives at Simplex Improvement take downtime very seriously. They feel that a Safety Stock level of 20 cords is necessary to prevent outages.

Number of Kanban Needed = (100 cords / week x 2 weeks +20 safety cords ) / 20 = 11 Kanban Cards

If the number of Kanban needed turns out to be a fraction, always round up to the next whole number.

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Lead Time (Customer Lead Time)

The elapsed time from order placement to order delivery when demand exceeds capacity. Lead time is not to be confused with cycle time.

For more discussion on lead time and the difference between it and cycle time, please watch the Cycle Time 1 of 2 video.

Production Lead Time

The amount of time a product actually spends a in a manufacturing stream.

Lean (or Toyota Production System)

A business philosophy that emphasizes the use of time, quality and cost as competitive advantages. There are five major steps that characterize a Lean journey.

  1. Clearly define Value from a customer perspective

  2. Choose a Product Family line and map the Value Stream

  3. Create Flow of materials and information along the Value Stream

  4. Create level Pull from the final customer through the Value Stream

  5. Pursue perfection in the form of zero waste

Level Loading

See Heijunka

Level Selling

A method of Level Loading sales to combat artificial spikes in demand caused by seasonal stocking, fear of stock outs, poor sales forecasting, quarter end sales results etc.

Example:

Simplex Improvement noticed a sharp increase in sales as new incentives were put in place to boost performance. The 12 member sales team was taking the market by storm and far exceeding expectations. A byproduct of the incentives was an increase in sales volume just before the close of each quarter.

Because the incentives were generating such great results, Simplex Improvement felt it was best to keep them in place. The quarterly spikes, however, caused issues with level loading production. A production employee determined that Heijunka should be applied to the sales force and suggested that each of the 12 employees' quarters end on a different month. Simplex Improvement implemented her idea and was able to keep the incentives program (as well as the increased sales) while eliminating many of the associated production issues.

The top right diagram shows quarterly demand spikes and the bottom right diagram shows the results after heijunka has been applied to the sales force. The quarterly demand remains reletively flat and quarter end spikes have been eliminated.

Level Selling 1

Level Selling 2

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Mass Production

The traditional approach to manufacturing, in which a producer attempts to achieve the lowest cost per unit of a product by producing in large batches.

To lean more about mass production and its role in lean history please watch the History Series.

Milk Run

A replenishment system based on filling small orders on a standardized route multiple times. In this system a material handler follows the standard route, visiting each location multiple times throughout a shift. At each stopping point, the material handler replenishes what was consumed and removes Kanban cards in the form of actual cards or empty bins. The process is repeated on the next cycle of the Milk Run.

The diagram below shows a material handler following a predefined milk run. In this example the material handler is responsible for taking the appropriate withdrawal kanban card from the heijunka board, keeping the bins of raw materials stocked using a two bin system, withdrawing the completed product from shipping stock and moving it the shipping area, and placing the production kanban card in the kanban post for the workcell. To see the material handler complete the milk run please watch the Perfection Series 2 of 2 video.

Milk Run

Mistake Proofing

See Error Proofing

Muda

The Japanese word for “waste”. Muda is anything that consumes resources and does not add value to the product. Muda is a broad term that encompasses all Seven Deadly Wastes.

The illustration on the right clearly shows waste. Three lanes are open yet there is only one customer waiting in line. For more information on muda and the different types of waste please watch the videos in the Waste Series.

Muda

Mura

The Japanese term for “unevenness”. Mura refers to unevenness in production or conveyance of products.

The illustration on the right clearly shows unevenness of lines in a store. There are two lanes open yet four customers are waiting in lane two and only one customer is waiting in lane three. For more information on mura and other types of waste please watch the Waste 1 of 2 video.

Mura

Muri

The Japanese term for “overburden”. Muri refers to unachievable expectations for workers or machinery.

The illustration on the right clearly shows how one clerk is overburdened in a store. There is only one lane open yet several customers waiting in line. For more information on muri and other types of waste please watch the Waste 1 of 2 video.

Muri

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Nemawashi

Is a Japanese term which implies laying the foundation for future improvements. This is done through researching multiple alternatives, meeting stakeholders etc. in an effort to create support and ensure successful implementation. Nemawashi original definition means to dig around the roots of a tree to move it to another location. Nemawashi original definition means to dig around the roots of a tree to move it to another location.


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One Piece Flow (Single Piece Flow)

A work agreement that stipulates each work station along a production line will only have a single piece in process. In a One Piece Flow environment, there are no supermarkets between stations. Ideally, the amount of time needed to complete the entire work cycle at one station is identical for all stations on the production line. This means that each part is completed and passed on to the next work station at exactly the time the part is needed. In other words, the entire line conveys parts at the exact same time with no waiting time.

The diagram below is an example of one piece flow. Each operator has only one paper airplane they are working on and a new paper airplane is only started after a completed airplane exists the system.

One Piece Flow

Operator Load Chart

A histogram that shows the total work content for a production line by worker. The precise tasks each operator performs is captured and represented on the graph with time associated by task. The time balance of tasks along the line can quickly be assessed with this chart. When combined with a line representing Takt Time, the chart can quickly point at a particular work station that exceeds the allowable time set by the customer.

The diagram on the right shows an operator load chart. The different colored blocks represent the time it takes for an operator to complete that specific task. To see more on operator load charts and how they are used in the airplane simulation example please watch Lean Simulation Series 2 of 2.

Operator Load Chart

Overall Equipment Effectiveness (OEE)

The metric used as part of a comprehensive Total Productive Maintenance (TPM) Program.

OEE = Availability % x Speed % x Quality %

Example:

Simplex Improvement is concerned about machine 5 on the computer monitor production line. It always seems to malfunction at the peak of production periods. The president of Simplex Improvement decides that she wants to start a TPM program. Machine 5 is selected as a candidate. The base line is taken from historical data and it is determined that the machine is only available 50% of the time due to breakdowns. The machine is designed to produce a monitor every 30 seconds. In reality it is producing a monitor every minute. Even at this slow pace only 80% of the monitors produced by machine 5 are acceptable.

The OEE of Machine 5 = 0.50 x 0.50 x 0.80 = 20%

A ranking of 85% or above is considered to be world class.

Overproduction

Producing more than is required at any given moment by the final customer or the next work station. Taiichi Ohno considered Overproduction to be the worst of all of the forms of waste.

For more of overproduction and the different forms of waste please watch Waste Series 1 of 2.

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Pace Setting Process

The process along the value stream that serves as the stabilizer for peaks and valleys of external demand. The pace setting process should not be confused with the bottleneck of the process. In general the Pace setting process is the last supermarket along the value stream.

In the diagram below the final supermarket, circled in orange, is the pace setting process. Once an item is pulled from this supermarket processing step 4 pulls from the processing step 3 supermarket, 3 pulls from 2, and so on. The final supermarket controls the pace at which all products are pulled and processed.

Pace Setting Process

Pack-Out Quantity

The packaging quantity desired by the customer. Pack-Out Quantities may vary as the process progresses. An internal customer may request small batches within a Pack-Out Quantity whereas an external customer may request large quantities to save on shipping costs.

Pitch

The amount of time allotted to produce a specified bundled quantity of a product.

Pitch = Takt Time x Pack-Out Quantity

Example:

A customer requires a computer monitor every 2 minutes. Sending a single monitor via a small package carrier every 2 minutes is cost prohibitive. The customer instead requests that 500 monitors be placed on a shipment of trucks.

Pitch = 2 minutes x 500 monitors = 1,000 minutes

In other words, the customer requests a bundle of 500 monitors be sent every 1,000 minutes.

Plan Do Check Act (PDCA)

A scientific approach to problem solving pioneered by Edwards Deming.

Plan Do Check Act

Plan

Understand the problem or improvement proposal. Take the necessary steps needed to prepare for running a small-scale trial of the solution

Do

Run a trial on a small scale

Check

Evaluate the results

Act

Take action on the results. If the experiment was successful, then standardize and implement it on a larger scale and move back into the Plan phase. If the experiment was unsuccessful, then take stock of what was learned and move back into the Plan phase.

Point of Use

Storing parts, tools or equipment at the exact point they are used. Point of Use storage of needed items minimizes the waste of travel and motion.

Poka Yoke

See Error Proofing

Process Village

A facility that is organized by process functions rather than by Value Streams. Process Villages are the traditional and intuitive way to organize a facility. Batching like items in a common area seems to be the logical approach. The Lean approach is to break Process Villages into streams of linked equipment. This approach is much more conducive to an improved flow of value.

The diagram on the right shows the Simplex Ski Company laid out in process villages. All of the equipment that does a specific type of work is grouped together.

Process Village

Product Family (or Value Stream Group)

A group of products that flow along the same or similar manufacturing process within a facility. Defining Product Families is one of the first steps in Lean implementation. After the product families are clearly defined as separate entities on paper, one Product Family should be selected as a Model Line for Lean implementation.

The example below shows the three different product families for Simplex Ski Company. Notice the blue and green skis go through the same production processes and are therefore one product family. For more discussion on identifying product families please watch the Value Stream Series 1 of 5 video.

Product Family (Value Stream Group)

Pull

Working in reaction to demand. A Pull system involves a supplier and customer. The customer provides a signal — an empty bin, a card, a container, etc. — to trigger the supplier to deliver or begin processing a replacement for what was consumed.

Supermarket Pull

A type of Pull System that holds a specified and controlled amount of Finished Goods and Work In Process along the production line. Supermarket Pull Systems are used when:

  1. The customer is unwilling or unable to wait the total amount of time needed to process a good from start to finish

  2. The cost of holding inventory is low

  3. The customer can only choose from a relatively small number of finished goods
Example: Best Buy has computers on the shelves ready to be purchased. This is an example of Supermarket Pull.

The diagram below shows supermarkets located between each processing step. When a customer pulls a good from the finished goods supermarket (after processing step 4), processing step 4 then knows to pull product from the processing step 3 supermarket, processing step 3 pulls from processing step 2, and so on. For more information on supermarket pull please watch Pull 1 of 2.



Supermarket Pull

First In First Out Pull System (FIFO Pull System)

A type of Pull System that holds that processes goods in a First In First Out manner. Only a limited amount of Work In Process is allowed to enter a FIFO Pull System at any given time. Only a pull of the oldest Work In Process from a FIFO Pull System allows an opening for newer items to enter the system. FIFO Pull Systems are used when:

  1. The customer is willing to wait for a product to be completed in the order in which it entered the system

  2. The supplier is unwilling or unable to hold an entire supermarket of Work In Process
Example: Dell’s original model allowed customers to order a computer that was customized to their specific needs. The computer was built from scratch and would arrive at their door three days later. This is an example of FIFO Pull.

The diagram below shows a FIFO pull system. When a customer pulls a good from the finished goods supermarket (after processing step 4), a signal is sent to the beginning of the production process to replenish the pulled part. The part is then processed in the order in which it was pulled. For more information on FIFO pull please watch Pull 1 of 2.



First In First Out (FIFO) Pull

Hybrid FIFO and Supermarket Pull

A type of Pull System that holds inventory at strategic points generally early in the production line. A hybrid system allows the customer the freedom to customize product without waiting for the entire production cycle. Hybrid Pull Systems are used when:

  1. The customer is unwilling or unable to wait the total amount of time needed to process a good from start to finish

  2. The cost of holding inventory is low in at the beginning of the production line

  3. The customer is willing to accept the choices for customizing a generic product
Example: Subway carries breads, meats and vegetables in supermarkets. Sandwiches are made using a FIFO System using these supermarkets. This is an example of a company gaining the benefits of both systems in a Hybrid Pull System.

The diagram below shows a hybrid FIFO and Supermarket Pull system. The second half of this system uses FIFO and the first half uses a supermarket pull. When a customer pulls a product from the finished goods supermarket (after processing step 4), a signal is sent back to processing step 3 to produce a part. Processing step 3 then pulls from the processing step 2 supermarket which then triggers 2 to pull from 1. Meanwhile processing steps 3 and 4 process the part in the order in which it was pulled. For more information on Hybrid FIFO and Supermarket Pull please watch Pull 1 of 2.



Hybrid FIFO and Supermarket Pull

Push System

Working in anticipation of demand. The assumption made by manufacturers employing a Push System is that all of the products produced will sell. This is true only in those cases where capacity cannot meet demand. When used in an assembly line, a Push System is very costly. A true Push System has no inherent controls to trigger a worker to produce or tell him to stop. This leads to high levels of capital tied up along the line in the form of work in process. Incentives for individual work stations or operators to beat quota only compound the problem.

The diagram on the right shows a push system. The worker producing the different shapes is producing in anticipation of demand and not based on what the customers are ordering. To learn more about push systems please watch Pull 1 of 2.

Push

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Right Sizing

Creating tooling or machinery that is conducive to a Lean manufacturing environment. Tooling should be easy to use, easily added or removed to accommodate changes in demand See Capacity Linearity, easy to set up and easy to maintain.

Set based Concurrent Engineering

The development approach used by Toyota in the design phase of production. A Set-based approach starts with a broad base of solutions and gradually eliminates weaker alternatives. This approach costs more initially, but saves Toyota significantly more money in the long run. Set based Concurrent Engineering is the alternative to the traditional Point based approach.

Point Based Example

A manager in the Point based Engineer team was asked to guess a number between 1 and 100. He could ask as many questions as needed. He immediately took the point based approach:

  • Is it 1? -No
  • Is it 2? -No
  • Is it 3? -No
  • ...
  • Is it 29? -Yes, you win!

Set-based Example

Another manager in the Set-based Concurrent Engineering team was asked to do the same. He defined the following broad categories:

  • Numbers 1-20 are in set 1
  • Numbers 21-40 are in set 2
  • Numbers 41-60 are in set 3
  • Number 61-80 are in set 4
  • Numbers 81-100 are in set 5

  • Is the number in set 1? -No
  • Is the number in set 2? -Yes

  • Is the number greater than 30 (ie is the number in the second set of this set)? -No
  • Is the number greater than 25?
  • ...
  • Is it 29? -Yes, you win!

When considering the infinite number of directions engineering designs can take, a set- based approach combined with the process of elimination is much more economical in the long run.

Setup Reduction

See Single Minute Exchange of Dies

Seven Deadly Wastes

See Waste

Single Minute Exchange of Dies (SMED)

A concept of reducing setup times to below 10 minutes pioneered by Shigeo Shingo. Setup time is defined as the time that elapses from the last good product run on the piece of equipment to the first good product run. Setup activities can be categorized into two subgroups: Internal and External work. Steps to reducing setup times are:

  1. Document sequential tasks operator performs while setting up
  2. Clearly separate internal from external work
  3. Convert as much internal work to external work as possible
  4. Minimize internal work
  5. Minimize external work
  6. Standardize both internal and external work

Single Minute Exchange of Dies (SMED)

The diagram above shows the steps to reducing setup times. For more information on SMED watch Heijunka Series 2 of 4.

Internal

Any task that requires shutting the machine down. For example, installing stamping dies requires machines be turned off, so this task would be classified as an internal activity.

External

Any task that can be performed while the machine is still running. For example, gathering tooling and supplies for the next job in the production schedule can be done in advance, so this task would be classified as an external activity.

Single Piece Flow

See One Piece Flow

Spaghetti Chart (Spaghetti Diagram)

A diagram that captures the macro-level movements of an individual performing a specified task from a top-down view. A Spaghetti diagram can be used as a simple yet powerful tool to show just how much walking is involved with the specified task. When combined with the actual walking distance captured by a pedometer, the diagram and data can be used as a baseline for future Kaizen activities.

Spaghetti and Meatball Chart (Spaghetti and Meatball Diagram)

A specialized Spaghetti Chart that uses circled numbers in sequence at each stopping point as a means of collecting information. A traditional Spaghetti Chart only gives the audience a general idea of how much the individual moved. A Spaghetti and Meatball Chart illustrates not only how much the individual moved but also shows why the individual was moving from point to point.

The diagram on the right shows a spaghetti and meatball chart for the task of pumping gas. From this chart we can see the operator is making several trips back and forth to the cleaning solution used to wash the car's windows. To view the gas station example and see how spaghetti and meatball charts are used watch Heijunka Series 4 of 4.

Spaghetti and Meatball Chart

Standard Inventory (Standard Work In Process)

The minimum amount of inventory needed at each work station to maintain smooth production.

The diagram on the right shows standard inventory in the peanut butter and banana sandwich production line. Two pieces of bread are in the toaster while the operator continues making a sandwich. This ensures that once that sandwich is completed, bread is already toasted and ready for the next sandwich in the loop. To see the peanut butter and banana production line and further discussion of standard inventory watch Standard Work Series 2 of 3.

Standard Inventory (Standard WIP)

Standard Work

A specific set of instructions that control the pulling, pacing, sequencing and inventory of an individual or cell. Stability and Standard Work make up the foundation of a Lean organization. Standard Work encompasses three essential elements of Lean.

  1. Takt Time: controls how much is produced and sets the pace to meet customer demand.
  2. Sequence of Operations or Tasks: controls the quality standards of the products and ensures minimal deviation from customer expectations.
  3. Standard Work In Process: controls variation in equipment and operator output to smooth the flow in a cell.

Standard Work must be built from actual shop floor observation. Repeated times must be demonstrated to be standardized. Times built into Standard Work can not be based off of averages with tight standard deviations. They must be exact with no deviation.

Capacity Sheet

The main function of the Capacity Sheet is to help production planners determine whether a cell can meet the customer’s volume demands, i.e. meet Takt Time. If a particular machine or operation is the bottleneck preventing the cell from producing to Takt Time, it will be quickly revealed by the Capacity Sheet.

The example below shows a capacity sheet for a peanut butter and banana sandwich production line. To see how to fill in the capacity sheet step by step watch the Standard Work Series 3 of 3 video.

Process Capacity Sheet

Work Combination Sheet

A graphical view of the work area, flow of materials, Standard Work In Process and work sequence of a cell. A Work Combination Sheet provides an excellent overview of the cell. It can be used a quick training guide to those new to the area. It also provides a visual standard that allows the user to quickly identify deviations from the standard sequence. Standard Work In Process should be carefully calculated and decreased over time. Just enough Standard Work In Process should be kept on hand to keep the operation running smoothly. Safety checks on the product being produced and the equipment being used to produce it should be clearly marked and built into the Standard Work Combination Sheet. In the case of the product being produced, time should be allotted for a standard safety check as part of the work cycle. Quality checks must occur prior to conveying the product to the next station. Ample time for standard quality check must be built into the standard work cycle.

The example below shows a capacity sheet for a peanut butter and banana sandwich production line. To see how to fill in the work combination sheet step by step watch the Standard Work Series 3 of 3 video.

Standard Work Combination Sheet

Standard Work Chart

Details the work involved with a cell, including automated tasks. The work should be observed a minimum of 10 times or until repeated times begin to appear during the study. The lowest repeated time should be strived for. Once a standard time is determined, the work involved should be carefully studied to ensure consistency in both sequence and timing. Average times to complete tasks must never be used.

The example below shows a capacity sheet for a peanut butter and banana sandwich production line. To see how to fill in the standard work chart step by step watch the Standard Work Series 3 of 3 video.

Standard Work Chart

Stability

A state of acceptable levels of variation suitable for Lean implementation. Stability is the foundation for Lean. Implementation of Lean drives out instability and variation. A strong stable foundation of stability is essential for progressing along the Lean path.

For more on stability please visit our Stability Series.

Supermarket

A controlled amount of finished goods or work in process used to smooth both external and internal fluctuations in demand, equipment availability and other unforeseen variability. Having Supermarkets along a production line decreases customer wait times and allows for smoother delivery of product. The size or amount stored in Supermarkets should be decreased slowly over time as production and equipment issues are solved.

The symbol on the right is used to denote a supermarket in value stream mapping.

Supermarket

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Takt Time

The pacing mechanism that controls a Lean organization. Takt Time is calculated by Total time available / Units of customer demand. The Takt Time is the heartbeat of a Lean organization. Ideally, the entire production floor would simultaneously convey parts in the exact right amounts at the end of each Takt Time. Takt time provides a continuous update in the status of a production floor. Takt Time falls along the same principle of small incremental entities that is the trademark of Lean. A Takt provides an incremental schedule for the worker while a traditional environment works against a convoluted master schedule.

Example:

Simplex Improvement wants to see if it is feasible to complete 200 monitors in a single shift. There are 480 total minutes available in a shift (60 minutes x 8 hours). However, there is a 30-minute break for lunch and two 25-minute breaks in production for scheduled down time. This leaves 400 minutes.

Takt Time = 400 minutes / 200 monitors = 2 minutes

In order for Simplex Improvement to meet customer demand, the system would have to complete a monitor every 2 minutes.

The diagram below shows workers working to a 30 second takt time in a two person cell. For more information about takt time watch the Takt Time Series.

Takt Time

Takt Image

A multiple of Takt Time used to artificially simulate the cadence set by Takt Time for processes not directly on the production line. In general, remotely located processes producing large volumes of small parts that support the production line operate on a Takt Image.

Example:

Simplex Improvement finds it very difficult to control the production of capacitors for their computer monitor production line. Every monitor contains 100 capacitors. The monitor production line runs on a 2 minute Takt Time, yet because of production constraints, producing 100 units at a 2 minute Takt Time is infeasible. The engineers decide to establish a Takt Image to give the capacitor production line a sense of cadence-driven production. They determine that the line functions best when bins of 1000 capacitors are pulled from the production line, which equates to a Takt Image of 20 minutes. In other words the capacitor line functions at a Takt Image of 20 minutes instead of a Takt Time of 2 minutes.

Target Cost

A price point set by a supplier and customer that benefits both groups. The Target Cost must be high enough for the supplier to gain an acceptable level of revenue yet low enough to be purchased at an acceptable cost. Setting Target Costs is essential for companies that work together under exclusive agreements, because in this kind of arrangement, the free market cannot set the price for either group.

Example:

Denso is Toyota's exclusive supplier of electronic components. Because there are no competitors in this relationship, both groups must find a price that is fair and mutually beneficial. When a fair price for a component is set, Denso will work to reduce the cost for producing the item to make a higher profit.

Total Productive Maintenance (TPM)

A comprehensive machine maintenance system that maximizes the availability and performance of equipment. Total Productive Maintenance implies the total participation of all employees in the company including the executive leadership, the shop floor and the maintenance department. Detailed maintenance lists for weekly, monthly and yearly inspections, as well as lubrication and parts replacement are part of a TPM program. Training operators to identify and correct small abnormalities is also included. Prevention of machine related issues is the goal of TPM.

Total Work Content

The total amount of work required to complete a product from start to finish, expressed in terms of time. In poorly organized assembly lines and production environments, it is difficult to capture the Total Work Content. A proven approach to measuring Total Work Content is to time a single operator processing an order from start to finish with no interruptions. The theoretical number of workers in a cell, Takt Time and Total Work Content are directly related.

Theoretical number of worker in cell = Total Work Content / Takt Time

Example:

Simplex Improvement is having a difficult time properly implementing a work cell capable of meeting the Takt Time needed for the computer monitor line. The president of Simplex Improvement asked for the Total Work Content to produce a single monitor. The engineers did not know offhand, so they went to the shop floor to find out. The line was set up for 6 operators but they asked a single operator to perform all tasks from start to finish on a single monitor. The operator finished the monitor from start to finish in four minutes or 240 seconds. In other words, the Total Work Content is 240 seconds. The Takt Time was determined to be 30 seconds.

Theoretical number of workers in cell = 240 seconds / 30 seconds = 8 workers. If the line is correctly balanced, 8 workers not 6, are required in order to meet Takt Time.

The diagram on the right shows the total work content for a process. To learn more about takt time and how it relates to total work content please watch Takt Time 1 of 2.

Total Work Content

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Value

Changing the form, fit or function of a product in a manner that the customer is willing to pay for. This does not include rework. Tasks can be broken down into either non value added or value added activities.

The diagram on the right illustrates how there are generally more non value added operations than value added operations in a value stream. For more information on value please watch the Value Series.

Value

Value Stream

The flow a product takes from start to finish through an entire production process.

Value Stream Manager

A Manager that oversees the production of a product from start to finish. Value stream management is in stark contrast with the traditional departmental approach to management. Since a Value Stream Manager controls the entire process of production, departmental conflicts stemming from competing goals are avoided.

Value Stream Map

A pictorial snapshot, showing both material and information flow, of how a product is produced from start to finish. Value Stream Maps create a common language between all manufacturers implementing Lean. They display the relationships between product and information flows, as well as inventory. There are three main categories of Value Stream maps: Current State Map, Future State Map, and Ideal State Map

Current State Map

A Value Stream Map that depicts the current state of the system. It is used as a baseline to be compared to later maps. Creating a Current State Map is one of the first steps in a Lean journey. Kaizen Bursts on the map show the steps the organization is taking to move toward the Future State Map.

The example below shows a current state value stream map for Simplex Ski Company completed for the red triangle line. The yellow kaizen bursts on the map show that the areas of focus are going to be quality for tracing, cutting, and binding and uptime for painting. For more information on creating value stream maps and to see the Simplex Ski Company example watch the Value Stream Mapping Series.

Current State Value Stream Map

Future State Map

A Value Stream Map that shows an aggressive yet achievable goal no more than 90 days after the creation of the Current State Map. The Kaizen Bursts found on the Current State Map link it to the Future State Map. After a Kaizen Event proves to be sustainable, a new version of the Current State Map should be generated. These maps should be carefully stored in order of completion to document a Lean journey. Once the an organization achieves the level or performance depicted on the Future State Map, it should generate another Future State Map for the next 90 day period.

The example below shows a future state value stream map for Simplex Ski Company completed for the red triangle line. For more information on creating value stream maps and to see the Simplex Ski Company example watch the Value Stream Mapping Series.

Future State Value Stream Map

Ideal State Map

A Value Stream Map with zero waste. The Ideal State Map should function as a guiding light for an organization’s Lean journey. All Future State Maps should bring the organization a step closer to the Ideal State Map. Generating an Ideal State Map is not only a good exercise to get individuals radically re think (kaikaku) the current state, it is an essential part of the Lean journey. With no long term vision, the Future State Maps will have no direction.

The example below shows an ideal state value stream map for Simplex Ski Company completed for the red triangle line. For more information on creating value stream maps and to see the Simplex Ski Company example watch the Value Stream Mapping Series.

Ideal State Value Stream Map

Visual Control

Any visual device or indicator that creates a clear signal of the status or condition.

The diagram on the right is an example of a visual control. The hoses are color coded blue for air and red for gas. It would be clear to see if the hoses were mistakenly interchanged. Additionally the hoses have been error proofed. The ends of the hoses only fit in their respective fixture. For more on visual controls watch the Jidoka Series.

Visual Control

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Waste

Any use of resources that does not add value to the product. Waste comes in different forms. Ohno divided waste into seven categories.

  1. Overproduction: Producing more than is needed at that given time

  2. Waiting: Time spent waiting – as caused by outages, machine downtime, absenteeism, etc. – when there is an actual demand for product

  3. Movement: Moving product or inventory

  4. Over Processing: Processing a product beyond the specifications set by the customer; generally caused by a poor understanding of what the customer considers valuable.

  5. Inventory: Money and resources tied up in inventory due to erratic customer demand and poor equipment capabilities

  6. Motion: Any motion by an individual in excess of the minimum amount needed to add value to the product

  7. Rework: All resources associated with repairing or reprocessing a defect
For more information on waste please visit our Waste Series.

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