Section D: Lean

Question 1

Lean Production

Answer 1

Lean Production

A philosophy of production that emphasizes the minimization of the amount of all the resources (including time) used in the various activities of the enterprise.

It involves identifying and eliminating non-value-adding activities in design, production, supply chain management, and dealing with customers.

Lean producers employ teams of multiskilled workers at all levels of the organization and use highly flexible, increasingly automated machines to produce volumes of products in potentially enormous variety.

Lean production contains a set of principles and practices to reduce cost through the relentless removal of waste and through the simplification of all manufacturing and support processes.

Question 2

What are the objectives of Lean

Answer 2

The objectives of lean are to Make only those products and services customers actually want Match the production rate to the demand rate Make products and services with perfect quality Make products and services with the shortest possible lead times Include only features actually in demand, excluding all else Keep labor, equipment, materials, and inventory continually in motion, with no waste or unnecessary movement Build worker learning and growth into each operational activity.

Question 3

Pull Rather Than Push

Answer 3

one major difference between conventional MPC and lean

Question 4

Push System

Answer 4

Push System

1) In production, the production of items at times required by a given schedule planned in advance.
2) In material control, the issuing of material according to a given schedule or issuing material to a job order at its start time.
3) In distribution, a system for replenishing field warehouse inventories where replenishment decision making is centralized, usually at the manufacturing site or central supply facility.

Question 5

Pull System

Answer 5

Pull System

1) In production, the production of items only as demanded for use or to replace those taken for use.
2) In material control, the withdrawal of inventory as demanded by the using operations. Material is not issued until a signal comes from the user.
3) In distribution, a system for replenishing field warehouse inventories where replenishment decisions are made at the field warehouse itself, not at the central warehouse or plant.

Question 6

The House of Lean

The Roof: Eliminate Waste

Answer 6

Focus on the customer to produce only what is wanted in the best quality, at the lowest cost, and using the shortest lead time possible by eliminating waste in all of its forms.

Question 7

Waste

Answer 7

Waste

1) Any activity that does not add value to the good or service in the eyes of the consumer.
2) A by-product of a process or task with unique characteristics requiring special management control. Waste production can usually be planned and somewhat controlled. Scrap is typically not planned and may result from the same production run as waste.

Question 8

Muda

Answer 8

Muda (waste) : In lean manufacturing, costs are reduced by reducing waste within system.

Question 9

Mura

Answer 9

Mura : A Japanese word meaning unevenness or variability.

Question 10

Muri

Answer 10

Muri : A Japanese word meaning strain or overburden.

Question 11

Shingo’s seven wastes

Answer 11

Shingo’s seven wastes :

Shigeo Shingo, a pioneer in the Japanese just-in-time philosophy, identified seven barriers to improving manufacturing.

They are the:

• waste of overproduction,
• waste of waiting,
• waste of transportation,
• waste of stocks,
• waste of motion,
• waste of making defects, and
• waste of the processing itself

Question 12

The 8th waste:

Answer 12

Waste of Unused people skills

Question 13

Lean identifies these forms of waste in regular continuous improvement sessions and by getting out on the shop floor and talking to people. This is very important to lean and can be expressed as gemba or genchi genbutsu in Japanese. The Dictionary defines these terms as follows:

Answer 13

Lean identifies these forms of waste in regular continuous improvement sessions and by getting out on the shop floor and talking to people. This is very important to lean and can be expressed as gemba or genchi genbutsu in Japanese. The Dictionary defines these terms as follows:

Gemba : The place where humans create value; the real workplace. Also a philosophy: “Go to the actual place, see the actual work.”

Genchi genbutsu : A Japanese phrase meaning to visit the shop floor to observe what is occurring.

Question 14

The House of Lean

Pillar One: Just in Time

Answer 14

The primary elements of just in time are to have only the required inventory when needed; to improve quality to zero defects; to reduce lead times by reducing setup times, queue lengths, and lot sizes; to incrementally revise the operations themselves; and to accomplish these activities at minimum cost.

Question 15

Takt time

Answer 15

Sets the pace of production to match the rate of customer demand and becomes the heartbeat of any lean production system. Computed as the available production time divided by the rate of customer demand.

For example, assume demand is 10,000 units per month, or 500 units per day, and planned available capacity is 420 minutes per day. The takt time = 420 minutes per day ÷ 500 units per day = 0.84 minutes per unit. This takt time means that a unit should be planned to exit the production system on average every 0.84 minutes.

Question 16

An immediate benefit provided by quick changeovers is a reduction in lead time. Reducing lead time using lean, or by improving lead time in conventional systems, can provide a number of other benefits:

Answer 16

Reducing lead times allow these benefits:

There will be a direct and immediate reduction in product cost, because setup time is a direct cost.

It can eventually reduce lot sizes—and thus order quantities—because setup time will not be as large a component in the tradeoff analysis between the cost of setups and other costs.

Reducing lot sizes will also eventually improve quality because defects will have less chance to be replicated across as many units.

By reducing lot sizes, WIP inventory and queues (orders awaiting production at a work center) will be reduced, because the total amount of inventory in process or waiting to be run at individual work centers is partly a factor of the order size.

When less inventory is held between work centers, it will be easier to establish cellular layouts because the work centers can be physically nearer to each other.

Question 17

Kanban

Answer 17

A method of just-in-time production that uses standard containers or lot sizes with a single card attached to each.

It is a pull system in which work centers signal with a card that they wish to withdraw parts from feeding operations or suppliers.

The Japanese word kanban, loosely translated, means card, billboard, or sign, but other signaling devices such as colored golf balls have also been used. The term is often used synonymously for the specific scheduling system developed and used by the Toyota Corporation in Japan.

Question 18

The House of Lean

Pillar One: Jidoka

Answer 18

Jidoka, which can be translated as automation with a human mind, is all about empowering shop floor workers to take ownership of the quality of their processes and to help the organization to improve.

The APICS Dictionary , 16th edition, defines jidoka as “the Japanese term for the practice of stopping the production line when a defect occurs.”

Question 19

Andon

Answer 19

andon as a sign board with signal lights used to make workers and management aware of a quality, quantity, or process problem.

Question 20

The House of Lean

The Foundation: Standardization and Operational Stability

Answer 20

Leveling, standardized work, reducing variability, avoiding overburdening processes or employees, and kaizen (a form of improvement) are the main tools that lean organizations use to reduce variation and allow work to be harmonious rather than in a constant state of emergency.

Total productive maintenance and heijunka are important examples of how operational stability are achieved.

Question 21

The House of Lean

The Foundation: Standardization and Operational Stability

Answer 21

Leveling, standardized work, reducing variability, avoiding overburdening processes or employees, and kaizen (a form of improvement) are the main tools that lean organizations use to reduce variation and allow work to be harmonious rather than in a constant state of emergency.

Total productive maintenance and heijunka are important examples of how operational stability are achieved.

Question 22

Total productive maintenance (TPM)

Answer 22

Total productive maintenance

Preventive maintenance plus continuing efforts to adapt, modify, and refine equipment to increase flexibility, reduce material handling, and promote continuous flows.

It is operator-oriented maintenance with the involvement of all qualified employees in all maintenance activities.

Question 23

The House of Lean

The Center: Culture of Involvement and Continuous Improvement

Answer 23

A House of Lean that is built correctly creates a culture of continuous improvement with a high degree of respect for people, in terms of both designing processes so they are safe and maintaining and improving morale.

Question 24

quality at the source

Answer 24

quality at the source

A producer’s responsibility to provide 100 percent acceptable quality material to the consumer of the material.

The objective is to reduce or eliminate shipping or receiving quality inspections and line stoppages as a result of supplier defects.

Question 25

supplier partnership

Answer 25

supplier partnership

the establishment of a working relationship with a supplier organization whereby two organizations act as one.

Question 26

Hoshin Planning

Answer 26

Hoshin Planning

Hoshin : A Japanese word meaning statement of objectives.

Hoshin planning : Breakthrough planning. A Japanese strategic planning process in which a company develops up to four vision statements that indicate where the company should be in the next five years.

Company goals and work plans are developed based on the vision statements. Periodic audits are then conducted to monitor progress.

Hoshin planning is lean’s planning methodology, and one way to translate it is as strategy deployment.

Question 27

Hoshin planning uses the plan-do-check-action cycle to ensure that critical results are achieved and feedback is used to remove obstacles in the path.

Plan-do-check-action is defined as

Answer 27

Plan-do-check-action is defined as

A four-step process for quality improvement.

Plan - a plan to effect improvement is developed.
Do - the plan is carried out, preferably on a small scale. Check - the effects of the plan are observed.
Action - the results are studied to determine what was learned and what can be predicted.

The plan-do-check-action cycle is sometimes referred to as the Shewhart cycle.

Question 28

Hansei

Answer 28

reflection

Question 29

Kaizen

Answer 29

Kaizen : The Japanese term for improvement; refers to continuing improvement involving everyone—managers and workers.

In manufacturing, kaizen relates to finding and eliminating waste in machinery, labor, or production methods.

Question 30

Kaizen event

Answer 30

Kaizen event : A time-boxed set of activities carried out by the cell team during the week of cell implementation.

The kaizen event is an implementation arm of a lean manufacturing program.

Question 31

Kaizen blitz

Answer 31

Kaizen blitz : A rapid improvement of a limited process area; for example, a production cell. Part of the improvement team consists of workers in that area.

The objectives are to use innovative thinking to eliminate non-value-added work and to immediately implement the changes within a week or less.

Ownership of the improvement by the area work team and the development of the team’s problem-solving skills are additional benefits.

Question 32

Are there differences between a Kaizen event and a Kaizen blitz?

Answer 32

Kaizen event and kaizen blitz are basically synonyms, but, if they are treated as different, the main difference would be whether the improvement initiative is proactive (event) or reactive (blitz). The idea is to focus a sudden burst of energy to deconstruct a process and put it back together in a better way.

Question 33

Kaizen is a team effort. What japanese word means voluntary study groups?

Answer 33

Jishuken

a Japanese word meaning voluntary study groups

Question 34

Value stream

Answer 34

Value stream :

The processes of creating, producing, and delivering a good or service to the market.

For a good, the value stream encompasses the raw material supplier, the manufacture and assembly of the good, and the distribution network.

For a service, the value stream consists of suppliers, support personnel and technology, the service “producer,” and the distribution channel. May be controlled by a single business or a network of several businesses.

Question 35

Value stream mapping

Answer 35

Value stream mapping :

A lean production tool to visually understand the flow of materials from supplier to customer that includes the current process and flow as well as the value-added and non-value-added time of all the process steps.

Used to lead to reduction of waste, decrease flow time, and make the process flow more efficient and effective.

Question 36

Value stream mapping

Answer 36

Value stream mapping :

A lean production tool to visually understand the flow of materials from supplier to customer that includes the current process and flow as well as the value-added and non-value-added time of all the process steps.

Used to lead to reduction of waste, decrease flow time, and make the process flow more efficient and effective.

These are basically flowcharts designed to determine how to make a process lean.

Question 37

poka-yoke

Answer 37

poka-yoke (mistake-proof)

Mistake-proofing techniques, such as manufacturing or setup activity, designed in a way to prevent an error from resulting in a product defect.

For example, in an assembly operation, if each correct part is not used, a sensing device detects that a part was unused and shuts down the operation, thereby preventing the assembler from moving the incomplete part to the next station or beginning another operation.

This could be to use a template to ensure that parts are put in the right locations, to design a part so it can be installed in only one way (e.g., rather than upside down), to color-code parts, or to use automated sensors or counters to show how many operations have been done.

Question 38

five Ss (5S) as

Answer 38

5S

Five terms beginning with “S” used to create a workplace suitable for lean production: sort, simplify, scrub, standardize, and sustain.

Sort means to separate needed items from unneeded ones and remove the latter.

Simplify means to neatly arrange items for use.

Scrub means to clean up the work area.

Standardize means to sort, simplify, and scrub daily.

Sustain means to always follow the first four Ss. Sometimes referred to by the Japanese equivalents: seiri, seiton, seiso, seiketsu, and shitsuke.

The adage “Have a place for everything and keep everything in its place” sums up much of the philosophy of the five Ss.