Lean Production System

Prakash .g

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• Lean production focuses on eliminating waste in processes (i.e. the waste of work in progress and finished good inventories)

• Lean production is about expanding capacity by reducing costs and shortening cycle times between order and ship date

• Lean is about understanding what is important to the customer

• Lean production is not about eliminating people

Lean Production System

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Lean Production System

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Taiichi Ohno (1912 †1990)

Shigeo Shingo1909 †1990

Founders of the Lean Production System (TPS)

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Lean Production System

• The production system developed by Toyota motor corporation to provide best quality, lowest cost, and shortest lead time through the eliminating of waste.

• The Lean production system was established on two concepts:– JIDOKA: Automation with a human touch, means that when the problem

occurs, the equipment stops immediately, preventing defective product from being produced.

– JUST-IN-TIME: In which each process produces only what is needed by the next process in a continuous flow.

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Toyota/Lean Production System house

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Just-In-Time SystemsWhat is JIT ?

JIT is a philosophy of continuous improvement in which non-value-adding activities (or wastes) are identified and removed for the purposes of:

Reducing Cost Improving Quality Improving Performance Improving Delivery Adding Flexibility Increase innovativeness

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Producing only what is needed, when it is needed

(not early, not late; not less, not more) Achieving high volume production using minimal

inventories An integrated but simplified system JIT’s mandate:

Elimination of all waste in production effort

Just-In-Time Systems

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Attacks waste (anything not adding value to the product)

Achieves streamlined production by reducing inventory

Exposes problems and bottlenecks caused by variability

What Does Just-in-Time Do?

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Waste (“muda” in Japanese) is ‘anything other than the minimum

amount of equipment, materials, parts, space, and worker’s time,

which are absolutely essential to add value to the product.’

— Shoichiro Toyoda Founder, Toyota

© 1995 Corel Corp.

What is Waste?

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Sources of Waste

Overproduction Waiting Unnecessary transportation Inventory Inefficient work methods Inefficient processing Unnecessary motions Product defects

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Waste in Operations (1 of 3)

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Waste in Operations (2 of 3)

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Waste in Operations (3 of 3)

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Main Components of JIT

Pull System Continuous Flow Processing Takt Time Flexible Workforce (Shojinka) 3 M’s

Just-In-Time

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The Pull System Pull System is a flexible and simple method of controlling/balancing the flow of resources.

Produce only when your customer demands the product in the required quantity.

Run the production according to this demand

Pull System consists of:– Production based on actual consumption– Small Lots– Low inventories– Management by Sight– Better Communication

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The Pull & Push System

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Continuous/One-Piece Flow

Producing and moving one item at a time (or a small and consistent batch of items) through a series of processing steps as continuously as possible, with each step making just what is requested by the next step.

It is also called the one-piece flow, single-piece flow, and make one & move one.

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Continuous/One-Piece Flow

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Takt time is the pace of production required to meet customer demand. Since takt time is defined by the customer, it becomes a very important number in a lean environment.

How: Only 2 variables are used to calculate Takt time: Available Time &

Customer Demand (schedule):

Available time is total shift time minus meal and scheduled break times

TAKT Time

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TAKT Time

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Flexible Workforce (Shojinka):

Flexible workforce or shojinka means to alter (decrease or increase)

the number of operators within a shop, to equip with demand changes.

Continually optimizing the number of workers in a work center to meet the type and volume of demand imposed on the work center. Creating Flow and Eliminating Waste.

Flexible Workforce (Shojinka)

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Multi-machine HandlingType of Part

A B C D

Machine 1

Machine 2

Machine 3

Machine 4

One person handles one process, four machines

Unfinished Parts

Finished Products

Flexible Workforce (Shojinka)

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Multi-process HandlingType of Part

A B C D

One person handles four processes, four machines

Flexible Workforce (Shojinka)

Machine 1

Machine 2

Machine 3

Machine 4

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3 M’s MUDA = Non-Value Added

MURA = Overburden

MURI = Unevenness

3 M’s

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1 TON

4 ton

Capacity : 4 tons

Muda . Mura . Muri

12 TONS

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X

X

2 =

MURI (OVERBURDEN)

6 =

MUDA (NON-VALUE ADDED)

= MURA (UNEVENNESS)

Muda . Mura . Muri

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The most efficient way to deliver 12 tons of good to the destination is:

X 3 =

NO MURI (OVERBURDEN)

NO MUDA (NO WASTAGE)

NO MURA (NO UNEVENNESS)

Muda . Mura . Muri

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KanbanWhat is Kanban?

• Card system that controls production & inventory

•Communicates demand for work or materials from the preceding station

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Kanban is one of the Lean tools designed to reduce the idle time in a production process. The main idea behind the Kanban system is to deliver what the process needs exactly when it needs it.

In Japanese, the word “Kan” means “card" and "ban" means “signal," so Kanban refers to signal cards. Lean uses visual cards as a signaling system that triggers an action to supply the process with its needs either from an external supplier or from a warehouse.

Kanban

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Kanban

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Reduction of eliminating non-value added activities Reduction of floor space and warehouse space per unit of output Reduction of setup time and schedule delays as the factory becomes a

continuous production process. Reduction of waste and rework by detecting errors at the source. Better utilization of machines and facilities. Better integration of and communication between functions such as

marketing, purchasing, design, and production. Quality control built into the process.

Benefits of JIT

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Providing machines and operators the ability to detect when an abnormal condition has occurred and immediately stop work. This enables operations to build in quality at each process and to separate men and machines for more efficient work.

Jidoka highlights the causes of problems because work stops immediately when a problem first occurs. This leads to improvements in the processes that build in quality by eliminating the root causes of defects.

Jidoka - AutomationWhat is Jidoka/Automation?

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Jidoka - Automation

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Jidoka - Automation

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Why Jidoka?

• Increase quality• Lower costs• Improve customer service• Reduce lead time

1. Detect the abnormality. 2. Stop. 3. Fix or correct the immediate condition. 4. Investigate the root cause and install a countermeasure.

Jidoka Steps

Jidoka - Automation

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Prevention Techniques• Poka Yoke - Mistake-Proofing

– Visual control of quality– Prevents defects from happening

• Andons– Commonly lights to signal production line status

• Red: line stopped• Yellow: call for help• Green: all normal

– Andon signals require immediate attention

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Poka Yoke – Mistake Proofing

What is it for?

• To eliminate the possibility or opportunity for passing on errors or making mistakes in a process.

Where could we use it?

• In the development or improvement of any process.

• When you want to make wrong actions impossible or more difficult to do.

• When there is a need to make it possible to reverse actions

• When you need to make it easier to discover that errors occur.

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Poka Yoke - Examples

Spellcheck:

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AndonAndon is an information tool which provides instant, visible and audible warning to the Operations team that there is a abnormality within that area.

When the equipment shuts down because of a quality problem, flags or light, usually with accompanying music, signal that help is needed to solve the problem.

This signaling system is called the andon system.

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Visual Management Andon Lamp

• Red - line stoppage • Yellow - call for help• Green - normal operation

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Benefits of Lean Production

Lean will improve:Quality performance, fewer defects and rework.

Fewer Machine and Process Breakdowns.

Lower levels of Inventory.

Greater levels of Stock Turnover.

Less Space Required.

Higher efficiencies, more output per man hour.

Improved delivery performance.

Faster Development.

Greater Customer Satisfaction.

HIGHER PROFITS!

INCREASED BUSINESS!

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Lean Production System

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