Lean Manufacturing

Agenda

Background Toyota Production System Key Lean Techniques Advantages and Disadvantages People and Customers Economics Changes in Lean Current Lean Practices Case Studies

Definition Lean Manufacturing – A way to eliminate waste and

improve efficiency in a manufacturing environment Lean focuses on flow, the value stream and

eliminating muda, the Japanese word for waste Lean manufacturing is the production of goods using

less of everything compared to traditional mass production: less waste, human effort, manufacturing space, investment in tools, inventory, and engineering time to develop a new product

Lean and Just-in-Time

Lean was generated from the Just-in-time (JIT) philosophy of continuous and forced problem solving

Just-in-time is supplying customers with exactly what they want when they want it

With JIT, supplies and components are “pulled” through a system to arrive where they are needed when they are needed

What is Waste?

Waste is anything that happens to a product that does not add value from the customer’s perspective

Products being stored, inspected or delayed, products waiting in queues, and defective products do not add value

Seven Wastes Overproduction – producing more than the customer

orders or producing early. Inventory of any kind is usually waste.

Queues – idle time, storage, and waiting are wastes Transportation – moving material between plants,

between work centers, and handling more than once is waste

Inventory – unnecessary raw material, work-in-process (WIP), finished goods, and excess operating supplies

Motion – movement of equipment or people Overprocessing – work performed on product that adds

no value Defective product – returns, warranty claims, rework

and scrap

Origins

Lean Manufacturing is sometimes called the Toyota Production System (TPS) because Toyota Motor Company’s Eiji Toyoda and Taiichui Ohno are given credit for its approach and innovations

Underlying Principles to TPS

Work shall be completely specified as to content, sequence, timing, and outcome

Every customer-supplier connection, both internal and external, must be direct and specify personnel, methods, timing, and quantity of goods or services provided

Product and service flows must be simple and direct – goods and services are directed to a specific person or machine

Any improvement in the system must be made in accordance with the “scientific method” at the lowest possible level in the organization

Toyota Production System

Since the Toyota Production System requires that activities, connections, and flow paths have built-in tests to signal problems automatically, gaps become immediately evident.

Results of the TPS are improvements in reliability, flexibility, safety, and efficiency.

These lead to increase in market share and profitability.

Timeline

Key Lean Manufacturing Techniques

5S

Single Minute Exchange of Dies

Kanban

Cellular Manufacturing

5S

Strategy for creating a well organized, smoothly flowing manufacturing process

5S Examples

Before After

Benefits of 5S

Increases organization and efficiency Avoids wasted motion Increases safety Eliminates unnecessary inventory Offers improvements at an inexpensive

cost

5S Drawbacks

If not fully implemented, may result in “Jive S” Store things Stick to the rules Superficially clean Switch to new fixtures Serve reluctantly

Can not be considered an end goal – must be part of a continuous improvement movement

Single Minute Exchange of Dies (SMED)

Method that focuses on the rapid conversion from manufacturing one product to the next

SMED and Lean

SMED needs to be treated as a constant improvement program

Setup times can not be minimized overnight

Continuous evaluation and exploration of further improvements is absolutely necessary

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Simple CNC Example

New batch of parts arrives Change over tools for the batch Set offsets for new tools Load NC program Validate

Run parts Load part onto machine Cycle start and wait Unload and visually inspect (adjust if necessary)

External elements of work can be completed while the machine is still running e.g. get the next tool, get all your clamps, get lifting equipment in place, put equipment away, etc.

Internal elements of work can only be done while the machine is stopped e.g. change the tool, adjust the machine depth, sharpen a tool (which requires the machine to be stopped), etc..

SMED Examples

SMED Examples

SMED Examples

For example: A slide clamp reduced the time required to load and unload parts to fixture. 2 hold-down clamps eliminated the need to tape parts during a glue-up operation. Set slide allows quick (temporary) alignment of 2 parts.

SMED Examples

SMED Examples

Split thread bolts Handles Toggle clamps U-shaped washers

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Make the tool part of the screw device -- you don’t need a tool, and this will save time in disassembling and reassembling the tooling and fixturing!

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Reduce the amount of turns required in order to activate the screw.

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Reduce the amount of screw turns and eliminate the tool!

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Benefits of SMED

Increases throughput by reducing setup times Eliminates setup errors Increases safety Reduces the cost of setups Reduces waiting times and inventory buildups Decreases the required skill level of the

operators

Kanban

A system that uses replenishment signals to simplify inventory management Signals (usually cards) hold product details

What to make, when to make it, how much to make, and where to send it

Cards stay attached to a bin that holds the product When bin is empty, it is returned to the start of the

assembly line for replenishment Full bins are returned to the customer, and the cycle

continues

Kanban Example

Supermarket Ordering System

Benefits of Kanban

Highly visible systems Simple, effective, and inexpensive Reduces inventory and eliminates stock-

outs Improves the quality of service Improves lead times

Cellular Manufacturing

Dividing the manufacture of products into semi-autonomous and multi-skilled

teams known as work cells

Cellular Manufacturing Example

Functional LayoutCellular Layout

Benefits of Cellular Manufacturing

Simplifies material flow and management

Reduces interdepartmental travel Reduces throughput time Reduces lot sizes Simplifies scheduling

Lean Manufacturing Advantages and Disadvantages

Advantages: Increased overall

productivity Reduced amount of

floor space required Reduced manufacturing

lead time Improved flexibility to

react to changes Improved quality

Disadvantages: Difficulty involved with

changing processes to implement lean principals

Long term commitment required

Very risky process - expect supply chain issues while changing over to lean

People

Transition to Lean is difficult since a company must build a culture where learning and continuous improvement are the norm.

Success of lean requires the full commitment and involvement of all employees and of the company’s suppliers.

How People Benefit from Lean

Element Traditional Lean Improvement

Communication Slow & Uncertain Fast & Positive Quality & Coordination

Teamwork Inhibited Enhanced Effective Teams

Motivation Negative, Extrinsic Positive, Intrinsic Strong Motivation

Skill Range Narrow Broad Job Enrichment

Supervision Difficult and Fragmented

Easy & Localized Fewer Supervisors

How Customer’s Benefit from Lean

Element Traditional Lean Improvement

Response Weeks Hours 70-90%

Customization Difficult Easy Competitive Advantage

Delivery Speed Weeks-Months Days 70-90%

Delivery Reliability

Erratic Consistent & High Up to 90%

Delivery Quantities

Large Shipments JIT as Required Locks in JIT Customers

Quality Erratic Consistent & High Delighted Customers

House of Lean

Economics

Reduction of Inventory Less space necessary to hold inventory

Reduced Waste Decreased Production Cost

Increased market share Able to provide what the customer wants quickly

Increased competitive advantage Faster response to the customer Lower Cost Higher Quality

Changes in Lean since the beginning

Inventory Comparison

Inventory Turnover – annual cost of goods sold from the income statement divided by the value of inventory from the balance sheet

Quality Control 6 sigma process

Combination of old and new ideas 6 ingredients

Genuine focus on the customer Data- and fact-driven management Process focus, management, and improvement Proactive management Boundarlyless collaboration Drive for perfection, tolerance failure

Lean Maintenance

A Simultaneous Approach

6 Tools for Lean Maintenance

Visual Controls 5S Seven Wastes Single Minute Exchange of Dies Poka-yoke Total Productive Maintenance

Other impacts of Lean

Bell South – service industry Management system and operations

Control Process management, work measurement,

management control, and people development Combines lean and 6 sigma

Woburn Safari Parks Feed logistics Animal Resource Planning

Background Poli-film America Inc. a division of a German owned company. Manufactures protective masking that prevents abrasion and

staining of exposed surfaces during manufacturing and delivery

Industries Using Material: Plastics Automotives Construction Electronics Laminates Furniture Textiles

High demand product 24/7 production

Problems An enterprise resource planning system that

encompassed an unstable database The database was untrustworthy account of inventory,

hand counts were necessary to confirm the numbers counted by computers

Led to many employees spending many hours and led to low processing and limit of work utilization

Lack of frequency in supplies and storage – errors in production and set limits

Unable to trace items Main concern – program’s ability to adapt to

changing processes and production goals while still maintaining inventory traceability real time data with multiple distribution sites

Results Chose a new program to implement in later 2003

Greatest impact on company’s inventory flow and order distribution Real time traceability allowed him to cut down on the 2 mil lbs of

film and other materials by more than half and maintain a sufficient safety stock for when its time to reorder and restock

Benefits through Lean Time and money has seen dramatic cuts

Instead of 20 min to fill an order, takes less than 5 min currently Allowed company to expand for more regional coverage Been simplified for reports Reduce time taken to accomplish certain tasks and add more

responsibilities