1-1McGraw-Hill/Irwin ©2009 The McGraw-Hill Companies, All Rights Reserved

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Chapter 12

Lean Manufacturing(Just-in-Time)

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Lean Production

• Lean Production can be defined as an integrated set of activities designed to achieve high-volume production using minimal inventories (raw materials, work in process, and finished goods)

• Lean Production also involves the elimination of waste in production effort

• Lean Production also involves the timing of production resources (i.e., parts arrive at the next workstation “just in time”)

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JIT is an integrated set of activities designed to...

• achieve high-volume production using minimal inventories– raw materials– work in process, and – finished goods.

• Parts arrive at the next workstation "just in time".

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Just-In-Time Production

• Management philosophy• Pull system though the plant

WHAT IT IS

• Employee participation• Industrial engineering/basics• Continuing improvement• Total quality control• Small lot sizes

WHAT IT REQUIRES

• Attacks waste• Exposes problems and bottlenecks• Achieves streamlined production

WHAT IT DOES

• Stable environment

WHAT IT ASSUMES

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Minimizing Waste: Inventory Hides Problems

Work in

process

queues

(banks)

Change

orders

Engineering design

redundancies

Vendor

delinquencies

Scrap

Design

backlogs

Machine

downtime

Decision

backlogsInspection

backlogs

Paperwork

backlog

Example: By identifying defective items from a vendor early in the production process the downstream work is saved

Example: By identifying defective work by employees upstream, the downstream work is saved

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Waste--Operations

(1) Waste from overproduction

(2) Waste of waiting time

(3) Transportation waste

(4) Inventory waste

(5) Processing waste

(6) Waste of motion

(7) Waste from product defects

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Minimizing Waste: JIT Production

Produce...

...what is needed...

...when it’s needed...

...NOTHING MORE!

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Minimizing Waste: Quality at the Source

• Self-inspection

• Automated inspection

• Line-stopping empowerment

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Minimizing Waste: Kanban Production Control Systems

Storage Part A

Storage Part AMachine

Center Assembly Line

Material Flow

Card (signal) Flow

Withdrawal kanban

Once the Production kanban is received, the Machine Center produces a unit to replace the one taken by the Assembly Line people in the first place

This puts the system back were it was before the item was pulled

The process begins by the Assembly Line people pulling Part A from Storage

Production kanban

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Respect for People

• Level payrolls

• Cooperative employee unions

• Subcontractor networks

• Bottom-round management style

• Quality circles (Small Group Involvement Activities or SGIA’s)

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Toyota Production System’s Four Rules

1. All work shall be highly specified as to content, sequence, timing, and outcome

2. Every customer-supplier connection must be direct, and there must be an unambiguous yes-or-no way to send requests and receive responses

3. The pathway for every product and service must be simple and direct

4. Any improvement must be made in accordance with the scientific method, under the guidance of a teacher, at the lowest possible level in the organization

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Lean Implementation Requirements: Work with Vendors

• Reduce lead times

• Frequent deliveries

• Project usage requirements

• Quality expectations

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Lean Implementation Requirements: Reduce Inventory More

• Look for other areas

• Stores

• Transit

• Carousels

• Conveyors

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Lean Implementation Requirements: Improve Product Design

• Standard product configuration

• Standardize and reduce number of parts

• Process design with product design

• Quality expectations