LEAN PRODUCTION SYSTEM CONCEPT

Disusun Oleh; Candra Setia Bakti, ST., MT

LEAN THINKING

VALUE - what customers are willing to pay for

VALUE STREAM - the steps that deliver value

FLOW - organizing the Value Stream to be continuous

PULL - responding to downstream customer demand

PERFECTION - relentless continuous improvement (culture)

--- Lean Thinking, Womack and Jones, 1996

Key Principles of Lean Thinking

Defining Lean

“A systematic approach to identifying and eliminating

waste (non-value added activities) through continuous

improvement by flowing the product at the pull of the

customer in pursuit of perfection.”

Lean is:

Lean Goals- TPS

Zero defects 100% value-add Lot size of one Pull of the customer

GOAL

Lean Production System Goals - highest quality, lowest cost, shortest lead times

Heijunka Standardized Work Kaizen

Just-In-Time•continuous flow•takt time/pace•pull system•triggers

Jidoka•separate man & machine work•identify abnormalconditions•poka yoke

Stable Manufacturing Process

Involvement

8 Wastes Overproduction Excess

inventory Defects Non-value

added processing

Waiting Underutilized

people Excess motion Transportation

Lean = Eliminating the waste

Typically 95% of Total Lead Time is Non-Value Added!!!

Value added

5%

Non-value added

Value Added/Non-value Added Value-added:

ANY ACTIVITY THAT PHYSICALLY CHANGES THE MATERIAL BEING WORKED ON (not rework/repair!)

Machining Knitting Drilling Spreading/Cutting Assembly Dying Painting Sewing

Non-value added:

ANY ACTIVITY THAT TAKES TIME, MATERIAL, OR SPACE BUT DOES NOT PHYSICALLY CHANGE THE MATERIAL

Sorting Stacking Counting Checking

Just-in-TimeJust-in-TimePull System

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

– Eliminating waste of handling, storage, expediting, obsolescence, repair, rework, facilities, equipment, excess inventory (work-in-process and finished).

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

Transfer Washer AssemblyCutting Press Assembly Shipping

Weekly Schedule

Production Control

Traditionally...

one control operation takes the customers’ orders, creates, and sends out schedules to all processes.

Push System Material Movement

In traditional manufacturing, all process departments receive schedules and produce to it.

Each process produces their parts and forwards them to the next process.

This is commonly referred to as the Push System.

Transfer Washer AssemblyCutting press Assembly Shipping

Weekly Schedule

Production Control

I I II

I I

A problem may occur when a change is made either because the order changes, the equipment goes down, or material is not available.

What happens……?

Pull System Material Flow

Lean – flow through the factory with minimum interruption

I

Painting Cutting AssemblyPress

1Shift 1Shift 33

1Shift 204

C/T= 9sec1Shift

IFIFO FIFO

Flow where you can, Pull where you can’tFlow where you can, Pull where you can’t

Example of a Pull System

AProcess

BProcess

CProcess

D

Schedule

Process

Schedule is provided to final

production department

Each process upstream maintains standard stock levels.

Customer

Pull

AProcess

BProcess

CProcess

D

Schedule

Process

The final production department withdraws needed materials from its supplier operation

Customer

Pull

AProcess

BProcess

C D

Schedule

Process Process

Customer

The units are produced and shipped to the customer.

The supplying department now produces to fill up its stock level. It withdraws the supplies it needs from the upstream process.

Pull

AProcess

BProcess

C D

Schedule

Process

Customer

The customer’s needs are filled long before the initial department even knows about the request.

Process

Just-in-TimeJust-in-TimePull System

• Kanban

- A signal to indicate when more parts are needed(Order or Produce)

- Card, empty Bin, In Process Kanban (IPK) on plant floor

Types of Kanban

Main types: Withdrawal Kanban

Inter-process withdrawal

Supplier

Production Instruction Kanban In-process Kanban Signal Kanban (for lot

production with longer set-up time)

Between two processes (Internal to Plant)Between two processes (Internal to Plant)Between customer and supplierBetween customer and supplier

Internal to processInternal to process

Withdrawal Kanban Card

The information on a withdrawal Kanban includes: Item name and part number FROM-preceding process and storage location TO- subsequent or consuming process and delivery location Standard quantity and container type Item code (abbreviation of part number-optional) Parent product (name of final assembly-optional)

Just-in-TimeJust-in-TimePull System

Standard Production or “Move” Kanban

Just-in-TimeJust-in-TimeQuick Changeover (Set-up Reduction)

Single Minute Exchange of Dies (SMED)•a series of techniques for changeovers of production machinery in less than ten minutes (single digit minutes)

Set-up Reduction Program Goals•To achieve smaller lots•To maintain consistent quality•To minimize inventory•To reduce lead times•To address frustration of setup personnel

Identify internal vs. external

changeover tasks

Analyze each task’s real

purpose and function

Focus on no/low cost

solutions

Aim to eliminate

changeover time

Just-in-TimeJust-in-TimeBasic SMED Principles

No/Low Cost Solution: One-Turn MethodsPear-Shaped Hole Method

Tighten Here

Attach and Remove Here

Just-in-TimeJust-in-Time

Takt Time = Demand RateTakt Time = Demand Rate

WorkWork Time AvailableTime AvailableNumber of Units SoldNumber of Units Sold

Takt TimeTakt Time = =

GOAL: Produce to Demand

Just-in-TimeJust-in-Time

Developing a Lean FactoryDeveloping a Lean FactorySummary - Just-in-Time

•Pull Systems/Kanban•Point Of Use Storage•Quick Changeover/Setup Reduction•Continuous Flow•Takt Time