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