Just In Time Production System

  What is JIT ?

• Producing only what is needed, when it is needed
• A philosophy

  Just In Time Production System • An integrated management system.

• JIT’s mandate: Eliminate all waste.

  Perencanaan & Pengendalian Produksi © 2000 by Prentice-Hall Inc _{Russell/Taylor Oper Mgt 3/e}

  Ch 15 - 2 Basic Elements of JIT

7 Kind of Waste

  1. Flexible resources

  1. Over production

  2. Cellular layouts

  2. Waiting

  3. Pull production system

  4. Kanban production control

  3. Transportation

  5. Small-lot production

  4. Unnecessary process

  6. Quick setups

  5. Inventory

  7. Uniform production

  6. Unnecessary movement

  8. Quality at the source

  9. Total productive maintenance

  7. Rejection _{© 2000 by Prentice-Hall Inc}

  10. Supplier networks Ch 15 - 3 Introduction Procedure Awareness

  The 5S’s Principle Revolution _P In tr _{d e c} ro o _{u c d u o} ti

  Proper arrangement re

  =Organization ( )

5 S n

• Seiri ( 整理) _{Flow Multi process}
• Seiton( 整頓) =Neatness (Orderliness) _{o l p tr}

  Kanban _{manufacturing handling w o n a M} =Cleanliness _{o n e • Seiso(} 清掃) _{C r R} Quality Leveled _{l e} Changeover _{V is u u a d} Assurance Production _{c n o} ti

  清潔) =Standardization _{Maintenance Standard} • Seiketsu( _{& Safety} Jidoka operation

  仕付け) =Discipline

• Shitsuke(

JUST IN TIME

  5

  6 The 5S’s Principle The 5S’s Principle

• Seiton
• Seiri
• – having things in the right places/layout (eliminating searc>– putting things in o>– functional manage
• – distinguishing between the necessary and the unnecessary
• Seiso
• – cleaning (is a form of inspect>– getting rid of the unneces>– eliminating w
• – stratification management
• Seiketsu
• – continually and repeatedly maintaining the above 3Ss
• – visual management

  7

  8 The 5S’s Principle Flow Production

• Goods and material should flow in the factory much as water f
• Shitsuke

  in a river

• – doing the right thing as a matter of course
• But the river (the flow of in process inventory) tends to flood
• – practicing good habit and discipline
• High water volume conceals the rocks/problems. Low water volume reveals the rocks /problems
• A factory needs to have a smooth flow of inventory and operations
• Japanese management tends to view inventory as the root of all evil and the likely cause of poor performance in any business activity

  TI3122-Perencanaan dan

  9

  10 Pengendalian Produksi - Minggu 9 Lower Levels Of Inventory To Expose

  Inventory Hides Problems Problems

  Bad Bad Design Design Poor

  Lengthy Poor Quality

  Lengthy Setups Quality Setups

  Machine Inefficient Unreliable Machine Breakdown

  Inefficient Unreliable Layout Supplier Breakdown _{© 2000 by Prentice-Hall Inc © 2000 by Prentice-Hall Inc} Layout Supplier

  Ch 15 - 22 Ch 15 - 23 Multi-process Operations Multi-process Operations

• Productivity is important indeed but not as important as • Key points: respecting the humanity of our workers. Productivity and
• – Establish U shape manufacturing cells

  humanity must coexist in the factory. The factory must find

• – Abolish processing islands

  a way to satisfy both productivity and humanity

• – Make the equipment smaller
• People must be trained in the multiple skills to handle
• – Standing while working

  several processes

• – Multiple skills training
• – Separate human work from machine work
• The assignment where one worker handles 5 different machines/processes is better than the assignment where
• – Human automation (jidoka, 自働化）and pokayoke

  one worker handles 4 similar machines

• – Safety first

  13

  14 Push and Pull Systems Push and Pull Systems

• Push system
• Pull system

  15

  16 Kanban System The Origin Of Kanban

• Kanban

  a. Two-bin inventory system

  b. Kanban Inventory System

• – Card, label, signboard or visible representation

  Bin 1 Bin 2

  Kanban

• – The information system controlling the number of

  Reorder Q - R parts

  Card R

• – Synchronizing production lines and assembly lines

  Q = order quantity R = reorder point

• Types of Kanban:

  = demand during lead time

• – Production Kanban – Withdrawal Kanban
_{© 2000 by Prentice-Hall Inc}

  17 _{Russell/Taylor Oper Mgt 3/e} Ch 15 - 12

  Kanban Squares Dual Kanbans

  P W P

  X X

  X X

  X X

  X X

  X W

  Container with withdrawal kanban Flow of work

  X X P

  Container with production kanban Flow of kanban

  Flow of work Flow of information TI3122-Perencanaan dan ^{© 2000 by Prentice-Hall Inc}

  19 Ch 15 - 14

• Kanban Square
• – marked area designed to hold items

• Signal Kanban
• – triangular kanban used to signal production at the previous workstation
• Material Kanban
• – used to order material in advance of a process
• Supplier Kanbans
• – rotate between the factory and suppliers

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  99 100 101 102 103 104 105 106 Ch 15 - 18 ^{© 2000 by Prentice-Hall Inc}

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  Ch 15 - 15 ^{© 2000 by Prentice-Hall Inc} _{Russell/Taylor Oper Mgt 3/e} Kanban Racks

  407 409 410 412 408 411

  Ch 15 - 16 ^{© 2000 by Prentice-Hall Inc} _{Russell/Taylor Oper Mgt 3/e} Signal Kanban

  407 408 409 407 408 409

  Ch 15 - 17 ^{© 2000 by Prentice-Hall Inc} Kanban Post Office

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  Types Of Kanbans

• Do not move nonconforming parts to a downstream process
• Ensure that downstream processes withdraw parts from upstream processes in the correct quantity at the right time
• Do not let upstream processes produce more than the quantity of parts withdrawn by downstream processes
• Ensure that production is leveled
• Do not attempt to transmit large demand variation with the Kanban system
• Balance cycle times for smooth production, and constantly improve cells and workstations
• – N = number of kanbans or containers
• – d = average demand over some time period
• – L = lead time to produce parts
• – S = safety stock
• – C = container size

  Ch 15 - 19 ^{© 2000 by Prentice-Hall Inc} _{Russell/Taylor Oper Mgt 3/e} Determining Number Of Kanbans where

  No. of kanbans = mand during lead time + safety stock container size average de

  N dL S C

25 Kanban Golden Rule

• Making production of various product model and volume completely even
• Production scheduling methods: once a month production, once a week production, once a day production, and level production
• Suppose a factory should process the following prod>Product X: 1000 units per month
• Product Y: 600 units per month
• Product Z: 400 units per month

  Ch 15 - 20 ^{© 2000 by Prentice-Hall Inc} Kanban Calculation Example

  Problem statement: d = 150 bottles per hour L = 30 minutes = 0.5 hours dL = (150)(0.5) = 75 S = 10% dL = 10% x 75 = 7.5 C = 25 bottles Solution:

  Round up to 4 (allow some slack) or down to 3 (force improvement) N dL S

  C ( x . ) .

  .

  150 0 5 7 5

  25 75 7 5 25 3.3 kanbans or containers

  28 Level Production Once a Month Production Once a Week Production

  

Product Week 1 Week 2 Week 3 Week 4 Product Week 1 Week 2 Week 3 Week 4

X (1000) X 250 250 250 250 Y 150 150 150 150

  Y(600) 100 100 100 100

  Z Z(400)

  29

  30 Quality Assurance Once a Day Production

• Quality assurance is the starting point in building

  Product Week 1 Week 2 Week 3 Week 4 products X 50 units a day ：Operator,

• Elements where defects most often occur material, machine, method, and information

  Y 30 units a day

• Overall plan for achieving zero defects

  Z 20 units a day

• Operator: Basic training and multiple skills training
• Material: Preventive inspection
• Machine: Pokayoke and preventive maintenance
• Method: Flow production and standard operations
• Information: Visual control
• Basic strategy for zero defects: The 5S’s

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  32

• Shortening setup time could minimize lot sizes, therefore reduce the stock of intermediate and finished products
• Through small lot sizes, the manufacturing lead times (MLT) of various kinds of products (mixed scheduling) can be shortened
• Through short MLT, the company can adapt to customer orders and demand changes very promptly
• SMED (single minute exchange of dies) is not only a technique but also a concept. It was developed by Shigeo Shingo • Single minute means that the setup should be performed within 9 minutes 59 seconds
• The pokayoke system possesses two functions: it can carry out

  100% inspections and, if abnormalities occurs, it can carry out immediate feed back and action:

• – When there is a working mistake, the material will not fit the tool
• – If there is irregularity in the material, the machine will not start
• – If there is a working mistake, the machine will not start the machining process
• – When there are working mistakes or steps left out, corrections are made automatically and machining continues
• – Irregularities in the earlier processes are checked in the later process to stop the defective products
• – When a step is forgotten, the next process will not start

33 Pokayoke (Mistake-proofing)

  34 Setup

• Standard operations is an effective combination of workers, materials and machines for the sake of making high quality products cheaply, quickly, and safely
• Basic elements of standard operati
• Preset desired settings
• Use quick fasteners
• Use locator pins
• Prevent misalignments
• Eliminate tools
• Make movements easier
>Cycletime • Work sequence
• Standard in process inven>The principles of motion economy and 3Ms are very useful tools for establishing improving standard operations
• 3M: Muda ( 無駄) or waste, Mura (斑) or inconsistency, and Muri ( 無理) or irrationality

  Ch 15 - 25 ^{© 2000 by Prentice-Hall Inc} Reducing Setup Time

  36 Standard Operations

• Total productive maintenance (TPM) treating the causes of breakdowns before the breakdowns actually happen is the key to achieving zero breakdowns
• Accidents happen because of deterioration
• Stages on the path to breakdown: latent minor defects, apparent minor defects, performing below expectations, stops intermittently, and completely stop (breaks down)
• Jidoka ( 自 動 化 ) means automation, i.e., a mechanism where the machine operates by itself once the switch is thrown but has no feedback control for detecting errors and no device for stopping the process if a malfunction occurs.
• Jidoka ( 自 働 化 ) means autonomation, i.e., a mechanism to detect abnormalities or defects and to stop the line or machine when abnormalities or defects occur

  37 JIDOKA

  38 Maintenance and Safety

• Four basic maintenance activ>Shojinka means to alter (decrease or increase) the number of workers at a shop when the production demand has changed (decrease or increase)
• The prerequisite for realizing shoji>Maintenance prevention (MP)
• Preventive maintenance (PM)
• Corrective Maintenance (CM)
• Independent maintenance and improve>Proper design of machinery layout (U-shaped layout)
• Well-trained and multifunctional workers
• Continuous evaluation and revision of the standard operations<
• The maintenance cycle: MP-PM-CM
• The CCO (cleanliness, checking and oiling) habit must be an integral part of the routine tasks

  TI3122-Perencanaan dan

  39 Maintenance

  40 Shojinka( 少人化) Visual Control Tools Visual Control

• Make them easy to see from a dist>What is being managed and where should people look? ---- What are the important po>Put the displays on the things they are for
• Make them so that anyone can tell what is right and what is w>What constitutes an abnormality ----- What are the standa>Make them so that anybody can use them easily and conveniently
• Make them so that anybody can follow them and make them
• It is discernible? ----- What are the tools used for inspection,

  necessary correction easily

  and is the inspections easy to do (including easy of evaluation)?

• Make them so that using them makes the workplace brighter and more ord>What should be done? ----- What are the emergency procedures and what are long term remed
• Example: kanban/label, display, marks, andon, color

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  42 Visual Control Andon

  Tool board Visual kanbans _{Mesin A Mesin B Mesin C Mesin D}

  1. Tiap mesin mempunyai lampu, dan 2.

  Lampu merah juga menyala pada lampu merah akan menyala untuk Andon di ruang perawatan

  Work station Library shelf m e n u n j u k a n m e s i n y a n g membutuhkan perhatian

  How to Ruang Perawatan sensor

  Andon

  3. Pekerja perawatan akan menuju tempat terjadinya masalah dengan 30-50 Machine controls sesegara mungkin _{M M M M e A e B e C e D s s s s in in in in}

  Good Better Best

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• Continuous improvement
• Requires total employment involvement
• Essence of JIT is willingness of workers to
• – spot quality problems
• – halt production when necessary
• – generate ideas for improvement
• – analyze problems
• – perform different functions

  3. Lower costs

  11. Better use of human resources

  10. Increased capacity

  9. Simplified scheduling and control activities

  8. Better relations with suppliers

  7. Greater flexibility

  6. Increased productivity

  5. Shorter lead time

  4. Reduced space requirements

  2. Improved quality

  Ch 15 - 29 ^{© 2000 by Prentice-Hall Inc} _{Russell/Taylor Oper Mgt 3/e} Kaizen

  1. Reduced inventory

  Benefits Of JIT

  5. Become a certified supplier and accept payment at regular intervals rather than upon delivery Ch 15 - 34 ^{© 2000 by Prentice-Hall Inc}

  4. Use standardized containers and make deliveries according to a precise delivery schedule

  3. Consider establishing small warehouses near to the customer or consolidating warehouses with other suppliers

  2. Use small, side loaded trucks and ship mixed loads

  1. Locate near to the customer

  Ch 15 - 33 ^{© 2000 by Prentice-Hall Inc} _{Russell/Taylor Oper Mgt 3/e} Trends In Supplier Policies

  12. More product variety