Appunti e esercizi del corso di Production management

INTRODUCTION TO JUST IN TIME

The Just-in-Time method was introduced by Toyota, indeed, the success of the company was possible because they completely disrupted the planning, manufacturing, sourcing and delivering of cars. This method manages all resources in order to maximize and optimize the production capacity. Toyota model is like a production chain of Lean manufacturing.

The levels to understand the Japanese technique are:

1. Philosophy
2. Methodologies
3. Planning

That are summarizable with the Customer orientation, Continuous improvement, and Cooperation. The key words that bring the philosophy to the practices are simplicity, stability, repetitiveness, waste cooperation, and reduction (producing only the requested quantity). Indeed, the stock is a waste because the inventories are required if two steps in the supply chain, like supplier to customer, don't share the

1. Design simplicity
• Standardization of the components
• Modularization
• Mushroom BOM
2. Product Design at "Global cost"
• Variety Reduction Programs
• Group Technology
• Layout flow oriented
• Capacity fragmentation
3. Process continuity
• Lines assigned to products
• Lines mixed model
• Lines U shaped
4. Process Standard process
• Setup time reduction
• Process/resource reliability
• Total Productive Maintenance
5. Synchronize production
• Production planning
• Level production
• Synchronize
• Small batches
6. Management Simplicity
• Pull control
• Visual management
• Kanban
7. Growth
• Job enlargement
• Job enrichment
• Auto-control quality
8. Manpower Flexibility
• Time
• Location
• Task
9. Organization chart
• Few levels
10. Reliability
• Vendor reduction
• Closeness
• Equity
• Auto certified
• Vendor Rating
11. Supplier Synchronization
• Pull
• Small batches

urgency and hurry produce as soon as possible to avoid downstream stock-out

Kanban rules:

• No part may be made in the supplier area (upstream) unless there is a production Kanban authorize it workers do maintenance or work on improvement project during the waiting time
• There are precisely one conveyance Kanban and one production Kanban for each container
• Only standard containers may be used, and they always are filled with the prescribed small quantity

DATA CUT+FOLD (workforce + raw material) Volume in Volume in standard

Volume realized in 2003 APR

1.636,8 1.577,4 6.003 0,25 3.916 4.189 0,6 1500,75 3601,8equivalent unit (a) 1279 MAY 1.895,3 1.840,3 6.963 0,25 4.543 4.859 0,6 1740,75 4177,8JUN 1.636,8 1.578,5 6.005 0,25 3.917 4.188 0,6 1501,25 3603Month Working days Volume produced JUL 1.808,4 1.719,8 6.506 0,25 4.225 4.606 0,6 1626,5 3903,622 126JAN AUG 861,3 812,9 3.078 0,25 2.006 2.196 0,6 769,5 1846,818 102FEB SEP 1.636,8 1.540,2 5.797 0,25 3.785 4.049 0,6 1449,25 3478,219 106MAR OCT 1.981,1 1.874,1 7.054 0,25 4.609 4.944 0,6 1763,5 4232,41.722,6 1.664,1 6.310 0,25 4.127 4.413 0,6APR NOV 1577,5 378619 111 1.292,5 1.248,7 4.721 0,25 3.075 3.285 0,6MAY DEC 1180,25 2832,622 128JUN 19 109 Utilisation Efficiency Productivity Utilisation Efficiency ProductivityJUL Workforce Material21 119 =act. hour/paid hour =vol. std hour/act. hour =vol. std hour/paid hour =theo. cons/act. cons. =vol. std q.ty/theo. cons. =vol. std q.ty/act. cons.AUG JAN 96,3% 95,0% 91,5% JAN 93,5% 92,0% 86,0%10 57SEP FEB 95,8% 95,0% 91,0% FEB 93,5% 91,9% 86,0%19

hours Plant Utilisation Efficiency Productivitydays =work. days*work. h/days =prod. vol.*cycle time h/days

22 7,83 JAN172,26 124,738 90,1% 80,3% 72,4%18 FEB140,94 99,123 90,1% 78,1% 70,3%19 h/unitCycle time MAR148,77 101,379 87,9% 77,5% 68,1%19 0,047 APR148,77 100,956 88,6% 76,6% 67,9%22 172,26 118,064 MAY 88,4% 77,5% 68,5%19 148,77 100,956 JUN 89,2% 76,0% 67,9%21 JUL164,43 109,604 84,8% 78,6% 66,7%10 78,3 43,381 AUG 83,4% 66,4% 55,4%19 148,77 98,841 SEP 82,5% 80,5% 66,4%23 180,09 122,529 OCT 81,7% 83,3% 68,0%20 156,6 107,395 NOV 82,8% 82,9% 68,6%15 117,45 78,208 DEC 83,8% 79,4% 66,6%

ASSEMBLY LINE (machine)

Lack of materials Brekdown Maintenance Tests time Std. setup

Lack of orders T Organizational time T

Month 2003 Setup time

LO OT time T time T T time

LM F M pt44 10 19 14 19

Working Number of operators: 7.83

Cycle time (h/days): 4

PRODUCTION CAPACITY CHECK 2004

Quantity (unit): Time needed to produce the Equivalent quantity

RSk(BAR130)/Rsi

Std Rate RSi

Assembly time

Cycle time (hour/piece)

Model (Sales forecast equivalent quantity [h][pieces]

(Convertion in [piece/h]

(tot hour/piece) = eq. q.ty * ass. time (BAR130) = RSk/Rsi *

quantityformat BAR130)=1/ass. time2004)(a) BAR130 60 4,72 1,18 0,212 1,000 60,0 283,2

(b) BAR14 20 6,00 1,50 0,167 1,271 25,4 120,0

(c) BAR129 230 5,60 1,40 0,179 1,186 272,9 1288,0

(d)TAV14 44 6,00 1,50 0,167 1,271 55,9 264,0

(e) TAV18 60 5,20 1,30 0,192 1,102 66,1 312,0

(f) TAV57 618 5,20 1,30 0,192 1,102 680,8 3213,6

(g) TAV7S 120 4,60 1,15 0,217 0,975 116,9 552,0

(h)TAV61 168 5,20 1,30 0,192 1,102 185,1 873,6

(i) TAVS7 72 5,60 1,40 0,179 1,186 85,4 403,2

Sum= 7309,6

Available Production Capacity APC 2004 1293,7 piece

Month Working days 2004 =T*Pmix*P <-- by performance forecasting

TJAN 22 7391,5 h=total work. Days*work. h/days*n operat.Pmix

FEB 20 0,2 piece/h=total q.ty to be produced/time needed to produce

NPC

Total quantity to be produced

MAR 21 1549 piece=total eq. Quantity <-- by market forecasting

Time needed to produce

APR 20 7511 h=total time needed to prod. the eq. q.ty + std setup time

Std setup time

MAY 22 201 h=sum(ass. line std setup time)

PJUN 20 84,9%=U*ηU

JUL 23 87,8%=avg(ass.

line U)ηAUG 8 96,7%η)=avg(ass. lineSEP 21 NPC 2004OCT 23 1549 piece=t