IENG 471 - Lecture 04

1. IENG 471 - Lecture 04 Schedule Design IENG 471 Facilities Planning

2. Assignments • Current Assignment: • HW: (HW 2) • Product BOM • Product Operation Process Chart • Product Precedence Diagram • PERT Chart w/ timings • Next Assignment: • HW: (HW 3) Difficult HW Teams of 4 or 5 (NO LESS!) • required input for each of the workstations • equipment necessary for each machine • steady state cycle time for each machine • ideal machine assignment for each machine • compute the idle time • unit cost at each workstation • total cost per good unit • square footage for each workstation and the total space required IENG 471 Facilities Planning

3. Schedule Design Overview • Schedule Design is undertaken to decide for a facility design: • How much should the facility be designed to produce • When should the facility be able to produce the product IENG 471 Facilities Planning

4. Impacts of the Schedule Design: • The Schedule Design of the facility will impact: • Types of machines required • Processing equipment • Storage equipment • Material handling equipment • Number of machines required • Number of employees required • Space requirements • For all of the above, plus support functions (services, utilities, …) IENG 471 Facilities Planning

5. Information Req’d: Marketing • What products are to be produced • What volume of each product is expected to be produced (and when) • How probable are the production requirements • Seasonality and life cycle considerations • Where are the products to be delivered • Who will acquire the products • What are the product development plans IENG 471 Facilities Planning

6. Types of Manufacturing Systems: Job Shop Batch/Cellular Mass Production Approximate Annual Volume: Production Volume Kalpakjian Type of Production No. Produced Typical Products Prototype 1 - 10 Anything Piece/Small Batch 10 - 5,000 Aircraft, Machinery, Dies Batch/High Volume 5,000 - 100,000 Trucks, Ag. Equip., Engines Mass Production Over 100,000 Cars, Appliances, Fasteners Job Shop IENG 471 Facilities Planning

7. Characteristics Type of Production System Job Shop Batch Prod. Mass Prod. General Equipment Special Production Rate Production Quantity Process Plant Layout Flow Line Labor Skill Part Variety Kalpakjian (Arrows point in the direction of increase) IENG 471 Facilities Planning

8. Drill Grind H. Mill H. Mill Drill Grind H. Mill H. Mill Drill V. Mill V. Mill Drill CMM V. Mill V. Mill Receiving Lathe Lathe Oven L. Paint Lathe Lathe P. Paint Shipping Example Job Shop Layout IENG 471 Facilities Planning

9. Example Mass Production Layout V. Mill H. Mill Drill Grind Drill CMM Lathe L. Paint Receiving Oven Shipping IENG 471 Facilities Planning

10. Example Batch/Cell Production Layout V. Mill Grind Drill Grind Drill H. Mill Drill CMM Lathe L. Paint Receiving Oven Shipping IENG 471 Facilities Planning

11. Volume, Variety & Automation Rembold, et. al. Transfer Line 100,000 10,000 1,000 100 1 Production Quantity High Medium Low Increasing Flexibility Batch Flow Line Increasing Productivity Flexible Mfg Sys Mfg Cell NC Machine 1 10 100 1,000 Low Medium High Part Variety IENG 471 Facilities Planning

12. Pareto Chart for Product Volume 120 120% 100% 100 80 80% Est. Volume Req’d 60% 60 Cumulative % 40 40% 20% 20 0 0% Prod F Prod E Prod A Prod B Prod C Prod D Prod H Prod G Product Type Which Type to Use?: Pareto Chart • 80% of any problem is the result of 20% of the potential causes* • Histogram categories are sorted by the magnitude of the bar • A line graph is overlaid, and depicts the cumulative proportion of products • Quickly identifies where to focus efforts IENG 471 Facilities Planning

13. Estimating Production Volume with Scrap • The production facility must operate in the “real world” • In the real world, things go wrong – defects! • To size the facility, the plant capacity must include extra volume for scrap: • At a single workstation (k) the formula is: where: • Ik is the input amount required for the process to achieve goals • Ok is the output amount required of the process, and • Pk is the percentage of scrap generated by the process per unit IENG 471 Facilities Planning

14. Estimating Production Volume with Scrap • Most processes are a sequence of operations • We need to know the sequence and individual scrap rates of each of the operations… • Good thing we got those Operation Process Charts! • Assuming that each unit must go through each operation in a chain of operations, the plant capacity must include extra scrap volume: • At end of a single chain of (n) individual operations, the formula for total input volume required is: where: • On is the output amount required at the end of the operation chain, and • Pk is the percentage of scrap per unit generated by the kth operation, starting with operation 1 and continuing through operation n IENG 471 Facilities Planning

15. Example 1: Express Input 1 as a function of the Quota I1 O2=I3 O3=I4 O1=I2 O4=Q 1 2 3 4 P4=0.5% P1=2% P2=5% P3=1% IENG 471 Facilities Planning

16. Example 2: Express Input 1 as a function of the Quota I1 O2+OR=I3 O3=I4 O1=I2 O4=Q 1 2 3 4 OR P4=0.5% IR P1=2% P2=5% P3=1% R PR=1% IENG 471 Facilities Planning

17. Example 3: Express Input 1 as a function of the Quota I1 O2=I3 O3=I4 O1+OR=I2 O4=Q 1 2 3 4 OR P4=0.5% IR P1=2% P3=1% P2=5% R PR=1% IENG 471 Facilities Planning

18. Example 4: Find Input 1 and the system Total Scrap Cost I1 O2=I3 Q=1000 O1=I2 1 2 3 P1=3% S1=$5 P2=5% S2=$10 P3=7% S3=$15 IENG 471 Facilities Planning

19. Example 5: Find Input 1 and the system Total Scrap Cost (Note: Proportion scrap reversed from Example 4) I1 O2=I3 Q=1000 O1=I2 1 2 3 P1=7% S1=$5 P2=5% S2=$10 P3=3% S3=$15 IENG 471 Facilities Planning

20. Critical Thinking With Models: How do the first three models inform us? I1 O2=I3 O3=I4 O1=I2 O4=Q 1 2 3 4 I = 1.090Q P4=0.5% P1=2% P2=5% P3=1% I1 O2+OR=I3 O3=I4 O1=I2 O4=Q 1 2 3 4 OR P4=0.5% IR P1=2% P2=5% P3=1% R I = 1.036Q PR=1% I1 O2=I3 O3=I4 O1+OR=I2 O4=Q 1 2 3 4 OR P4=0.5% IR P1=2% P3=1% P2=5% R I = 1.069Q PR=1% IENG 471 Facilities Planning

21. Critical Thinking With Models:How do the last two models inform us? I1 O2=I3 Q=1000 O1=I2 1 2 3 P1=3% S1=$5 P2=5% S2=$10 P3=7% S3=$15 • I = 1167 Tsc = $ 1870 I1 O2=I3 Q=1000 O1=I2 1 2 3 P1=7% S1=$5 P2=5% S2=$10 P3=3% S3=$15 • I = 1167Tsc = $ 1415 IENG 471 Facilities Planning

22. Critical Thinking With Models • How do the first three models inform us? • Ex 1. 4 stations, no rework: I = 1.090Q • Ex 2. 4 stations, rework at Sta. 2 (5% scrap): I = 1.036Q • Ex 3. 4 stations, rework at Sta. 1 (2% scrap): I = 1.069Q • How do the last two models inform us? • Ex 4. 3 stations, scrap rate increases from Sta. 1 to Sta. 3: I = 1 167 Tsc = $ 1 870 • Ex 5. 3 stations, scrap rate decreases from Sta. 1 to Sta. 3: I = 1 167 Tsc = $ 1 415 • What are the facility design implications? IENG 471 Facilities Planning