1 ISE 195 Fundamentals of Industrial & Systems Engineering

2 Production Systems Analysis (Topics in ISE 483)

3 Production System Characterized by –Number of machines –Number of part types –Part routings through the system –Processing times –Machine setups –Demand patterns –Raw material/component availability –Equipment layout/configuration –Operator availability Interested in: –Lead time for products –Cost of processing Decisions include: –System configuration –Scheduling methods parts

4 Planning & Analysis of Production Systems Product Design –Functional analysis –Design for X –Process planning System Design –Capacity planning –Layout design System Operation –Production planning –Scheduling

5 Production System Operation Operation Decomposition –Planning: Deciding what to do –Scheduling: Deciding when to do what you planned –Execution: Carrying out the planned tasks according to the schedule Hierarchical System Structure –Shop –Workstation –Equipment

6 Principles of Production Systems Little’s Law –WIP = Production Rate × Time in System Matter is conserved Larger scope implies reduced reliability Objects decay Exponential growth in complexity –M components, N states  N M possible system states Technology advances System components appear to behave randomly Limits of (Human) rationality Combining, simplifying, and eliminating save time, money and energy

7 Simulation Example Simple Assembly System: –Worker assembles one unit A and one unit B into a final assembly –Unit A (orders) arrive randomly with time between orders exponentially distributed with mean 6 minutes –Unit B comes from our warehouse on a forklift on regular deliveries of 10 at the start of each hour –Assembly time is triangle distributed with minimum of 2, mode of 4, and maximum of 5 minutes How long do orders spend waiting for assembly? How much space should I allocate to hold Unit B at the assembly station?

8 Decision Problems in Production Systems Product Design Process Planning System Design Production Planning Operational Planning Shop Floor Control

9 Production System Design Make vs Buy Decisions Capacity Planning Technology Acquisition Alternative System Configurations Production Cell Formation Part Type Selection Facility Layout

10 Production System Design Define Production Resource Requirements: Capacity Planning –Machines/Equipment –Tooling, fixtures, etc. –People Arrange and Configure Resources –Facility Location –Facility Design Layout Material Handling

11 Facility Layout Saw Grind Weld Lathe Mill Grind Mill Drill Lathe Drill Paint Drill Stores Assembly Warehouse Saw Mill Grind Lathe Paint Drill Assembly Warehouse Stores Process Layout “Focused Factory” Layout Inbound Stock Outbound Stock “U” Shaped Cells

12 Inventory/Supply Chain Management Plan production quantities to meet customer demands on time with a high level of certainty at a minimum cost/maximum profit Coordinate production/inventories between stages of the “Supply Chain” Issues –Costs for production, inventory, shortages, setups, etc. –Variability in demand, supply –Lead times in production, transportation

13 The Distribution Game Warehouse –Fixed Order Cost: $200 / order –Inventory Holding Cost: 21% / year –Purchase Cost for a Unit: $70 / unit –Order Delivery Lead Time: 15 Days Retailer –Fixed Order Cost: $2.75 / order –Inventory Holding Cost: 25% / year –Selling Price per Unit: $100 / unit –Order Delivery Lead Time: 5 –Demand each Day: 0, 1, 2, 3, 4 all equally likely –There are 365 days in a year Warehouse Retailers

14 Questions?