Production Planning Control Operations Scheduling Professor JIANG Zhibin Department of Industrial Engineering Logistics Management Shanghai Jiao Tong University
Production Planning & Control Professor JIANG Zhibin Department of Industrial Engineering & Logistics Management Shanghai Jiao Tong University Operations Scheduling
Operations Scheduling Contents 。Introduction Job Shop Scheduling Terminology ·Sequencing Rules Sequencing Theory for a Single Machine .Sequencing Theory for Multiple Machines Assembly Line Balancing Advanced Topics for Operations scheduling 國上浒充鱼大姿
Operations Scheduling Contents • Introduction • Job Shop Scheduling Terminology • Sequencing Rules • Sequencing Theory for a Single Machine • Sequencing Theory for Multiple Machines • Assembly Line Balancing • Advanced Topics for Operations scheduling
Introduction-What is Operations Scheduling Forecast of future demand Implement the production orders generated in MRP under given objectives Aggregate plan Allocate production resources (machine,workers et al.)to production orders (jobs or tasks Master production schedule(MPS) and their due dates)in an Schedule of production quantities by optimized manners; product and time period The results are time allocations of production resources to different Material Requirement Planning(MRP) jobs (job sequences on each Generate production orders and production resources); purchase order All the orders can be completed while all production resources are Operations Scheduling utilized with their loads being To meet quantities and time balanced. requirements for MRP 上济充通大学
Introduction-What is Operations Scheduling ? • Implement the production orders generated in MRP under given objectives ; • Allocate production resources (machine, workers et al.) to production orders (jobs or tasks and their due dates) in an optimized manners; • The results are time allocations of production resources to different jobs (job sequences on each production resources); • All the orders can be completed while all production resources are utilized with their loads being balanced. Forecast of future demand Aggregate plan Master production schedule (MPS) Schedule of production quantities by product and time period Material Requirement Planning (MRP) Generate production orders and purchase order Operations Scheduling To meet quantities and time requirements for MRP
Introduction-Objectives of Job Shop Scheduling Objectives of operations scheduling 1)Meet due date; 2)Minimize WIP inventory; 3)Minimize the average flow time through the systems; 4)Provide for high machine/worker(time)utilization(minimize idle time); 5) Reduce setup cost; 6 Minimize production and worker costs Discussion 1)and 3)aim at providing a high level of costumer service; V 2),4),5)and 6)are to provide a high level of workshop efficiency; Impossible to optimize all above objectives simultaneously; Proper trade off between cost and quality is one of the most challenging strategic issues facing a firm today;
Introduction-Objectives of Job Shop Scheduling • Objectives of operations scheduling 1) Meet due date; 2) Minimize WIP inventory; 3) Minimize the average flow time through the systems; 4) Provide for high machine/worker (time) utilization (minimize idle time); 5) Reduce setup cost; 6) Minimize production and worker costs • Discussion 1) and 3) aim at providing a high level of costumer service; 2), 4), 5) and 6) are to provide a high level of workshop efficiency; Impossible to optimize all above objectives simultaneously; Proper trade off between cost and quality is one of the most challenging strategic issues facing a firm today;
Introduction-Objectives of operations Scheduling Discussion (Cont. Some of these objectives conflicts,e.g. Reduce WIP inventory Worker idle time may increase or machine utilization may decrease; a Reasons:differences in the throughput rate from one part of the system to another may force the faster operations to wait. As an example,if there is no buffer for WIP between 1 and 2,what happens? Buffer Input (work-in-process) Output Fig8-3 A Process Composed of Two Operations in eries骈克鱼大
Introduction-Objectives of operations Scheduling • Discussion (Cont.) Some of these objectives conflicts, e.g. Reduce WIP inventory Worker idle time may increase or machine utilization may decrease; Reasons: differences in the throughput rate from one part of the system to another may force the faster operations to wait. Fig 8-3 A Process Composed of Two Operations in Series As an example, if there is no buffer for WIP between 1 and 2, what happens?