Lecture 13 - Production Activity Control. The contents of this chapter include all of the following: Production activity control, gantt chart, critical ratio scheduling, finite loading, scheduling, assignment method.
Lecture 13 Production Activity Control Books • Introduction to Materials Management, Sixth Edition, J. R. Tony Arnold, P.E., CFPIM, CIRM, Fleming College, Emeritus, Stephen N. Chapman, Ph.D., CFPIM, North Carolina State University, Lloyd M. Clive, P.E., CFPIM, Fleming College • Operations Management for Competitive Advantage, 11th Edition, by Chase, Jacobs, and Aquilano, 2005, N.Y.: McGrawHill/Irwin • Operations Management, 11/E, Jay Heizer, Texas Lutheran University, Barry Render, Graduate School of Business, Rollins College, Prentice Hall Objectives • • • • • • Production activity control Gantt chart Critical ratio scheduling Finite loading Scheduling Assignment method Production Activity Control • PAC in the MPC System – – • Production Activity Control Techniques – – – – • Shop Floor Control Vendor Scheduling Basic Data Gantt Charts Priority Scheduling Finite Loading Process Design Impact on Scheduling – – Batch Manufacturing – Work Orders Repetitive Manufacturing – JIT Production Activity Control in the MPC System Basic Data Routing Data and Operation Setback Chart Gantt Charts The incoming orders at Tom's Sailboard follow different routes through the shop but all orders must stop at each of the three work centers in the plant. The table below shows all tasks for four jobs that arrive over 5 days and need to be scheduled at the company. It is currently November 10 and Tom works a sevenday week _ Arrival Job/WC Processing time (days) Order date routing WC 1 WC 2 WC 3 (B)iff Nov. 10 132 1 3 1 (G)riffin Nov. 10 231 2 2 2 (H)erbie Nov. 12 321 3 1 2 (K)errie Nov. 14 213 1 3 1 Assume that the new material for all orders is in stock and that a firstcome/firstserved sequencing rule is used at all work centers. All three work centers are idle as work begins on orders B and G on November 10 Tom’s Sailboard a Construct a Gantt chart depicting the processing and idle times for the three work centers for these four jobs Order (B)iff (G)riffin (H)erbie (K)errie Arrival Job/WC Processing time (days) date routing WC 1 WC 2 Nov. 10 132 1 3 1 Nov. 10 231 2 2 2 Nov. 12 321 3 1 2 Nov. 14 213 1 3 1 WC 3 Tom’s Sailboard b How many days does each job wait in queue for processing at work center 2? The determination of how long jobs wait at work center 2 is as follows: B and G are processed immediately at work center 2, order K must wait 1 day (11/14) and order H waits 4 days (11/12, 11/13 at WC3) and (11/16 and 11/17 at WC2) Priority Sequencing Rules First Come, First Served • Shortest Operation Next • Earliest Due Date • Order Slack: (Time Remaining until Due Date – Sum of Remaining Setup and Run Time) • Slack per Operation • Critical Ratio: (Due DateNow)/(Lead Time Remaining) Lead Time Remaining includes setup, run, move and queue time for all remaining operations • The Bundy Company Using the horizontal loading procedure with earliest duedate priority sequencing rule, prepare a Gantt chart showing the production schedule for the three orders above Machine Center P-3 Machine K–1 Center Machine Center P-2 P-1 K-3 A-3 K-2 A-2 A-1 10 11 12 13 14 15 16 17 18 The Bundy Company Machine Center Using the vertical loading procedure and the shortest operationnext priority sequencing rule, prepare a Gantt chart showing the production schedule for the three orders above K-3 A-2 Machine K-1 Center Machine Center A-3 A–1 P-3 P-2 K-2 P-1 10 11 12 13 14 15 16 Process Design Impact Scheduling • • Batch Manufacturing: Work Orders Repetitive Manufacturing: JIT/Kanban Scheduling What is Scheduling? • • Last stage of planning before production occurs Specifies when labor, equipment, and facilities are needed to produce a product or provide a service Scheduled Operations • • • Process Industry – Linear programming – EOQ with non instantaneous replenishment Mass Production – Assembly line balancing Project – Project scheduling techniques (PERT, CPM) • Batch Production – Aggregate planning – Master scheduling – Material requirements planning (MRP) – Capacity requirements planning (CRP) Objectives in Scheduling • • • • • Meet customer due dates Minimize job lateness Minimize response time Minimize completion time Minimize time in the system • • • • Minimize overtime Maximize machine or labor utilization Minimize idle time Minimize workinprocess inventory Shop Floor Control (SFC) • • • Schedule and monitor daytoday job shop production Also called production control and production activity control (PAC) Performed by production control department – Loading check availability of material, machines, and labor – Sequencing release work orders to shop and issue dispatch lists for individual machines – Monitoring maintain progress reports on each job until it is complete Loading • • • Process of assigning work to limited resources Perform work with most efficient resources Use assignment method of linear programming to determine allocation Assignment Method Perform row reductions – subtract minimum value in each row from all other row values Perform column reductions – ‾ subtract minimum value in each column from all other column values ‾ Cross out all zeros in matrix – If number of lines equals number of rows in matrix, then optimum solution has been found. Make assignments where zeros appear ‾ use minimum number of horizontal and vertical lines ‾ Else modify matrix: subtract minimum uncrossed value from all uncrossed values add it to all cells where two lines intersect other values in matrix remain unchanged Repeat steps 3 and 4 until optimum solution is reached Assignment Method Initial Matrix Bryan Kari Noah Chris 10 Row reduction 5 0 1 0 Number lines PROJECT 10 6 10 Column reduction Cover all zeros 3 3 0 1 0 0 1 νυµβερ οφ ροωσ σο µοδιφψ µατριξ 0 Assignment Method Modify matrix 1 0 1 Cover all zeros 1 0 1 Number of lines = number of rows so at optimal solution PROJECT Bryan Kari Noah Chris PROJECT 4 Bryan 10 10 1 Kari 6 0 Noah 6 Chris 10 1 Project Cost = (5 + + + 6) X $100 = $2,100 Assignment Method Setup Solution goes here Only leader can be assigned to each project Click “Solve” for solution Sum of all rows and columns = Assignment Method Solution Assignments indicated by Cost of solution End of Lecture 13 ... Machine Center P-3 Machine K–1 Center Machine Center P-2 P-1 K-3 A-3 K-2 A-2 A-1 10 11 12 13 14 15 16 17 18 The Bundy Company Machine Center Using the vertical loading procedure? ?and? ?the shortest... chart showing the production schedule for the three orders above K-3 A-2 Machine K-1 Center Machine Center A-3 A–1 P-3 P-2 K-2 P-1 10 11 12 13 14 15 16 Process Design Impact Scheduling • • Batch Manufacturing: Work Orders... project Click “Solve” for solution Sum of all rows and columns = Assignment Method Solution Assignments indicated by Cost of solution End? ?of? ?Lecture? ?13