Line Balancing in Operations Management www.mbaknol.com Visit www.mbaknol.com for Management notes and presentations

Definition: Line balancing is the procedure in which tasks along the assembly line are assigned to work station so each has approximately same amount of work. Visit www.mbaknol.com for Management notes and presentations

Line Balancing Problem The objective of line balancing is to assign tasks to minimize the workers’ idle time, therefore idle time costs, and meet the required production rate for the line In a perfectly balanced line, all workers would complete their assigned tasks at the same time (assuming they start their work simultaneously) This would result in no idle time Visit www.mbaknol.com for Management notes and presentations

Line Balancing Problem Unfortunately there are a number of conditions that prevent the achievement of a perfectly balanced line The estimated times for tasks The precedence relationships for the tasks The combinatorial nature of the problem Visit www.mbaknol.com for Management notes and presentations

Line Balancing Problem Work stations are arranged so that the output of one is an input to the next, i.e., a series connection Layout design involves assigning one or more of the tasks required to make a product to work station. Visit www.mbaknol.com for Management notes and presentations

Example of Line Balancing You’ve just been assigned the job a setting up an electric fan assembly line with the following tasks: Task Time (Mins) Description Predecessors A 2 Assemble frame None B 1 Mount switch A C 3.25 Assemble motor housing None D 1.2 Mount motor housing in frame A, C E 0.5 Attach blade D F 1 Assemble and attach safety grill E G 1 Attach cord B H 1.4 Test F, G Visit www.mbaknol.com for Management notes and presentations 16

Example of Line Balancing: Structuring the Precedence Diagram Task Predecessors Task Predecessors A None E D B A F E C None G B D A, C H E, G 2 1 1 A B G 1.4 H 3.25 1.2 0.5 1 E C D F Visit www.mbaknol.com for Management notes and presentations 17

Kilbridge and Webstor Method Step 1- draw a precedence diagram and arrange them into different zones so that the average time is equal or nearly equal. Visit www.mbaknol.com for Management notes and presentations

Line Balancing Problem 3.4 mins B 2.2 mins E 2.7 mins A C 4.1mins D 1.7mins F 3.3 mins G 2.6 mins Visit www.mbaknol.com for Management notes and presentations

Here idle time=16.8 idle time %age=(16.8/9.2)X100=182.60% This is not acceptable Visit www.mbaknol.com for Management notes and presentations

Step 2- transferability; in this principle the activities are transferred from one zone to another as long as they don’t affect the sequence denoted by ordered pair .Step 3- from step 2 and by arranging the work centres, the lines balancing becomes Visit www.mbaknol.com for Management notes and presentations

Line Balancing Problem 3.4 mins B 2.2 mins E 2.7 mins A C 4.1mins D 1.7mins F 3.3 mins G 2.6 mins Visit www.mbaknol.com for Management notes and presentations

here idle time=4 min idle time %age=(4/6)X100=66.6% Visit www.mbaknol.com for Management notes and presentations

Thank You Visit www.mbaknol.com for Management notes and presentations