Operations Management Basics: Takt time, target manpower and line balancing
The expression of takt time is derived from the German word “Takt” for the pace of a piece of music. In Operations Management, the takt time is defined as the maximum time it can take to produce a unit in order to keep up with demand. If, for example, the demand is at 6 units per minute, the takt time would be at 10 seconds per unit.
Once the takt time has been determined, the target manpower can be calculated as the ratio of total labor content (the time sum of all worksteps needed to produce one flow unit) and takt time. The target manpower is the number of employees (or other resources) needed to operate the process at takt time if the work could be divided evenly between them Since this is an idealized calculation, the outcome will most likely not correspond exactly with reality, one reason being that it is not always possible to evenly split work between employees if different skills are needed. Still, calculating the target manpower provides a good starting point for line balancing.
Line balancing is the process of dividing an existing workload as evenly as possible between all of the available resources in order to increase overall productivity. If, for example, one workstation has a lot of idle time, maybe it can take over some of the workload from the workstation at the bottleneck. The basic line balancing procedure consists of four steps:
(1) Calculate the takt time
(2) Assign tasks in a way that keeps all processing times below the takt time
(3) Make sure that all tasks are assigned
(4) Minimize the number of workers needed
The general ability of an organisation to adjust its capacity and scale it up and down in order to adjust to changes in demand (the so-called staffing to demand) is an important form of flexibility, which can be achieved e.g. with temp workers or overtime work. A special form of line balancing is the so-called dynamic line balancing, which includes walking around the workstations during production, looking for pileups and rearranging resources in order to keep up with demand.
These lecture notes were taken during 2013 installment of the MOOC “An Introduction to Operations Management” taught by Prof. Dr. Christian Terwiesch of the Wharton Business School of the University of Pennsylvania at Coursera.org.