Production line balancing
The line balancing problem is solved with a heuristic procedure based on sorting
the work elements (tasks) with respect to the following criteria:
cumulated rank value (the task time + the sum of the cumulated rank values
of all immediate successors)
positional weight (the sum of the task times of all successors)
number of successors
the precedence graph must be
defined with the graphical editor. Note that the nodes (tasks) must be numbered
from left to right.
the cycle time or the planned production quantity per period must be entered.
The period length is assumed to be 480 time units. If the cycle time is entered,
production quantity is adapted and vice versa.
procedure works as follows: Beginning with station 1 all tasks in the set of
candiate tasks are checked whether they could be assigned to the current station.
If no further task can be assigned, the next station is opened. If a task is
assigned to a station, all arcs leaving the tasks in the precedence graph are
deleted. The set of candidate tasks is identified as those tasks with no incoming
During the procedure two kinds of pictures may be displayed.
The workload graph shows the assignment of tasks to the stations
generated. The coloured bar segments show the tasks (task number/task time).
The precedence graph shows the different sets of tasks (green
- assignable; white - not assignable; other - station identification)
time of task i
precedence graph sorted in topological order
Tip: Move the mouse over
the nodes in the precedence graph. Then further informations will be displayed.
- Krajewski/Ritzman (1996), Chapter 10
- Nahmias (1997), Chapter 3
- Hopp/Spearman (1996), Chapter 18