Travel Charts and String Diagrams
The use of travel charts has already been described under facility layout (see figure on page 140). A string diagram (see figure below) is used for a similar purpose, the minimisation of movement, but, generally for the layout of individual workplaces. A scaled layout of the workplace is mounted on a board, and pins inserted at key positions. String is then wound from pin to pin, representing the movements taking place in the process. If more than one entity is engaged in the operation, strings of different colours are used. On completion, the strings are removed, measured, and the measurements scaled up to determine the total distance travelled.