Here we provide an overview of the classification scheme for the three basic
types of manufacturing system: (1) single-station cells; (2) multi-station
systems with fixed routing; and (3) multi-station systems with variable
routing. The unit then concludes with an in-depth focus upon single-station
manufacturing cells, which is only perfunctorily described here.
Single workstations are widespread, but typically come in one of two forms:
manned workstations—where a worker is in attendance continuously or for a
portion of each work cycle; and automated stations—where worker attention is
required less frequently than the set work cycle. Both systems are used for
assembly and processing operations, and their applications fit single, batch
and mixed model cases. Single-station cell systems are popular because they
are relatively inexpensive to implement (especially manned versions), they
are highly flexible, and they are easy to convert to automation when
required. See Figure 12.4.
Single workstations come in two forms: manned workstations, and automated
stations.
Multi-station Systems with Fixed Routing
A multi-station system with fixed routing is essentially a production line,
which consists of a series of workstations laid-out so that the part/product
moves from one station to the next, while a value-adding work element is
performed at each workstation along the way. Material transference between
workstations is usually accomplished by means of a conveyor system, or other
mechanical transport system, although there are cases where material may be
transferred by hand. See Figure 12.5. Conditions that favour the use of
production lines include:
Production lines are used for both processing and assembly operations, and
they can be either manually operated or automated.
A multi-station system with fixed routing is a production line.
Multi-station Systems with Variable Routing
A multiple-station system with variable routing is a group of workstations
organised to achieve some special purpose. It usually handles medium-sized
production quantities, although it has been used for production quantities
beyond this, in certain situations, such as:
·
Production of a family of parts having similar processing requirements.
·
Assembly of a family of parts having similar assembly requirements.
·
Production of a complete set of components that are used in the assembly of
one unit of final product.
Machines may be manual, semi-automated, or fully-automated. The first two
types—i.e. manually-operated and semi-automated—may be arranged into machine
groups called machine cells; and it is the emergence of numbers of these
cells that gives rise to cellular manufacturing. Fully-automated machines,
on the other hand, may be arranged into flexible manufacturing systems. See
Figure 12.6.
A multiple-station system with variable routing is a group of workstations
organised to achieve some special purpose.
