A. Fixed Automation
A system in which the sequence of processing (or assembly) operations is fixed by the equipment configuration. The operations in the sequence are usually simple. lt is the integration and coordination of many such operations into one piece of equipment that makes the system complex.
Typical features:
Suited to high production quantities
High initial investment for custom-engineered equipment
High production rates
Relatively inflexible in accommodating product variety
The economic justification for fixed automation is found in products with very high demand rates and volumes. The high initial cost of the equipment can be spread over a very large number of units, thus making the unit cost attractive compared to alternative methods of production. Examples of fixed automation include mechanized assembly lines (starting around 1913 - the product moved along mechanized conveyors, but the workstations along the line were manually operated) and machining transfer lines (beginning around 1924).
B. Programmable Automation
The production equipment is designed with the capability to change the sequence of operations through reprogramming to accommodate different product configurations. The operation sequence is controlled by a program, which is a set of instructions coded so that the system can read and interpret them. New programs can be prepared and entered into the equipment to produce new products.
Typical features:
High investment in programmable equipment
Lower production rates than fixed automation
Flexibility to deal with variations and changes in product configuration
Most suitable for batch production
Physical setup and part program must be changed between jobs (batches)
Automated production systems that are programmable are used in low and medium-volume production. The parts or products are typically made in batches. To produce each new batch of a different product, the