AUTOMATED PRODUCTION SYSTEMS
The technology of automation has indeed spawned newer and non-sophisticated machines. Increasingly ,these machines are getting lined up for broader purposes .Four categories of machines are discernible : automated flow lines, automated assembly systems ,flexible manufacturing systems, automated storage and retrieval systems.
Automated Flow Lines :
In this, several automated machines are linked together by automated parts transfer and handling machines.
The individual machines on the line, use automated raw materials feeders and automatically carry out their operations without the need for human intervention .As each machine completes its operations ,partly completed parts are automatically transferred to the next machine on the line in a fixed sequence until the work of the line is finished .These systems are generally used to produce an entire major component ,for example ,rear axle housings for trucks. They are common in the automobile industry.
Automated flow lines are also called as fixed automation or hard automation in as much as the lines of machines are designed to produce one type of component or product. These demand high investment and are highly inflexible. Hence, these machines are justified when demand for the product is high, stable and predictable .But the demand is never stable Shortened product life cycles and changes in production technology render the fixed automation lines unpopular and call for flexible manufacturing systems.
Automated Assembly Lines :
Here ,the automated assembly machines are linked together by automated materials-handling equipment .Materials are automatically fed to each machine ,which is some type of robot, which joins one or more materials, parts, or assemblies. Then the part-completed work is automatically transferred to the next assembly machine. This process is repeated until the whole assembly is completed. The purpose of these systems is to produce major assemblies or even completed products.
Product-design modifications are essential to make the automated assembly system successful Table below show the principles to be observed while redesigning products for automated assembly.
Principles of Product Redesign
1. Reduce the amount of assembly required
2. Reduce the number of fasteners required.
3. Design components to be automatically delivered and positioned
4. Design products for layered assembly and vertical insertion of parts.
5. Design parts so that they are self-aligning.
6. Design products into major modules for production.
7. Increase the quality of components.
Three advantages are claimed in favor of automated assembly systems .First ,these systems can provide manufacturers with low per unit production costs improved product quality and quicker production rates. Second, because some of the machines tend to be standard robots are available at competitive rates, initial investment is not high. Third, these robots can be reprogrammed to other products and operations, thereby reducing the dependence on stable product demand.
Flexible Manufacturing Systems (FMS) :
FMS are groups of production machines, arranged in a sequence, connected by automated materials handling and transferring machines and integrated by a computer system. To elaborate, FMS is a computer controlled system .It contains several work-stations ,each geared to different operations. Work-station machines are automated and programmable .Automated materials-handling equipment move components to the appropriate work-station ,then on to the programmed machines that select, position and actuate the specific tools for each job. Hundreds of tool options are available .Once the machines has finished one batch, the computer signals the next quantity or component, and the machine automatically repositions and retools accordingly. Meanwhile, the just batch is automatically transferred to the next work station in its routing.
An FMS is generally appropriate when.
1. All products are variations of a stable basic design;
2. All products utilize the same family of components;
3. The number of components is only moderate (10to50)
4. The volume of each component is moderate (1,000 to 30,000 units annually), but in lot sizes as small as one unit.
FMS technology can help produce moderate variety of products in modest volumes, that too quickly and with high quality. Operations costs also can be reduced with an FMS ;lower direct labor costs lead to lower manufacturing costs. But FMS requires very large investments in equipment, planning and control systems, and human resources.