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Automation is a technology concerned with the application of mechanical, electronic, and computer- based systems to operate and control production. This technology includes automatic machine tools to process parts, automatic assembly machines, industrial robots, automatic material handling and storage systems, automatic inspection systems for quality control, feedback control and computer process control, computer systems for planning, data collection and decision-making to support manufacturing activities.
Following are some of the advantages of automation
- Automation is the key to the shorter workweek. Automation will allow the average number of working hours per week to continue to decline, thereby allowing greater leisure hours and a higher quality life.
- Automation brings safer working conditions for the worker. Since there is less direct physical participation by the worker in the production process, there is less chance of personal injury to the worker.
- Automated production results in lower prices and better products. It has been estimated that the cost to machine one unit of product by conventional general-purpose machine tools requiring human operators may be 100 times the cost of manufacturing the same unit using automated mass-production techniques. The electronics industry offers many examples of improvements in manufacturing technology that have significantly reduced costs while increasing product value (e.g., color TV sets, stereo equipment, calculators, and computers).
- The growth of the automation industry will itself provide employment opportunities. This has been especially true in the computer industry, as the companies in this industry have grown (IBM, Digital Equipment Corp., Honeywell, etc.), new jobs have been created. These new jobs include not only workers directly employed by these companies, but also computer programmers, systems engineers, and other needed to use and operate the computers.
- Automation is the only means of increasing standard of living. Only through productivity increases brought about by new automated methods of production, it is possible to advance standard of living. Granting wage increases without a commensurate increase in productivity will results in inflation. To afford a better society, it is a must to increase productivity.
FIXED AUTOMATION
It is 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. It is the integration and coordination of many such operations into one piece of equipment that makes the system complex. The typical features of fixed automation are :
- High initial investment for custom–Engineered equipment;
- High production rates;
- Relatively inflexible in accommodating product changes.
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 and machining transfer lines.
PROGRAMMABLE AUTOMATION
In this the production equipment is designed with the capability to change the sequence of operations 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. Some of the features that characterize programmable automation are :
- High investment in general-purpose equipment;
- Low production rates relative to fixed automation;
- Flexibility to deal with changes in product configuration; and
- Most suitable for batch production.
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 system must be reprogrammed with the set of machine instructions that correspond to the new product. The physical setup of the machine must also be changed over: Tools must be loaded, fixtures must be attached to the machine table also be changed machine settings must be entered. This changeover procedure takes time. Consequently, the typical cycle for given product includes a period during which the setup and reprogramming takes place, followed by a period in which the batch is produced. Examples of programmed automation include numerically controlled machine tools and industrial robots.
FLEXIBLE AUTOMATION
It is an extension of programmable automation. A flexible automated system is one that is capable of producing a variety of products (or parts) with virtually no time lost for changeovers from one product to the next. There is no production time lost while reprogramming the system and altering the physical setup (tooling, fixtures, and machine setting). Consequently, the system can produce various combinations and schedules of products instead of requiring that they be made in separate batches. The features of flexible automation can be summarized as follows :
- High investment for a custom-engineered system.
- Continuous production of variable mixtures of products.
- Medium production rates.
- Flexibility to deal with product design variations.
The essential features that distinguish flexible automation from programmable automation are ;
- the capacity to change part programs with no lost production time; and
- the capability to changeover the physical setup, again with no lost production time.
These features allow the automated production system to continue production without the downtime between batches that is characteristic of programmable automation. Changing the part programs is generally accomplished by preparing the programs off-line on a computer system and electronically transmitting the programs to the automated production system.
Therefore, the time required to do the programming for the next job does not interrupt production on the current job. Advances in computer systems technology are largely responsible for this programming capability in flexible automation. Changing the physical setup between parts is accomplished by making the changeover off-line and then moving it into place simultaneously as the next part comes into position for processing.
The use of pallet fixtures that hold the parts and transfer into position at the workplace is one way of implementing this approach.
For these approaches to be successful; the variety of parts that can be made on a flexible automated production system is usually more limited than a system controlled by programmable automation.
Strategies of Automation
There are certain fundamental strategies that can be employed to improve productivity in manufacturing operations technology. These are referred as automation strategies.
- Specialization of operations : The first strategy involves the use of special purpose equipment designed to perform one operation with the greatest possible efficiency. This is analogous to the concept of labor specializations, which has been employed to improve labor productivity.
- Combined operations: Production occurs as a sequence of operations. Complex parts may require dozens, or even hundreds, of processing steps. The strategy of combined operations involves reducing the number of distinct production machines or workstations through which the part must be routed. This is accomplished by performing more than one operation at a given machine, thereby reducing the number of separate machines needed. Since each machine typically involves a setup, setup time can be saved as a consequence of this strategy. Material handling effort and non-operation time are also reduced.
- Simultaneous operations: A logical extension of the combined operations strategy is to perform at the same time the operations that are combined at one workstation. In effect, two or more processing (or assembly) operations are being performed simultaneously on the same workpart, thus reducing total processing time.
- Integration of operations: Another strategy is to link several workstations into a single integrated mechanism using automated work handling devices to transfer parts between stations. In effect, this reduces the number of separate machines though which the product must be scheduled. With more than one workstation, several parts can be processed simultaneously, thereby increasing the overall output of the system.
- Increased flexibility: This strategy attempts to achieve maximum utilization of equipment for job shop and medium volume situations by using the same equipment for a variety of products. It involves the use of the flexible automation concepts. Prime objectives are to reduce setup time and programming time for the production machine. This normally translates into lower manufacturing lead time and lower work-in-process.
- Improved material handling and storage systems: A great opportunity for reducing non-productive time exists in the use of automated material handling and storage systems. Typical benefits included reduced work-in-process and shorter manufacturing lead times.
- On-line inspection: Inspection for quality of work is traditionally performed after the process. This means that any poor quality product has already been produced by the time it is inspected. Incorporating inspection into the manufacturing process permits corrections to the process as product is being made. This reduces scrap and brings the overall quality of product closer to the nominal specifications intended by the designer.
- Process control and optimization: This includes a wide range of control schemes intended to operate the individual process and associated equipment more efficiency. By this strategy, the individual process times can be reduced and product quality improved.
- Plant operations control : Whereas the previous strategy was concerned with the control of the individual manufacturing process, this strategy is concerned with control at the plant level of computer networking within the factory.
- Computer integrated manufacturing (CIM) : Taking the previous strategy one step further, the integration of factory operations with engineering design and many of the other business functions of the firm. CIM involves extensive use of computer applications, computer databases, and computer networking in the company.
