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.
2. TYPES OF AUTOMATION
Automated production systems can be classified into three basic types:
- Fixed automation,
- Programmable automation, and
- Flexible automation.
2.1. 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; and
- 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.
2.2. 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 characterise 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.
2.3. 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: (1) the capacity to change part programs with no lost production time; and (2) 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.
The relative positions of the three types of automation for different production volumes and product varieties are depicted in Fig. 10.1.
3. COMPUTER INTEGRATED MANUFACTURING
The computers had done a dramatic impact on the development of production automation technologies. Nearly all modern production systems are implemented today using computer systems. The term computer integrated manufacturing (CIM) has been coined to denote the pervasive use of computers to design the products, plan the production, control the operations, and perform the various business related functions needed in a manufacturing firm. Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) in another term that is used synonymously with CIM.
The good relationship exists between automation and CIM with a conceptual model of manufacturing. In a manufacturing firm, the physical activities related to production that take place in the factory can be distinguished from the information-processing activities. The physical activities include all of the manufacturing processing, assembly, materials handling and inspections that are performed on the product. These operations come in direct contact with the physical activities during manufacture. Raw materials flow in one end of the factory and finished products flow out the other end. The physical activities (processing, handling, etc.) take place inside the factory. The information-processing functions form a ring that surrounds the factory, providing the data and knowledge required to produce the product successfully. These information processing functions include: (1) business activities, (2) product design, (3) manufacturing planning, and (4) manufacturing control. These four functions form a cycle of events that must accompany the physical production activities.
4. REASONS FOR AUTOMATION
Following are some of the reasons for automation:
- Increased productivity: Automation of manufacturing operations holds the promise of increasing the productivity of labour. This means greater output per hour of labour input. Higher production rates (output per hour) are achieved with automation than with the corresponding manual operations.
- High cost of labour: The trend in the industrialized societies of the world has been toward ever-increasing labour costs. As a result, higher investment in automated equipment has become economically justifiable to replace manual operations. The high cost of labour is forcing business leaders to substitute machines for human labour. Because machines can produce at higher rates of output, the use of automation results in a lower cost per unit of product.
- Labour shortages: In many advanced nations there has been a general shortage of labour. Labour shortages stimulate the development of automation as a substitute for labour.
- Trend of labour toward the service sector: This trend has been especially prevalent in India. There are also social and institutional forces that are responsible for the trend. There has been a tendency for people to view factory work as tedious, demeaning, and dirty. This view has caused them to seek employment in the service sector of the economy government, insurance, personal services, legal, sales, etc. Hence, the proportion of the work force employed in manufacturing is reducing.
- Safety: By automating the operation and transferring the operator from an active participation to a supervisory role, work is made safer.
- High cost of raw materials: The high cost of raw materials in manufacturing results in the need for greater efficiency in using these materials. The reduction of scrap is one of the benefits of automation.
- Improved product quality: Automated operations not only produce parts at faster rates but they produce parts with greater consistency and conformity to quality specifications.
- Reduced manufacturing lead time: With reduced manufacturing lead time automation allows the manufacturer a competitive advantage in promoting good customer service.
- Reduction of in-process inventory: Holding large inventories of work-in-process represents a significant cost to the manufacturer because it ties up capital. In-process inventory is of no value. It serves none of the purposes of raw materials stock or finished product inventory. Automation tends to accomplish this goal by reducing the time a workpart spends in the factory.
- High cost of not automating: A significant competitive advantage is gained by automating a manufacturing plant. The benefits of automation show up in intangible and unexpected ways, such as, improved quality, higher sales, better labour relations, and better company image.
All of these factors act together to make production automation a feasible and attractive alternative to manual methods of manufacture.
5. ADVANTAGES OF AUTOMATION
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, colour 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.
6. DISADVANTAGES OF AUTOMATION
Following are some of the disadvantages of automation:
- Automation will result in the subjugation of the human being by a machine. Automation tends to transfer the skill required to perform work from human operators to machines.
In so doing, it reduces the need for skilled labour. The manual work left by automation requires lower skill levels and tends to involve rather menial tasks (e.g, loading and unloading workpart, changing tools, removing chips, etc.). In this sense, automation tends to downgrade factory work.
- There will be a reduction in the labour force, with resulting unemployment. It is logical to argue that the immediate effect of automation will be to reduce the need for human labour, thus displacing workers.
- Automation will reduce purchasing power. As machines replace workers and these workers join the unemployment ranks, they will not receive the wages necessary to buy the products brought by automation. Markets will become saturated with products that people cannot afford to purchase. Inventories will grow. Production will stop. Unemployment will reach epidemic proportions and the result will be a massive economic depression.
Source: KumarAnil, Suresh N. (2009), Production and operations management, New Age International Pvt Ltd; 2nd Ed. edition.