There are a number of ways to classify process technologies. For example, we could classify them in terms of the nature of the process; that is, process to change shape or form, chemical processes, information processes, assembly processes, and so on. But we choose to focus on a classification that highlights the historical progression of processes. This classification will also be useful in comparing how each affects the competitive priorities of cost, flexibility, quality, and the ability of the enterprise to perform on time. Thus, we have a three part classification of process technologies
The role of labor and labor costs in these three classifications is high in manual technologies, intermediate in mechanized technologies, and diminishes to near zero in automated technologies. On the other hand, capital costs increase in the reverse order. All three of these types of process technologies are important in operations systems today, depending on product volume, the stability of product design, and competitive requirements.
General versus Special Purpose Technologies:
Under mechanized and automated technologies we have recognized two sub categories, general and single purpose. But based on product volume and its standardization, a machine could be either dedicated solely to a product or product line, making it a special purpose machine, or it could be general in its application to a wider range of product designs.
General purpose machines have general use capabilities in their fields of application. For example, a typewriter is a general purpose machine; it can be used for various kinds of copies: letters, manuscripts, and some kinds of charts and figures. On the other hand, typewriter can be made a specials purpose machine by adapting it to special uses in accounting. But specialized computer programs can do these accounting tasks much more efficiently, producing the typed accounting reports easily.
In the machine shop, we find the general purpose lathe, drill, press, milling machine, and planers, which are capable of performing their functions by generating cylindrical surfaces, holes, and flat surfaces on a wide variety of parts and materials.
General purpose machines find field of application with low volume production and changing product designs situations that demand flexibility. Yet where the situation warrants it, we find special designs of these types of machines meant to produce one part or a group of parts much more efficiently than could their general purpose machine equivalents. Special purpose machines commonly evolve from their general purpose equivalents as the volume of a particular part or product grows and the design stabilizes. With specialized machine designs, higher production rates can be achieved with lower overall costs.
Whether a mechanized technology has lower costs than a manual one depends on the balance of labor and capital costs, though difference in material costs often enter the equation too. But the investment in machines required by mechanization carries with it a risk that there will not be sufficient use of the machine to return its investment plus a profit. The same general concept applies to the economic justification of a special purpose machine compared to its general purpose equivalent.
Progression of Technologies:
Since the beginning of the industrial revolution, there has been a continuous substitution of machine power for human power, and the â€œmechanizedâ€ classification is the result. Progressive mechanization for the production of high volume standardization parts led to the first automated systems, called â€œhard automation.â€ But with the advent of computers, and particularly the microprocessor chip, automated processes began to substitute machines for the control functions of the human operator as well, opening the field of automation to low volume products. New and exciting advanced process technologies have been developed, su9ch as
* NC machines: Numerically controlled machines where machine tools are computer controlled;
* FMS: Flexible manufacturing systems that combine NC machines in flexible systems of production.
* CAD / CAM: Computer aided design and manufacturing systems that combine product design and manufacturing instructions;
* CIM: Computer integrated manufacturing in which all aspects of manufacturing are integrated through a design and manufacturing data base;
* GT: Group technology that organizes planning and facilities for small-lot manufacturing by grouping various parts and products with similar design and production process into efficiency systems that can use NC machines, robots, or other advanced technologies.