Programmable Automation Technologies. Daniel Kandray
environment, as “...technology concerned with the application of mechanical, electronic and computer-based systems to operate and control production” (p. 9).
Each of these definitions provides some key terms and phrases. However, Webster’s definition implies that automation replaces or eliminates workers and that automation is accomplished only with machines—statements that are misleading. Automation does not always replace the worker; it more often displaces the worker to other tasks. Additionally, automation can be implemented in many forms. Often it is with a machine, but it can also be a device or software added to an existing process.
For example, consider the automation of the manual drafting process. The implementation of computer-aided drafting (CAD) is a great example of the automation of a manufacturing support system. CAD automates the creation of engineering drawings, a key component in the manufacturing material conversion process. Prior to the implementation of CAD, engineering drawings were created by hand with paper and pencil at drafting tables. The combination of computer hardware (the machine) and CAD software automated this process. Early CAD systems were two-dimensional and essentially duplicated the manual drawing process, but were much more accurate and faster than manual drafting. Human intervention was still required to operate the software, but to a lesser degree. Hence, manual drafters (the workers) were not replaced. The author observed in the plants with which he was associated that most of the drafters were trained to operate the CAD system. Since the CAD system is more productive than manual drafting, most excess drafters (workers) were displaced to other activities or other companies, and eventually an entire new generation of drafters trained primarily in CAD.
When companies first switched to CAD from manual drafting, a machine, the computer, was required. Computers have since become standard pieces of equipment in the engineering department. Hence, subsequent automation of the CAD process was accomplished only with software, an example of how automation does not always entail insertion of a machine into the process. Consider another example, solid modeling software. Solid modeling software automates the product development process, including the two-dimensional CAD drafting process. It models products as three-dimensional solid objects in the virtual world of a computer. The model enables better visualization of the product. Additionally, rapid prototypes, computer numerical control programs, and engineering drawings can all be created directly from this model.
The definitions above imply that automation only occurs in a production environment. However, automation can occur anywhere people are performing tasks. Consider a grocery store. Modern grocery stores have electronic barcode scanners to determine the price of goods purchased during checkout. The barcode scanners automated the task of a cashier manually entering the price of each item into the cash register. Now, many stores have added automated checkout, which allows the consumer to swipe the purchased goods and pay a machine directly, further reducing the level of cashier involvement. Often this allows more checkout lines than the store would normally be able to payroll. However, a worker is still needed to supervise the automated checkouts and assist shoppers as needed.
Machines and or systems that perform tasks automatically inevitably consist of some combination of mechanical technology (gears, cams, bearings...), electrical technology, and/or computer technology. Early automated machines were mostly mechanical. More modern automated equipment utilizes electrical and computer technology to a greater extent. Additionally, many automated machines or systems are combinations of many smaller automated machines. Thus, automated machines can be further automated with the application of even more technology.
The preceding discussion highlights the fact that a more encompassing definition of automation is needed than is typically found in the literature. So, the author defines automation here as follows:
Automation is the application of mechanical, electrical, and/or computer technology to reduce the level of human participation in task performance.
Note that in this definition “task” is an intentionally vague term. Tasks are not limited to work-related activities. They can be related to any activity requiring human participation. Consider the television remote control, for example. It automated the task of manually changing the television channel, a purely entertainment-related activity. The definition also makes clear that humans are not necessarily replaced. Their level of participation may be greatly reduced, typically displacing them to other activities. This point is important because often great fear exists in the workforce when system automation is considered. Workers inevitably assume that such automation will eliminate jobs, which, as discussed, does not always occur, particularly in a company that values its workforce. Thus, the distinction between “displacing” workers and “replacing” them needs to be emphasized. The other notable aspect of the definition is that it emphasizes that automation can be implemented with various forms and combinations of technology.
Now that a clear definition of automation has been established, the different automation types that have evolved in manufacturing are discussed.
1.3.1 Types of Automation
Automation in a manufacturing facility can occur in the manufacturing support systems and/or in manufacturing systems. Automation in manufacturing support systems is primarily accomplished through the use of computer technology to automate the business operations of the facility. Computer-aided design (CAD) software and computer-aided manufacturing (CAM) software have dramatically impacted the way products are designed and engineered. Shop floor control systems combined with material resource planning systems provide management with a very fast and accurate picture of a facility’s current status. Computer-integrated manufacturing (CIM) takes the automation of the manufacturing support systems a step further. CIM is intended to integrate and thereby automate the entire manufacturing enterprise. In other words, CIM links the automation in the manufacturing support systems directly with automation in the manufacturing systems, resulting in a completely integrated manufacturing facility. However, the focus of this text is not on the automation of manufacturing support systems. Rather, it is on a specific type of automation of manufacturing systems.
Automation in manufacturing systems is centered on reducing the level of human participation in manufacturing processes. Three standard types of automation can be defined. Each type has very specific capabilities relating to the sequence of the processing steps and the definition of the product being processed. The three types are:
• Fixed automation
• Programmable automation
• Flexible automation.
Fixed automation equipment typically consists of processing stations linked together with some form of material handling, which progressively moves the workpiece through the processing steps. Fixed automation can be considered special purpose automation because it is designed to automate a specific process or series of processes. Therefore, the processing sequence is fixed by the organization of the processing stations. In general, it is relatively inflexible in accommodating any type of product variety. However, if it is capable of handling soft product variety, conversion of the machine allowing it to run the variation may be time-consuming. The time to make this change is often termed “changeover time” or “setup time.” Fixed automation can handle a wide variety of product complexity from simple to very complex products; but, the cost of creating such a specialized machine is often quite high. Consequently, fixed automation is typically only used with extremely high volume products. To accommodate the volume, these systems operate at very high rates. Hence, fixed automation equipment is most often associated with flow-line manufacturing systems, often as assembly lines. Early fixed automation was created using mostly mechanical technology combined with electrical technology to drive its mechanical components. Current systems make extensive use of computer technology and often integrate programmable automation into the machine, as well.
Whereas fixed automation is “fixed” to a specific operation progression, programmable automation has the capability to alter both the type of operation to be performed and the order in which it is to be executed. Thus, it can adjust the process to accommodate the product, which makes it capable of handling hard product variety. Programmable automation equipment is multipurpose equipment that can be programmed, and repeatedly reprogrammed, to perform a wide variety of processing