Here's what you need to know about automation, manufacturing applications

Automation is the application of machines to tasks once performed by human beings or, increasingly, to tasks that would otherwise be impossible. Although the term mechanization is often used to refer to the simple replacement of human labour by machines, automation generally implies the integration of machines into a self-governing system. Automation has revolutionized those areas in which it has been introduced, and there is scarcely an aspect of modern life that has been unaffected by it.
 

The term automation was coined in the automobile industry about 1946 to describe the increased use of automatic devices and controls in mechanized production lines. The origin of the word is attributed to D.S. Harder, an engineering manager at the Ford Motor Company at the time.
 

In general usage, automation can be defined as a technology concerned with performing a process by means of programmed commands combined with automatic feedback control to ensure proper execution of the instructions. The resulting system is capable of operating without human intervention. The development of this technology has become increasingly dependent on the use of computers and computer-related technologies.
 

The developments described above have provided the three basic building blocks of automation: (1) a source of power to perform some action, (2) feedback controls, and (3) machine programming. Almost without exception, an automated system will exhibit all these elements.

Power source

An automated system is designed to accomplish some useful action, and that action requires power.
 

Electrical power is the most versatile, because it can be readily generated from other sources (e.g., fossil fuel, hydroelectric, solar, and nuclear).
 

It can be readily converted into other types of power (e.g., mechanical, hydraulic, and pneumatic) to perform useful work. In addition, electrical energy can be stored in high-performance, long-life batteries.

Feedback controls

Feedback controls are widely used in modern automated systems. A feedback control system consists of five basic components: (1) input, (2) process being controlled, (3) output, (4) sensing elements, and (5) controller and actuating devices.. The term closed-loop feedback control is often used to describe this kind of system.
 

The input to the system is the reference value, or set point, for the system output.
 

Using the previous example of the heating system as an illustration, the input is the desired temperature setting for a room. The process being controlled is the heater (e.g., furnace). In other feedback systems, the process might be a manufacturing operation, the rocket engines on a space shuttle, the automobile engine in cruise control, or any of a variety of other processes to which power is applied.
 

The output is the variable of the process that is being measured and compared to the input; in the above example, it is.
 

The sensing elements are the measuring devices used in the feedback loop to monitor the value of the output variable.
 

In the heating system example, this function is normally accomplished using a bimetallic strip. This device consists of two metal strips joined along their lengths. The two metals possess different thermal expansion coefficients; thus, when the temperature of the strip is raised, it flexes in direct proportion to the temperature change.
 

As such, the bimetallic strip is capable of measuring temperature. There are many different kinds of sensors used in feedback control systems for automation.

Machine programming


  

The programmed instructions determine the set of actions that is to be accomplished automatically by the system.
 

The program specifies what the automated system should do and how its various components must function in order to accomplish the desired result.
 

The content of the program varies considerably from one system to the next. In relatively simple systems, the program consists of a limited number of well-defined actions that are performed continuously and repeatedly in the proper sequence with no deviation from one cycle to the next.
 

In more complex systems, the number of commands could be quite large, and the level of detail in each command could be significantly greater. In relatively sophisticated systems, the program provides for the sequence of actions to be altered in response to variations in raw materials or other operating conditions.
 

Manufacturing applications of automation and robotics

One of the most important application areas for automation technology is manufacturing.
 

Three types of automation in production can be distinguished: (1) fixed automation, (2) programmable automation, and (3) flexible automation.
 

Fixed automation, also known as “hard automation,” refers to an automated production facility in which the sequence of processing operations is fixed by the equipment configuration.
 

In effect, the programmed commands are contained in the machines in the form of cams, gears, wiring, and other hardware that is not easily changed over from one product style to another.
 

This form of automation is characterized by high initial investment and high production rates. It is therefore suitable for products that are made in large volumes.

Examples of fixed automation include machining transfer lines found in the automotive industry, automatic assembly machines, and certain chemical processes.
 

Programmable automation is a form of automation for producing products in batches. The products are made in batch quantities ranging from several dozen to several thousand units at a time.

For each new batch, the production equipment must be reprogrammed and changed over to accommodate the new product style.

This reprogramming and changeover take time to accomplish, and there is a period of nonproductive time followed by a production run for each new batch.

Production rates in programmable automation are generally lower than in fixed automation, because the equipment is designed to facilitate product changeover rather than for product specialization.

Flexible automation is an extension of programmable automation. The disadvantage with programmable automation is the time required to reprogram and change over the production equipment for each batch of new product.

This is lost production time, which is expensive. In flexible automation, the variety of products is sufficiently limited so that the changeover of the equipment can be done very quickly and automatically.

The reprogramming of the equipment in flexible automation is done off-line; that is, the programming is accomplished at a computer terminal without using the production equipment itself.

Accordingly, there is no need to group identical products into batches; instead, a mixture of different products can be produced one right after another.

Source: Britannica