Machines have been doing the work behind commerce since the beginning of industrialization. A machine, by definition, involves some arrangement of mechanisms that gain the user an advantage in applying force to accomplish work. Many of these devices consist of a single piece. Things like levers, motors and wheel axle arrangements are examples. Other devices include multiple parts and pieces. These more complex contrivances are arrangements designed to increase advantage and improve efficiency.
The pieces in multiple part machines are fashioned in different ways. Some are cast while others are machined. These parts vary in size from microscopically small to large engine parts weighing hundreds of pounds. Machined parts are formed by passing a piece of work through another apparatus designed to remove material to form the part into the needed shape. An example of this process is large part milling in which metal is removed from the workpiece using a high-speed rotary cutting tool.
Two basic classifications of these different mechanisms are simple and complex machines.
There are a few mechanisms that are known as simple machines. These include the inclined plane, lever, wedge, wheel, axle, pulley and screw. The screw is a variation of the inclined plane that has been rearranged in a twisting process. These are some of the first tools discovered and used by early man.
The different arrangements and degrees of complexity in this classification are almost endless. Still, if a complex machine is disassembled into its constituent parts each of these parts is simply a variation of the 7 simple machines.
Complex machines have evolved over time to include techniques that incorporate some form of energy input process. Generally, the energy source harnessed to operate these devices involves converting a fuel containing chemical energy into kinetic energy using a chemical reaction known as combustion. Automotive engines are an example of this arrangement.
Simple and complex devices and their use is a result of human’s higher intellectual capacity. While some simple mechanisms are used by specific species other than humans, complex machinery requires the thinking abilities that humans possess. Machines drive our daily lives and have enabled the rise of civilizations and conveniences of modern life.