The human race hag distinguished itself from all other forms of life by using tools and intelligence to create items that serve to make life easier and more enjoyable.Through the centuries,both the tools and the energy sources to power these tools have evolved to meet the increasing sophistication and complexity of mankinds ideas.
In their earliest forms,tools primarily consisted of stone instruments. Considering the relative simplicity of the items being made and the materials that were being shaped,stone Wag adequate.When iron tools were invented,durable metals and more sophisticated articles could be produced.The twentieth century has seen the creation of products made from the most durable and,consequently,the most difficult—to-machine materials in history.In an effort to meet the manufacturing challenges created by these materials,tools have now evolved to include materials such as alloy steel,carbide,diamond,and ceramics.
A similar evolution has taken place with the methods used to power our tools.Initially,tools were powered by muscles;either human or animal.
However as the powers of water,wind,steam, and electricity were harnessed mankind was able to further extend manufacturing capabilities with new machines,greater accuracy,and faster machining rates.
Every time new tools,tool materials,and power sources are utilized,the efficiency and capabilities of manufacturers are greatly enhanced.However as old problems are solved,new problems and challenges arise so that the manufacturers of today are faced with tough questions such as the following:
How do you drill a 2-mm diameter hole 670-mm deep without experiencing taper or runout ? Is there a way to efficiently deburr passageways inside complex castings and guarantee 100%that no burrs were missed? Is there a welding process that can eliminate the thermal damage now occurring to my product?
Since the 1940s,a revolution in manufacturing has been taking place that once again allows manufacturers to meet the demands imposed by increasingly sophisticated designs and durable,but in many cases nearly unmachinable,materials.This manufacturing revolution is now,as it has been in the past,centered on the use of new tools and new forms of energy.The result has been the introduction of new manufacturing processes used for material removal,forming,and joining,known today as nontraditional manufacturing processes.
The conventional manufacturing processes in use today for material removal primarily rely on electric motors and hard tool materials to perform tasks such as sawing,drilling,and broaching.conventional forming operations are performed with the energy from electric motors,hydraulics,and gravity.Likewise,material joining is conventionally accomplished with thermal energy sourses such as burning gases and electric arcs.
In contrast.nontraditional manufacturing processes harness energy s(mroe8 considered unconventional by yesterday's standards.Material removal call now be accomplished with electrochemical reactions,high—temperature plasmas,and high—velocity jets of liquids and abrasives.Materials that in the past have been extremely difficult to form,ale now formed with magnetic fields,explosives,and the shock waves from powerful electric sparks.Material-joining capabilities have been expanded with the use of high—frequency sound wave8 and beams of electrons.
In the past 50 years,over 20 different nontraditional manufacturing processes have been invented and successfully implemented into production.
The reason there are such a large number of nontraditional processes is the same reason there are such a large number of conventional processes ;each process has its own characteristic attributes and limitations,hence no once process is best for all manufacturing situations.
For example,nontraditional processes are sometimes applied to increase productivity either by reducing the number of overall manufacturing operations required to produce a product or by performing operations faster than the previously used method.
In other cases,nontraditional processes are used to reduce the number of rejects experienced by the old manufacturing method by increasing repeatability,reducing in·process breakage of fragile workpieces,or by minimizing detrimental effects on workpiece properties. Because of the aforementioned attributes,nontraditional manufacturing processes have experienced steady growth since their introduction.An increasing growth rate for these processes in the future is assured for the following reasons:
(1)Currently,nontraditional processes possess virtually unlimited capabilities when compared with conventional processes,except for volumetric material removal rates.Great advances have been made in the past few years in increasing the removal rates of some of these processes,and there is no reason to believe that this trend will not continue into the future.
(2)Approximately one—half of the nontraditional manufacturing processes are available with computer control of the process parameters,The use of computers lends simplicity to processes that people may be unfamiliar with, and thereby accelerates acceptance.Additionally,computer control assures reliability and repeatability, which also accelerates acceptance and implementation.
(3)Most nontraditional processes are capable of being adaptively- controlled through the use of vision systems,laser gages,and other in—process inspection techniques.If,for example,the in·process inspection system determines that the size of holes being produced in a product are becoming smaller,the size call be modified without changing hard tools,such as(1rills.
(4)The implementation of nontraditional manufacturing processes will continue to increase as manufacturing engineers,product designers,and metallurgical engineers become increasingly aware of the unique capabilities and benefits that nontraditional manufacturing processes provide.