NON TRADITIONAL MACHINING

  With the development of technology, more and more challenging problems are faced by the scientists and technologists in the field of manufacturing. § The difficulty in adapting the traditional manufacturing processes can be attributed mainly to the following basic sources:

 (i) New materials with low machinability. 

(ii) Dimensional and accuracy requirements.

 (iii) A higher production rate and economy.   

§ The many new materials and alloys that have been developed for specific uses possess a very low machinability. Producing complicated geometries in such materials becomes extremely difficult with the usual methods. Also, sometimes the combination of the material properties and the job dimensions is such that the use of the traditional processes becomes impossible. Examples of these types of jobs are machining a complicated turbine blade made of super alloys, and producing holes and slots (both through and blind) in materials such as glass and semiconductors. At times, the job becomes difficult because of the dimensional complications. So, drilling a noncircular hole or a micro hole becomes problematic (and sometimes impossible) if the traditional processes are used. Apart from the situations cited, higher production rate and economic requirements may demand the use of non traditional (or unconventional) machining processes.  

 § To tackle such difficult jobs, two approaches are possible, viz  

 i) A modification of the traditional processes (eg: hot machining) and

 ii) The development of new processes.  

  

Non-traditional manufacturing processes is defined as a group of processes that remove excess material by various techniques involving mechanical, thermal, electrical or chemical energy or combinations of these energies but do not use a sharp cutting tools as it needs to be used for traditional manufacturing processes.   


  On completion of the course, the students will be able to
1. Understand the compare traditional and non-traditional machining process and recognize the need for Non-traditional machining process.
2. Understand the constructional features, performance parameters, process characteristics, applications, advantages and limitations of USM, AJM and WJM.
3. Identify the need of Chemical and electro-chemical machining process along with the constructional features, process parameters, process characteristics, applications, advantages and limitations.
4. Understand the constructional feature of the equipment, process parameters, process characteristics, applications, advantages and limitations EDM & PAM.
5. Understand the LBM equipment, LBM parameters, and characteristics. EBM equipment and mechanism of metal removal, applications, advantages and limitations LBM & EBM.  

VTU NON TRADITIONAL MACHINING NOTES

  Contents (Syllabus)

 
MODULE 1 


INTRODUCTION
Introduction to Non-traditional machining, Need for Non-traditional machining process, Comparison between traditional and non-traditional machining, general classification Nontraditional machining processes, classification based on nature of energy employed in machining, selection of non-traditional machining processes, Specific advantages, limitations
and applications of non-traditional machining processes. 08 hours 


MODULE 2
Ultrasonic Machining (USM): Introduction, Equipment and material process, Effect of process parameters: Effect of amplitude and frequency, Effect of abrasive grain diameter, effect of slurry, tool & work material. Process characteristics: Material removal rate, tool wear, accuracy, surface finish, applications, advantages & limitations of USM.
Abrasive Jet Machining (AJM): Introduction, Equipment and process of material removal, process variables: carrier gas, type of abrasive, work material, stand-off distance (SOD). Process characteristics-Material removal rate, Nozzle wear, accuracy & surface finish. Applications, advantages & limitations of AJM.
Water Jet Machining (WJM): Equipment & process, Operation, applications, advantages and limitations of WJM.     08 hours


   MODULE 3
ELECTROCHEMICAL MACHINING (ECM)
Introduction, Principle of electro chemical machining: ECM equipment, elements of ECM operation, Chemistry of ECM. ECM Process characteristics: Material removal rate, accuracy, surface finish. Process parameters: Current density, Tool feed rate, Gap between tool & work piece, velocity of electrolyte flow, type of electrolyte, its concentration temperature, and choice of electrolytes. ECM Tooling: ECM tooling technique & example, Tool & insulation materials. Applications ECM: Electrochemical grinding and electrochemical honing process. Advantages, disadvantages and application of ECG, ECH.
CHEMICAL MACHINING (CHM)
Elements of the process: Resists (maskants), Etchants. Types of chemical machining processchemical blanking process, chemical milling process.
Process characteristics of CHM: material removal rate, accuracy, surface finish, advantages, limitations and applications of chemical machining process.   10 hours 


MODULE 4

ELECTRICAL DISCHARGE MACHINING (EDM)
Introduction, mechanism of metal removal, EDM equipment: spark erosion generator (relaxation type), dielectric medium-its functions & desirable properties, electrode feed control system. Flushing types; pressure flushing, suction flushing, side flushing, pulsed flushing. EDM process parameters: Spark frequency, current & spark gap, surface finish, Heat Affected Zone. Advantages, limitations & applications of EDM, Electrical discharge grinding, Traveling wire EDM.
PLASMA ARC MACHINING (PAM)
Introduction, non-thermal generation of plasma, equipment mechanism of metal removal, Plasma torch, process parameters, process characteristics. Safety precautions. Safety precautions, applications, advantages and limitations.  08 hours

 
MODULE 5
LASER BEAM MACHINING (LBM)
Introduction, generation of LASER, Equipment and mechanism of metal removal, LBM parameters and characteristics, Applications, Advantages & limitations.
ELECTRON BEAM MACHINING (EBM)
Introduction, Principle, equipment and mechanism of metal removal, applications, advantages and limitations.    08 hours