This document provides an overview of advanced machining processes, also known as unconventional or non-traditional machining. It begins with an introduction and outlines the course objectives to understand these processes and their advantages over conventional techniques. These processes are classified based on the type of energy used, including mechanical, electrical, chemical/electro-chemical, and thermal. Examples of specific processes are described within each category, such as abrasive jet machining, electrical discharge machining, electrochemical machining, and laser beam machining. Diagrams are provided to illustrate key principles and applications for several of the machining methods.

1. Advanced/Unconventional/Non-
traditional Machining Process -
An introduction
Mr.C.Dharmaraja
Assistant Professor
Department of Mechanical Engineering
University College Of Engineering
Dindigul

2. ME 2026 - Syllabus
1. INTRODUCTION 5hrs
• Unconventional machining Process – Need –
classification – Brief overview of all techniques.
2. MECHANICAL ENERGY BASED PROCESSES
10hrs
• Abrasive Jet Machining – Water Jet Machining –
Ultrasonic Machining. (AJM, WJM and USM).
Working Principles – equipment used – Process
parameters – MRR-Variation in techniques used
– Applications.

3. 3. ELECTRICAL ENERGY BASED PROCESSES 8hrs
• Electric Discharge Machining (EDM)- working Principles-
equipments-Process Parameters-MRR- electrode / Tool –
Power Circuits-Tool Wear – Dielectric – Flushing – Wire cut
EDM – Applications.
4. CHEMICAL AND ELECTRO-CHEMICAL ENERGY BASED
PROCESSES 12hrs
• Chemical machining and Electro-Chemical machining (CHM
and ECM)-Etchants-maskant-techniques of applying
maskants-Process Parameters – MRR-Applications.
• Principles of ECM-equipments-MRR-Electrical circuit-Process
Parameters-ECG and ECH Applications.
5. THERMAL ENERGY BASED PROCESSES 10hrs
• Laser Beam machining (LBM), plasma Arc machining (PAM)
and Electron Beam Machining (EBM).
• Principles-Equipment-Types-Beam control techniques –
Applications.

4. Objective of the course – ME2026
• To give a perspective view with adequate
depth to understand the UCM processes,
its relative advantages over conventional
techniques

5. Non-traditional Machining Processes
Manufacturing processes can be broadly divided into two groups:
a) primary manufacturing processes : Provide basic shape and size
b) secondary manufacturing processes : Provide final shape and
size with tighter control on dimension, surface characteristics
Material removal processes once again can be divided into two groups
1. Conventional Machining Processes
2. Non-Traditional Manufacturing Processes or non-conventional
Manufacturing processes
Conventional Machining Processes mostly remove material in the
form of chips by applying forces on the work material with a
wedge shaped cutting tool that is harder than the work material
under machining condition.

6. Conventional Machining

7. Non-traditional Machining Processes
The major characteristics of conventional machining are:
– • Generally macroscopic chip formation by shear
deformation
– • Material removal takes place due to application of cutting
forces – energy domain can be classified as mechanical
– • Cutting tool is harder than work piece at room
temperature as well as under machining conditions
Non-conventional 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.

8. Principle of conventional machining
Material is removed principally by SHEARING process – involves physical contact
with a metal cutting tool

9. Non-traditional Machining Processes
The major characteristics of Non-conventional machining:
1. Material removal may occur with chip formation or even no chip
formation may take place. For example in AJM, chips are of
microscopic size and in case of Electrochemical machining material
removal occurs due to electrochemical dissolution at atomic level.
2. In NTM, there may not be a physical tool present. For example in
laser jet machining, machining is carried out by laser beam. However
in Electrochemical Machining there is a physical tool that is very much
required for machining
3. In NTM, the tool need not be harder than the work piece material.
For example, in EDM, copper is used as the tool material to machine
hardened steels.
4. Mostly NTM processes do not necessarily use mechanical energy to
provide material removal. They use different energy domains to
provide machining. For example, in USM, AJM, WJM mechanical
energy is used to machine material, whereas in ECM electrochemical
dissolution constitutes material removal.

10. Classification of NTM processes
classification of NTM processes is carried out depending on the nature
of energy used for material removal.
1. Mechanical Processes
• Abrasive Jet Machining (AJM)
• Ultrasonic Machining (USM)
• Water Jet Machining (WJM)
• Abrasive Water Jet Machining (AWJM)
2. Electrochemical Processes
• Electrochemical Machining (ECM)
• Electro Chemical Grinding (ECG)
• Electro Jet Drilling (EJD)
3. Electro-Thermal Processes
• Electro-discharge machining (EDM)
• Laser Jet Machining (LJM)
• Electron Beam Machining (EBM)
4. Chemical Processes
• Chemical Milling (CHM)
• Photochemical Milling (PCM)

11. UCM Processes
• Energy in its direct form is used to remove
the materials from the workpiece
• Employs fundamental machining energy
such as: Mechanical, Electro-chemical,
Chemical and Thermo-electric

12. Need for UCM processes
1. Limitations of conventional processes - tool material
hardness > W/p hardness
2. Rapid improvements in the properties of materials –
high strength alloys
3. Product requirements
• Complex shapes
• Machining in inaccessible areas
• Low tolerances
• Better surface integrity
• High surface finish
4. Precision and ultra precision machining – requires
material removal in the form of atoms or molecules
5. Low cost of production – especially in producing
desired accuracy and surface finish in hard w/p
materials
6. High production rate

13. Case studies to highlight the need for UCM
processes
• Square blind hole in any material with
high surface finish (about 10 microns)
• Square blind hole with certain accuracy
requirement

14. Square blind hole manufacturing – increased
production time

15. Square blind hole manufacturing – shape of the
job and accuracy pose problem in manufacturing

16. Small hole drilling – size of the job creates
problem

17. Contoured die block – increased strength of work
material and inadequacy of the control system

18. Surface profiles generated by boring and turning

19. Preferred orientation of lay lines along axial
direction

20. Contact length in cylindrical piston and cylinder
and elliptical piston and cylinder

21. Brief overview of all techniques
• Mechanical energy based
• Electrical energy based
• Chemical and electrochemical energy
based
• Thermal energy based

22. Conventional Machining VS
NonConventional Machining
• The cutting tool and workpiece are always in physical contact, with a
relative motion against each other, which results in friction and a
significant tool wear.
• In non-traditional processes, there is no physical contact between the
tool and workpiece. Although in some non-traditional processes tool
wear exists, it rarely is a significant problem.
• Material removal rate of the traditional processes is limited by the
mechanical properties of the work material. Non-traditional processes
easily deal with such difficult-to-cut materials like ceramics and
ceramic based tool materials, fiber reinforced materials, carbides,
titanium-based alloys.

23. Continue…
• In traditional processes, the relative motion between the tool and work
piece is typically rotary or reciprocating. Thus, the shape of the work
surfaces is limited to circular or flat shapes. In spite of widely used CNC
systems, machining of three-dimensional surfaces is still a difficult task.
Most non-traditional processes were develop just to solve this problem.
• Machining of small cavities, slits, blind or through holes is difficult with
traditional processes, whereas it is a simple work for some non-
traditional processes.
• Traditional processes are well established, use relatively simple and
inexpensive machinery and readily available cutting tools. Non-
traditional processes require expensive equipment and tooling as well as
skilled labor, which increases significantly the production cost.

24. Mechanical Energy
Principle: Erosion
Examples: USM, WJM & AJM

25. USM & WJM

26. Water Jet Machining
Fig : (a) Schematic
illustration of water-
jet machining. (b) A
computer-
controlled, water-jet
cutting machine
cutting a granite
plate. (c) Example
of various
nonmetallic parts
produced by the
water-jet cutting
process.

27. Abrasive Jet Machining
Fig : Schematic illustration of Abrasive Jet Machining

28. Electro Chemical Machining
Fig : Schematic illustration of the electrochemical-machining
process. This process is the reverse of electroplating.
Principle: Electrolysis; Based on Faraday’s law

29. Chemical machining
Principle: Chemical attacks metals and etch them by removing small
amounts of material from the surface using reagents or etchants
Fig : (a) Missile skin-panel section contoured by chemical milling to improve the stiffness-to weight ratio of the part.
(b) Weight reduction of space launch vehicles by chemical milling aluminum-alloy plates. These panels are
chemically milled after the plates have first been formed into shape by processes such as roll forming or stretch
forming. The design of the chemically machined rib patterns can be modified readily at minimal cost.

30. Thermo-electric
EDM, WEDM, LBM, EBM

31. Electrical-Discharge Machining
Fig : Schematic illustration of the electrical-discharge machining process.
This is one of the most widely used machining processes, particularly
for die-sinking operations.
Principle: Sparking between two electrical contacts results in loss of
material

32. Examples of cavities produced by the electrical-discharge
machining process, using shaped electrodes
Two round parts (rear) are the set of dies for extruding the aluminum the
aluminum piece shown in front

33. WIRE EDM
Fig : (a) Schematic illustration
of the wire EDM process. As
much as 50 hours of
machining can be
performed with one reel of
wire, which is then
discarded. (b) Cutting a
thick plate with wire EDM.
(c) A computer-controlled
wire EDM machine.

34. Laser Beam Machining
Fig : (a) Schematic illustration of the laser-beam machining process. (b) and
(c) Examples of holes produced in nonmetallic parts by LBM.
Principle: Transformation of light energy into thermal energy

35. Electron-Beam Machining
Fig : Schematic illustration of the electron-beam machining process. Unlike LBM, this process
requires a vacuum, so workpiece size is limited to the size is limited to the size of the
vacuum chamber.
Principle: Transformation of kinetic energy of high-speed electrons
into thermal energy as they strike the workpiece

39. AJM processed egg shell

40. Drilling of holes into fragile glass disks

41. Complex shapes that can be cut with WEDM

42. WEDM parts

43. Variety of shapes that can be cut with a
computer controlled laser

44. Glass fiber spinning head drilled by EBM

45. Important characteristics of UCM
processes
• Performance is independent of strength barrier
• Performance depends upon thermal, electrical
or/and chemical properties of w/p
• Use different kinds of energy in direct form
• In general, low MRR but better quality products
• Comparatively high initial investment cost

46. Selection of UCM processes
• Following factors should be considered when
selecting a specific process for a particular
application:
1. Process capability – MRR, Surface finish,
Surface damage, Tolerance, Corner radii
2. Physical parameters – potential, current,
power, gap, medium
3. Shape capabilities – holes (L/D), through
cavities, pocketing, surfacing , through cutting,
special applications
4. Properties of w/p material to be cut – Electrical
5. Economics of the processes – capital cost,
tooling cost, power required, removal
efficiency and tool wear