MAE CLASSES (MAE)

BE MECHANICAL [Ph. No: 9557064555]

S6 [Visit Us: www.maeclasses.com]

Non-conventional /Modern machining processes

Water Jet Machining

For machining softer materials such as plastics and fibers simple water jet machining is used.
Unlike conventional processes, downtime for the replacement of worn or broken cutting tools is
virtually non-existent with WJM because the “tool” never dulls or breaks
Additionally, the health hazards associated with cutting materials such as asbestos and fiberglass are
minimized because almost no airborne dust is generated by this process.

Abrasive Jet Machining Definition:

In abrasive jet machining, a focused stream of abrasive particles, carried by high pressure air or gas is
made to impinge on the work surface through a nozzle then work material is removed by erosion by
high velocity abrasive particles.
Process: In Abrasive jet machining abrasive particles are made to impinge on work material at high
velocity. Jet of abrasive particles is carried by carrier gas or air. The high velocity stream of abrasives
is generated by converting pressure energy of carrier gas or air to its Kinetic energy and hence high
velocity jet.
Nozzles directs abrasive jet in a controlled manner onto work material. The high velocity abrasive
particles remove the material by micro-cutting action as well as brittle fracture of the work material.
Commonly used abrasive material – Al2O3 SiC Glass beads Crushed glass Sodium bi carbonate
ULTRASONIC MACHINING
Ultrasonic Machining is a non-traditional process, in which abrasives contained in a slurry are driven
against the work by a tool oscillating at low amplitude (25-100 microns) and high frequency (15-30
kHz).
Process: Ultrasonic machining is a mechanical type non-traditional machining process. It is employed
to machine hard and brittle materials (both electrically conductive and non-conductive material)
having hardness usually greater than 40 HRC. The process was first developed in 1950s and was
originally used for finishing EDM surfaces.
In ultrasonic machining, tool of desired shape vibrates at ultrasonic frequency (19 to 25 kHz. ) with an
amplitude of 15-50 Microns over work piece. Generally, tool is pressed down with a feed force F.
Between the tool and work, machining zone is flooded with hard abrasive particles generally in the
form of water-based slurry.
As the tool vibrates over the work piece, abrasive particles act as indenter and indent both work and
tool material. Abrasive particles, as they indent, the work material would remove the material from
both tool and work piece.
In Ultrasonic machining material removal is due to crack initiation, propagation and brittle fracture of
material.
USM is used for machining hard and brittle materials, which are poor conductors of electricity and
thus cannot be processed by Electrochemical machining (ECM) or Electro discharge machining
(EDM).
The tool in USM is made to vibrate with high frequency on to the work surface in the midst of the
flowing slurry.
The main reason for using ultrasonic frequency is to provide better performance. Audible frequencies
of required intensities would be heard as extremely loud sound and would cause fatigue and even
permanent damage to the auditory apparatus.
ELECTRIC DISCHARGE MACHINING
• EDM is a non-contact machining process that removes material using electrical discharges
(sparks) between a tool and a conductive workpiece, separated by a dielectric fluid.
• A potential difference is applied between the tool (negative) and workpiece (positive),
causing dielectric breakdown and forming a plasma channel.
• The spark generates extreme heat, melting and vaporizing the material.
• Plasma collapse creates shock waves that eject molten material, forming craters on the
workpiece surface.
• The dielectric fluid insulates until breakdown, cools the tool and workpiece, and flushes away
debris.
• EDM works on electrically conductive materials like hardened steel, titanium, and tungsten.
• Common types include die-sinking EDM (for cavities) and wire EDM (for precision cutting).
 • The process enables machining of complex shapes with high precision but has a slow material
removal rate.
• It is widely used in aerospace, medical implants, and tool & die making.
• No mechanical contact reduces tool wear, but electrode wear affects accuracy over time.

ELECTRIC DISCHARGE MACHINING Electrochemical Machining

Electron Beam Machining (EBM)

• It is a thermal process that uses a focused beam of high-velocity electrons for drilling, cutting,
welding, and annealing.
• The kinetic energy of electrons is converted into heat upon impact with the workpiece.
• This heat causes rapid melting and vaporization of the material, enabling precise machining.
• By controlling operating parameters, various processes like drilling, cutting, slotting, welding,
annealing, and rapid manufacturing can be performed.
• EBM is highly effective for machining hard materials with extreme precision.
• The process is conducted in a vacuum to prevent electron scattering and ensure energy
concentration.
• EBM allows for deep penetration with minimal heat-affected zones.
• It is widely used in aerospace, automotive, and microelectronics industries.

Electrochemical Machining (ECM)

• Electrochemical Machining (ECM) is a non-traditional machining process that removes
material using anodic dissolution.
• A direct current (DC) is passed through an electrolyte between the tool (cathode) and
workpiece (anode).
• The electrolyte dissolves the material from the workpiece without generating heat or
mechanical stress.
• ECM is ideal for machining hard and complex materials that are difficult to machine using
conventional methods.
• No tool wear occurs since there is no direct contact between the tool and workpiece.
• The process produces smooth, burr-free surfaces with high precision.
 • Common electrolytes used are sodium chloride (NaCl) and sodium nitrate (NaNO₃) solutions.
• ECM is widely used in aerospace, automotive, medical implants, and turbine blade
manufacturing.

Sheet metal work involves shaping and cutting metal sheets through various operations.
Blanking: Cutting flat sheets into desired shapes.
Punching: Creating cylindrical holes using a punch and die.
Piercing: Cutting non-cylindrical holes with a punch and die.
Perforating: Making multiple evenly spaced holes in a pattern.
Slitting: Cutting a sheet in a straight line along its length.
Notching: Removing metal from the edge to achieve a specific shape.
Lancing: Partially cutting and bending the sheet.
Forming: Bending sheets along a curved axis.
Drawing: Creating cup-shaped parts from flat sheets.
Embossing: Forming figures, letters, or designs on the sheet.
Planishing: Straightening a curved metal sheet.
Marking: Scratching lines on the surface for guidance, also called scribing.