THIS PRESENTATION IS ABOUT ULTRASONIC DRILLING USED IN MACHINING PROCESS.

1.  Presented by
Debashish Bose
Reg no-1101298278
Branch-Mechanical
Roll No-14
 Guided by
Jukti prasad padhy
Lecturer
Dept. Mech Engg.

2.  Introduction
 Literature Review
 History
 Ultrasonic Waves
 Working Principle
 Mechanism
 Process Parameters
 Materials That Can Be Machined
 Various Work Sample
 CNC Ultrasonic Drilling Machine
 Limitations
 Applications
 Advantages
 Disadvantages
 Conclusion
 References

3.  Ultrasonic drilling is a non-traditional, loose
abrasive machining process.
 In this the mirror image of a shaped tool can be
created in hard, brittle materials.
 Material removal is achieved by the direct and
indirect hammering of abrasive particles against a
workpiece.

4.  Farrukh Makhdum, Luke T Jennings, Anish Roy and Vadim V
Silberschmidt conducted experiments on commercially available
samples of a carbon fibre-reinforced plastic at a feed rate of 16
mm/min. In this study, a thrust force reduction in excess of 60% is
observed when compared to conventional drilling.
 B. Azarhoushang, J. Akbari designed an ultrasonically vibrated tool
holder and also investigated the ultrasonically assisted drilling of Inconel
738-LC. The obtained results show that the application of ultrasonic
vibration can improve the hole quality considerably up to 60%.
 M Wiercigroch,Wojewoda and A.M.Kritsov conducted experiment on
Ultrasonic percussive drilling with diamond-coated tools on rocks such
as sandstone, limestone, granite and basalt, in order to investigate the
applicability of this technique to downhole drilling. The studies showed
that an introduction of high-frequency axial vibration significantly
enhances drilling rates.
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5.  NASA originally developed a prototype of the
Uitrasonic Drilling Machine in 2000, which weighed
in at 1.5 pounds, or .7 kilograms.
 A second drill was developed to fit onto the
Sojourner Rover, which had a drill head that
weighed in at one pound alone, or .4 kilograms.

6.  The Ultrasonic waves are sound waves of frequency
higher than 20,000 Hz.
 Ultrasonic waves can be generated using
mechanical, electromagnetic and thermal energy
sources.
 They can be produced in gasses (including air),
liquids and solids.

7.  In the process of Ultrasonic drilling, material is removed
by micro-chipping or erosion with abrasive particles.
 The tool is oscillated by a piezoelectric transducer and
an electric oscillator at a frequency of about 20 kHz.
 The tool forces the abrasive grits, in the gap between
the tool and the workpiece, to impact normally on the
work surface, thereby machining the work surface.

8.  During one strike, the tool moves down from its
most upper position with a starting speed at zero,
and speeds up to reach the maximum speed at the
mean position.
 Then the tool slows down its speed and eventually
reaches zero again at the lowest position.
 When the grit size is close to the mean position, the
tool hits the grit with its full speed.

9.  The smaller the grit size, lesser the momentum it
receives from the tool.
 As the tool continues to move downwards, the
force acting on larger grits increases rapidly,
therefore some of the grits may be fractured.
 Eventually, the tool comes to the end of its strike
and grits with size larger than the minimum gap will
penetrate into the tool and work surface to
different extents.

11. Piezoelectric Transducer
 Piezoelectric transducers utilize crystals like quartz
whose dimensions alter when being subjected to
electrostatic fields.
 The charge is directionally proportional to the applied
voltage.
 To obtain high amplitude vibrations the length of the
crystal must be matched to the frequency of the
generator which produces resonant conditions.

12. Abrasive Slurry
 The abrasive slurry contains fine abrasive grains.
The grains are usually boron carbide, aluminum
oxide, or silicon carbide ranging in grain size from
100 for roughing to 1000 for finishing.
 It is used to microchip or erode the work piece
surface and it is also used to carry debris away from
the cutting area.

13. Tool holder
 The shape of the tool holder is cylindrical or conical,
or a modified cone which helps in magnifying the
tool tip vibrations.
 In order to reduce the fatigue failures, it should be
free from nicks, scratches and tool marks and
polished smooth.

14. Tool
 Tool material should be tough and ductile. Low carbon
steels and stainless steels give good performance.
 Tools are usually 25 mm long ; its size is equal to the
hole size minus twice the size of abrasives.
 Mass of tool should be minimum possible so that it
does not absorb the ultrasonic energy.

15.  Amplitude of vibration – 15 – 50 μm
 Frequency of vibration – 19 – 25 kHz
 Feed force – related to tool dimensions
 Feed pressure
 Abrasive size – 15 μm – 150 μm
 Abrasive material – Al2O3
- SiC
- B4C
- Diamond dust
 Contact area of the tool
 Volume concentration of abrasive in water slurry

16.  Hard materials like stainless steel, glass, ceramics,
carbide, quartz and semi-conductors are machined
by this process.
 It has been efficiently applied to machine glass,
ceramics, precision minerals stones, tungsten.
 Brittle materials

17. 1- The first picture on the left is a plastic sample that has inner grooves
that are machined using Ultrasonic Drilling.
2- The Second picture (in the middle) is a plastic sample that has complex
details on the surface
3- The third picture is a coin with the grooving done by Ultrasonic
Drilling.

18.  4-axis CNC drills holes
as small as 0.010",
multi-sided holes,
multiple hole and slot
patterns, and many
other complicated,
irregular shapes.
 Works on hard, brittle
materials such as
ceramic and glass with
precision to 0.0005".

19.  Under ideal conditions, penetration rates of 5
mm/min can be obtained.
 Specific material removal rate on brittle materials is
0.018 mm cubic/Joule.
 Normal hole tolerances are 0.007 mm and a surface
finish of 0.02 to 0.7 micro meters.

20.  A nearly limitless number of feature shapes
and cavities of varying depths can be machined
with high quality and consistency.
 Features ranging in size from 0.008" up to
several inches are possible in small workpiece.
 Machining, wire drawing, punching or small
blanking dies.

21.  Requires little power to operate.
 Nearly zero torque is needed to operate the drill.
 The drill is able to properly function at both extremely
low and high temperatures.
 Does not produce electric, thermal, chemical abnormal
surface.
 Can drill circular or non-circular holes in very hard
materials

22.  Difficult to drill much past an inch into very dense
material.
 Ultrasonic drilling provides very little tolerance
surrounding the bit, henceforth no pathway is
created for the cutting fluid.
 Low Material Removal Rate.
 High tool wear occurs.

23.  USD has been shown to possess several advantages
including reduced thrust force and torque.
 Comparative experiments of the hole quality
demonstrated up to 60% improvement in average
surface roughness and circularity for the workpiece
machined.
 USD leads to significant improvements on the hole
oversize and surface finish.
 The design of tool and transducer capacity plays an
important role in providing a resonance state in
USD to maximize the material removal rate.

24.  Cutting forces in ultrasonically assisted drilling of
carbon fibre-reinforced plastics by Farrukh Makhdum,
Luke T Jennings, Anish Roy and Vadim V Silberschmidt.
 Ultrasonic-assisted drilling of Inconel 738-Lc by B.
Azarhoushang, J. Akbari.
 Industrial Applications of Ultrasound-A Review II.
Measurements, Tests, and Process Control Using Low-
Intensity Ultrasound by Lawrence c. Lynnworth.
 Assessment of ultrasonic drilling of C/SiC composite
material by H. Hocheng, N.H. Tai and C.S. Liu.