The document discusses various types of grinding processes including conventional grinding, micro grinding, ultra precision grinding, and piezoelectric nano grinding. Conventional grinding includes surface grinding, cylindrical grinding, internal grinding, and centerless grinding. Micro grinding uses a nickel coated ceramic tool with microscale diamond particles to machine at the nanoscale. Ultra precision grinding can achieve mirror finishes with dimensional accuracy of a few micrometers and surface roughness of 5nm. Piezoelectric nano grinding uses the piezoelectric effect to remove small fragments of material from a substrate for applications such as biomedical devices.

1. Micro and Nano
Grinding
7ME6.1A (Part III)
Er. Mohit Ostwal
Assistant Professor
Department of Mechanical Engineering
Jodhpur Institute of Engineering and Technology-Coed

2. Conventional Grinding
• Horizontal Wheel surface grinding
• Vertical spindle surface grinding

3. Conventional Grinding
• Creep feed grinding
• Outside Diameter cylindrical grinding

4. Conventional Grinding
• Internal grinding with chucking machine
• Centreless Grinding
workpiece is supported by a blade instead
of by centers or chucks. Two wheels are
used. The larger one is used to grind the
surface of the workpiece and the smaller
wheel is used to regulate the axial
movement of the workpiece.

5. Conventional Grinding
• Jig Grinding
• Double disk Grinding

6. Conventional Grinding
• Thread Grinding
• Slot Grinding

7. Conventional Grinding

8. Conventional Grinding

9. Micro Grinding and Ultra
Precision Process
• In order to achieve fully ductile mode grinding, material removal must take place
at the nanoscale.
• The nanogrinding process is a process that relies on using a nickel coated
ceramic material with microscale diamond particles bonded to it that are cubo-
octahedral in shape to machine nanoscale features in a variety of workpiece
materials.
• The diamonds are bonded to the piezoelectric material by gaseous deposition,
laser cladding or directly bonding a porous tool to the material via an adhesive
paste.
• The process is executed by applying a known sinusoidal frequency to the
piezoelectric crystal in order to achieve a desired oscillatory displacement.
• Rapid vibration of the crystal will allow material removal rates to be increased,
thus making it a nanomanufacturing process.
• The nanogrinding process is accompanied by wear of the diamond grains, and
the rate of this wear plays an important role in determining the efficiency of the
nanogrinding process and the quality of the nanomachined surface.
• Wear mechanisms in nanogrinding processes appear to be similar to that of
single-point cutting tools, the only difference being the size of swarf particles
generated.

10. Ultraprecision Grinding
• Using this machine coupled with
ductile mode theory, mirror finishes
can be achieved on the workpiece
without the intervention of
polishing.
• Dimensional accuracy in the range of
a few micrometers
• Surface form accuracy in the range
of lOO nm or better.
• Surface texture in the range of 5nm,
or better.
• Speed range of 10,000 -70,000 rpm.
• Grinding wheels from 3 mm - 15 mm
in diameter. Sometimes 30
mm(small aspheric components,
particularly lenses and lens molds).

11. Ultraprecision Grinding
• The machine is capable of generating arbitrary confocal shapes on
materials ranging from optical glass and infrared materials to non-
ferrous metals, crystals, polymers, and ceramics.
• The machine temperature is maintained stable to less than ±0.5 C.
Grinding is done in a flood-cooled environment.
• Machine has two vertical spindles with hydrostatic bearing of high
precision and rigidity.
• It can machine at extremely fine depth of cut (0.1 |Lim) and
capable of producing at submicron flatness and nanometer surface
Micro grinding roughness (5 nm Rmax) on optical glass (NbF), Mn-
Zn ferrite and electronic materials using diamond abrasive grinding
wheels.

12. Piezoelectric Nano grinding Process

13. Piezoelectric Nano grinding Process
• Piezoelectric Effect is the ability of certain materials to generate
an electric charge in response to applied mechanical stress.
• The process relies on applying an electric current to the diamond
coated piezoelectric material that causes material to strain.
• When the diamond coated piezoelectric material is placed in
closed proximity to substrate, the diamond removes extremely
small fragments of substrate, when the electric current is applied
to the material.
• The magnitude of the applied current controls the material
removal rate.
• Used to process the biomedical materials especially in the
production of nanoscale ducts and channels in micro and
nanofluidic devices.
• A substrate is a solid substance or medium to which another
substance is applied and to which that second substance
adheres.

14. Nanogrinding apparatus
1. Holding a polished specimen between the jaws of a vise so that a
piezoelectric crystal oscillator traverses back-and-forth across the
specimen, thus machining the specimen by creating a cut depth
between the diamonds adhered on the piezoelectric crystal and
the workpiece material.
2. The work pieces are mounted in a vise that was attached to a x-y-
z linear slide in order to achieve accurate positioning of the
workpiece.
3. The piezoelectric crystal was mounted on a steel framework that
was orthogonal to the workpiece.
4. The whole unit was located within a tetrahedral space frame to
dampen excess vibrations.

15. Nanogrinding Tools
• Porous nanogrinding tools are composed of abrasive particles (sub
micron) embedded in vitrified bond.
• Vitrified bonds are composed of glasses that are formed when
clays, ground glass frits, mineral fluxes (feldspars & chemical
fluxes such as forax) melt when grinding wheel is fixed at
temperature in range 1000⁰C to 1200 ⁰C.

16. NANOGRINDING
SOME TERMS RELATED TO NANOGRINDING
• Frits- Pre-grounded glass with a predetermined oxide content.
• Flux- Low MP silicious clay that reduces surface tension at
bond bridge abrasive grain interface.
• Pre-fitted bond- Bond that contains no clay minerals.
• Clays are used to provide to provide vitrified grinding wheels
with green strength during heat treatment process.
• Bonding Layer is approx. a few micrometer in thickness and is
caused by use of high clay content bonding system.

17. Nanogrinding tools

18. Nanogrinding Tools

19. Preparation of Nanogrinding Wheels
• Raw materials use are:
1. Hymen Prima Ball Clay
2. Standard poreclain clay
3. Potash Feldspar
4. Synthetic Quartz
• Following Analysis are performed:
1. Chemical Analysis
2. Rational Analysis- Mineralogical composition of raw materials.
• Fusible Bonding system – Ball Clay (66 wt%) and Feldspar (34 wt%)
• In general Ball clay (12.77 wt%) and Feldspar (4.93 wt%) quartz.
• Raw materials are mixed in mortar, pressed in a mold and fired at
various temperatures. Heating rate of 2.9 C/min. (950 to 1050 C).
• Cooled down at a rate of 1.8 C/min. To avoid thermal fracture.