Upload
vananh
View
256
Download
10
Embed Size (px)
Citation preview
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 1
Grinding
� Grinding is a surface finishing operation
where very thin layer of material is removed
in the form of dust particles.
� Thickness of material removed is in range of
0.25 to 0.50 mm.
� Tool used is a abrasive wheel.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 2
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 3
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 4
Abrasives
� Abrasive is the material employed for
sharpening, grinding and polishing
operations.
� Natural abrasive – emery, corundum,
quartz, sandstone, diamond, etc.
� Artificial abrasive – carborundum,
aloxite, alundum, etc.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 5
Applications of abrasives
� Corundum : is a natural mineral which consists of aluminium oxide. Hardest natural substance after diamond. � Used for shaping, finishing and polishing other tools.
� Emery : natural abrasive consisting of aluminium oxide and little amount of iron oxide.
� Silicon carbide : synthetic abrasive harder than aluminium oxide.� Used to grind metals like iron, brass and soft bronze.
� Used in non metals like wood and leather industries.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 6
� Zirconia aluminia : it is a mixture of
zirconium oxide and aluminium oxide.
� Used in casting and foundry industries.
� Cubic boron nitride : is made up of
boron nitride with a cubic crystalline
structure.
� Used for hard coating material.
� Diamond :
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 7
Bonding materials
� These are adhesives which holds the
abrasive grains together.
� Vitrified process :
� Silicate process :
� Elastic process :
� Rubber or vulcanite process :
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 8
Grinding machines
�Grinding machine is a power operated
machine tool where, the work piece is fed
against constantly rotating abrasive wheel
to remove thin layer of material from
work.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 9
Principle of grinding machines
� Work piece is fed against the rotating abrasive
wheel.
� Due to action of rubbing or friction between the
abrasive particles and work piece material is
removed.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 10
Classification of grinding
machine
� Bench grinding machine
� Surface grinding machine
� Cylindrical grinding machine
� Center less grinding machine
� Internal grinding machine
� Special purpose grinding machine
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 11
Surface grinding machine
� It is machine basically used to grind flat
surface.
� Job is mounted to a table which moves
longitudinally as well as in transverse
direction.
� Manual feed or power feed.
� Work piece can clamped in two ways
� Manual clamps.
� Magnetic chuck.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 12
� Internal pump and piping arrangement for
coolant.
� Protective guard for safety.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 13
� Base
� Column
� Table traverse
and vertical feed
hand wheel.
� Wheel guard
and protective
guard.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 14
� Working
� Work piece is clamped to the table by
operating magnetic chuck.
� Required grade of grinding tool is fixed to
spindle.
� Grinding operation is carried out be
operating both table traverse wheel and
vertical feed hand wheel.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 15
Cylindrical grinding machine
� It is a process of grinding curved surfaces.
� Surface may be straight or tapered.
� Work piece is mounted on two centers, one
is tailstock centre and the other is headstock
centre.
� Head stock center may or may not revolve.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 16
Working principle
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 17
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 18
Centre less grinding machine
� It is used to grind curved surface work piece
which are long and slender.
� Work piece rests on a work-rest blade and is
backed by a second wheel called as
regulating wheel.
� Grinding wheel pushes the work piece down
the work-rest blade against the regulating
wheel.
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 19
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 20
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 21
Cutting terminology
� Speed : it is the peripheral speed of the
work piece per unit time. (m/min)
� Feed : it is the distance travelled by the
tool during each revolution of the work
piece. (mm/revolution).
� Depth of cut : it is the perpendicular
distance measured from the original
surface to the machined surface of the
work piece. (mm)
�www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 22
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 23
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 24
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 25
www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 26