CENTRE-LESS GRINDING
It is used to grind cylindrical work-piece without actually fixing the work-piece using centres or a chuck, due to which the work rotation is not provided separately.
Its process consists of wheel, one large grinding wheel and another smaller regulating wheel. The work-piece is supported by the rest blade and held against the regulating wheel by the grinding force which is mounted at an angle to the plane of grinding wheel. The regulating wheel is generally a rubber or resinoid bonded wheel with wide face. The axial feed of the work-piece is controlled by the angle of tilt of the regulating wheel. Typical work speeds are about 10 to 50 m/mm.
There are three types of centre-less grinding operations possible. They are:
a) Through feed centre-less grinding.
b) In feed centre-less, the grinding is done by plunge feeding so that any form surface can be produced. This is useful if the work-piece has an obstruction which will not allow it to
be traversed past the grinding wheel. The obstruction could be a shoulder, head, round form, etc.
c) End feed centre-less grinding, where tapered work-piece can be machined.
Fig.5. Cutting action of abrasive grain
Conventional grinding machines can be broadly classified as:
(a) Surface grinding machine
(b) Cylindrical grinding machine
(c) Internal grinding machine
(d) Tool and cutter grinding machine
Advantages
A grinding wheel requires two types of specification
dimensional accuracy
good surface finish
good form and locational accuracy
applicable to both hardened and unhardened material
Applications
surface finishing
slitting and parting
descaling, deburring
stock removal (abrasive milling) finishing of flat as well as cylindrical surface
grinding of tools and cutters and re sharpening of the same.
Conventionally grinding is characterized as low material removal process capable of providing both high accuracy and high finish. However, advent of advanced grinding machines and grinding wheels has elevated the status of grinding to abrasive machining where high accuracy and surface finishas well as high material removal rate can be achieved even on an unhardened material
It is used to grind cylindrical work-piece without actually fixing the work-piece using centres or a chuck, due to which the work rotation is not provided separately.
Its process consists of wheel, one large grinding wheel and another smaller regulating wheel. The work-piece is supported by the rest blade and held against the regulating wheel by the grinding force which is mounted at an angle to the plane of grinding wheel. The regulating wheel is generally a rubber or resinoid bonded wheel with wide face. The axial feed of the work-piece is controlled by the angle of tilt of the regulating wheel. Typical work speeds are about 10 to 50 m/mm.
There are three types of centre-less grinding operations possible. They are:
a) Through feed centre-less grinding.
b) In feed centre-less, the grinding is done by plunge feeding so that any form surface can be produced. This is useful if the work-piece has an obstruction which will not allow it to
be traversed past the grinding wheel. The obstruction could be a shoulder, head, round form, etc.
c) End feed centre-less grinding, where tapered work-piece can be machined.
Fig.5. Cutting action of abrasive grain
Conventional grinding machines can be broadly classified as:
(a) Surface grinding machine
(b) Cylindrical grinding machine
(c) Internal grinding machine
(d) Tool and cutter grinding machine
Advantages
A grinding wheel requires two types of specification
dimensional accuracy
good surface finish
good form and locational accuracy
applicable to both hardened and unhardened material
Applications
surface finishing
slitting and parting
descaling, deburring
stock removal (abrasive milling) finishing of flat as well as cylindrical surface
grinding of tools and cutters and re sharpening of the same.
Conventionally grinding is characterized as low material removal process capable of providing both high accuracy and high finish. However, advent of advanced grinding machines and grinding wheels has elevated the status of grinding to abrasive machining where high accuracy and surface finishas well as high material removal rate can be achieved even on an unhardened material
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