ABRASIVES
An abrasive is
a material, often a mineral that is used to shape or finish a work piece
through rubbing which leads to part of the work piece being worn away. While
finishing a material often means polishing it to gain a smooth, reflective
surface which can also involve roughening as in satin, matte or beaded
finishes. Abrasives are extremely commonplace and are used very extensively in
a wide variety of industrial, domestic, and technological applications. This
gives rise to a large variation in the physical and chemical composition of
abrasives as well as the shape of the abrasive. Common uses for abrasives
include grinding, polishing, buffing, honing, cutting, drilling, sharpening,
lapping, and sanding.
1.
Grit or grain:
It indicates the size of
the abrasive grains used in making a wheel.
·
Coarse wheels are used for
fast removal of materials and for soft and ductile materials.
·
Fine grain wheels are used
to grind hard and materials.
2.
Grade:
It refers
to the tenacity or hardness with which the bind held the cutting
points. It is denoted by the 'A' -softest and 'Z'-the
hardest hard wheels are recommended for soft materials and
soft wheels are recommended for the hard materials.
3.
Structure or grain spacing:
The
structure refers to the number of cutting edges per unit area of wheel face as
well as to the number and size of void spaces between grains & denoted by
numbers. Soft, tough and ductile materials and heavy cuts require an open
structure where as hard and brittle materials and finishing cuts require a
dense structure.
Comments
Post a Comment