 PVA products
are chemically bonded and unlike vitrified or resinoid products.
These are very soft and flexible. The structure of these wheels
is like a natural sponge and has three dimensional pores.
Grades
and sizes :
The product is available in 46 grit to 400 grit in green silicon
carbide but we can supply any grit upto 1200 grit in silicon carbide
or aluminium oxide. These are available as grinding wheels, mounted
points, honing stones and blocks in size upto 260 mm in diameter.
Bigger sizes can be manufactured on request.
Usage
:
These products are mainly used for polishing applications like polishing
of watch cases, audio and video heads, printing rolls, cylinders,
compressor parts, surgical equipment, vehicle rims, tools and auto
parts, dies & moulds etc. PVA products can polish any
material ferrous or non-ferrous, metal or non-metal. Some examples
are stainless steel, brass, steels, copper, aluminium, bronze, glass,
stones etc. Besides polishing, these products can be used for burr
removal, descaling, rust removing and for any such applications.One
can achieve finishes as high as 0.03 micron on steel components.
Basically a mirror finish can be easily obtained with these products.
Equipment
:
No special machines are required to use PVA wheels. The whels can be used with all
conventional machines like bench grinders, electric hand grinders, surface grinders,
cylindrical grinders, tool and cutting grinders, etc. The wheel is flexible and hence can
be easily dressed with conventional dressing tools or even by a used piece of a vitrified
grinding wheels. It can be dressed to any desired shape easily. These products are used
mainly for polishing and as such too much of material removal cannot be expected. For
burr- removal coarse abrasives can be used
Limitations :
Due to its flexible nature the maximum
operating speed is 25 mps
- Wheels are hydrophilic
in nature , hence absorbs moisture and stops cutting. No coolant
is required.
- Storage should be
in polythene bags and at dry place. In cas of efficiency going
down due to moisture absorption, the wheels can be dried in sun
for an hour or so or can be dried in oven at 45 deg. C for about
an hour for regaining its original properties.
- For fine finished,
some wax or a drop or two of oil can be applied to the cutting
surface.
How
to use :
The wheels should be
mounted on the conventional machine. The flanges should be 2/3 rd
the wheel diameter. In case of mounted points, conventional electric
grinder can be used. After mounting, the wheels should be dressed
to required shape and then some wax or wax based compound or oil
can be applied to wheels, if fine finish is required. For burr-
removal , descaling etc., nothing is to be applied. After polishing
the component with the wheel, the same can be buffed using a cloth
wheel if mirror finish is required.
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