Page 484 - NORTON cutting-off and grinding wheels - industrial

484 TECHNICAL INFORMATION
TECHNICALINFORMATION
AVAILABILITY SUMMARY
ABRASIVE TYPE BOND ABRASIVE COLOUR
IPA VTX White
SGB-3SG-5SG-ES5-1TGP VX-VXP Blue
A–19A VS Brown
86A VS-VXP-VTECH Ruby
38A VS White
37C V-VP Black
39C V-VS Green
SELECTING THE RIGHT PRODUCT
There are nine main factors to be considered when
selecting a grinding wheel for any application:
• The material to be ground – its type & hardness
• The stock to be removed
• The workpiece geometry & surface finishes
required
• The grinding machine, the type of machine, the
power available & its conditions
• Wheel speeds & feeds
• Grinding contact area
• Grinding fluid – whether the operation is wet or dry
• The severity of the grinding operation
• The dressing method
MATERIAL TO BE GROUND
The type of material affects the selection of
abrasive, grit size and grade. Alumina type
abrasives are the most suitable for grinding high
tensile materials such as steel and ferritic cast
irons. The more friable types of alumina are
preferred on harder steels and applications having
large arcs of contact.
Low tensile strength materials and non-metallic
materials are most efficiently ground or cut with
silicon carbide abrasive.
The hardness of the material governs the amount of
penetration that can be achieved by the abrasive.
For this reason finer grit size wheels are required
to grind hard materials and soft materials are best
ground with medium to coarse grit size wheels.
For most efficient operation, the grade must be
adjusted to suit the hardness of the material. As a
general guide, the harder the material, the softer
the grade of wheel required.
STOCK TO BE REMOVED
This affects the choice of abrasive size and
bond type.
High stock removal rates, as in fettling operations,
require coarse grit wheels, typically 12 to 24 mesh.
Fine finishes and tight limits on finished workpiece
geometry require finer grit sizes.
Final surface finish is often achieved by ‘spark
out’. No further infeed is applied and the wheel is
allowed to grind until the majority of the grinding
sparks cease.