Page 463 - NORTON cutting-off and grinding wheels - industrial

TECHNICALINFORMATION
463
TECHNICAL INFORMATION
NARROW BELTS & WIDE BELTS
The results achieved when sanding with belts depends on several factors including:
• The machine condition & available horsepower
• The belt speed
• The grinding pressure
• The contact wheel
• The choice of the belt in relation to the shape of the part & material type
• The use of coolant (when machine & belt allows)
BELT SPEED
The speed of the belt has a direct relationship with its cut rate, as well as the amount of heat generated,
the surface finish achieved, and the stress on abrasive grain. Some abrasives like zirconia alumina and
ceramic support much higher stresses because they have a better resistance to uncontrolled fracture.
Some materials are more sensitive to heat generation. The chart below gives the recommended speed
range according to material.
RECOMMENDED GRINDING BELT SPEED
Heat sensitive materials,
plastics, etc.
5-15m/s Stainless steel, high-speed steel
& tool steel
20-30m/s
Sintered metals & carbides 8-15m/s Grey cast iron & cast steel 30-40m/s
Titanium & similar alloys 8-15m/s Carbon steel 30-40m/s
Glass, porcelain & special steel 8-15m/s Brass, copper, zinc, bronze & tin 25-35m/s
Heat-resistant plastics 20-30m/s Aluminium & light metal 20-35m/s
Wood 15-30m/s Varnish 10-15m/s
GRINDING PRESSURE
The amount of grinding pressure depends on:
• The force used
• The size of the contact area between the belt & the workpiece
• The backing on which the belt runs (generally a contact wheel)
Higher pressure increases the cut rate and the amount of heat generated increases the stress on the
individual abrasive grain (a minimum stress is necessary to achieve a controlled fracture of the abrasive
grain), and generally generates a rougher finish.