Page 487 - NORTON cutting-off and grinding wheels - industrial

TECHNICALINFORMATION
487
TECHNICAL INFORMATION
SINGLE & MULTI˜POINT DIAMONDS
Diamonds are the first choice where close tolerances, fine finishes, speed and flexibility are required. Since
diamond dressing is primarily a machining operation rather than a crushing operation, the surface formed
on the wheel is closer than that obtained from mechanical dressers. This results in a slower cutting wheel
with better form holding characteristics and superior finish control.
By varying the depth of cut per pass made by the diamond and changing the traverse rate, different wheel
surfaces, and hence different cutting actions, can be achieved.
The following are general recommendations for dressing with single-point diamonds.
DIAMOND SIZE
The size of diamond is important when selecting a dressing tool and several factors are relevant in this
selection, e.g. large, coarse grit wheels require a larger diamond than smaller, fine grit wheels. If a fine
finish is required, the use of a diamond which is too large can adversely affect the finish and cancel the
effect of fine grit selection. The trend today is away from single-point dressers and towards multi-point
dressers employing a matrix shape to suit the form required.
A useful formula for determining single-point & multi-point diamond size is:
Wheel diameter (mm) x Wheel thickness (mm)
ROUGHING FINISHING
Diamond infeed mm per pass 0,025mm 0,012-0,020mm
Diamond traverse rate mm/wheel rev. 0,18mm 0,10mm
The diamond should always be applied at the centreline of the wheel with a 5°-15° drag angle.
SINGLE˜POINT MULTIPLY THE DIAMETER OF THE WHEEL BY ITS THICKNESS
Diameter
Thickness
Diameter x Thickness
(mm) Carat
<6000 0,33 Carat
6000-18000 0,50 Carat
>18000 1,0 Carat
For best results, always use a coolant when dressing
MULTI˜POINT MULTIPLY THE DIAMETER OF THE WHEEL BY ITS THICKNESS
Diameter
Thickness
Diameter x Thickness
(mm) Carat
<30000 1,3 Carat
30000-60000 2,5 Carat
>60000 5,0 Carat
For best results, always use a coolant when dressing
COOLANT
Dressing with diamonds should always be carried out using a copious supply of coolant. The coolant should
always be turned on fully before the diamond touches the wheel. The diamond life will deteriorate rapidly if
it is allowed to become hot and then cooled rapidly as can be experienced with an intermittent coolant flow.
ROTATION OF THE DRESSING TOOL
To ensure maximum diamond life, single-point and conical cluster diamond dressing tools should
be systematically rotated after every four or five dressings to ensure that the keen edge generated from
the drag angle is constantly presented to the wheel.