Page 496 - NORTON cutting-off and grinding wheels - industrial

496 TECHNICAL INFORMATION
TECHNICALINFORMATION
• Mount wheel between hand-tightened flanges
• Using a dial indicator, tap the wheel lightly with a rubber or wooden block to minimize runout to less than
25 microns
• Tighten flange securely & recheck with indicator
• Allow a newly mounted wheel to operate for one full minute before grinding
• The use of one permanent mounting for the life of the wheel is recommended whenever possible:
– If the grinding machine has a tapered spindle, mount each straight, flaring cup or dish wheel on a
separate collet or adapter
– When changing wheels the entire unit is removed, keeping the wheel in running truth
– When needed again, the entire unit can be placed directly on the spindle or arbor, thereby eliminating
the time & abrasive lost in retruing
TRUING œ MAKING WHEEL ROUND & CONCENTRIC WITH THE SPINDLE AXIS
• Prior to truing the wheel, run a wax crayon over the wheel face. Important: do not use any liquid based ink
on super abrasive wheels
• Any crayon left on the wheel face after truing will reveal untrued areas
• Norton Brake Controlled Truing Devices are most commonly used to true Diamond & CBN straight,
cup & cylinder wheels
– Always use Brake Controlled Truing Device dry
– Bring the Diamond/CBN wheel & the truing wheel together until they almost touch
– Start the Diamond/CBN wheel to normal speed; start the truing wheel in the same direction
– Bring the two wheels together until they touch
– Make sure the truing wheel is spinning at time of contact
– Traverse the wheel back & forth at 10-20mm/s
– Downfeed 0,01-0,02mm at the end of each traverse
– At the end of truing, the Diamond/CBN wheel should be smooth & in truth
DRESSING OPENING THE FACE OF A TRUED WHEEL
The core material (the part of the wheel that holds and supports the abrasive-bearing section) should
never contact the workpiece during grinding; rubbing will generate excessive heat. As the abrasive section
of a cup wheel wears, the core material may become exposed - necessitating dressing.
• Use a single-point carbide or steel tool to dress an exposed resaloy core
• Clamp the tool in a vice
• Direct the cutting edge accurately to leave a 1,5mm of abrasive section exposed
DRESSING THE ABRASIVE TO EXPOSE THE GRITS
Purpose: to expose the grinding stone face to give a better cut
After each truing operation, dressing is necessary to give a more precise cut to the wheel. This operation
consists of highlighting the grits by eliminating part of the bond and is generally carried out using vitrified
bonded abrasive sticks.
Selection of the stick specification depends mainly on the nature of the bond of the super abrasive grinding
stone and its grit size.
STICKS RECOMMENDED
BOND GRIT SIZE TRUING STICKS
Resin 126 & bigger 38A 150 HVBE
107 - grit - 64 38A 220 HVBE
54 & finer 38A 320 HVBE