Simply said: The slower the wheel rotates
the softer the wheel acts. The lower the
SFPM (Surface Feet Per Minute), the lower
the friction. And the reverse is also true.
The faster the wheel rotates the harder it
acts. The higher the surface feet per minute
the higher the friction. The higher the fric-tion
the higher the heat. Now couple this
with the kind of grinding wheels you use:
Aluminum oxide, silicon carbide, diamond,
CBN BORAZON® , etc., and the changes in
speed are necessary. Grit size, hardness,
porosity, and bond all add to make a differ-ence.
but the basics remain the same. Keep
records of the change in action in order to
The Variable Speed Control has a readout
in RPM and Hertz. Some of the controls
also read out in Amps and Watts. Track
your findings and results when precision
grinding your various materials. As the
wheels wear and get smaller in diameter
it will be necessary to adjust to a higher
speed. Transversely, when using a new full
size (Aluminum Oxide) conventional abra-sive
wheel it may be necessary to reduce
the base SFPM (Surface Feet Per Minute)
until the wheel acts too soft.
Then slowly increase RPM’s as required
to optimize the grinding ratio. Variable
Speed Control capability is also beneficial
when form grinding, slot grinding, face and
side wheel grinding. You will also benefit
when trying to achieve extreme flatness
and low surface finishes by having this
additional control over the grinding rate.
Now, more than ever before, with the
advent of harder, tougher materials, the
demand for greater flexibility in precision
grinding requires the grinding wheel to
grind over a tremendously greater variety
Another interesting factor also happens
when using different bonded CBN BORAZON® grinding wheels. Some require low
SFPM of 1,000 to 2,000 SFPM and yet even
others require much higher SFPM in the
area of 7,000 to 15,000. You can now
understand the reasons for this variable
NOTE: When using conventional abrasive
wheels check their balance more frequently.
In optimizing production, slight changes
will adversely effect SFPM and grind.
Even coolants need to be checked out for lubricity, PH, cleanliness, proper volume
and filtration. Coolant nozzles and their
placement is critical as well as breaking
the air flow around the wheel.
Get the answers to your
grinding questions. Call our
Certified Abrasive Engineers.
Harry G. Sachsel C.A.E.