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ACCURACY CHECKS
COMPUTERIZED CROWNER RETROFIT SYSTEM
In
order to obtain a measurement of profile accuracy, an auxiliary LVDT was mounted
independent of the feedback LVDT on the back of the wheelhead (see sketches and
photo below), and the wheelhead pivoting motion recorded on an x-y plotter as
the carriage traversed the roll face. The tests were done on two different
Farrel grinders. The first plot (below left) shows the results for a .010"
concave setting and a 70 degree cosine target shape on an 80" face roll.
Due to the wheelhead pivot ratio, the maximum movement a
t the LVDT position at
the back of the wheelhead was about .027". This is the best way to
demonstrate system
accuracy, since the contribution of any bed distortion or
other wheel related
effects are not included.
The resultant plot is a true magnified trace of the actual wheel motion as
controlled by the crowner system. The second check (below right) was done
on another grinder using a similar setup, but with a different crown setting and
on a longer roll face with two different traverse speeds.