[ATM] HCF ripple

[Gilbert Gagne <gil5941@earthlink.net>]

Vladimir wrote:

<The trouble with HCF is the ripple.

<HCF lap has 5mm hexagons and they should be averaged out very efficiently
<but this is according to literature not the case.
<How come?
<I could not find any plausible explanation.

The reason the ripple develops is obviously related to the periodic structure
of the HCF lap. Ever drive on a "washboard" gravel road or notice the "thump-
thump" associated with expansion gaps on old concrete roadways? Smooth surfaces
are by nature unstable and once irregularities develop, motion tends to amplify 
them. The forces generated by polishing motions are being modulated by the periodic 
structure of the HCF lap setting up vibrations that result in the observed ripple.
Once this ripple develops it is very difficult to eliminate even if polishing 
resumes on a pitch lap as the ripple will now generate similar vibrations.

Gil Gagne
Port Orange, FL

_______________________________________________
ATM mailing list http://www.atmlist.net/