Ramp wear and debris from load/unload lift-tab roughness

The technique of Suk et al. [1] is used to measure in-situ wear and debris generation versus suspension lift-tab roughness during ramp load/unload on a polyoxymethylene (POM) ramp. Image processing isolates depressed and raised portions on the ramp which are proportional to wear and debris, respectively. Both wear and debris grow logarithmically and are respectively proportional to average roughness (Ra) and peak roughness (Rp) as determined by Wyko measurements of the spherical lift-tab. As roughness tends toward zero, both are (not surprisingly) minimized. With a very smooth lift-tab wear is more accurately characterized as "deformation" and debris is almost absent. High roughness can increase initial coefficient of friction and require a substantial wearing-in period.