Variable speed brush
and drum sander

Not only the speed of the conveyor belt can be adjusted, but the speed of the upper roller can also be adjusted.
And it can be replaced with various rollers, which can not only grind wood, metal, etc.
Materials can also be used in semiconductor applications.

The head can be replaced with various brush heads

Different heads can be replaced according to different needs. 
There are many different heads that cannot be replaced. 
With different operating speeds, you can Achieve diverse applications.