Scale Error

[[SH...]]

Each three axis of the CMM must have a measuring scale,my doubt is that how our CMM machine reading this measuring scale,I mean what technology are using?? Scale error of the CMM are related to these measuring scales.

Should I clean the measuring scale in a particular interval? and what solution should I use for it??

[[No...]]

I wouldn't recommend cleaning the glass scales yourself regularly, as they are quite susceptible to damage by scratches etc. The more frequently you clean them, the higher the probability for damage. A damaged scale can turn into a very expensive experience. We never clean our scales, we let the tech guy do it during the annual maintenance.
I'm no expert in how the scale is read, but usually it's a glass scale with engraved or etched scale-lines which are read by an optical sensor similar to a light barrier.