Linear Scale

[CHANDRU]

Hei Friends,

Will Any Body Please Help Me How To Check Linear Scales Whether They Are Ok Or Not Externally.we Have To Retroffit A Grinding Machine.before Proceeding We Want To Make Sure That All The Linear Scales Are Ok And Other Things.


Thanks And Regards,
Chandru

[ironDigit]

if these are glass scales ,maybe holding them against a bright light is an option ?

[toastydeath]

I know this is a kind of dead thread, but the poor guy didn't get an answer.

You need an interferometer, and you set it up on the machine table in line with the axis you want to measure.. The table is moved incrementally, and see how much the scale differs from the what the interferometer says the table actually moved. The error is difficult to interpret. As a result, if it is outside your acceptable tolerance, more testing and investigation is necessary to determine exactly what is causing the discrepancy between the interferometer and the scale. It could be a bad scale, it could be thermal resonance, a problem with the optical experiment you just preformed, abbe error, misalignment of the scale, or many other things.

Your best bet is to get a company that does this professionally, as the equipment is expensive, and the test error prone.

[Al_The_Man]

If you want to check them electronically, identify the A & B channel connection and preferably check with an oscilloscope for the Two square wave quadrature signals, they also may have a complement signal for each channel.
If you inspect the glass scale or want to clean it, use lint free cloth with denatured alcohol.
One thing to be aware of if they are Heidenhain scales is that they may be low level sine wave signal that requires a special interface to square up the pulses to TTL level.
Al.