Inspecting andor cleaning encoders

[lavrgs]

It seems my X axis has a problem. It loses its position. For example when running a g code sequence that moves it back and forth .500" the DRO says everything is okay but the indicator gets further and further off. There is a grumbling noise in the servo motor that won't go away with tuning and swapping the drive from the y axis the does not improve the condition. My first thought is encoder problem but I may be off on that "guess". I did take the rear cover off the motor ( Baldor CC22529 - no info on google) and am not sure I want to go any further until I know what "all that stuff" is. I'm not sure what the encoder is supposed to look like or where it is. From what I've read there may be a tach on the very back ... I have a picture of one similar but not exactly like mine - on mine there's an enclosure that has the coupler inside. It looks like there's an access hole to loosen the coupler screws but before I go any further I think I's better get some advice...

Thanks in advance,

Bill

[Al_The_Man]

I would check there is nothing loose (couplings etc) mechanically first.
Al.

[lavrgs]

Is the red/silver item in the picture the encoder? Is it "timed" to anything or is the position on the shaft not important?

[zpsbob]

Check and make sure everything is tight. If problem persists, swap X and Y motors (make sure same number of teeth on timing pulleys) If it follows motor, encoder is missing counts. If not, could be cable or maybe transducer card.

Bob

[Al_The_Man]

Is the red/silver item in the picture the encoder? Is it "timed" to anything or is the position on the shaft not important?

That is the encoder, the glass scale can be cleaned carefully with lint free tissue and de-natured alcohol.
The will be no motor timing, the only thing that can change by removing is the marker pulse position, you may show a slight difference in the home position.
Al.

[lavrgs]

Thanks for the help - when I get home "I'm goin' in" With any luck I can either clean or find something loose that will fix the problem. If not I will have to search out my next options.

Thanks again

[lavrgs]

Well that wasn't so difficult...I opened the encoder took a can of air and blew a little (very little) bit of dust off the encoder and viola!!! x axis is back running true. I set it up to run several cycles back and forth and it returned to zero about 150 times.
I guess if it was, in fact, dust on the encoder that caused the x axis to lose it zero point and wander I am surprised at how little it took to cause the erratic motion. The encoder still had the glyptol on the screws, meaning it had never been opened. The only pathe for debris would have to be through the opening for the wires which has a rubber grommet and is pretty tight. Bottom line is I'm glad it works but I don't feel 100% confident cleaning the glass scale was really the issue