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loriny
06-09-2009, 09:36 PM
Sometimes - usually when doing a long tram in x axis the carriage will bind on my prt 4g. Any ideas what to look for? Would it be a missed step in one motor or a mechanical issue?
Lorin
ken_rychlik
06-09-2009, 11:42 PM
Pull the spring and motor assemblies loose on the x axis. With the motors loose swing them down out of the rack. Roll the carriage by itself with no motors attached and you will know which direction to go from there.

Kenneth
cnc_works
06-10-2009, 12:39 AM
I had the same symptoms or close to it. Long transitions on the X axis at rapids and it would bind. Turned out to be worn racks...sad story because with shipping it is an expensive fix. I slowed my rapids down to less than 200ipm and it stopped the binding 'til I can replace the racks.

Good luck!

Donn
loriny
06-10-2009, 02:01 PM
Ordered pinions. Some wear on them. It rolls freely with motors out of way. Greased it well for now and wii update if I find anything.
Lorin
cnc_works
06-10-2009, 05:33 PM
Mine rolled perfectly by hand as well. It was only at rapid speeds that it would bind. Get a magnifying glass and a mirror to check your racks, especially in the area it tends to bind. If that is the problem it will show wear on the teeth similar to the worn pinions. (Mine did it mostly in the middle four feet where there was the most wear).

Donn
robredick
06-14-2009, 03:20 AM
Try the cables to your motors. I had a bad connection once and it really racked my brain. I noticed that the far motor was a bit cooler that the others so I reconnected the wires to connectors. VavavaVoom, no more problems.
loriny
07-14-2009, 02:22 PM
It seems good now. New pinions, cleaned and greased racks tight connections and almost perfectly square carriage. Now I can vacuum the table top at 10+IPS and not lose a step. Now I just have to figure out why it seems to come slightly off square when I power up. This is even after loosening the bolts on the carriage to get it right square blocking one side and tramming the other. I think I will try get my stops set right square and stop to them daily. Does anyone have any other ideas? Would it work better to build stops right on my rails and stop the carriage it self?(easier adjusting possibly)
Thanks for all the advice

EDIT I found some more info in the assembly section posted by Jerry Hicks and will try his ideas. It appears this is normal.

Lorin