Phase 2 Rebuild

The “moose in heat” sounds my printer makes prompts me to whatever I can to restore the peace.
There are three steps involved that I am aware of:
1. Remove the rear base frame rail and add clearance for the Y stepper motor by notching the surface so there is no contact.
2. Remove the x and y SIMO carriages and mill a shallow slot to increase the clearance between the carriage and the feed screw.
3. verify/set the stepper driver voltage settings per the forum thread "Pololu driver voltage settings"
 
Y Stepper Motor Clearance
The Y stepper motor touches the rear rail. The easiest thing to do is to slide the rear rail off and then cut a shallow notch so it no longer touches.

Above: First mark the location of the stepper on the inside of the rail

Right: loosen, but do not remove, the deck screws that hold the rail in place as well as the two screws on the right angle brackets. The rail slides out
.


The marks were scribed into the magic marker at equal distances from the ends of the rail

I used a table saw with a carbide blade set to 1/16 inch depth to make multiple passes over the area. Then filed off any rough edges.

Left: I removed a cork strip that was on the back end of the Y stepper motor and then re-installed the rail. With everything lined back up and tight a piece of paper easily slips between the Motor and the Rail.

SIMO Carriage Modifications

One theory on the noise is that the feed screw is whipping as it spins around and rubs on the SIMO carriage.
The fix would be to mill a narrow slot down the middle of the inside of the carriage.

You will need a TORX driver to remove the screws at the end of the rail.

Expect them to be a little tight, there are traces of thread -locker on the screws.



Above: The end block is tight on the rail. I used a very large screwdriver and the SIMO carriage to remove the end block.
Right: once the end block is free it will rotate.



Above: Pull the end block free from the feed screw.
Right: continue, with a smaller screwdriver this time, to remove the SIMO carriage from the rail.


Left: while there is a "shiny" line down the middle of the SIMO carriage, there are no signs of rubbing on the coating on the feed screw (above). I don't know if the shine is from very very light contact (enough to make noise, but not show wear) or is from the manufacturing process?



Left: Carriage mounted on my Sherline Mill bed.
Above: Finished milling shallow slot

Left: Re-attached the AB Nut, but left the screws loose
Above. Carriage re-mounted on rail. Tighten the AB nuts now.

Above: Replace the end block. Alternate tightening the screws so that it sits squarely.

Right: Front rail of the base has been removed. I've already removed the screws from the Y-rail end block. Process is the same as for the X-rail.


With the end block removed the Y-carriage slides off the same way the X-Carriage did.

When re-installing the carriage I left the screws holding the AB nut loose until I had the carriage seated on the rail. Then I reached in thru the slots in the top deck to tighten them.

Re-attach the end block and replace the front base rail and you are done.


Pololu Driver Voltage Settings
I'm holding off on this step until I finish the mechanical changes. I want to see if the noise level has dropped any before I check & modify the stepper driver settings.






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