I bought the printrbot simple tensioner kit thinking it would fix slanting in X. Argh! Nope now it slants the other way.
It’s very doubtful it’s slipping on the sandpaper drum. Maybe on the shaft?
There is one last thing I can try, disassemble everything to pull the X motor then reattach the zip tie.
Any other ideas why X slant?
I think this is a firmware issue because how could the slant be so uniformed from a slippage problem.
Is your tube under the sandpaper rubbing on the motor? Try a dab of superglue on the shaft before shoving the tube/sandpaper on. You could glue the sandpaper to the tube too. I have never seen this requirement, btw. I am suggesting to rule out slippage. Also is the string super tight? Does a slower print speed solve the problem? If it does, it’s slipping.
Sand paper drum is glued to the tubing. Nothing is rubbing. Will try 50% speed.
@Wayne_Friedt I didn’t believe it either but my Y axis was fixed with better friction. Apparently this super fishing line has a scale like texture. It catches better in one direction and slips better in the other. The slant would vary with speed - fast speed sever slant (45degrees)
sounds like your issue may be mechanical, but… and this may be weird… our printer at work seemed to get fixed when we split out the braided motor control wires and spread the wires apart. Seems like there was EM bleed somewhere in there that was causing a constant offset. Again, may not be your issue, but its something in case you are desperate like we were…
I’ve see this on other printers, with those printers it was the Z axis not being perfectly vertical which caused each layer to be slightly off from the last.
You need a way to determine where and if it is slipping. Draw a line across the line and the sandpaper with a marker before you start. Also draw a radial line on the end of the stepper shaft and tubing. After printing see if the lines still match up. For the line you might need to move the carriage back until the mark on the line is on the sandpaper.
I also have the simple and it gives me very similar problem.
When I use slic3r I have a customer code to home X and Y every layer and that gives good results but is not ideal. When I tried Cura I wrote a plugin where I can specify an interval on what layer it will home the printer which is better buy still not ideal.
It’s my quick fix cause I don’t have the time to analyze this in detail.
Slipping pulley on the x axis stepper? That was the cause when i had similar issue.
Time to get sketchup out and design a D shaft press on part to hold the drum. Maybe this would eliminate the question of slippage on the x and y. The drum could be glued to the printed part and press on.
Does it use that Spectra line?
Yes
Running at 30 for everything doesn’t fix it.
One thing that is troubling - the new sanding drums diameter forces the X steps/mm down toward 80s/mm. This results in horrid resonances. I suspect enough that the tension adjuster bolt is unwinding. The spectra line starts out tight and is very loose after 10 layers of a 80mm rectangle.
Going to disassemble and make some adjustments.
Meanwhile looking at nylon rack and pinion to replace X string and drum.
Is this typical of the Printbot simple or is yours just extra special.
@Wayne_Friedt I don’t know. Ask @Brook_Drumm .
It is possible that my Simple is special. It was upgraded from Beta. The laser cut parts for the upgrade show signs that the laser cutter slipped 2mm at some point. Some perimeter cuts didn’t line up. They looked like a squared G instead of a rectangle. The big left and right side pieces don’t agree on distance from bottom plate slots to bottom of legs - so it wobbles without a 2mm slim. I chalk that up to early production.
I was able to print a very good Make calibration piece. Only the arch failed.
I ran into problems when I tried to print things bigger than 50mm in X. The slippage has something to do with long moves. Replacing original tubing with black slingshot rubber gave it enough grip in Y but X still slipped.
The sanding drum can’t be slipping. I suspect the slippage is on the shaft. Leverage wise that makes sense. The inertia of the build platform is on a large radius and the motor force on a short radius.
Printer is torn apart right now and with the zip tie off the tubing is fairly easy to turn on the shaft. Maybe tubing with a D shaped hole would help?
