Solved X-axis drifting

Hey guys!
Ive been stalking this forum since january when I bought my used R1 unit. As expected Ive had to tinker and do some heavy maintenance. But there is one problem I cant get rid off, and its driving me crazy!
My x-axis is drifting to the right (towards x-stepper), most often the first few layers. Sometimes in the middle of a print. Some days its impossible to print anything at all! Other days it turns out OK. But its been getting worse, so tightened the belt, oiled the bearings, switched stepper drivers with the y-axis. The pulley is not loose.
I tried turning acceleration down to 100 just to try something, only made it worst actually.
Im almost out of ideas, Im hoping someone have had a similar experience and solved it =) Any suggestions?

Great forum btw, have already helped me tons

 

No idea on my part, I'm having that happen in both the X & Y directions, and it doubles back on itself throughout a print.

 

The drive cog is tightly scewed in place, there is no play there. If thats what you meant? If I force the carriage by hand while motors are enabled/locked, the steppers seem to skip, not the belt. I dont see or hear anything odd happen while printing.

 

Can you try printing a calibration cube? I'm curious to see how it does on taller objects and if it's printing at the correct height.

 

Thanks for the suggestions guys! =) I actually did adjust the driver pot late last night.
X and Y had been set to 0.380V = 950mA.
Extruder and Z had been set alot higher, 0.600V = 1500mA.
I turned X driver up to 0.480V = 1200mA.
Only had time for 1 test print, but that print turned out waaay better, pretty good actually =) But there is still a small drift the first 4 or 5 layers.
But since I have already tried to change place of X and Y drivers, I dont think the driver is the real problem. Could the stepper itself be the problem maybe? A bad coil or something like that? Will try to find how to meassure that, if its even possible =)
Btw, its not just isolated to a single axis, its isolated to a single direction, layers always move to the right, never to the left.

I can print a calibration cube when I get home from work. Any specific cube or size you want me to print? =)

 

just something you know the height of. 10mm is fine.

 

Test cube turned out OK =) Its about ~0.3mm too big in all directions though. Seems like turning the VREF pot up did alot of good! =D Can anyone tell me what the VREF is supposed to be set to? I only know the steppers can take 1.7A and the drivers depend on the cooling.
But last nights test print is still a bit off, on the first few layers. Iphone dont like taking pics up close but I tried, hope you see what I am refering to.
Oh, and I should probably add that I am using this command on all startup scripts:
M92 X69.56
For some reason my X-axis is way off scale otherwise. 69.56 is a value I meassured and calculated, dont really remember how but it seems to do the job ^^ Could this be related? Its been that way for as long as I have owned the printer, dont know the reason behind it.

 

I'd suggest tightening the set screw for the X axis pulley again.

 

OK, here's a weird similar problem that got me for a while on a 2D Xerox printer.
They use similar belts which are called Gilmer timing belts. They have steel cords in the rubber.
Believe it or not , the steel cords can snap in the rubber with no observable problem. This causes a "stretch' point in the belt that can drive you crazy. The way to find it is to hold the belt with both hands and try to pull it apart. The 'stretch' area then becomes obvious. Hope this helps. Frank

 

Hello again! The problem disapeared for a while after turning up the ref voltage on the driver. I printed some great looking stuff without ANY problem! =D
BUT then all of a sudden the problem is back no matter what I try I cant get it to go away.
What I have done so far:
- Tightened the belt (maybe even too thight now)
- Tightened the set screws
- Oiled the bearings using very thin oil for small ball bearings (almost no friction)
- Made sure the filament is not holding back the extruder
-Turned down acceleration, very smooth movement, no jerks or vibrations.
- Replaced stepper motor
- Replaced stepper driver
- Replaced arduino board
- Switched place of X & Y, and endstops. Problem still on the physical X-axis, so seems to be something "after" Ramps board.
- Stepper drivers has awesome cooling now, thanks to a Noctua fan and Mikes great printer feet (I modified them even higher)
- The endstop cables where parallel to a stepper cable, so rerouted that cable.
- Unplugged endstop cable after homing procedure. Layers still shifting.
- Tried printing from SD card. same results.
- Tried Frankn´s idea, but I couldnt find and stretch-point on the belt really.

I cant come up with any more troubleshooting steps now. Im out of ideas again...

EDIT: And oh, thanks for all the advice so far =D

 

You have done everything but replace the belt and bearings. The belt is easier. Frank

 

I was thinking about replacing the belt too, so late last evening I put a marking on the belt and pulley, as to verify that the belt is actually skipping, otherwise there would be no point in replacing it I thought =)
The belt DOES skip! And when I was inspecting my markings something caught my eye.. The teeth on the pulley didnt really line up with the teeth on the belt.. Hmm, thats odd I thought..Then I noticed the teeth on the pulley seemed to be further apart than on the belt.
And yeah, they were..
For some unknown reason, my printer has been fitted with a GT2 belt and a GT3 pulley. WHY would anyone do that?? That cant be by design, right? Must be a major screw up?

Cant believe Ive been able to get anything decent printed with that setup.. Ordered a new GT2 pulley but I wont get it until next week =(
But I think the problem has been identified, do you agree? =)

 

I bought a replacement very cheap and quick, now it seems to be working perfectly =D Gonna try something big but I think my problem is finally resolved.
Wrong belt pulley caused belt to skip and layers shifting.

Thank you all for your suggestions and support! =D And thanks mike for the great printer feet you designed ;D