**** UPDATE: To make a long thread short, even though the values had been working for some time, it turns out the Y Axis voltage really does need to fall between .5 and .6 The values of .25 to .3 had been working in this printer and has been working in others. Its still a mystery as to why now it became an issue. The positive of this adventure is I have new and better bearings in place and my XY assembly has never been better calibrated. Thanks again for all the support. **** So I have successfully printed several things now, and now I am trying to print the 1.1 parts. To make a long story short the last couple time I have tried that holds the hotends the Y axis has started to drift about the same point in the print. To answer the question yes, I have check all of the screws and belts its all tight, I used blue loctite with all the grub screws too when I assembled it. The drift was in x too on one of the prints. What I am wondering is if this could be the steppers over heating or something else. It could be coincidence but it seems like the drift happened at almost the same layer the last two times I tried the print. One more thing to note, I am starting to hear what I can only describe as a creaking or grinding from the left side of the printer as the Y approach the front of the machine, the sound is there if I move the Y axis by hand as well, I tried loosening the Y axis mount thinking it was binding or stressing the acrylic but that doesn't seem to be the case, could this be the sign of a bad bearing? I am using white lithium grease on the rods. The creaking sound has only developed in the last week or two I believe, when I assembled the Bigbox everything ran smoothly and silently. Could it be possible that the bearing is catching after warming up or something 1/4 of the way through the print?
Make a gauge to measure between the two Y rods to see if they are parallel. Pack the bearing with grease, they are meant to have wipers and be sealed, but I have found that if you put grease on the rods and then move the bearing over it, it gets sucked up inside............which can only be a good thing. Clean off the surplus as it attracts dust which then gets in the bearings too. Post on bearings ... http://forum.e3d-online.com/index.php?threads/lm8luu-bearing-problem.1108/page-2#post-11908
I will check the Y axis rod distance when I get home good point. I regreased the whole big box this weekend when I started to notice the sounds,
I posted somewhere (search on bamboo ! ) about how I made adjustable gauges from cheap materials so that you don't need any precision measuring kit, you are just comparing one distance between the rods with another. A quick check is also to use the front panel menu to release the motors and then you can move the X-Carriage in the X and Y directions with the only resistance being the belts. This will not only allow you to highlight where the movement is worst but allow you to evaluate how effective any remedial work is.
I bought a Gage a while back that should do the trick I think with a littler tinkering. Even with the steppers off there is still a fair bit of extra resistance, however I don't really feel anything odd when I move it back and forth by hand it just makes a strange sound that wasn't there before as I move it to the front.
Check if one of the X axis anchors (either the idler or the stepper side) is chafing the lexan/plexi wall. They run VERY close to the walls and if the Y axis anchors are slightly off, can end up scraping against it.
There wasn't any rubbing against the acrylic, I have some misumi bearings that I was waiting to put in place until I had the parts ready for bb1.1 instead of waiting I tore out the old bearings and put in the new ones. The motion is back to being relatively silent again and very smooth. I don't know if this will have any bearing on my original problem of layer shifting or not but at least I can rule out the bearings now.
@Greg Holloway I have checked the grub screws, greased the rods, changed the bearing for X and Y, checked the grub screws again. Belts are tight checked the voltages. After all that, I am still shifting in Y, new print on the left one of the old failers on the right. My last idea is the driver, I swapped the Y and E2 drivers and adjusted voltages appropriately. If this doesn't do it I have no idea what do try next... Any help would be greatly appreciated thanks.
Sorry half the time I try to embed a photo off a Google Drive it doesn't seem to work :/ Anyway the image with 2 prints is the one I ment to upload last night. The single print is the print after switching the drivers last night.
Just to double check as I made the same mistake. Did you get all 4 points for grub screws on the y? I originally missed the ones where the motor connects to the metal bar at the back, once thread lock was applied there it fixed my wavy prints and drift backwards.
I 100% recommsioned X and Y. Didn't find any loose set screws, reapplied loctite to all the grub screws and marked pullies incase the slip. Now on to my 5 try for the 1.1 lower X carriage...
It looks like with all your prints in the beginning the Y-axis is moving well, but after a while the problems begin. Could this possibly be a (driver) overheating problem ? The fact that you had it on the X-axis as well puzzles me a bit. I've had Y-axis problems as well, but I solved them by replacing the driver with a Seeed driver I had from an earlier project.
The X axis only happend once I think it may have gotten caught on the print after the Y axis made a mess not sure. I swapped the driver from the second Extruder to the Y axis and still had the issue. I agree that its odd it seems to have issues only after printing a while, it could be over heating maybe. The last time I stopped it it was a minute or two later I felt the drive and it felt ok, not sure how fast they cool though. Have have some tiny heat sinks that just came in, I should throw those on. Edit: I just felt the driver it indeed is hot
It was probably foolish but I poped the heatsinks on while it was running, the drivers were definitly quite hot expcailly Y and Z.
I've looked at my drivers with an infrared camera after they've been printing for a while (with the cover on and fan turning). They're always "quite hot" like 70-75C.
