So I know there have been some threads on this, but its been a while since ive seen someone really try to address the issue.
Back story. This is my third taz. The first was returned for nozzle issues, and heating block concerns.
The second had a bent lead screw causing largely the same issues.
This one has never given great prints, but I guess i kind of accepted that it wouldnt. Its just gotten to the point where its really affecting things.
So here is a picture
This printer has less than 50 hours on it, and its already doing this.
Im not printing fast, maybe 50mm/s, this is PLA in the picture, Which is obviously a pretty easy filament. Its well dialed in from a first layer, etc persepctive, thats not a concern. Dimensionally the parts are good as well, very accurate, its just they look like crap for lack of a better term.
Its time to get this thing working better or get rid of it to be quite honest.
Is there some things I can try? I know I dont want to remove the bearings, as thats not really an intended thing. If a lead screw it bent that would be yet again the millionth one of those
First: I have the same issue, and I know there are many others. Maybe not as heavy as you have, but simmilar.
Easy “workaround”: Print any color, but not white! My white parts look nearly as your parts, with other colors you can’t see the effect in such a intense way. Of course the problem is still there, but it’s not that visible.
Real fix:
.) Mount the bearings in a way they are designed to to remove the bearing play. Needs a press-fit metal bearing holder, I tried to print something but every design I tried was either too weak or not as precise as needed…
.) Get bearings that doesn’t need a press fit. I’m in the process of replacing the IGUS RJMP-01-10 bearings with IGUS RJUM-01-10. They are very hard to get here, at the moment I have 4 an the Z axis, 7 more are on the way. I will try to add a short video I made for comparison, it’s like night and day. But I can’t show a difference in print quality as long as the X and Y are stil bad…
.) Do the “overkill” way and install something like the Openbuild rail system. But thats the most expensive solution…
Edit: The video is in the attachment. First you can see the play on the original bearing, then the RJUM. I’m appliying the same force in both cases! Bearing.rar (6.19 MB)
so those will fit the same size slots, just replace the original bearings with these? or do i need to print parts as well?
how many total bearings do i need?
If thats all it takes, then why the heck wouldnt they include them from the start. lol
Yes, they are are direct drop-in replacement. There are 11 bearings on the TAZ: 4 for Z, 3 for X and 4 for Y axis.
You may wait a few days, I guess I should get the last bearings until end of next week. I can post some pictures from printed parts then. But I’m very sure that’s all (at last if you lead screws are not completely bent).
I think the reason is the price. They cost about 100% more than the RJM according to the igus website…
Edit because of a mistake: RJM is the original bearing, not RJMP. So the price is double compared to RJUM…
im seeing 10$ per bearing we are looking at $110. If it fixes my problem than thats easy ill do that.
I will wait until you get yours in though to make sure.
So are you going to print replacement parts for something too? seems like if these are the fix, then perhaps just replacing these will be enough?
I will not print replacement parts.
But I did a modification to the lead screw nut holder, you can see the yellow part in the video or see the latest post in this thread. It’s designed to allow some play in X and Y axis to prevent Z wobble. I think it works, but as long as all the other bearings have this hughe play the effect is not that visible. I guess if the Z bearings do their job and contact the Z rods with minimal play, they will also nearly eleminate any Z-wobble also without that device.
That seems to work great. It could be a fan speed issue since it’s PLA, but it sure looks like pretty major banding, and worse than you should see on a stock Taz 5. You might want to check for leadscrew misssallignment or even a bent screw. That isn’t normal at all.
I certainly do george but 2 things stopping me from going your route.
Build volume (i do need the few extra inches) and sunk costs. Sunk costs much less of a big deal.
I love the idea of the taz, i really do. I love the interchangeable tool heads, i love everything about the printer except its print quality.
If I can resolve that, im happy end of story. If i cant, then who knows.
Depending on how much time and effort and funds you want to throw at fixing the problem, The openbuilds extrusion modifications improve the print quality quite a bit.
Which one of those would be most likely to resolve the issue? or at least minimize it?
I like your z wobble idea, It basically is like removing the bearings, but not because you are allowing its tiny amount of movement to be dispersed from the lead screw, but not remove the bearings themselves.
The Anti Z wobble part and the new Drylin bearings would probably eliminat emost of the wobble for the least expense. The X and Y Openbuilds project would also resolve things and improve some other quality aspects, but the part cost is pretty high. The Openbuilds Z axis tends to help some, but if you do the X and Y mod first, it has less impact.
You may also want to consider printing the strengthened extruder mount and Discojohn’s Reinforced Hexagon Extruder body, which looks kind of goofy but fixes the Forward and back Y axis flex http://www.thingiverse.com/thing:1149597
In your particular machines case, either something is already very much out of allignment, or you have a bent leadscrew. To start, you might try loosening the right side Z motor and attempting a test print. If that doesn’t help, lock it back down and loosen the right Z nut. If that fixes the issue, the leadscrew may be out of parallel, or possibly bent. Also try loosening the Z bearing block and the X end plate. Try them all one at a time, on both sides. Whichever ends up improving the wobble is probably the source of the issue. If you find it is only on one side, check that leadscrew for straightness. Also check the measurements from leadscrew to leadscrew at the top and the bottom, they should be identical.
You may also try resetting the Z axis couplers. If one side is off significantly on angle, or if it is up too high or low and the couple spring section is up above the center of where the motor shaft and the leadscrew shaft meet, that can cause a similar issue. Check all of those things first, then attempt the modifications to improve.
