Uhhhgg - Couple issues that were not here before

Ok, I have not had to print anything in a little while - I appreciate all the help on my last post with larger ABS prints. Calibrations, turning the fan off, and hot boxing it have helped. Though my temp hotbox solution has been moving the Taz into a small bathroom and closing the door. Now I don’t have to listen to it either. So its a start.

I just started printing a bunch of stuff again and am noticing that the starts and stops of my outer shell of prints are either over or under extruding maybe? This is happening on ABS and PLA.

See picture.

I am also noticing that when the bed moves to a certain point on the outer edge of Y movement it starts to vibrate or flutter - I can see the resulting vibes on the printed parts in that area too. Maybe there is something wrong with the belt or bearings in this area. But this is not happening in the area of my stops and starts where the picture is taken.

I think there maybe something up with my change in direction possibly having a little backlash. But I’ll need to run a test part to see.

Piercet - I am going to eventually do the rail conversions - Being a machinist - this is really frustrating that after spending $2k this thing still needs to be modified for the simplest of things, deflection, crappy bearings with slop in them etc. sigghhh.

The picture is hideing.

A couple of things to check though, The bearings on the Y rods and X rods can get gummed up with fuzz or plastic shards over time and will cause a bucking vibration. A belt too tight can also cause that harmonic. A too loose belt will usually just cause layer shifting.

You also want to check the bearing holders. they can shift over time. you generally want them set to contact either the innermost or outermost rod surface. Someone found a set of bearings with a tighter tolerance recently in one of the threads around here too, those might help as an interim step if you don’t want to go with the all up openbuilds modification.

edit: also, regarding the Y axis. Depending on which Taz version you own, check and see that you have the Taz 5 style bed to frame clamps. The Taz 3 style ones can move. It is also possible for the rod ends to move on the metal y endplates. If you have one that is out of true at one end, you will get bed skewing at the end of the print that shows up as vibration flutter sometimes too. Check rod center to rod center, and lower edge to lower edge on both sides of the rod mount end pieces at all 4 corners.

Sorry about there - lets try pictures again.

White is PLA - yellow is ABS.

Here is ine if the Vibration in Y.

The vibration in Y picture looks exactly like the "vibration due to bearing contact looseness or debris in the bearings or overtight belt issue. " What happens is the bed or the nozzle moves along and basically something causes it to change its motion plane slightly, and then it oscillates to recover. It can be the bed itself that is causing it, or it could be the X axis moving forward or backwards in the Y axis direction. A loose nozzle mount or loose X carriage bearings can cause that as well, but usually you will see oddness in the X axis as well.

The other picture is more difficult to see what is going on. Both X and Y are in play in the place it is having issues, as well as an overhang, and the whole thing is sitting on a support layer. It could just be the support layer was rough enough it created a persistant bobble, but you would expect that to work its way out after a few layers. It could be mechanical, it could also be the model itself has a flaw at that location. Can you post the STL file for that?

Either way, it does have the same harmonic pattern going around the curve. It’s interesting that the pattern is there on the outside curve, but less visible on any of the inside ones. Is it present on the other side of the part as well, or just that side? If it’s just on that one side, that may indicate which side of the printer a mechanical issue could be present at.

With the printer off, check the Y bed and the X carriage for movement up and down or side to side. If it can move at all, undo the screws holding the bearings and move the bearings out further until the movement stops.