Ok... working on print quality issues.

Ok… working on print quality issues. I have replaced my threaded rod with lead screws and nuts. At about 10mm, I start getting wavy crap and artifacts. I also did not see any stringing until the very top of the print.

Any thoughts?

What speed are you printing at and do you have a cooling fan.

The stringing looks like it gets worse as the print area gets smaller. This is probably caused by inadequate cooling. You could try either slowing the print speed to let the layers cool a bit more or point a large fan to blow across the print bed and see if it helps.

@Michael_Scholtz Speed is 30-35 mm/s perimeter - infill and I do have a fan.

Print speed is a funny thing. To fast and the inertia makes the print head over run in the corners to slow and the print get warm and distorts especially a problem with small prints. A cooling fan with Pla is almost a requirement for decent prints. Can you tell us more about the printer and the layer heights, temp, bed temp, print speed and anything you may feel relevant

@Brad_Dudenhoffer I just re-adjusted the X and Y belts. Some how the X was binding as it approached the home position, but only during a move command, not if I hit home X. Weird… really starting to look like a speed issue… your thoughts?

Do you have a shroud for your fan to help direct the air directly at the point below the extruder head ?

@David_Wille yes.

I have something for belt tension I replaced my spring tensioner with this Belt tensioner found on #Thingiverse Belt tensioner by Redsalamander - Thingiverse

Hmmm… I think your speed is just fine. Slow enough for the small parts. I always print slow just because, never over 40. And I tend to slow mine down to 25-30 just to keep things really tight on small prints

I would look at your belts if you were just there. You want them to be guitar string tight. Zero slack. Make sure too that they are as straight as possible. Do some manual moving to make sure they don’t drag or snag at all while moving, or that would cause the anomoly in the print, especially in smaller tighter movements Also, double check all your nuts and bolts relative to moving parts ie: All belts, around all steppers, and at rails. Anything loose will cause vibrations - your number one enemy, which sometimes aren’t a big problem for prints, but the smaller your piece, the bigger the effect of vibrations especially when shaping as small a part as this through corners, holes, curves.

Double check all that. Perhaps your problem is there. Check the z rails stepper as well, especially if the printer uses a threaded one. If the joining piece to the stepper is loose at all, it will cause this type of problem.

I don’t think it’s a leveling issue, or the anomoly would be consistent throughout your print.

Hope this helps !!

All bolds are added points/edits

@Michael_Scholtz I have already put tensioners on the X and Y axis.

Ps. Read last the fact that you just installed new threaded rod. Make sure you’ve oiled her up nicely. Might just be some slight friction in the new thread! or dust, dirt, left over metal scrap even

@David_Wille Thank you for the detailed comments. After my current print finishes, I will check all of the screws.

@David_Wille Will do.

@Nathan_Walkner Do you mean the Z axis lead screws?

Yes I believe he is referring to them Keith. He’s right about the Z threaded rod, if there isn’t some form of support for the top of the rod ie: only connected to the stepper at bottom but bare on top. It can, and in many cases it will tend to “wobble” as the print head arm raises along the axis.

Search a “printrbot simple” as an example in Google to see a printer with this design. You’ll see the Z rod has no support on top. A common mod many people perform on printers with said design is to print a support strut to place there. Essentially making a bridge for the rails to support the top of the Z Rod with the new strut.

There are printers out there that do no suffer from this Z rod “wobble”, though it is a common issue in many 3d printers. Some Z rods in printer kits have even been reported as skew or even warped, causing the same problem.

This might be your issue. Though its not as common a problem as I mentioned. It is however something that can occur with a 3d printer. Most newer Designs of printers include a strut for this point of the Z axis now, or are built in a way that the threaded rod is the length of the entire design, making it connected to something, top and bottom for the extra support.

It is supported at the top. Not connected but through a hole in the upper frame. I also periodically measure both sides of the Z axis to confirm both are the same height.

@Nathan_Walkner Another great tip! I will check it. EDIT: I ran my Z axis up to 170mm ( almost max ) then back down 100mm and the right side was 1mm too high… any thoughts on that one?

For bent rods I also have a solution to help.
its a mini pipe bender I made for initially straightening arrows but once i realised I used it to straighten threaded rods that I removed because they where bent. http://www.thingiverse.com/thing:984957 They may now be straighter than the ones fitted. But I do have to say your problem does not look like bend Z rods. It would be a consistent banding running down your print that resembles the pitch of the rod, Print a tall 10mm round tube. if it looks like a threaded rod it may be a bent rod. if this is related to the Z axis I suspect it may be the build platform not moving down smoothly or sticky bearings ( but it does depend on your printer design ) here’s pictures of what that looks like https://plus.google.com/+MichaelScholtz1/posts/7ae3CwbG65Q