Printable x and y carriage replacements (Level 2 - Techie Consumer) (Page 6 of 11)

Apologies if this is a silly question, but: how much slack are the bearings supposed to have?  Is the slack intentional and it's supposed to be tensioned away, or not?

More specifically:  Even if I print the brackets at +20% flow rate, the bearings freely move ~1.5-2mm radially and 0.8mm axially (although everything else is very tight, except for the Y-rod setscrew holes, but I don't seem to need those, since the holes are super-tight).  Therefore I jammed the bearings into the brackets with a couple of layers of gaffer's tape.  However, I don't see tape in the Thingiverse makes and I noticed that inserting the X carriage top piece will tension the X bearings, which seemed to mostly eliminate play even without tape (but I still added tape, and I didn't try to operate the printer without it, this was just moving by hand before fully assembling).

Reason I ask is that I seem to have some occasional layer alignment issues along Y, and wondering if I installed improperly (or I should just keep trying to fiddle with belt tension and alignment -- but circles come out fine and X-Y dimensions are correct to within 0.1mm).

I also wrapped my bearings with several layers of tape before pushing them into the carriages.  Intuition told me that was the right thing to do. 

Ok, good to know -- that makes at least 3 that have the bearings *inserted* tight (you, another person in this thread that mentions tape, and Adrian who used larger diameter bearings).  I was wondering if play was intentional to allow some flex/rotation to avoid binding, because most photos I saw did not show any tape.  I don't want to hijack this thread with photos of issues I'm having which may be unrelated -- haven't ruled out belt tension, Y-pulley bracket, or stepper issues.  If I'm stumped after a few days, I'll post a separate thread.  Thanks!

Edit 12/15: After fiddling with belts almost an entire afternoon, fiddling with acceleration and jerk parameters, swapping out Y pulley brackets, upgrading PSU, swapping out stepper drivers to DRV8825, and adding cooling to almost everything, it seems that cause was hotend (E3D) not sitting quite tight in the mount (Mk5).  D-OH!!  Reason I didn't think to check earlier is that hotend felt snug by hand and, more importantly, layer shifts always occurred at the *same* spot in the print, so I thought jerks can't cause so regular/repeatable errors. 

The major lesson was that I was apparently wrong on that: an imperceptibly loose hotend can cause repeatable errors.  Oh, well, on the plus side, I guess that means everything else is really precise, and I also have an overkill-upgraded printer.

Is there any way to get the rods out of the ends without destroying the current end carriages? Right now I just need to replace the exrtuder carriage.I read they were glued in.

I seem to recall seeing STL files for stock carriages on Thingiverse a while back. If your printer is still working it may be worth a search on the Thingiverse site for Solidoodle carriage and see if you can locate them and print a set before you try removing the rods from the factory assembly.

I probably have the files bookmarked on my desktop computer but at the moment I'm 3000 miles away from it so I can't help with a link.

Also there's probably a few folks on here that have factory X carriage assemblies gathering dust in a box so in a worst case you could create a new post to see if anyone has one they would part with if you're unsuccessful in getting yours apart without breaking it.

Well I printed at .4 infill it seems solid enough at least to get up and running. Am I for rude awakening or can I get enough prints out to repair and replace?

I am using the LM8UU and they are loose I tried increase flow but still loose. I will do the tape trick but be good to have the file modified to add some ribs in the walls to hole the bearing then we can sand down as needed to make them snug

The Stock rods and the new bearings felt like sandpaper on wood@!!! OMG it was so rough and hung up in my hand would not even slide more then few incheses without grabbing.

I ordered 2 new linear shafts (NOT RODS) and they slid much smoother the whole length of the rod. They are still loud and are linear bearings not radial-linear like I have seen for more $$. So then slid front to back but rotating them they are stiff since they have only 4 rows of bearings vs others that have 8+

I was hoping the 2 shafts would be enough and reuse y or x but I am hesitant will not be a big improvement so ordered 2 more shafts with carriage apart and that way I retain original carriage.

I also have a spare nema 17 servo I am hoping this will bolt to the original and help eliminate issues and mount a fan too and I already have surestepr driver so I can crank up  the current too.

I will do the same for the Y as well (but that is easy swap.)

between the bearings and improved y rod bearings I will add I hope I can run at 50-100mms perimeters and not 30 and 100mm/s infil and not 55 for quick jobs

and for larger circles prints I get no missteps or or z bumps.

I have tried to locate the stl for the fan mount below your nema 17 stepper motor on the X drive.  No luck, have tried several others found on thingiverse, but they didn't fit properly.  Can you direct me to said STL please?  TIA.

Is it a nema 17 or 14? Anyway I want to print something similar also.. Im guessing thingiverse number 32994 or 32923.

I did a preliminary search on this thread, but I can't find any comments on this potential problem I noticed:

I printed out probably V_1 of these parts, a while back. Right now I am reassembling my printer after a big set of upgrades, and I am using these carriages.

But it looks like between the X-motor and the corresponding pulley, there is some Z_axis height difference. Is this...normal? Should I try to fix it? (I could put the X motor pulley upside down and then that would get me a few millimeters closer to even.)

Does anyone need pictures?

My X-axis motor has a pulley where the pulley collar and the pulley flange is in line with the X-rods, and on the other side the X_not-motor_pulley is roughly centered on the X-rods. So there's about 3-4 mm of movement (over approximately 250mm distance, so the effect is probably small. But I am upgrading to fishing line so I hope it will not get tangled by that mild height difference.)

Any help would be appreciated.

Thanks!
-TOmek

Thanks Ward!

When I flipped it upside down it made me feel better about the (no longer perceivable) height difference. I thought I would ask before I do something like that and your confirmation made me feel better about doing so.

Could you flip the z-screw mount upside down and gain enough?

Yep those offset ones are a pain.  Just have to learn Sketch-Up:)