I'm getting ghosting/vibrations/rippling along my X axis and I don't know what else to try
Hello all.
I recently bought and assembled the i3 MK3S+ kit. All self tests passed, calibration complete, and for the most part, I'm happy with the performance and the prints I'm getting. However, I'm noticing one issue that has proven to be very stubborn and persistent.
The issue that I'm noticing is pretty pronounced ghosting/rippling/vibrations along my X axis (i.e. on the sides of cubes/models that are perpendicular to the X-axis of the build plate). I first noticed this when printing Benchy models, and have started printing ghosting/ripple test cubes as I've taken steps to try to ameliorate the issue to see if I'm getting any improvement, but I've not yet really seen any noticeable improvement.
Here are the steps I've taken:
- Tightening most screws I could access that seem like they might impact X-axis rigidity
- Changing base upon which the printer is sitting, as well as orientation. Changes tried:
- Started with printer on desk that did not have great rigidity and wobbled a bit
- Built a stable and level shelf and put the printer directly on it with the stock anti-vibration feet
- Printed squash ball feet and mounted the printer on 4 two-yellow-dot squash balls
- Took all feet/vibration dampers off
- Put ~30 pound 18x18inch paver on the shelf and put the printer on top with the stock rubber feet on the printer
- Put foam cubes under the paver
- Put thick felt furniture pads under the paver
- With each of the above, I tried with multiple printer orientations on top of the surface
- Checked belt tensions:
- X: 250
- Y: 270
I am printing with default Prusament PLA settings via PrusaSlicer Version 2.3.1+x64 with the "0.15mm QUALITY @MK3" profile.
What else can I check here? I am not sure what stone I've left unturned and would greatly appreciate some guidance. Ghosting model pictures attached. Please note that these models were printed with the "X" face perpendicular to the X axis, and the "Y" face perpendicular to the Y axis.
RE: I'm getting ghosting/vibrations/rippling along my X axis and I don't know what else to try
Note that the smudge/discoloration in the top-left corner of the "X" picture above is sharpie, and is unrelated to the problem I'm facing here.
RE: I'm getting ghosting/vibrations/rippling along my X axis and I don't know what else to try
Print out the physical belt tension gauge (from the prints library) - it must be printed in Prusament PETG to be accurate. Then check your belt tensions and adjust to the middle of the sweet spot.
Second thing to check is that the screws that hold the back plate on the extruder are not over-tightened. They should be barely any tightness at all. Over tightening can make the X axis sluggish or "skippy".
RE: I'm getting ghosting/vibrations/rippling along my X axis and I don't know what else to try
Thanks very much for your reply @dan-rodgers.
Could you please clarify: to which specific extruder screws you are referring? I'm just not fully confident my ability to identify the exact screws that should be loosened because I'm very paranoid about making the problem worse or introducing even worse problems in my efforts to correct this one.
Secondary question, and not particularly important, more just for my own edification: Why does the belt tension gauge only print reliably with Prusament PETG (as opposed to Prusament PLA, which is the only Prusa filament I happen to have on-hand right now)?
X Carriage back plate screws and that's how it goes
The specific screws I was referring to are on the back of the extruder assembly when it is mounted on the X rails. The extruder is carried by a thing called an x carriage - which adapts the shape of the extruder assembly so it rides on the three bearings that live on the X rail. Think of the X carriage as a sandwich - one side is screwed tightly to the extruder, and the other side determines how much tension is put on the three X bearings. There are three (or is it four) screws that hold that back plate on - if you remove the plate, that is the first step in detaching the extruder from the printer. Do not remove the plate.
Instead, it is often that the screws that hold the back plate (and squeeze the bearings) was put on too tightly when the assembly of the X carriage was completed. These screws.
To the question on why does the gauge need to be a specific kind of plastic to work? PLA is too brittle and would not make a good tension gauge. It would bend. PETG is flexible and strong, but different brands, printed at different temperatures, have unique stiffnesses. That particular design - which is only available as a G code - will print the gauge at 250 degrees - which is the temp for laying down prusament PETG. The specific PETG has a known stiffness characteristic that the physical dimension of the gauge pattern is attuned to. Print it in any other PETG (I have tested this myself) and you get a gauge that reads differently than the true prusament gauge. Since getting belt tension is a "sweet spot" kind of range, having the gauge show correctly saves you a lot of frustration.