RE: MK4 vibration noises
Hello,
Yes, it disturbs/annoys me a lot.
My speed for the first layer is 40mm/s.
The default settings from Prusa for PETG or PLA.
And does it disturb/annoy you? If no, I may have a problem ahah!
You should try to increase first layer speed a little (I think I go with 30mm/s on my first layer), to see if it resolve the noises.
RE: MK4 vibration noises
I had the exact same issue and it took me several months to figure out what did cause it. Support just said regrease and it once disappeared but got much worse over time. I tested the y-belt tension using the prusa app and it said it's perfectly tensioned ... well .... here are the instructions to fix it:
Testing for issues on the Y-axis:
Disable the motors and remove the belt. Move the y-table around. If you hear some scratching while moving, make sure the bearing is greased enough and/or the bearing balls aren't damaged or even the rod (you will see some scratches on the rod then). If the rod has scratches, replace the bearing and the rod. => See 2./3./4./5.
Disable the motors, slightly press together the belt and move the y-table. If the sound almost vanishes while pressing the belt, you need to increase the tension. => See 6.
It slightly rattles when moving back and forth but not in between => See 5.
Loudness all the time: See 1.
Solutions:
1. You got an early bird y-motor that's damaged (check via Prusa support)
2. Regrease the y-rods (just slightly) => that's when the sound appeared after some weeks of usage
3. Check if the right bearing is greased correctly. And maybe the bearing needs to be replaced with a misumi (normally not needed but was in my case)
4. The bearing in the y-pully might need to be greased or replaced => happens after hundreds or thousands of hours, also unlikely
5. Screws have become very loose or you tightened the bearing screws too strong damaging the bearing
This one is the most likely and it almost made me mad figuring it out (was the main reason for me):
6. Tension the y-belt more, don't use the 90 hz recommendation using the prusa app (that's when the soundonly appears on slow movements and not on fast movements). On slow movements the stepper won't have enough grip and you will hear loud sounds, on fast movements the sound is almost unhearable. Tension the belt then just so that you bearly hear the sound, don't overtighten it !
As for the x-axis:
Have a look if your x-carriage has melt due to the heat of the extruder (happened to me as well) ... Temporary fix is to reprint the x-carriage using ABS. Also make sure you didn't tighten the x-carriage screws too much and mind the orientation of the bearings in the x-carriage vs. balls in the bearings
RE: MK4 vibration noises
Hi miroslav.h4, I have a question to your statement "Then order new 8mm x 330mm rods and new, really good quality LM8UU bearings from your local professional CNC machine parts supplier." - when ordering some good rods for the MISUMI LMU8 bearings, which tolerances for the rod I have to look for, because there are sevveral available (see e.g. https://lecktor.com/en/41-linear-rods). Thank you for your support.
RE: MK4 vibration noises
@first Posting!
what was the problem and how was it solved?
RE: MK4 vibration noises
Has anyone had any experience with PTFE linear bearings on 3d printers?
I developed a bad vibration on the X axis and found slop in the bearings. I put a set of PTFE linear bearings in their place and the X axis is now dead silent. They need no lubrication and I'm thinking that the lack of any serious load should have them running forever.
RE: MK4 vibration noises
Hi, what kind of bearings did you use? Do they have the same dimensions?
RE: MK4 vibration noises
This is the bearing that I used. https://bearingsdirect.com/khp08-metric-closed-thin-plain-linear-bearing-ptfe-lined-8x15x20mm-fg08/
It is 4mm shorter than the original, so I just placed them so that they are farthest apart in the housing. I used these because I happened to have 4 of them in my shop. McMaster-Carr has an exact replacement size, but I no longer have access to order from them.