Minor Kit Issues
Greetings, all! I'm new to the world of 3D printing and my Prusa i3 Mk3 kit arrived last week. I've been fortunate that my print quality has been mostly excellent so far.
Firstly, I noticed that my first calibration after setup indicated that everything was perpendicular. After moving the printer to another room (and a very flat table), I re-ran calibration and now it indicates that X/Y is slightly skewed. I know that the printer will correct for that, but I'd like to get it as close to perfect as possible. I've viewed the calibration info, but I don't know enough about these details to understand how to correct them:
Y distance from min:
Left = 9.95mm
Right = 10.42mm
Measured Skew: 0.13
[0;0] point offset:
x = -3.93 mm
y = -0.57 mm
Secondly, I've noticed that the Y-axis seems to have developed a loud rattling sound, but only whenever it moves in one direction. I've also noted that this noise does not happen when the build plate is moved quickly by hand. It almost sounds like bearing noise. I was very careful during the build to line up the bearings properly.
If anyone has any suggestions for correcting either of these issues, I'd really appreciate it!
Re: Minor Kit Issues
Bearings is what it sounds like to me too. Have you checked the U-bolt tightness and that the bearings are seated properly in the Y-carriage? Too tight can generate noise; too loose can also, but a different noise.
I'd also check the belt tension.
If you haven't yet, you might peruse the comments in the online assembly manual; there's a lot there from other kit builders who've encountered problems, and tips on correcting them.
It's also possible you may have one or more bad bearings (it happens). That may take some effort to figure out, but if that's the problem, customer service should send replacements.
That's "MISTER Old Fart" to you!
Re: Minor Kit Issues
Thanks for your response! I have not yet checked the U-bolt tightness. The manual was a bit vague about how tight they should be, but very adamant on not over-tightening them, so I definitely could have messed that up.
I'm fairly confident that the belt is at the correct tension, but as this is my first build, I didn't have anything to compare it to. Initially, I believe I had over-tensioned the belt because some of the teeth seemed to slip from the carriage mount. I've since loosened it a bit and it hasn't seemed to have adversely affected quality yet.
Someone on Reddit suggested that the bearings need an actual grease and not just oil, so I may clean the current lubricant out and then put some white lithium in there instead.
Re: Minor Kit Issues
Thanks for your response! I have not yet checked the U-bolt tightness. The manual was a bit vague about how tight they should be, but very adamant on not over-tightening them, so I definitely could have messed that up.
I'm fairly confident that the belt is at the correct tension, but as this is my first build, I didn't have anything to compare it to. Initially, I believe I had over-tensioned the belt because some of the teeth seemed to slip from the carriage mount. I've since loosened it a bit and it hasn't seemed to have adversely affected quality yet.
Someone on Reddit suggested that the bearings need an actual grease and not just oil, so I may clean the current lubricant out and then put some white lithium in there instead.
Oil is fine. Ive been using machine oil for 3 months and have printed 9kgs of filament so far no issues with bearings, i did however upgrade the stock bearings to misumi bearings during assembly(stock bearing are IMO of poor quality).
I look at it like this when it comes to bearing lubrication. In a sealed or long service interval situation grease is better, it will last longer and leak out slower. But in a situation where servicing times is a non issue and can be done frequently then i feel oil is the better option.
I put a light coat of oil on the smooth rods every spool change and move the axis by hand back and forth a few times for the bearings to absorb the oil, this has worked well for me so far.
Belt tension can be good but go bad pretty quick, ive had the grub screws on the pulley come loose a few times, keep your eyes on them, when they get loose they will cause ringing in your prints before they come fully loose, the ringing/small layer shifts is a warning sign to check the belt tension so watch out for it as its better to catch at the grub screw loose stage vs the grub screw falls out and pulley falls off stepper motor stage.