Now I don't know what a Prusa should print like. Maybe this is as good as it can do, but I was hoping for more.

I've just assembled my printer yesterday and am seeing the exact same thing.

So far I've tried to:

- Take a bit of tension of the belts

- Print a e linearity tower, but for me the best results are with it set to 0

I've done several other tests. I've tried different types of feet, rigid, absorbing, and the factory ones. I've moved the printer to a marble base 45x45x6 cm. Weight 30 kg!

Long story short: the quality cannot be improved. The only way to improve the print is to lower the speed. It looks like that 15-20 mm/s for external perimeters is the best parameter you can use.

I think the real problem is the x-axis and x-carriage stability. The two rods are not so stable (eg. you can easily move the x-carriage 1-2 mms on the Y-axis). That's the reason why I'm getting ghosting especially in the movements that are simultaneously involving X and Y movements.

Example of a 45 deg perimeters. Up: 30 mm/s with different acceleration(200 to 1000mm/s2), Bottom 40 mm/s.

Example of only x movement perimeter

Best

R

I am in the process of re-printing my printer parts more accurately now that I have some experience under my belt, to see if it improves anything, but mainly so that I have a spare set in case something breaks, and am going to use grease in the bearings instead of oiling as it is more viscous than oil and may help reduce ringing.

Here is my result before modifications and after modifications of going from standard 1.8 Deg motors on X and Y to 0.9 Deg motors and modified firmware.

But beware, surface finish is a rabbit hole. The next thing that will show up is VFAs, which are reduced by changing the X/Y motors for 0.9 degree steppers, at that point ringing becomes the most prominent visual artifact. 

I've replaced the X bearings and the Y bearings with new fully lubricated bearings. I've done the full calibration.

I've reprinted the benchy. Same ghosting, same pattern, same result :( 

I'm running out of options and ideas.

So I'm not understanding if I should look for better greasing or better friction 🤔 

@chocki @bobstro: I've already tried to move the printer to the floor, to use felts, to feed the filament by hand from above the printer without the reel on top. Without success :(

@bobstro: I've did the extruder linearity and it looks like I'm not needing correction so far. Regarding the cube. It's 5cm x 5cm x5cm. I wanted to have a longer side to diagnose problems

@chocki: I'm going to try this: http://www.desiquintans.com/ringing.

Guys, thank you so much for your help!

This is an awesome community!

I'm trying to investigate why, if I set an "external perimeter speed" equal to 15 mm/s or less, ghosting is disappearing.

I'm going to focus on slicer settings as I don't see anything in your pics that looks unusual.

Slowing down perimeter speeds does several things:

• It reduces the effect of acceleration and jerk between turning a corner and moving the nozzle up to full speed. Acceleration and jerk are well-known contributors to ghosting. This is more of a happy side effect. Prusa has made significant changes to the Mk3 acceleration and jerk settings since original release.
• It reduces bed sway on direction changes. Compare faces on the X & Y walls to see if movement of the heavy bed impacts the severity of ghosting.
• It gives the filament more time to heat and extrude evenly. This is more of an issue with adhesion.

You can try the extruder linearity correction calibration procedure to see it if helps with the moire patterning. I found it beneficial. It's always hard to tell from pics if this is a problem or just a lighting issue.

Did you notice any change moving the printer onto the floor? A vibrating surface can contribute to issues. I wound up mounting my Mk3 on a concrete paver when I moved it to a cabinet.

Edit: How big is that XY cube? It looks large in the pics.

If you have carried out modifications, it cant hurt to try values around the PRUSA settings to see if your particular setup benefits from a slight tweak.

http://www.desiquintans.com/ringing

Iv'e actually considered bolting heavy weights to the side of my printer, but ultimately it depends on what you are trying to print, if perfect test pieces is your goal, then you will be chasing the never ending nirvana for a long time, there comes a time, when you have improved your prints to a level that is acceptable and cost is not exorbitant.

For me this was reverse Bowden feed, granite chopping board, solid feet with felt pads, skelestruder, better pulleys and probably the biggest improvement for me anyway, 0.9 deg OMC stepperonline X + Y motors.

I am going to try some misumi bearings and rods, and use semi fluid grease instead of oil for lubrication, not because I think it is better for wear, but because it is more viscous which should help dampen down ringing a bit, but this will only likely be visible after all the improvements I have already made, my main artifact now is the pulley teeth, and some ringing but that's it, no more improvements after this.

If you do go this far, put the slab on some sorbothane hemispheres to isolate any vibration from whatever you are using as your work table on which the printer stands, this wont help with the ringing, but will silence the vibration transferred into the table right down.

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/can-i-use-these-lubricants-of-my-mk2-or-3/#post-170794

But whatever you choose, like Tim stated, even car engine oil is better than nothing at all, the grease PRUSA supply is good, but you could definitely do with more to initially grease the bearings, this would then be followed up by occasionally lightly greasing the rods, no more than a thin film.

Also for info, after a few months, check your extruder cooler where the cooling fan is for gossamer filaments buildup which can eventually melt and drip onto your heater block as I found out. I'm going to get a can of compressed air or some sort of blower, and with a finger on the fan to stop it spinning, blow air back through the cooler to give it a clean out every so often.