MK4S and Ghosting in structural profile  

MK4S and Ghosting in structural profile

Hi,

I'm having real trouble to get clean prints with my MK4S, as I get ghosting in every prints in structural profile, on both axis.
It's a printer that I built in kit, and I triple checked every step (I already built a MK3s and a MK4 so I'm used to building).

Here are all what I tried to reduce it:

• Belts: I checked belt alignments many time to be sure there are not rubbing anywhere (I changed Y motor mount to well centered belts on pulley)
• Tensionning: I tried all tension on each belts ("just right", too tight or too lose, with the Prusa app AND G2 belt tension print test)
• Input Shaper: I changed IS value with Prusa Accelerometer and according to a test print. Both gave me different values, but none solved the issue.
• Filament: I tried with PLA (Generic profile), PETG (generic profile), Prusament PETG (Prusament PETG profile AND generic PETG profile)
• Flow: I tried to change flow to be sure it was not too high
• Speed: I tried to reduce print speed, reduce acceleration and of course ghosting was less visible, but I didn't buy MK4S to print at 10mm/s print and 1000mm²/s acceleration...
• Temperature: I changed filament temperature to try to tune it
• Rods and Bearings: I tried to switch rods and bearings from standard ones to Misumi
• Nextruder: I tried different screw tensions (I calibrated each time)
• Nozzle: I tried to switch from HF nozzle to a regular one

All that steps didn't show any improvement.

I contact Prusa Support, they checked everything I already checked and after 1 hour they just told me that they can't find issue and they have to discuss internally with their team.

I don't have any news news since a week, and I'm considering returning the printer as I can't get quality print as I should.

Does anyone have another input/idea before I send printer back?

Thanks a lot, I will show some prints as soon as I can.