Mk4 Kits (3.5, 3.9 and 4.0): What are you doing?  

RE: Mk4 Kits (3.5, 3.9 and 4.0): What are you doing?

Going by the feedback on this forum and other sites, so far I’m less than impressed with the MK4 but I guess it’s too soon  to make a final decision.

As I’m running my MK3S+ with a Bondtech LGX extruder and a Mosquito hotend and I intend to keep it this way, my only upgrade path is the MK3.5. As you said, to get this working we rely on Bondtech to release a firmware compatible with the new 32 bit board of the MK3.5. 

I asked Bondetch about this question and they answered promptly, As soon as Prusa releases the MK3.5 upgrade they will buy a kit and see what they can do in order to adapt the firmware to their extruders. If there’re no further delays, Prusa will start shipping MK3.5/3.9  kits by the end of July, so don’t hold your breath waiting for Bondtech to release an adapted firmware. That won’t happen anytime soon. Maybe by September/October, maybe never  ?

That said, I’m still on the fence regarding cost of the MK3.5 kit vs improvements. Yes, the 32 bit board and LCD screen are nice but input shaper/pressure advance are still unknown factors. If Prusa persists on the absurd policy of releasing firmwares with embedded “standard” IS profiles, instead of adding an accelerometer to the MK4 printers/kits to let the user do a proper custom calibration, then for sure I’ll pass on the MK3.5 upgrade.

RE: Mk4 Kits (3.5, 3.9 and 4.0): What are you doing?

Posted by: @artur5

If Prusa persists on the absurd policy of releasing firmwares with embedded “standard” IS profiles, instead of adding an accelerometer to the MK4 printers/kits to let the user do a proper custom calibration, then for sure I’ll pass on the MK3.5 upgrade.

I would ask if you have ever used an IS Profile and an accelerometer to do a custom calibration.  I have, and it is not a simple process that the average user can do.  I will tell you that there may be nothing stopping you from doing it yourself.  All you have to do is buy a Klipper-compatible accelerometer and download the Prusa firmware from GitHub once it is released to the public.  

A word of warning, it is not easy in the slightest.  I have done it now on three printers.  

RE:

 I have done it on my Voron 2.4. The difficult part for me was setting up the software in Klipper. Once I figured it out, the rest was quite easy. Connect the accelerometer board installed on the extruder to the RPI by a tiny ribbon cable and enter the command SHAPER_CALIBRATE on the  dashboard. Calibration was automatically performed and the correct values entered in the printer.cfg file as soon as you save the configuration. You also must write down the maximal acceleration speeds suggested by the calibration and don't use higher values in your slicer profiles, in order to avoid excessive smoothing.

On a Prusa printer the process should differ of course, because there's no Klipper console. I wonder how they will do it on the XL, which indeed has an accelerometer.

RE: Mk4 Kits (3.5, 3.9 and 4.0): What are you doing?

I have done it on four different printers now, and in general, I agree, but it is not something everyone can do.  

Prusa has not prevented you from doing it; several folks have done it on printers, but they have had to download the non-complied firmware and do it themselves with Klipper.  For example, some have modified the firmware on the Mini by removing the little tab and installing custom firmware.  I have not done it to a Mini, but my two Anycubics, a reality, and my BIQU now run Klipper, and I used an accelerometer to get it maximized.  

Posted by: @artur5

 I have done it on my Voron 2.4. The difficult part for me was setting up the software in Klipper. Once I figured it out, the rest was quite easy. Connect the accelerometer board installed on the extruder to the RPI by a tiny ribbon cable and enter the command SHAPER_CALIBRATE on the  dashboard. Calibration was automatically performed and the correct values entered in the printer.cfg file as soon as you save the configuration. You also must write down the maximal acceleration speeds suggested by the calibration and don't use higher values in your slicer profiles, in order to avoid excessive smoothing.

On a Prusa printer the process should differ of course, because there's no Klipper console. I wonder how they will do it on the XL, which indeed has an accelerometer.