• Improved phase stepping calibration
• Fixed homing issues with no tool picked
• Fixed toolchanger service moves being affected by user feedrate override
• Relaxed nozzle cleaning checks to prevent false nozzle cleaning failed errors
• Relaxed print fan selftest thresholds to reduce false failures
• Known issue - Power panic resulting in a BSOD

This is the stable release of firmware 6.4.1 for the Prusa XL bringing targeted stability improvements and fixes - most notably addressing several homing and toolchanging reliability issues.

Improved phase stepping calibration

The switch to the new universal phase stepping calibration in the 6.4 release caused a regression in the calibration quality for some XL users. In 6.4.1, the calibration method has been refined and further improved by backporting phase stepping fixes from the 6.5 releases. These changes enhance overall calibration reliability and address regressions introduced in earlier 6.4 builds.

Fixed homing issues with no tool picked

Homing without a tool picked could cause audible motor skipping or put the printer into an invalid state under certain conditions. The fix ensures that the axes are properly homed before attempting a tool pick, preventing both issues.

Fixed toolchanger service moves being affected by user feedrate

Tool parking, picking, and alignment moves could be slowed down if a low feedrate was set in G-code beforehand. This could lead to unreliable tool changes. All toolchanger service moves now run at their intended speeds regardless of the user feedrate setting.

Relaxed print fan selftest thresholds to reduce false failures

The print fan selftest could incorrectly report a failure on some units due to tight RPM thresholds that did not account for normal fan-to-fan variation across different fan shroud revisions. The thresholds have been relaxed to reduce false failures.

Release notes: 

https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.4.1

• Improved phase stepping calibration
• Fixed homing issues with no tool picked
• Fixed toolchanger service moves being affected by user feedrate override
• Relaxed nozzle cleaning checks to prevent false nozzle cleaning failed errors
• Relaxed print fan selftest thresholds to reduce false failures
• Known issue - Power panic resulting in a BSOD

This is the stable release of firmware 6.4.1 for the Prusa XL bringing targeted stability improvements and fixes - most notably addressing several homing and toolchanging reliability issues.

Improved phase stepping calibration

The switch to the new universal phase stepping calibration in the 6.4 release caused a regression in the calibration quality for some XL users. In 6.4.1, the calibration method has been refined and further improved by backporting phase stepping fixes from the 6.5 releases. These changes enhance overall calibration reliability and address regressions introduced in earlier 6.4 builds.

Fixed homing issues with no tool picked

Homing without a tool picked could cause audible motor skipping or put the printer into an invalid state under certain conditions. The fix ensures that the axes are properly homed before attempting a tool pick, preventing both issues.

Fixed toolchanger service moves being affected by user feedrate

Tool parking, picking, and alignment moves could be slowed down if a low feedrate was set in G-code beforehand. This could lead to unreliable tool changes. All toolchanger service moves now run at their intended speeds regardless of the user feedrate setting.

Relaxed print fan selftest thresholds to reduce false failures

The print fan selftest could incorrectly report a failure on some units due to tight RPM thresholds that did not account for normal fan-to-fan variation across different fan shroud revisions. The thresholds have been relaxed to reduce false failures.

Release notes: 

https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.4.1

It looks like I am getting some artifacts at directional changes.. i.e close to the edges of my print, around holes etc.

I'm using print settings from Polymaker:

Nozzle temp: 215 (first layer), 210 all others

Bed Temp: 60

Max volumetric speed: 15 mm3/s

Retraction length: 1 mm

Retraction speed: 30 mm/s

Any idea what is happening here?

Thanks in advance!

Since it took me some time to figure out how to get around the quirks of ASA by both adjusting my print settings and other tweaks, I'd like to share my experience so far.

First of all, a word about safety. Don't put your printer in your bedroom. I put it in the basement near a window and I recommend having it open while printing. Styrene poisoning could be dangerous, so it's better to be safe than sorry.

The Department of Health and Human Services (DHHS), National Toxicology Program (NTP) listed styrene as "reasonably anticipated to be a human carcinogen" in the Report on Carcinogens, Twelfth Edition, released on June 10, 2011.

— cdc.gov

I was amazed at how well ASA can handle bridges. I could easily bridge 4cm gaps which combined with the higher strength means that I can print many things with 0% infill while still being quite strong. Also ASA can be sanded and polished really well to a point where you can't see the difference compared to an injection molded part. I still need to try out acetone vapor smoothing and will update this post when I get to it. But I would recommend doing it outside such that your filament spools don't glue themselves together.

ASA really, really likes to warp under certain conditions. Not always! You can optimize 3D models for ASA printing. Features that like to warp the most are curved overhangs. The ones you find on the first 10 layers of Gridfinity bins for example. Round corners that expand outwards. Warping is made even worse as soon as the print fan starts spinning. I recommend turning the print fan off entirely. ASA is printed at 255-265°C in an enclosure at ~45°C, it cools down quick enough by itself. To do this, modify the filament settings in your slicer to disable the fan for the first 1000 layers. Another trick I learned is that you can increase the time per layer to let the layer harden to reduce warping by printing more of the same thing at once. That way, the new layer can't pull on the layers underneath as much.

I'm using the Prusa silk (sand blasted) steel sheet and warping can cause a print to deform and come off this print bed. I first tried using a brim of 5mm, which does improve it, but it only really helps to hold it down. A brim did not prevent warping entirely. What did massively improve bed adhesion was applying a decent layer of a regular white glue stick (mine is solvent free and the cheapest paper glue you can find in a store). When I tried to remove a small 1x1 Gridfinity bin, I almost lifted the steel sheet with it. I applied the glue stick as two thin layers. After printing, wipe off the glue with IPA. You can probably also use warm water if you dry it afterwards to prevent it from rusting.

Depending on what color of filament you use and specifically what pigments the manufacturer uses, you might need to lower the printing temperature. The default in Prusa Slicer is 265°C, but I noticed that my white filament ordered from orbi-tech started to form bubbles and turn brown. Lowering the temperature to 260°C resulted in no discoloration and the prints came out just as good.

ASA is relatively hygroscopic. After it was raining for one day while I was printing, I noticed many bubbles forming in my 3D prints after a few days. The filament had absorbed the ambient moisture. After drying it in a dehydrator at 50°C for 2h, it was dry enough to print at a good quality.

What are you experiences with this material? Are there other plastics I should look into printing with? I'm only around 2 weeks in to this hobby and would like to learn more.

¹ I compared 5 local German producers (not resellers) of PLA and ASA filaments and ASA is around 27k€/m³ compared to PLA at 21k€/m³. I'm using k€/m³ for a proper comparison independent of material density.

yesterday I did a first print on my new Core One+ (factory assembled). The print turned out nicely. However I noticed that after the print finished the bed stayed at about half height. The panel indicated that the print finished (100%) the LED strip did light up green. It seems that the only way to get the bed back to the bottom is to navigate to the menu and adjust the Z-axis height manually with the rotary knob. This seems a bit odd to me. I'd expect the printer to move the bed all the way down by itself after finishing a print. Is this normal on a Core One+, is there any setting that makes the printer move the bed back down automatically once a print finishes?

I‘m trying to print a few small ABS parts, and I keep having first-layer adhesion problems. I tried both satin and textured sheets, thoroughly cleaned with isopropyl alcohol 99%, even tried applying a layer of glue stick (which admittedly was very old), but the first layer adhesion is very poor so it starts coming off as soon as the nozzle ends one line and quickly moves to a new position.

I‘m puzzled because (1) the satin sheet is said to be very suitable for ABS as far as I found out, and (2) the glue stick method is said to work if nothing else does. However, the applied glue dried to a absolutely non-sticking dry layer on the 100C heat bed (well, maybe it was too old), and it did not improve adhesion even a bit.

So my questions are:

(1) is the satin sheet suitable for ABS (as noted even by Prusa) or not? Am I doing something wrong? Is 99% IPA maybe too concentrated?

(2) shouldn’t glue stick improve adhesion?

Thanks for any tips/opinions …

Melt.

Looking for a sanity check. Is there another alternative that makes more sense, given I have to re-build the extruder assembly?

But thinking about it, I'm putting 1 kg of freshly dried filament with a large surface area in a bag with a small bag of gel that might or might not be as dry as the filament. Is the desiccant really buying anything or would it be better to just bag the filament, squeeze out as much air as possible and call it a day?

Things were working fine until I upgraded the firmware on each.  The MK4 was upgraded to 6.5.3.  The MMU was upgraded to 3.0.4.

Immediately after the upgrade, I began getting the following warning:

        The G-code isn't fully compatible

        Nozzle flow rate doesn't match.

I've checked that the nozzle diam of 0.4 is set in both the printer and Prusa Slicer.  I've also confirmed that the "High Flow Nozzle option is unchecked for each extruder in the slicer.

Any suggestions to get me past this will be appreciated.

Is it worth the upgrade, or better to just spring for a MK4S or CORE1?

Thanks for the input...