Hey guys, From today, we have an additional person joining the Customer Service/Technical Support Team to help us get through the backlog of Hemera tickets. We are very aware of the delayed response time and are trying our best to work through everyone's tickets as quickly as possible, this should hopefully become much easier from today with an extra pair of technical hands. Georgia
Were you able to improve the print quality? Your latest photos show a significant sign of changing something at 1/4 and 3/4 layer height. In the front of the brown sample, I believe I see evidence of non-uniform microstepping of either your bed (Y-axis) or X-axis (because each full step is clearly showing), perhaps due to settings or stepper brand (I hear MOONS' steppers have that problem less).
I've tried so much at this point I have forgotten where I started and what I've done lol. Short answer is no I never did resolve the uneven extrusion yet. I do use that small breakout board on the x & y axis and it uses TMC 2209 drivers the only thing I haven't tried yet would be to disconnect the daughter board and plug the steppers directly back into the mini Rambo. However with a cylinder test I would assume that the uneven extrusion is still there regardless of what steppers are used to drive the x & y axis. I guess for giggles I can plug the steppers directly into the board taking the daughter board out of the scenario and print a few tests prints just to see. I was convinced it it's just a extruder issue only but I guess I could be wrong but it sure doesn't seem to be an issue with x and y or z. All of those taxes are smooth as butter and there's no binding anywhere it seems like the extruder itself is what's an even if that makes any sense. But it's definitely worth a shot to take that out of the equation.
Well definitely not the daughter driver board. I swapped the steppers back to the mini Rambo taking the daughter board out of the equation. It did not get any better and might have even for worse. Now I'm out of ideas. Surely it has to be something I'm missing. The machine is rock solid and I 99% guarantee it's not anything mechanical with the build of the machine. I have double checked that 100 times and everything seems perfect. Like dead on perfect. No binding , perfectly square , rigid as hell, smooth movement on the rods etc.... Surely I'm not the only human that has seen such poor extrusion? This is also the 2nd extruder assembly, E3D sent a replacement just in case there was a gear issue etc.. so now I'm at a brick wall. Anything firmware related I need to adjust? I even adjusted the e jerk to a low value with little to no result. I don't get any skipped steps from what I can tell and voltages are on the high side of the range for all drivers. Comparison Phots from swapping steppers back below. https://drive.google.com/folderview?id=10OfCME6Ga9SS8f-j5p9NqXdEgZMIKEIO
In regards to the change in the print , that was just temps and speed. I was playing with cold vs. hot at different speeds. Not really much change other than the matte vs. shiny effect.
Thanks for posting back and your perseverance... When I was referring to non-uniform microstepping, I was thinking of user guy-k2 on the Prusa Forums who switched stepper motors, not stepper drivers. Read more here. Did you also check the effect of using a different stepper drivers for the extruder stepper motor? Can the spool of filament turn freely? Are you sure that the power supply is okay? Do you have a different one to try? To help analysis by other users, if possible, use the same filament with the same test object every time when trying out stuff. Also make sure when taking a photo to put the object on a table with the right lighting and take the photo perpendicular to the object with as many layer lines in sharp focus as possible. What would also help at this point is an overview photo of the entire printer and a steady close-up video with sound of the printer printing. Your latest photos don't really show the issue for reasons above, but I think I see multiple issues combined. Some ringing/vibration on the corner, slight intermittent underextrusion or wobble, patterns from whole steps made by the extruder motor and VFA for your X and Y axis. You mentioned a high Vref for the board, but I'm not familiar with its capabilities or options. Have you tried driving the X, Y and E steppers with minimal current? Or decrease and increase microstepping? Enable or disable interpolation? We still have to find that parameter that shows a significant change in behavior. I'm also hoping some other users will chime in.
First off thank you for all the help and trying to decipher the possible issues. I honestly appreciate it. Now onto the list! 1- I really can't swap anything on the extruder stepper driver. This is the stock mini rambo Prusa board with a daughter board for the X-Y axis to make the machine quiet. The rest of the drivers are stock to the mini rambo in which only Z and E are running off. Here is a link to the board just for information. https://vmod.wordpress.com/prusa-mk2s-ext-driver-board-v2-3/ 2. Yes my spools are mounted inside my cabinet with bearings on the spool shafts. It takes little to no effort to have them unwind. All my printers use this same method of filament delivery and before the extruder change the old straight V6 did not produce the same artifacts. 3- Yes the power supply seems to be find, it puts out about 12.7 volts and doesn't seem to drop with basic movement and heating as far as I can tell.At the moment I do not have a spare power supply for this printer. A .I'm sure I can get a video , I ran out of the brown filament from before so I had to swap over. I understand the need for the same print but I was sick of printing round trash cylinders over and over . As far as the photos I try to use downward facing light, purposely, to show all the inconsistency of what seems to be extrusion. B. As far as the voltages they are still within the motor specs for the X and Y motors. The recommended vref was .81 and I am running at .90. On the E axis E3D recommended .5 volts and I had to bump up a bit to .6 to use the load filament command since it loads so quickly and will sometimes barely skip at .5. I am sure it would print at .5 it mainly was just the filament loading and unloading that needed a small increase in voltage. I have went back and forth with the stepper currents, I don't see any noticeable change either way. If anything the bump in voltage helps but if so its minimal at best. As far as increasing or decreasing the micro stepping honestly I am not sure on how to do so. I would assume I would have to edit the firmware for the stepper drivers and not aware on how to do so. Same would go for adjusting interpolation. It was even a bit of a chore for my novel mind (pertaining to firmware) to edit the stock firmware for the new extruder steps and voltage adjustments and get the OLED screen working. I am not real experienced in firmware and the Prusa one is a bit hard since there is not much information of editing the firmware such as the Creality printers have. Makes me wonder though , if I use TMC drivers now did I need to adjust the firmware for those TMC drivers? Possibly not since the stock on board drivers were as bad if not worse but just a thought. I know that they were not edited but it was not mentioned anywhere in the information for the break out board of any need to adjust the firmware values for the stepper drivers. C. I too see some basic ringing / ghosting on certain prints; but I am not as concerned with that as much as the rough extrusion. I would suspect the two are directly related and whatever the root cause is would address both. The model printed had holes almost at the walls so some of that might be from the model itself and some just from basic ringing. I know that everyone says their machine is solid and built right but as a perfectionist I know with zero doubt this machine was built extremely well. There is zero movement in the frame etc... the only weak spot is from the 8mm rods but it still takes a bit of force to create deflection which would not be present while printing. I also read the article for the .9 vs. 1.8 steppers. I can understand that possibly helping with some VFA. I swapped stepper drivers back to the main board vs. the TMC break out just to take that off the list. Keep in mind a few things. This machine was new. It has only had the Hermes extruder from it's first print. However before the conversion from the old MK2S I did not have the same VFA as I do now. In reality this should be a better printing machine. It's a much more rigid frame and all new bearings. (Misumi rods and bearings as I mentioned before). The parts that were reused, and seemed to be functioning fine before, are the steppers for X-Y-Z and the main board. I would not even mind buying a few .9 degree steppers such as the mentioned LDO .9 degree motors but I would like to make sure that would fix the issue prior to doing so. It's only 30$ for X and Y so it's not a huge cost but it is additional work and money. I guess I have a hard time seeing how there is suspect operation of those steppers when the same thing happens with round objects (even vase mode) regardless of speed? I assume the theory would be the uneven movements that slow and speed up the travel with no change in extruder speed. I can see how that would also cause artifacts.
Video and some more pics of things. Did a temp tower at the moment but I will do something different and make a small video of that as well once this finishes. https://drive.google.com/drive/folders/11SYYYjQoxqR_cAGvOkcd8VPL-h8l7mol?usp=sharing
I am experiencing same things, but muuuuuch less pronounced than you have it. One of the big causes for me was that the extruder's full steps were visible when printing a 2-walled object with no infill. It helped to change the driver (I had A4988 for extruder) to TMC2100, and activate stealthChop. spreadCycle looked just as bad. Doing this helped to minimize these issues a lot.
I do not doubt that swapping drivers would help;unfortunately unless I change the board out , which I am thinking about doing, I don't have a way to move the extruder off the on board driver. I have been debating swapping to the SKR 1.4 turbo with TMC 2209's just not sure I can make the firmware work right. Not much info on doing that with the Prusa. I would need firmware for the SKR and Prusa MK2 if I had that I would move to the SKR board.
The mini rambo board only have A4982 drivers. I don't think stealth chop is an option for this board. It's max is 16x micro stepping not many options on this old of a board that is still 8 bit.
Oh, got it. In that case it is definitely the driver, A4988 has horrible step curve, and I assume its similar for A4982.
Sort of what I was thinking but hoping not. I ordered a SKR 1.4 board / TMC 2209 drivers just hope I can figure out the firmware. I am a firmware noob overall I am sure someone else has tried the SKR board on the Prusa just need some firmware help! So if anyone has any idea of where or whom has done this before any pointers or firmware is greatly appreciated.
Hi Kraken, Chris Warkocki did amazing work using the SKR v1.4 with TMC on his Prusa. Check out his channel: https://www.youtube.com/channel/UC3PX8aZvkadWgz9yrqONlGQ. My MK3 still runs factory board but my Ender 3 also has SKR v1.4 + TMC2009 + Hemera, here is my configuration if helps: https://github.com/gdombiak/marlin_config
The Good: Well I have successfully swapped the board over to the SKR 1.4 Turbo and slashed my way through making the firmware in Marlin 2.0 for the printer. I did learn a bit and the video you mentioned was helpful as well as the videos from Chris Riley. Both have some great information and Chris Riley was a great help as well. https://www.youtube.com/channel/UCqRiv7rQuxge63bqJ2hVNUQ The not so good: Currently I am using TMC 2209's on all the axis. Dual drivers on the Z axis and the BTT TFT35 v3 for the screen. Some things have improved but I still see the uneven extrusion and for the life of me don't understand why. I am running all the drivers in stealth chop including the extruder; 16x micro-steps on them all except for the extruder which is at 32x. In addition I changed the X and Y steppers to .9 degree motors from stepper online in hope that would also make things a bit better and if it did it was only slightly. Voltagers all seem to be set correctly and I do not see anything mechanical that would cause the issue. I did re-calibrate both the e-steps and extrusion multiplier when I swapped to the new boards. General Info and Thoughts: Overall the print surface is much smoother (to the feel) than what I had before with the mini rambo and the Allegro drivers. Seems like the main issue effecting the print quality is all based into the extruder. Very similar to the Prusa topic of "Linearity Correction". That seems to be the issues that is adding the diagonal pattern of lines into he print making it look a bit more rough than it is. I think some of this is a direct issue related to specifically geared extruders. Both the Bondtech and Hermes seems to fall victim to this, that is just my theory but seems to hold true in many instances. Can this be adjusted in Marlin? If so any ideas on how to do so? https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration My ideas on what to try: 1.If possible in Marlin adjust the Linearity Correction for the extruder. So far I do not see a way to do so. At this point there is nothing else mechanical it can be in my opinion. 2. Drop the TMC driver off the extruder and use the LV8729 in place of the TMC. I think that might help with some of the issues but I still need to test this out. I ran one from the start on my Tevo Tarantula pro on the extruder and overall it prints as well if not better than this Bear / Frankenstein I have built. 3. Give up , accept defeat and say "this is as good as it gets". I am sure some people would be very happy with thew print quality I get off this machine, I know many would since the masses accepted the terrible print quality of the Prusa MK3 from the beginning. However I sincerely doubt I will be able to do so Prints and Firmware: I added some pictures and firmware in case anyone, with a better understanding of Marlin; is willing to look over the firmware to see if I missed anything important. https://drive.google.com/drive/folders/136AMTY4dYBI3rv6FE76VZ3xWWoY3f04I?usp=sharing
Gato I noticed in your config you turned off stealth chop for the extruder. I have left mine active. Did you see improved print quality on the extruder bu disabling stealthchop for E0?
The 'downside' of a printer with a super rigid motion system and an extruder with such a short filament path, is that it's unforgiving. Any remaining issues are no longer dampened or obscured by bigger problems. I believe this salmon skin could indeed be caused by a combination of driver and extruder motor and quoted by various people as being the last remaining and hardest issue to address. There's also the phenomenon of stepper clipping, but I don't believe that should be the issue here. It's probably non-uniform microstepping. TMC drivers have a programmable adaptive/incremental microstep table to better tune the driver to a specific motor. Which could help, but this would probably cost a lot of energy and time to get right. These TMC drivers can also switch automatically from StealthChop2 to SpreadCycle at a certain speed threshold. StealthChop2 is very quiet, but also less powerful. The switch from one mode to the other also causes a jerk in the movement. I was seeing a decrease in XY-ripples with SpreadCycle mode on my TMC2224, which I discovered because of a clear improvement in surface print quality with higher (!) print speeds. I think someone suggested (possibly dc42 on the Duet forums) to configure the switchover threshold TPWMTHRS either so low that StealthChop is only used at (almost) standstill or so high that it's only used for high speed travel moves or at speeds used with retraction/advance moves. You might also try using SpreadCycle exclusively, but the coils may whine or hiss in the audible spectrum without properly tuning other driver parameters such as TOFF. EDIT: found the source again. And another reference here.
Ah yes, the salmon skin... I've experienced this myself ever since I got my Hemera. I am absolutely positive that it happens because of the super short filament path (as opposed to my previous Titan+V6 combo), which makes the driver's full steps show up as a "peak" in extrusion amount. I used to have A4988 driver for my extruder and the salmon skin was REALLY bad. Swapping it out for TMC2100 and switching to stealthChop halved the visibility of the pattern, but not completely eliminated it. Unless there is a way in Marlin to compensate, I think we are out of luck. Hemera is just so super precise that it makes this issue more obvious than other extruders... EDIT: Here is how it looks like for me now with TMC2100: EDIT2: Messed up the driver name lol EDIT3: I have already said most of this previously, I am just slow this morning at figuring out which thread is which >.>
Well I have went through all I can think of to fix the issue. Seems like the Hermes / Hemera is not going to produce print quality that some other type of system would. This machine I have finished now is one of the most sound builds I have seen or done myself. Nothing is perfect but this one is as close as it could be. I am very disappointed in the Hermes and it would be nice for E3D to address the issue. However they have been silent from what I have seen on this forum. I feel real issues are being ignored for the most part. Short of the issue with the gears seems like any other design or performance issues have been overlooked. I wonder that if in testing any of the issues were reproduced? I guess at this point the only thing left is adjusting things in firmware to help but I feel the Marlin setup I am running seems to have all the options enabled that I think would help. I have yet to see any feature in Marlin to adjust the linearity as Prusa firmware had that I previously mentioned. If anyone knows of any other thread addressing the issue please let me know. At this point I am out of options. Everyhting I changed and swapped (board, .9 degree steppers, TMC drivers) has not fix much. The only other option I had was to use the LV8729 on the extruder. However seems like with the SKR 1.4 the LV8729 doesn't seem to work on E0. I had read about some bugs dealing with this but not sure the cause. When installed there is no movement on the extruder. So I am stuck on the last thing that I could try. I doubt it would fix it but at this point that is all I have left. https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration
