RE: Prusa CORE One kit assembly instructions
Quick door handle update: If you install the door in the "standard" orientation, with hinges on the left, then you can use screws to attach the door handle without further tweaks.
There are two convenient holes in the right frame part which receive the screw heads. The upper one is also the adjustment hole for the belt tensioner (but Prusa must have put the handle screw hole at that exact height deliberately). The lower hole seems to serve no other purpose than to make room for the screw head on the door handle.
For whatever reason, the left frame part does not have the lower hole. Probably an oversight? I had installed my door right-hinged, in preparation for the location where the printer will be placed eventually, and hence found the screw head bumping into the metal frame. I will flip the door over to the standard orientation for the time being.
RE: Prusa CORE One kit assembly instructions
A few more mixed observations from my build:
Don't push your printer around on the bench! Two of the angular rubber feet have already come off on my printer. Only the rubber itself came off, leaving the adhesive film behind on the printer, so it was not me having greasy fingers when I stuck them on... While testing some replacement double-sided tape to reattach the feet, I noticed that the rubber is surprisingly adhesive-repellent. Sanding it lightly with fine-grit paper seems to have helped.
After attaching the right side wall with the filament sensor, make sure that the filament sensor cable is not bulging inward and rubbing against the linear bearing which travels on the right Y rod. The cable is guided through a cable tie attached to the CoreXY frame, and if it gets stuck there, it will form a slight loop that can get in the way. I encountered a lot of Y homing errors, then realized that the Y movement had a lot of resistance towards the back, and finally spotted the culprit.
I did end up lubricating the Z lead screws, although the trapezoidal nuts are apparently made of POM and are supposed to be self-lubricating. The Z drive was groaning like a bear on the whole way down during the Z motion test. And towards the bottom end, the front left lead screw started to oscillate so much that it rattled against its loose cage in the CoreXY assembly. Some grease from the included lubricant tube fixed the vibrations; I hope this does not come back to haunt me at some point.
RE: Prusa CORE One kit assembly instructions
Thank you for sharing this information. I will definitely add the rubber feet at the very end.
I have already noticed the noise of the Z-axis in some Youtube videos or during live builds. I didn't like it either. I have only seen a few videos where this was not the case. If the noise comes back, I would definitely contact support. Are you otherwise satisfied with the core one?
RE: Prusa CORE One kit assembly instructions
The Z drive was groaning like a bear on the whole way down during the Z motion test.
It can be heard at timestamp 1:43:40 Then when the benchy is finished.
https://www.youtube.com/live/_bx6HS0TPWI?si=0iRNzEvpNOQCHA6R
RE:
Are you otherwise satisfied with the core one?
I have not really printed anything yet. 🙄 Some little glitches the other night -- side filament sensor passed the initial test, but then immediately decided to get stuck in "I see filament" mode. And at first I thought NFC was not working, but the Core One is just very selective in where you place your phone. It takes the "near" in NFC seriously; you better know exactly where your phone's NFC antenna is located...
The printer should be ready to roll now, but I have a few other things to attend to (which I successfully procrastinated on in favor of the build). Hope to get some prints done tonight!
I did enjoy the build a lot, and the resulting printer certainly feels solid. In contrast to a Bambu printer, the whole design is still on a "I could design this myself if I had the time" level, which personally I enjoy. A very similar experience to building my Elecraft K2 transceiver years ago, which also had less features than the Japanese off-the-shelf competition, but felt more "relatable".
I also like the user interface -- the menu structure is logical and quick to get used to, and the choice of rotary encoder and touch display works well for me. If the print quality is convincing, this will definitely be a keeper!
RE: Prusa CORE One kit assembly instructions
Thank you for the first impressions. Yes, take your time and when you're ready, feel free to give feedback on your first printed parts.
RE: Prusa CORE One kit assembly instructions
A few more mixed observations from my build:
Don't push your printer around on the bench! Two of the angular rubber feet have already come off on my printer. Only the rubber itself came off, leaving the adhesive film behind on the printer, so it was not me having greasy fingers when I stuck them on... While testing some replacement double-sided tape to reattach the feet, I noticed that the rubber is surprisingly adhesive-repellent. Sanding it lightly with fine-grit paper seems to have helped.
After attaching the right side wall with the filament sensor, make sure that the filament sensor cable is not bulging inward and rubbing against the linear bearing which travels on the right Y rod. The cable is guided through a cable tie attached to the CoreXY frame, and if it gets stuck there, it will form a slight loop that can get in the way. I encountered a lot of Y homing errors, then realized that the Y movement had a lot of resistance towards the back, and finally spotted the culprit.
I did end up lubricating the Z lead screws, although the trapezoidal nuts are apparently made of POM and are supposed to be self-lubricating. The Z drive was groaning like a bear on the whole way down during the Z motion test. And towards the bottom end, the front left lead screw started to oscillate so much that it rattled against its loose cage in the CoreXY assembly. Some grease from the included lubricant tube fixed the vibrations; I hope this does not come back to haunt me at some point.
If it makes you feel any better I've been lubricating all of my z lead screws on all of my printers, after 5+ years and combined tens of thousands of hours I've not had and issues.
The key is to keep them clean, which isn't much of an issue for me because every printer is in an enclosure.
RE:
Off-topic in this thread, but since the question came up here: I finally ran my first prints! tl;dr summary: I'm very happy indeed, but there are VFAs.
Mind you, I'm coming from a very modest starting point: An older Anycubic i3 bedslinger -- slow, manual bed leveling, and with its bowden extruder I never managed to dial in proper filament retraction, hence any start and stop of filament flow was messy. Hence, my first print was an enclosure I had designed for an electronic project and which always looked terrible on the Anycubic, especially the openings in the side wall. It was essentially the trigger for wanting a better printer.
Printed with a new roll of Galaxy Black PLA, in 0.2 mm structural and speed modes, standard Core One setup with the 0.4 mm HF nozzle, standard print profile. In either mode I am really happy with the first layer (on the smooth print sheet which does not hide anything) and with the precise control of filament flow, especially around the holes in the side wall.
But VFAs (belt ripple?) do show up in both modes -- they are less visible in the "speed" print, but I think that is more due to its matte surface than a reduction in VFA amplitude. Pitch is 2.0 mm for walls oriented at 0° and 90°, and 2.8 mm for walls at +- 45°. It would be really nice to see a reduction via calibrated phase stepping, since I would find these annoying in objects which are meant to be looked at.
Acoustic noise is ok for me: In structural mode, the chamber fans are the most dominant sound, and they do not sound unpleasant -- just pink noise from the air flow. (I would not want to crank up the fans much more, although the chamber temperature did rise to less-than-ideal 27°C). In speed mode, the motors do become quite audible, but nothing has ever rattled along. The motor noise has characteristic frequencies proportional to the travel speed; I think one really hears the stepping frequency here, and am again hoping for calibrated phase stepping to quiet them further. But while the printer is eventually meant to run in the basement, I have no issue at all to keep it in my study for the next few weeks while I familiarize myself with it.
Finally, vibrations: The printer sits on my regular desk at the moment. (A sturdy desk, but not a workbench or such.) In structural mode, I have no issue at all with sitting right next to it and working at that same desk. In speed mode, the vibrations in the desktop become quite noticeable, but not concerning at all. I don't think I will be getting a paving slab any time soon. 🙂
Edit: Hmm, those pictures are not too helpful to assess quality. The Galaxy PLA dos not hide all that much in real life (when printed with a glossy surface), but the glitter structure really stresses the image compression on my phone's camera...
RE: Prusa CORE One kit assembly instructions
Woohoo! Congrats on first prints!
MK4S/MMU3
RE:
Thank you for the detailed insight!
Apart from the VFA's, the print looks really good!
I also hope that the prusa team will quickly find a solution to the phase stepping calibration problem.
RE: Prusa CORE One kit assembly instructions
Since my kit should be arriving soon, I quickly constructed an extra tray for the small parts.
Designed so that the parts can be removed easily.
That way you can keep an overview and nothing is forgotten.
But I forgot something essential, the extra cut-outs for the gummy bears. Maybe in version 2.
Perhaps a useful tool for all those who assemble their kit.
https://www.printables.com/model/1256558-parts-tray-for-prusa-core-one-kit
RE: Prusa CORE One kit assembly instructions
You beat me to it, Jürgen. Glad to see your printer is performing as expected. The VFAs you describe are similar to what I see, at first I thought this was due to me assembling it.
Did you manage to have the gantry align so that it touches both front stop blocks without a gap on either side? I still have a 1mm gap. The angle of the brackets (linear holders) is not perfect, but I think the belt tension easily overpowers the stiffness these brackets provide...
RE: Prusa CORE One kit assembly instructions
I have been running a Prusa Assembled Core one. It has been running good for me. The new firmware 6.3.1 fixes the painful door bug. I also re-calibrated the door after loading 6.3.1.
Lubricating Z is OK, just keep it clean. I learned this on my MK3s that was not in an enclosure. The Z leadscrews started to rust. Lubrication solved that and noise.
I would like Phase Stepping Calibration to reduce the noise. An accellerometer most likely will be needed.
The rubber feet are functional, but not great. Someone will come up with a great mod.
I didn't like the lack of access on the top so I used this lid mod. I had to print at %100.8 to get it to fit. PrusaSlicer has no shrinkage adjustment yet.
Just waiting for my filter fan to print noxious filaments.
One last thing, I do not recommend wood fill, carbon fill etc to go throght the High Flow nozzle. Wood Fill plugged up my high flow nozze.
RE: Prusa CORE One kit assembly instructions
PrusaSlicer has no shrinkage adjustment yet.
Prusaslicer now has shrinkage compensation. It is under the "Filament" tab. I can't say exactly where, as I'm not at my computer at the moment.
RE: Prusa CORE One kit assembly instructions
Did you manage to have the gantry align so that it touches both front stop blocks without a gap on either side? I still have a 1mm gap. The angle of the brackets (linear holders) is not perfect, but I think the belt tension easily overpowers the stiffness these brackets provide...
Yes, it's pretty spot-on now. I checked the two brackets with a machinist square before I installed them, and had to correct one of them, which was about 1 mm out on the 40 mm arm length. Once I had installed the complete X rail, I nevertheless found a residual ~ 1 mm gap. I just corrected that by bending the installed rail -- having experienced during the earlier correction how soft the brackets were, I was no longer concerned about damaging the linear bearings.
The X/Y homing still bangs the Nextruder into the front right corner several times, but I assume that is deliberate, to obtain a more accurate home position? Not entirely sure why they need that to be so precise -- is it just to enable resuming after a power outage? If so, I wish I could turn the "accurate homing" option off. Power outages are not a concern here, while the banging is annoying me on every print...
RE: Prusa CORE One kit assembly instructions
After mounting the core x y assembly I noticed one of the belts (teeth side) being in contact with the zip tie that holds the cable of the thermistor at the exhaust fans. Everything seems to be aligned correctly.
I worry that either belt or zip tie will wear off eventually.
Does anyone of you have the same issue?
Could that maybe be a source of the wfa some of us are seeing? anything touching the toothed side of the belt could create vibrations.
/Anders
RE: Prusa CORE One kit assembly instructions
Could that [zip-tie touching the belt teeth] maybe be a source of the wfa some of us are seeing? anything touching the toothed side of the belt could create vibrations.
I had speculated the same, half-seriously. Removed the zip-tie in my Core One build, but sadly am still getting very noticeable VFAs.
RE: Prusa CORE One kit assembly instructions
I also bent the bracket in place now. Perfectly aligned now, and I also observe the banging to find the home position...
For the belt touching the zip tie, there is >2mm clearance now after the belt is fully tensioned. I dont think its a concern anymore.
RE: Prusa CORE One kit assembly instructions
Could that [zip-tie touching the belt teeth] maybe be a source of the wfa some of us are seeing? anything touching the toothed side of the belt could create vibrations.
I had speculated the same, half-seriously. Removed the zip-tie in my Core One build, but sadly am still getting very noticeable VFAs.
Thanks for confirming, we are still searching then.
/Anders
RE: Prusa CORE One kit assembly instructions
As I have now read several times that the screw holes of the motor mounts are a bit wide, I would also like to share my experience. I was also worried about the posts. Now I have installed the parts myself and at least with my parts it was no problem. Sure, the screws go in easily and I only tightened them gently, but as they only hold the pulleys and there is no axial load on the screws, I'm not worried about them ever not doing their job. So no brass thread is needed.