RE: Prusa Bear Mini Mk3s
How is this way better than the stock mini? Appreciate the taller extrusions etc but without the firmware to home the dual z motors it's going to be a pain.
RE: Prusa Bear Mini Mk3s
In my opinion there are quite a few advantages:
- more rigit frame => less ringing even at higher speeds (stock fw)
- assuming you did not change the extruder before, you'd get a direct drive extruder which is more precise, allows tpu printing, arguably better overall
- for me, at least, it was very difficult to get the X axis perfectly level with the bed on the original frame, this one is easy, you just roate one of the lead screws until you get it where you want.
- it is a fun project, if you're into that 🙂
The dual-lead screw system does not require fw changes as it is not a "real" dual stepper setup, you won't get automatic x-axis tramming because both steppers are driven by the same driver, but you do get dual x-axis support and sync motion.
At the end of the day, if you're not into diy-ing, I'd say the gains may not be that great, it all depends on your particular use-case and if it solves any issues for you. It is an expensive project and the Mini is great in it's stock form... it's also a great start for klipper fw, having a more rigid frame allows greater accels/speeds. My "standard" speeds are 130-150mm/s @ 3500 mm/s^2 and it prints great! - but klipper is another adventure, costing you a raspberry pi:))
RE: Prusa Bear Mini Mk3s
As many of us are finding with the Mk4 upgrade, one reason not to do it is that is become near to impossible to upgrade when there is a major upgrade down the road.
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Chuck H
3D Printer Review Blog
RE: Prusa Bear Mini Mk3s
For me the main reason was the much more rigid frame, as i has quite some skew issues with the mini.
I have had my issues with this build, but never had any issues with the dual leadscrew.
it's been very very reliable since i built it.
RE: Prusa Bear Mini Mk3s
Me too, couldn’t stand the slight skew the Mini was prone to (my OCD side speaking haha). Love how prints on the Bear mini produce more precise parts due to the rigid frame. It needs more tuning in extrusion multiplier and linear advance for various materials to dial in for tighter tolerances. But overall I’m quite happy with the upgrades.
RE: Prusa Bear Mini Mk3s
Having used a gantry style i3 in the past, I'm recalling how much I hated dual Z steppers, it's so nice to not have to constantly check for alignment.
The dual Z towers also over-constrains the axis to a degree, I would have to say that the mini prints better easier. (Similar to why the monoprice mini was/is so popular)
That being said, the Z tower is floppy, the bed compensation does a pretty good job of masking this, I wouldn't fault anyone for wanting to stiffen it up a bit to minimize how much the Z motor moves while printing.
RE:
I'd like to check with those who have done the Mini Bear conversion to see if you had any jamming when loading TPU filament? I have had 50-60% chance of jamming when loading Sainsmart TPU filament with the Mini Bear, but never experienced this when printer was still a Mini+ with Revo Micro hot end. Once I cleared the jam manually the printing goes without issues. I have the Bear Extruder paired with a Revo Six hot end. The jam happens right after the extruder gears where the soft TPU filament curls up and the extruder gears just slips. Looking for some way to resolve this...
RE: Prusa Bear Mini Mk3s
Hi, could you tell me where can find the linear guide mod to lgx shortcut? will be great! Thanks
RE: Prusa Bear Mini Mk3s
Could you share your linear guide mod? Im very interested
RE:
The problem with this mod is that it WILL destroy your bed when not running a start.gcode
I don't want to be responsible for people destroying their bed.
My hidden model on printables is far from updated, so i would have to update this.
Maybe i could attach the files here...
RE: Prusa Bear Mini Mk3s
I have posted a linear rails mod. But I also run Klipper, I never tested it with stock fw. In any case, if someone wants to try it out: https://www.printables.com/model/473490-prusa-mini-mk3s-bear-linear-rails-mod
RE: Prusa Bear Mini Mk3s
Will be great if you attach the files, Thanks
RE: Prusa Bear Mini Mk3s
I already created my own linear rail mod, without the Z, but i do like this one quite a bit. Nice work!
How did the alignment go on Z? It's always a bit of pain to get that sorted with two rails.
RE: Prusa Bear Mini Mk3s
I already created my own linear rail mod, without the Z, but i do like this one quite a bit. Nice work!
How did the alignment go on Z? It's always a bit of pain to get that sorted with two rails.
Thanks! I borrowed most of the work from anothe guy (he's credited in the post)
Z worked quite nicely. I started by securing the rails into the motor mounts and top caps and after that, once I confirmed the alignment is ok by moving the x-axis up and down by hand (z-screws not connected), I started securing the screws in the slots. It was a bit more fiddly with the Y-axis for me :)) but using the same procedure, tightning screws while moving the bed to make sure it stays aligned.
RE:
Still excellent work!
But you might want to level/skew the x a bit, this is hard to check when the z-screws are in place
I think i'll try this, i might need to tweak some of it to make it fit my LGX extruder. The distance between rails and belt might be off a bit. I got both of the X-axis mount steps extracted.
One question though, are these MGN12C or H ?
RE:
Here you see the differences.
My belt is a bit lower. Have to figure out a way to get this higher, not much room due to the screw holes, or adjust the x mounts.
RE: Prusa Bear Mini Mk3s
Still excellent work!
But you might want to level/skew the x a bit, this is hard to check when the z-screws are in place
I think i'll try this, i might need to tweak some of it to make it fit my LGX extruder. The distance between rails and belt might be off a bit. I got both of the X-axis mount steps extracted.
One question though, are these MGN12C or H ?
H variant. C should also work, with some adjustments.
RE: Prusa Bear Mini Mk3s
Here you see the differences.
My belt is a bit lower. Have to figure out a way to get this higher, not much room due to the screw holes, or adjust the x mounts.
You could try to use my x-carriage as is and adjust extruder mounts if necessary?
RE: Prusa Bear Mini Mk3s
It's a great work, for me MGN12H, because I will install in mk3s, there's a lack of this kind mod, there's no support or comunity because LGX shortcut mosquito is expensive.
RE: Prusa Bear Mini Mk3s
And the problem with the LGX shortcut is the placement of the Pinda probe
It's not on the same Y position as the nozzle. This means it will probe off-bed, thinking your bedlevel is 10cm lower. Then when you autolevel, the nozzle will digg into your bed with brute force.