Prusa Bear Mini Mk3s  

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Tomson
(@tomson)
Active Member

Hi @3dpgva

Ok good to know. Maybe it´s better to keep that OEM then. Do you have dimesions of the aluminium extrusions and partslist for what you take from MK3s, ex. i guess the smooth rods for the extruder are gonna be to short if you use the minis.

Regards/Tomson

 

Posted : 16/03/2021 5:05 am
3DPGVA
(@3dpgva)
Eminent Member

Hi @tomson

Please check here in the comments everything is explained

https://www.prusaprinters.org/prints/36473-prusa-mini-mk3s-smokistyle-upgrade-bear/comments#comment-58329

So for the Frame mesurments are the following:

front/back extrusions : 300mm -->2040 aluminum extrusion

left/right Y axis : 285mm -->2040 aluminum extrusion

left/right Z axis : 350mm -->2040 aluminum extrusion

top : 300-80 = 220mm -->2020 aluminum extrusion

Happy Making

Posted : 09/04/2021 3:22 pm
3DPGVA
(@3dpgva)
Eminent Member

@tomson

for the linear rails only the z ones are not stock y rails and x are the stock ones

Posted : 09/04/2021 3:23 pm
Tomson
(@tomson)
Active Member

@3dpgva

Hi again yes i found it eventually . Working on the frame right now.

On the schematics for dual Z axis is Stepper 1 Left Stepper?

Posted : 09/04/2021 4:21 pm
correa229
(@correa229)
New Member

Hey Team!   

I'm in love with this design and very interested in building my own.  I'm attempting to pull together a basic Bill of Materials to share with those following but have a few questions and could use eyes from y'all and @3dpgva

Questions:
* Are the belt lengths for the Y and X-axis the same as the standard mini?
* Are the Z rods and steppers the same as the standard mk3s?
* Does the v6 hotend use the mini thermistor and heat element, or require the ones found in the mk3s?

Tentative BOM

  • 1x Prusa Mini (kit or assembled)
  • 1x e3dv6 hot end 
  • 1x prusa i3 mk3s extruder
  • 2x prusa mk3s smooth z rod
  • 2x misumi linear bearing LMU8
  • 2x prusa mk3s z stepper motors
  • 10x right angle brackets 5 hole
  • ~50x t-nuts
  • 2x 300mm -->2040 aluminum extrusion - front/back extrusions : 
  • 2x 285mm -->2040 aluminum extrusion - left/right Y axis : 
  • 2x 350mm -->2040 aluminum extrusion - left/right Z axis : 
  • 1x 220mm -->2020 aluminum extrusion - top : 
  • All printed parts from github repo

 

Does the above seem accurate and is there anything I should plan on adding to the list?

Posted : 12/04/2021 12:27 pm
Tomson
(@tomson)
Active Member

@correa229

Hi.

Maybe i´m not the right one to answer your question the best bec i have only start building my own and not finished yet. But i can help you as far as i have come anyway. Always good to brainstorm a little. Mostly bec i haven´t sort out yet for the software. I´m little confused about firmware/software. All steppers are going the reversed way except for the Y axis. And how can i do first layer calibration if  i´m not changing the firmware. For the stepper rotation you can just change the pin in the socket but for the rpm you need to change the firmware. I´m not afraid to brake the pin in the Buddyboard bec of the warranty bec i think that ship have sail already with all the difference i made anyway. This is what i bought except for the PC Blend and the filamentsensor. You can use your Y and X axis from the Mini. I bought them bec i wanted to build it on the side so i didn´t be without the Mini to long. The X axis on the Mini is little short but you can print a piece about 10mm, 8mm cylinder and use the hole one the side for M3 to resist the pressure from the belt tension. If you don´t have the Mini yet it might be cheaper to buy just the parts. Purely financially it`s crazy anyway if you count what you can buy a MK3s+ for but i didn´t do it for the money i did it bec of the passion for the hobby and i like what 3DPGVA did with the little fellow 🙂 

This post was modified 4 weeks ago 2 times by Tomson
Posted : 14/04/2021 10:15 am
3DPGVA
(@3dpgva)
Eminent Member

hi @correa229

dont use

  • 2x prusa mk3s z stepper motors (it uses TR8*4) use 2x prusa MINI z stepper motors (it uses TR8*4)

most probably then you need to change the firmware or some heavy mods on GCODE, the goal here is not to change the firmware the only thing to change is when printing to add 1 line of gcode on the start code and thats it.

Y and X linear rails are the original ones, only the z rails you need to buy, we will try in the future to make it to use the 10mm rails for z Axis.

The heat thermistor and the hotend heater are stock.

so to conclude:
if you buy a prusa mini you will need the following:
aluminum extrusions for the frame
bondtech gears as the MK3S

+ 1x z stepper for mini (because the mini has already one 😉 )

some PETG filament to print the parts
5 x 1 lmmu bearings (4 for z and 1 extra for the X axis)
E3D v6 hotend (nozzle e3dv6, throat, heating block and the heatsink)

bolts and nuts i dont know how many yet, never counted them since we have a lot of printers on our farm i used the ones laying around.

Hope i helped something.
write us here we are glad to help

 

Happy printing/building

cheers

 

Posted : 16/04/2021 5:49 pm
3DPGVA
(@3dpgva)
Eminent Member

Hi @tomson, 
I dont know which one is which since they are going to work the same way same direction 😉
cheers

 

Posted : 16/04/2021 5:59 pm
Tomson
(@tomson)
Active Member

Hi @3dpgva

I have order 1 more Mini-stepper. I based the order to what it´s look like and Z-axis looked so tall beside the std MINI 🙂

But now that i can see the stepper motors being placed next to each other, it does not make much difference. When I placed the order, the Mini was still assembled. My bad, should have disassembled the Mini first. But you use MK3 stepper for the extruder right? Can you use both?

I made a test-cad and print for the 10mm rails if somebody want to test 🙂 I have only test mounted them but it should work.

Take care all of you.

Posted : 18/04/2021 6:46 pm
correa229
(@correa229)
New Member

@tomson

I too am curious on whether the E-stepper is mk3s or mini.

I appreciate all the context added here and am adjusting my BOM listing to align with all the notes.   I'll try to "publish" it here once we get confirmation.

All this has gotten me thinking, would it be possible to do all this with the stock mini hotend?  It does go up to 280 (which fits most of my uses) and I'm wondering if the extruder housing could be modified to fit atop the current hotend similar to the design of the mk3s and v6.  This would not only reduce costs, but also remove the need to adjust gcode for extrusion.  

Certainly something to think about, but for now it's time to order my aluminum extrusion pieces 🙂 

This post was modified 3 weeks ago by correa229
Posted : 21/04/2021 7:51 pm
Tomson
(@tomson)
Active Member

Hi @correa229

I using MK3 extruder stepper. I got my other MINI Z-stepper today and built it together and printed a benchy 🙂

3DPGVA using XYE steppers from MK3s and 2pcs of Z-steppers from the MINI. When I started the project I just went out on the pictures and ordered 2 z-steppers and 1 extruder from mk3 because they looked so long in the picture. But the z-stepper didn´t worked so I had to order an extra for a Mini. Now i´m using XYZ from the MINI and E from the MK3. 

 

Posted : 21/04/2021 9:42 pm
Tomson
(@tomson)
Active Member

You can use heater and hotend termistor from your MINI it is the same

 

Posted : 21/04/2021 9:54 pm
correa229
(@correa229)
New Member

@tomson

That is very helpful and I'm glad to hear!  Would love to see a video of of yours running if you get a chance to take one anytime soon.  I appreciate your advice and will go forward with my order of a kit and the additional required parts.  Hoping to get it built within the next month as the mini will be the longest wait.

Thank you!

Alex

Posted : 21/04/2021 10:09 pm
Tomson
(@tomson)
Active Member

Good morning @correa229 :

@tomson

I too am curious on whether the E-stepper is mk3s or mini.

I appreciate all the context added here and am adjusting my BOM listing to align with all the notes.   I'll try to "publish" it here once we get confirmation.

All this has gotten me thinking, would it be possible to do all this with the stock mini hotend?  It does go up to 280 (which fits most of my uses) and I'm wondering if the extruder housing could be modified to fit atop the current hotend similar to the design of the mk3s and v6.  This would not only reduce costs, but also remove the need to adjust gcode for extrusion.  

Certainly something to think about, but for now it's time to order my aluminum extrusion pieces 🙂 

If you want to save as much money as possible I have made a cad prototype using the MINI Z-smoothrods that I have printed and test assembled. I have not testdrive that but it should work. I think you miss a big point of doing this if you make something with the MINI hotend and extruder.

I suck at software so if i can make it work i´m pretty shore you can to 🙂 All other parts is from 3DPGVA design.

/Tomson

 

Posted : 22/04/2021 5:46 am
3DPGVA
(@3dpgva)
Eminent Member

@tomson

Hi Tom,

Yes i saw your remix for the Z its a way to make it cheaper, lets see how we can evolve this mini baby to the next step for cheaper, i have had some ideas on the past if you see the other project https://www.prusaprinters.org/prints/36631-prusa-mini-mk3s-smokistyle-upgrade-haribo/files

and also on github: https://github.com/3DPGVA/Prusa-Zaribo-MK3S-MINI---Ultra-Upgraded-

This is an ongoing project didn't had time to build it yet, but since you did remix the z rails for the 10mm this will make the cost cheaper, less aluminium extrussion to buy.

@correa229

yes we use e-steps differently on the mini,  check on the project i did uploaded a profile to use mk3s on the mini 😉

 

Happy building/testing/breaking and remaking

cheers

Posted : 22/04/2021 9:52 am
3DPGVA
(@3dpgva)
Eminent Member

@tomson

Tomson forgotten 1 more thing, to use the wizard you need to put a stop limit at 28.5cm from the stepper on the z height 😉

i think i might take a day or 2 to document the whole process, so many things going around our farm cant take some time to do this properly

cheers

Posted : 22/04/2021 9:58 am
Tomson
(@tomson)
Active Member

Hi @3dpgva

Yes i saw that project and i think it´s a great idéa so i am in 🙂 

I have some parts left over so that could be a fun project.

/Tomson

Posted : 22/04/2021 10:40 am
Tomson
(@tomson)
Active Member

@3dpgva

Hi again. Yes the stoplimit i found out yesterday than i did the wizard. I put some temporary limits but i think i put them 1-2mm to high. I was to exited to start printing so i save that for today:) 

Posted : 22/04/2021 10:43 am
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