Mu Draconis

mu draconis

Made by : William respository link: https://github.com/WilliamPrime/Mu-Draconis

i have a 3d printer :D

pitch, make a polar 3d printer, not because its practical, but because its something different :D

i would be taking inspiration from this, but making it more functional https://www.reddit.com/r/3Dprinting/comments/16dsugh/received_a_ton_of_constructive_criticism_on_my/

i want this to look very clean, probably be control only via klipper, no phyiscal controls

im still deciding if i want to have a heated bed or not, or if i want it to be a “fast” polar printer and use a nema 34 on the bed or something like that

the gantry should also be fairly easy to remove for shipping, so xt-60 connectors and other jst things will be needed to make sure that all the cables are easily detachable

also had the idea of having suction cup style things on the base so it sticks down to a table, its just a funny idea

so far i have some parts ive found and extracted out of dead 3d printers:

• ras pi 4 8gb
• big tree tech skr mini E3 (the mosfets for heaters and fans are dead, but stepper drivers still work)
• voron klipper expansion board
• hardmount v6 style hotend
• 70w 24v heater cartridge
• 40w 24v heater cartridge

im hopeing i can use them without them counting towards the cost of the BOM

first two days of planning, around 4hours into it:

ive decided quite a bit about my printer i want to use a 250mm round heated bed i want to use a slip ring so i can get power to the bed and have a heated bed on this printer i plan to use linear rods and linear bearing for both the x and z the x will 100% be belted im still deciding if the z should be belted or use a lead screw i also started to model out some of the components i plan to use in fusion 360, such as the bed as a starting point however it appears the technical drawing from the manufacturer REALLY isnt accurate

current rough BOM as of starting

Part name	price	notes
250mm dia hotbed	£13.89
ras pi 4 8GB	already owned
semi broken btt skr mini e3	already owned	dead mosfets, but stepper drivers still good
klipper expansion board	already owned	to compensate for the dead mosfets on the mainboard
nema 17 motor with leadscrew	£13.49	320mm leadscrew might trim down to 200mm
thermal fuse	£1.85	100c thermal fuse to prevent run away on the bed
nema 23, 76 mm motor for bed	£18.69	overkill, will prob change to help budget
slip ring	£13.02	3 channel, 30A per channel 22mm dia
bicycle bearing	£1.46	cheapest way to get a large bearing for bed (41mm id)
C14 S8B3 power panel	£1.36
mellow sherpa mini kit	£30.39	good, light extruder
gates 2GT 6mm belt 1m	£4.79
20t pulley x2	£3.30
20t idler x2	£3.10
LDO-42STH48-2804AH-R	£26.09	the goat of stepper motors, could use a cheaper 42STH48 2804AC-R instead for more torque i think
Meanwell LRS350	£23.59
pt1000 thermistor	£4.53	overkill but i maybe want high temp, no clue
250mm bed surface+magnet+sheet	£15.39
end stops x3	£3.20
mosfet for bed/heater x2	£3.28
200mm 8mm dia linear rod x2	£5.76
330mm 8mm dia linear rod x2	£6.32
Fushi LM8-UU/2pcs	£9.79
Fushi LM8-LUU/2pcs	£12.29

08/02/2025 (arround 5 total hours)

put another 2 or 3 hours into sketching out how im going to get this to work finally managed to start getting stuff modelled in fusion 360

the belting seems daunting but i recon its going to be nice

ive struggled to try and model the bed as almost all of the technical drawing on the aliexpress listings are horrible

15/02/2025 (arround 13 total hours)

made alot more progress ive been modelling the respective components im going to need for my build ive also started to model the assemblies so i can start combining them

ive decided to start with the bed because i think the bed will be the biggest challenge to make the bed is probably my biggest challenge because i need to deal with belts to rotate the bed, and also belt tensioning for that, but i also need to deal with getting power to the bed as i would like to have a powered bed, for that i also need to deal with the slip ring the solution i think i have come up with is 3d printing a custom hollow pulley/sprocket that will attach to the bed, that way the slipring can be on the inside of it and still deliver power

here are some images of the CAD that ive started to hobble together

18/02/2025 (arround 18 total hours)

started working on belt tensioners they were surprisingly tricky to design but im hoping maybe if i go all belts then i can reuse the belt tensioners across the printer

it feels quite voron 0 inspired, but that was what i was inspired by :D

im honestly not sure what the time frame was, probably arround 23 hours total time

anytime i was at my computer doing nothing i would try and get a lil bit done so i didnt really get much big stuff done but still stuff changed

07/04/2024 (arround 26 hours total probably more)

realised how much easier it would be if i just went the route of desiging some parts seperately then importing them into the main file i can definetly say it took me way to long to get that basic belt tensioner working :( but oh well

07/04/2024 arround 31 hours in

some more jumps got stuck as one of my parts was 0.2 degrees misaligned and that really threw me off BUT I FOUND THE ALIGN TOOL

i had been using components to make everything work but i realised how much it helps me to focus when i make things in smaller files where i can and combine them into a bigger file later :D

im doing this while sleep deprived

so im still working on the printer

made some overall progress on tidying up the hierarchy of mess in the component tree made alot of work on getting the motor for the x axis actually mounted i think it maybe gets easier and harder from here from hearing from other people the tool head might be hard but i also dread the weird bearing thing i made for the rotation axis

realised that i needed more material there to propperly support everything 2.5mm of pla didnt really feel enough also wanted extra thickness there so that i can use heat sets to mount my hot end stuff :D

another update

started and “finished” on the hotend i was anticipating alot more difficulty designing the ducts for the hot end fans than i actually encounter

however i did encounter some difficulty since my hot end is going on the same side of my carridge as my belts, im encountering issue of how to mount the hot end without sacrificing rigidity, i believe it shouldnt be too hard to just have the hot end on the other side, and then just flip the bed onto the other side of the bottom 2020 extrusion, and that should then fix the issue without needing any extra hardware, right now im trying to get the printer functional so i can refine the cad more and fix some the issues that can be fixed without needing more hardware.

you can also see the fan ducts are aligned with the centre of the nozzle, also not intentional :( sorry

this ended up being really spaghettic like, im not sure how to use mark down files properly, you can probably tell updated BOM is here https://docs.google.com/spreadsheets/d/1IZOwHB4fpJywedBBVYQKaOOAUHnNrE4fSURzN-7t6E4/edit?gid=0#gid=0

managed to count some bolts

now at least i know the hardware i need to add to my bom

bed assembly m3x8 8pcs m3x12 5pcs m3 x35 4pcs m3 x30 6pcs m3 x30 6pcs , 45 degree angle m3 nylock nut, 6pcs m5 t sloct nut , 2pcs m5x18 , 2pcs m5x10 , 2pcs m3 heat sets , 11pcs

frame m6x20 , 2pcs m3x12 , 21pcs m5x8 , 8pcs m5 t slot nut, 8pcs m3 x8, 6pcs m3x20, 8pcs m4x28, 2pcs m4 nut, 1pcs m3 heat set, 3 pcs