I’m going to DIY a Kossel Mini 3D printer. But I’m short of experience. I am searching for all accessories according to the BOM.
I found some parts( aluminum extrusions, nuts, bracket, electronics, power supply and motors) on a Chinese website named makeralot. The price on the website seem to good and I am thinking about order some parts from the website. But I am not sure if their motor can be used on the Kossel Mini?
Anyone know about this website? Help me take a look at this stepper motor, thanks.
See motor link below.
If the motor ok, i’ll buy most of the parts here.
Do not buy it our you will be very upset! They are junk and hard to get right! Especially if you are new to 3d printing. So do yourself a favor and do not purchase one!
Sintron use 17’s in their kits:
http://www.ebay.com.au/itm/Sintron-3D-Printer-Kossel-Mini-Full-Kit-w-Auto-level-for-RepRap-Rostock-Delta-/161802473549?hash=item25ac2dd04d:g:jJMAAOSwT6pV2MvQ
My Kossel Mini has 17’s, so YES you can use a 17 in a mini kossel.
Link to their motors only so you can check any details you may require.
http://www.ebay.com.au/itm/161598990720
(1) Form factor : NEMA17
Hope this Helps you a bit.
1 Like
KDan
July 18, 2016, 2:18pm
4
NEMA 17’s are the correct frame size for a Kossel Mini (most other 3D printers for that matter also)
Yes, that motor will work just fine. Kossel Mini’s actually work great with 34mm long motors also.
You can’t go wrong with either one, but personally I’d probably choose the 34mm motor because of lower rotor inertia.
Holding torque is lower, but it is still more than adequate for a Kossel Mini. Acceleration is important too - the smaller motor has a advantage there. 34 g.cm rotor inertia vs 54 g.cm for the larger one.
Another very important factor in choosing steppers for a high performance printer - especially Delta printers - is the inductance. To a large extent, this value determines the shape of the torque curve. Lower is better. Both of these motors have an inductance below 3mH - which is very good.
3 Likes
If you want to go for the flying extruder mod, I’d suggest you a nema11 for the extruder.
Mirth
July 18, 2016, 4:16pm
6
What many newbies don’t realise is that NEMA17 is an American standardised size. It’s got nothing (directly) to do with the torque. The length of the NEMA17 will determine the torque and so long as your Kossel doesn’t limit the length of motor there’s no reason why not.
Yes they will do just fine for the axis drives. Everyone started at some point. Please also find attached the nameplate of the ones I use in my Kossel mini.
KDan
July 18, 2016, 5:32pm
8
Yes, The NEMA reference is the frame size. It determines the size and location of the mounting holes. Those dimensions also constrain the mechanical diameter of the motor.
Length is the other parameter. For NEMA 17 sizes, you typically have single stack (34mm), double stack (40mm) and triple stack(48mm). There are larger ones too. Greater length translates to more torque in the same frame size.
However, there is a good reason to not use longer motors that needed though. Rotor inertia. You need sufficient torque to drive the load + some headroom, but not an excessive amount. Longer motors have more inertia and take longer to change direction. They also tend to have stronger resonances. These are not a desirable characteristics in a 3D printer which requires high acceleration and deceleration.
Low inductance and low rotor inertia are the most important parameters for a motor used in 3D printing applications…
http://reprap.org/wiki/Choosing_stepper_for_a_delta
1 Like
Mirth
July 18, 2016, 5:42pm
9
Wise words. Listen to this man.
KDan
July 18, 2016, 5:47pm
10
They might work, they might not. When you go to NEMA 11, the torque is really low. You need enough to overcome any parasitic drag in the mechanism. You also need enough to overcome the inertia of the machine itself (which is quite low in a Kossel design).
The Kossel mini apex brackets are drilled for NEMA 17 frame motors anyway…
Great Answer! And totally agree with all the written facts about inertia and inductance.
My kossel mini have 0.9 degree 0.8A Vexta steppers, they are running great and quietly.
Please use the A4988 motor drivers the DRV8825 ones have issues with low resistance motors (they will make a vibration at a low speed)
T.
The site you linked has a lot of misspellings, typos, and generally really bad. Do not source your critical parts on the cheap with questionable online retailers. At that price point, it looks like you might get more headaches than actual results. Get your critical moving parts from reputable and reliable sources. That being said, Linear bearings are very important but the cheap Chinese bearings (with a little manual TLC on your own) is good enough to last a long time. Electronics, you should buy a genuine Arduino mega or go for a Rambo or other genuine electronics. The cheap arduino megas are not built for durability and its very likely to break on you (like things browning out or fire during 3d printing.) and cost you a ton more in the long run.
