I have owned a DIY Kossel Mini for a couple of months now and decided I wanted to builder another one but this time not from a kit as I want to increase the size substantially. So far I have printed all the plastic components and purchased and received the 2020 extrusion I will be using. I found some stepper motors online they are far from the best but I am not sure how much torque I need for the X,Y,Z of a Kossel style Build. They Are 17HS3001-20B. See the specs below.
The Kossel I am building for myself is fairly large compared to the Mini, I Set my extrusion lengths to 1000mm and 450mm, giving me a rough circular build area of 320mm. See pictures below for comparison of my Mini and the custom one I am building
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Those look like fairly standard 40mm NEMA 17s. They’re more or less the industry standard among consumer 3D printers and should suit you fine.
According to a reliable source in physics I just consulted, it doesn’t actually take any more force to move the delta print head on the larger printer than on the smaller printer, as long as other factors remain the same (the angle of the delta arms, the size of the print head carriage, etc). If the motors drove the smaller Kossel fine, they’ll work for the larger one too.
Thank you for the reply, I am not sure what model steppers are on my mini kossel as they are not labelled anywhere. The price on these seem to good to be true at $6.80+shipping. I found them on a Chinese website that deals in 3d printer parts.
http://www.3dp2go.com/nema17-stepper-motor-40mm12a-nema17-17hs300120b-p-213.html
Also they have a 310mm round silicone rubber heater that I am thinking of purchasing for the printer. It is priced at $20. I am unsure though as I have dealt with heated beds yet. I was thinking of using a 600w PC PSU I have just lying around to power the printer, the 12V line is 18A, would it be enough to power the heater and can I run a heater this size through the electronics for the printer ramps/arduino. The heater link is below, I like the idea of it as the wiring and thermistor are all prewired and sealed within the bed.
http://www.3dp2go.com/300mm-round-silicone-rubber-heater-for-3d-printer-p-538.html
The heated bed is also not quite as big as the build surface this printer will have but I was thinking of getting some aluminum cut to fit the build surface under the glass bed and put the heater up under the aluminum so the aluminum acts as a heat spreader, I dont know how effective this will be.
My carriage will be very similar to the one on the mini just going to add a better fan shroud, for my delta arms I have already figured out the math for the length. Now I don’t have carbon fiber tube on hand but did have some smooth light weight aluminum rod on had just at 7mm outside dia. It is solid aluminum and bored out the centers at each end to be threaded for end pieces. I am hoping these will work out, if they do not I will have to search for long uncut lengths of carbon fiber tube.
I am going to try and source some glass for the heated bed locally, there are some automotive glass shops here that sell safety glass in whatever ever size/shape you want, it is layered glassed with two pieces of glass and a substrate between them which prevents shattering and sharding. I am not sure if this is a viable solution. I would have liked to use mirrored glass as I really like that look but do not know if I can locate something I can use
Hey, I got the same stepper motors w my folgertech kossel. The difference come in picture when you try to increase their speed. They start to skip steps around 60-70mm/s. If you dont mind printing no faster than 50-55mm/s, then you’ll be fine!) If you want to go for faster speeds, look for the motors rated at 2.5A. Cheers
3DStar
April 19, 2016, 6:54pm
5
Hello!
Torque is low to on the steppers you have 400Nmm is the equivalent of 56oz/in witch is a standard for Nema 17.
You could go with theses for faster operation and more torque.
The difference is not that yours are not able to do the jobs, but don’t forget that the head will be heavier,and inertia is going to fight against the motors.
Your going to have more ringing on your prints and with higher torque motors they will be able to compensate.
If your going to go with aluminium rods, I would to with higher torque motor, since even if it’s light its heavier there then the CF rods.
Only my 2 cents!
Éric
