Advice on motor-motherboard combonation

Ok so I'm trying to build a large Delta style printer like the Kossel. They use and sell a Ramps1.4 kit. Designed to work with Nema 17 motor of about 2.8 volts. My distance is greater and my effector platform rods are a little thicker and longer. But still carbon fiber. So I dont want to give of the speed that these delta machines usually have. so my question is this.

what is the limiting factor with using the "Under 3V" NEMA 17 motors specified by the REpRap Wiki? For instance, at 12 volt Nema would offer superior torque and speed would it not?

would a kit like this :
[www.builda3dprinter.eu]

work with a 12V nema 17? What changes would have to be made? would this require customer steppers and or RAMPS kit to be made?

would be grateful for any advice! Thank you in advance.

Not sure if it is relevant but would like to use [www.mattercontrol.com] for running and managing the printer.

Edited 1 time(s). Last edit at 12/19/2014 05:39PM by calmasacow.

The voltage rating of stepper motors is a little misleading, because it is the voltage drop of one winding of the motor when stationary multiplied by the current rating. You need to have much higher voltages available to drive the motors at speed, because of their inductance and back emf. So for a 12V stepper motor, you should be looking for stepper drivers that can produce up to about 50V. Even then, the 12V motor won't necessarily produce any more torque than a 3V motor, because it will almost certainly have a much lower rated current.

I suggest you choose stepper motors rated at around 1.2 to 1.5A, because that is about what the low-cost stepper drivers can provide without too much extra cooling. The motor datasheet will specify the torque, allowing you to compare different stepper motors. Then choose a supply voltage of 12V if the winding voltage at max current is 3V or less, and 24V if it is between 3V and 6V. This is only a rough guide, because ideally one should determine the maximum step rate needed, then read the winding inductance off the motor datasheet, and do the sums.

btw I wouldn't choose standard RAMPS or any other 8-bit Arduino electronics to run a delta, because the 8-bit processors barely have enough power for this application. I suggest you choose 32-bit electronics.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Well I had only selected that as it was what was recommended and including in the Kossel kits. What board would you recommend. Keeping in mind the printer type "Large Delta" and Software solution "MatterControl"?

Again, Thank you very much for your help and insight on this matter.

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calmasacow
What board would you recommend. Keeping in mind the printer type "Large Delta" and Software solution "MatterControl"?

Sorry, I don't know the "MatterControl" software, so I can't advise you. Given a free choice of software, if the motors you choose are happy with 1.2A or less, then I would choose the Duet board - but that's because I am writing the Delta firmware for it! Unlike most Delta firmware, it will generate the steps accurately instead of approximating each stepper motor movement as straight line segments, which may (or may not) improve print quality.

Other 32-bit solutions I am aware of (but have no experience of) are the Arduino Due + RAMPS-FD, and the Smoothieboard. But the Arduino Due doesn't have Ethernet, and AFAIK the Smoothieboard doesn't either.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42

Quote
calmasacow
What board would you recommend. Keeping in mind the printer type "Large Delta" and Software solution "MatterControl"?

Sorry, I don't know the "MatterControl" software, so I can't advise you. Given a free choice of software, if the motors you choose are happy with 1.2A or less, then I would choose the Duet board - but that's because I am writing the Delta firmware for it! Unlike most Delta firmware, it will generate the steps accurately instead of approximating each stepper motor movement as straight line segments, which may (or may not) improve print quality.

Other 32-bit solutions I am aware of (but have no experience of) are the Arduino Due + RAMPS-FD, and the Smoothieboard. But the Arduino Due doesn't have Ethernet, and AFAIK the Smoothieboard doesn't either.

Smoothieboard does now have Ethernet on them Smoothieboard

There is also the RADDS on due which will run Repetier firmware

Edited 1 time(s). Last edit at 12/21/2014 03:20AM by dougal1957.