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Opinion on motors

Posted by gusman 
Opinion on motors
December 29, 2016 01:34PM
Hello everyone!

Could you guys give me your opinions on these motors?
[www.ebay.com]

They are 5 volt motors, will they work with these electronics?
[www.ebay.com]

I'm building a corexy machine. The motors seem like a pretty good deal.

Any thoughts are greatly appreciated. Thanks!
Re: Opinion on motors
December 29, 2016 02:54PM
The only problem with those motors is they don't have a shaft, you'll have to supply one.

Don't go cheap on the electronics, it's the heart of the printer. You get what you pay for and that ramps probably won't last long, they don't even supply a heatsink on the bed mosfet. Also, the pololu style drivers will not be able to supply much more than an amp to the the motors without overheating. I recommend going with a DuetWifi, it'll have no problem driving those motors. It's the controller I'm using on my corexy with a 7" PanelDue.
Re: Opinion on motors
December 29, 2016 03:25PM
Good advice. Though, I'm on a tight budget with this printer. I would love to upgrade to the duet wifi in the future, it looks awesome!

I plan on putting heatsinks on the mosfets and a big fan on the whole control board.

As for the motor shafts, I was thinking either use 5mm threaded rod and a nut on either side. I just don't know how well pulleys will attach to threaded rod. Or epoxy a 5mm smooth rod in them.

It certainly doesn't have to be these motors, but if they would work with the electronics, I will probably try them since they seem to be a good deal.
Re: Opinion on motors
December 29, 2016 05:44PM
You are best to get the right motors for the job. 0.9 degree for XY, a good powerful ( 2-2.4 amp) motor for Z and a lightweight nema 17 for the extruder. Stepper online have them and they will only cost a few dollars more than the ones you linked to.

Get a 32 bit controller, the cheapest run Smoothieware. Here is an example [www.aliexpress.com] I don't know how reliable they are though.

The mechanical part can really soak up the cash, Filipe's G&C printer is probably the cheapest. You could make it even cheaper if you substituted ACP (aluminium composite panel) for the extrusion frame.

Get a decent hotend. There is nothing more frustrating than mysterious hotend problems. I like Tom's reviews on You Tube for this stuff.
Re: Opinion on motors
December 29, 2016 08:35PM
Threaded rods are going to be smaller than the hole diameter in the motor's rotor. That means you'll never get the shafts properly centered in the motors. That means the pulleys will wobble as they turn. The wobbling will pull on the belt and cause small variations in the position of the extruder relative to the bed. That means you'll get poor quality prints. If you're going to get those motors, you're going to have to get some proper steel shafts for them. That may require a hydraulic press to push the shaft into the rotor. The few pennies saved are not worth the hassle. Leave those motors to guys who have access to a machine shop and can properly finish them.


Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Opinion on motors
December 30, 2016 01:22AM
Ahh, good points guys! I'm very glad I asked.

Well I have some new stuff to look into then. I'll be following your threads, lots of useful info.

Thanks.
Re: Opinion on motors
December 30, 2016 03:35PM
The electronics you linked to are budget electronics and are not well suited to those 2.1A 0.9deg/step motors. 32-bit electronics with beefier stepper drivers, such as Duet WiFi, would be better matched to them.

However, unless you are building a large printer, motors that powerful are likely to be overkill. As has already been mentioned, they also need shafts.



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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