Power supply for using 6V 1.2A motors?

An eBay vendor has a 3D printer electronics kit that includes everything electric/electronic except a power supply for $219.95. They say their motors are 12V. I asked how much for that kit without the motors. $159 but they claim the 85 oz/in 6V 1.2A motors I have won't work with it.

My printer will have a very rigid frame, made from a piece of test equipment that likely orginally cost a few grand but cost me $10. :-) The Z axis slide is already part of the frame and the X axis for the extruder will run on an HSR25 rail while the Y axis for the table will be a single HSR30 rail - possibly with 'outrigger' roller bearings if there's any detectible rocking. Doubtful since the THK block and rail I have are very smooth moving.

Since the moving parts are going to be more massive than on the typical lightweight printer, I'll need those higher torque motors. Ballscrews will be used instead of belts.
I *was* going to build a frame of 40x40 extrusion, double braced with corner brackets and plates at every joint, but for $10 I have all the rigidity ready built. I've seen a Solidoodle 2 in operation, with the platform supported on just one side, and I could see it wiggling sideways very slightly, causing a slight ripple in the layers. That will not do for *my* printer. :-)

28.5" tall and 11.25" between the vertical posts.

Impact tester by g_alan_e, on Flickr

Quote
Galane
An eBay vendor has a 3D printer electronics kit that includes everything electric/electronic except a power supply for $219.95. They say their motors are 12V. I asked how much for that kit without the motors. $159 but they claim the 85 oz/in 6V 1.2A motors I have won't work with it.

They are likely trying to get you to buy their stuff. Stepper motors aren't really rated for a voltage. They have a current rating, and they have a winding resistance. Based on these two things a voltage can be calculated by multiplying them to get the "rated" voltage. For instance, my steppers are a 76oz-in model that has a current rating of 1.5 amps and resistance of 2.8 ohms so the rating is 4.2 volts. But I operate them at 12V just like almost everyone else with a 3D printer as the increased voltage results in a faster response in the torque curve.

What all is included in the kit at $159? Unless the electronics board is a premium board, that sounds a little pricey.

Here's the kit. [www.ebay.com] Looks like everything needed except the structural parts and a power supply. I'd need one motor to run the extruder and use the others I have for the 3 axis motion.

That's only saving $25 without the 5 motors.

Do you know of a comparable kit for less?

Edit: That's $159 after removing 4 motors from the kit, the motor for the extruder is still included.

Edited 3 time(s). Last edit at 05/08/2015 12:43AM by Galane.

I just got a prusa i3 mechanical kit and electronics from Sintron. They claimed, everything is included but the powersupply. That isn`t entirely true. Especially the mechanics weren´t complete. ( Also the acrylic frame is only 5mm thick instead of the usual 6mm )
The electronics kit I got, was OK though. Only missed a y-cable to power two z-steppers with one driver...
I saved 100EUR buying from sintron, compared to other prusa dealers.

I´d say, give it a try. Your steppers will work with 12V too
Olaf

Quote
Galane
Do you know of a comparable kit for less?

That kit comes with a lot more than just electronics (I wouldn't have included the extruder, hot end, bowden tube, wiring etc... I was just thinking controller, LCD, heated bed, and heater cartridge).

Just for comparison, RAMPS+controller+LCD+drivers will set you back $40. Another $10 for the heated bed. $1 per microswitch (you don't need the "fancy" ones shown). $80 will get you a REAL E3D hot end not or $56 for a REAL JHEAD. The rest can pay for any one of many different extruders you can find on eBay if you don't have some place locally where you can print one, odds and ends in wiring, etc.