New build - seeking advice on electronics/steppers

[richthorn]

I just bought an aluminum extrusion frame and I'm looking for some electronics to go along with it.

The CNC I'm going to be building has 3 Nema 23 motors (two on the Y gantry) plus a Nema 17 for the Z.

I've been considering the TinyG and the Gecko G540. Obviously the Gecko is considerably more money so what am I going to gain from going that route? I would also need to repurpose/build myself a PC with parallel to run LinuxCNC or similar.

I am a college student and on a very strict budget but this is my second CNC build and the first one I cut corners on and ended up completely wasting my money (if you don't count the invaluable lessons I learned in assembly and general knowledge)

So although it is a consideration that the Gecko is more money I am more than willing to pay double the cost if I need to. In the end it's less than $150 more and if that's what it takes then that's what I'll do I just don't want to spend money needlessly on the most expensive controller if I don't really need it. I guess the best way to put it is that I can afford either, I have the money saved, but would it be better spent elsewhere?

Second, I need some steppers. I'm in California so I've been considering these guys because they're not too much more than the eBay motors and they're going to get here quickly. Anyone have a good source on Nema 23 motors? The plans call for a double Y setup and it's a moving gantry so I don't want heavy 3lb steppers hanging off the gantry.

Thanks for the help

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[doorknob]

A few comments..

The G540 will handle a higher voltage and slightly greater current than the TinyG, which may permit you to achieve better performance from the G540. The stepper motor that you linked to has a somewhat high inductance, which could reduce the available torque at higher speeds. Using a PC running Mach3 or LinuxCNC should give you more of a "user interface" than you will have with the TinyG.

Note that the stepper has an 8 mm diameter shaft rather than the more typical 6 mm shaft, but you should be able to get appropriate shaft couplers for that size.

[richthorn]

A few comments..

The G540 will handle a higher voltage and slightly greater current than the TinyG, which may permit you to achieve better performance from the G540. The stepper motor that you linked to has a somewhat high inductance, which could reduce the available torque at higher speeds. Using a PC running Mach3 or LinuxCNC should give you more of a "user interface" than you will have with the TinyG.

Note that the stepper has an 8 mm diameter shaft rather than the more typical 6 mm shaft, but you should be able to get appropriate shaft couplers for that size.

One of the reasons I settled on those motors was because the TinyG could drive them but if I go with the Gecko I could get something that takes a bit more power. Thanks for the info on the inductance I didn't notice that.

[richthorn]

I had nearly settled on getting a G540 kit but then I found the DIY setup from HobbyCNC. It's a few hundred dollars cheaper which isn't a huge difference but would make it a lot easier to get a nice spindle with the extra money. Anyone have any experience with their setup or any thoughts on it vs the Gecko?

[doorknob]

Just be aware that the HobbyCNC board is a unipolar driver which can only work with 6-wire motors (or 8-wire motors, or some 5-wire motors) but can not work with 4-wire motors, whereas the G540 is a bipolar driver which is designed to work with 4-wire motors (or 8-wire motors, although there is also a way to use them with 6-wire motors).

[flightfollowing]

I've had a pretty good experience with the tinyg. However, the interface software is still evolving. Using it certainly makes a low cost and low labor machine:

http://www.cnczone.com/forums/open-s...xperience.html
and
http://www.cnczone.com/forums/bencht...eap-parts.html

[awerby]

I'd use a 23-frame stepper on the Z axis as well. That motor has to move a lot of weight (depending on what you're using for a spindle) so it needs a fair amount of torque.

[Fastest1]

Yes, My first machine was and is controlled with HCNC Pro I built from a kit. It was a wonderful and well thought out kit. Fun to build too as I had no experience besides rudimentary soldering. It was a little odd having to use a group for the build. I still think the experience and the product were great. I have a few G540's around and use the same steppers with both though none are 4 wire. I see no better performance in the G540 either. I have tested them back to back with smoothsteppers with no obvious differences.

Just be aware that the HobbyCNC board is a unipolar driver which can only work with 6-wire motors (or 8-wire motors, or some 5-wire motors) but can not work with 4-wire motors, whereas the G540 is a bipolar driver which is designed to work with 4-wire motors (or 8-wire motors, although there is also a way to use them with 6-wire motors).

[clembrant]

take a look ay xylotex