Thread: Best stepper driver? Gecko, Keling...

Hello
I need a driver board to and wondering the something, I have been looking at the HobbyCNC pro driver board 4axis kit with 4 305oz motors, cost about $350.00 with shipping, Link http://www.hobbycnc.com/products/hob...oard-packages/
but I'm just not sure which way to go, I'm building a 4ft x 4ft CNC, I will post some Pict's when I start putting it together if anyone is interested.
any help would be appreciated.
Thanks

I have the HobbyCNC Pro board. For the price, 25$ per axis, I do not think it can be beat.

After all the time I have spent with the hobbyCNC board, I would rather have bought a G540. I blew out two HobbyCNC board's. The G540 has built in protection. The HobbyCNC board has a nasty problem with Mid-band resonance. The G540 has built in compensation.

If you are just starting, go for the cheap HobbyCNC board. But, if you a little extra cash and get a G540, do it.
http://www.geckodrive.com/product.aspx?c=3&i=14469


My question: Is there any thing better, for the cost?

What is the best car?

You really need to read a bit more overhere, there are so much parameters that determin witch is the best drive.....

regards,

roy

In terms value, price, performance, resale value etc gecko is unbeatable, they not only perform well, the 540 and 203v vampire are nearly unkillable.
Amplexus Bob

OK, my application.
Looking to have a finished cutting area of about 3x2x1ft XxYxZ. This will be my 7th CNC to build. All other have used a HobbyCNC pro board. It is now time to move on from plywood and 8020 to steel.

Currently in the first stages of design. Making it from steel, for the most part. The main supports are W4x13 I-Beams.


In truth, most of my time has been spent on the motion issue. I started off with all thread, but it died. When I moved on to my 5~6th CNC's I used ACME lead screws. But was still disipointed as the nuts wore out. I would like ball screws, but they cost WAY to much. So I spent many days trying to get around the cost/presition problem and came up with this.

I call it a roller screw.


It is all 1-1/4IN 0.2 lead ACME lead screw. Three support rollers and the main going right through the center. The picture is a bit out of date. Newer version solves the issued of needing to tightnin the 3 support screws around the main.

The new CNC, R7, will have dual X's. So, a total of 4 axis's. I wanted to use a G540, but I quickly realized that do to weight issues, I need to go bigger. Now trying to find the best solution driver for the cost.

you have figured out how to make a roller screw? really? i have used commercial versions in work but home made? bravo, show me how.please.

Hey Dingba,

sorrry for my crude reaction, very nice design you got over there.
really, weight isn`t the problem at all when moving horizontal.

Let`s say, you need to move 200 Kilogram with a speed off 2meter/min.
Sorry for the metric system, but its for the example, you can scale it)
You would only need 200 x ( 2 / 60 ) = 6,7 watt
and for acceleration off 0,1 G. 200 x 0,981 = 196,2 Newton
This is all nema 17 territory for a stepper, since a ballscrew with 0,2 lead with 0,5 Nm delivers 500 Newton off thrust at the table. You have an extra off 300Newton.

But then there are bigger problems, Inertia and friction.
If you want to know for sure you would need to know the inertia off the system and we cann calculate the rest for u, best would be to calculate all the needed force and choose a stepper times 2. This to keep the inertia off the stepper at lowest and have the biggest possible acceleration.

For the drive i would say a gecko is best, since it has nice mid-band res. and is unkillable, also it morphs to full step at higher RPM.

If you cant calculate all this, smartest thing would be to go with linear bearings and ballscrews, the Chinese are allready cheaper then most acme screws.

Regards,

Roy b.

Acme screws are cheap, $10 a foot, about $11.5 after shipping and tax. Last time I looked a ball screws, even cheap ones, they were in the $200+ each. I need 3, two 4.5ft and one 4ft. Do you have a cheap vendor?

Currently using V-groove's, but I am early in the design and could be convinced to switch to linear bearings, and ball screws. :-) It all comes down to cost. The roller screw design is costing me about $50 each.

Inertia, no clue. Need to get the design much closer to done to get that information.

So NEMA 34's may be overkill... I am good with that ;-)

I was looking there. Managed to beat their price.
http://www.use-enco.com/CGI/INSRIT?P...&PMPXNO=948458

I can not afford their ball screws. 2~3X out of my price range.

I think I will just max out a G540. Should do fine for my needs, and cheaper then 4, G203V's.

For some odd reason, I am just fine with "severe overkill"

"Spinning 1-1/4" screws requires a lot more torque than 1/2" screws, if you want decent acceleration."

I figured that. The main reason for using 1000oz/in nema 34's

why not get the china ball screws mentioned in plenty of threads here? you could get all you screws mounts and couplers for a couple hundred dollars.

"couple hundred dollars" EACH!
I can build every screw i need + all the roller screws for the price of 1 preloaded ball screw asm.

Perhaps not. I think the bigest I have been able to find, that will not burn out the G540, are 750oz/in. Perhaps with some luck, I can find some 800's.