Compatibility question (newbie)

[Jan-Roger]

Hi people!

I'm getting started with my first project, and has found some steppers that I think would suit my needs. I am building a 30 x 50 inch router, that has the possibility to engrave harder materials, but primary will be working with wood. The steppers that I want to use: http://nanotec.com/page_zweiphasen_st8718_en.html (ST8718M4508)
I also found a controller, but I do have some difficulties interpreting all the properties of this controller. So my question is: will this controller work fine with these engines? The controller is named SSXYZMicro77, http://www.simplestep.com/products/ssxymicro77.html

I would like some opinions from you CNC experienced guys.

What is the most important properties on a controller to look for?

And at last; I don't want my cutter/mill to be running when it's not cutting any material (like when moving it into position). What is the solution to this? (Possibly a few I guess.. :-)

BR

Jan-Roger

[jeffs555]

Without knowing all the details of your design, it is impossible to know if the motors would work, but they would probably have plenty of torque. The controller is only rated for 2.5 amps, and the motors need 3.18 amps for full torque even in serial mode. Parallel mode which is generally better, would need over 6 amps, so that controller would not be able to generate full performance from the motors.

[ger21]

It looks like it uses the same chip as the Xylotex, as the specs are basically the same. But it also has a lot of features that you problably don't need, too. After lookiong at the price, I'd say that if you were going to spend that much money, buy Gecko 201's. You'll be able to run the motors wired parallel and get the best performance possible. If the money is tight, buy the Xylotex, which will give you the same performance as the SimpleStep board for 1/3 the price.

To turn the spindle on and off, you can use a relay and turn it on and off with G-code.

[Jan-Roger]

I've read about the Gecko's. How does these differ from other controllers? I would need 1 Gecko to each axis, so how should the connection between them/the PC be done? The 201's can deliver about 7 amps, which should be enough for my drives. Is there any chance they would run hot?

I have little knowledge of what software that is available, but since I find the Gecko name quite often on sites regarding CNC, I would assume they are compatible with most software?

Ger21: how would I hook this (the relay) up to my computer? Do I need an extra controller of some kind, or can I use my RS-port (+5V)? In that case, would I be using the same port as the one connected to the Geckos or do I have to use another port?

I am planning on a 2,5D mill, with the spindle traveling all 3 axis. To make this work, I am going to make a sledge, with two ball screws on both left and right side of my table, driven by a stepper, centered with belts attached to the ball screws. The two other axis; the same, but only one ball screw pr. axis.

I really appreciate your assistance. I've already started working on my machine, and eager to get it up and running. The drawback is that I have so little knowledge about CNC yet, that I stumble across many many challenges along the way. This forum has made the challenge a lot easier!

BR
Jan-Roger
Norge/Norway

[ger21]

If you go with Geckos, get a breakout board from either http://www.campbelldesigns.com/ or http://members.shaw.ca/axxus/

(there are others also)

These will let you hook up the Geckos, as well as relays and limit switches all to the breakout board.

Geckos ( http://www.geckodrive.com ) , as well as the Xylotex and most hobby drivers, work with step and direction software such as Mach2 or TurboCNC.

[Graham S]

A few basics:

Most prople run their machines from the parallel port, there are spare pins that can be used to trigger delays etc. The software you use should be configurable to do this.

Download turbo CNC and have a look:

http://www.dakeng.com/turbocnc.html

A break out board is a board that goes between the parallel port and your drives. It may just have connections to attach things like relays or it may have some things built in to it.

Notice Gerry mentioned Geckos because you can get them for the same money as the drives you are looking at however, Xylotex drives are cheaper and could drive steppers to run your machine I suspect.

Graham

[Jan-Roger]

Although the Gecko drives are more expensive, they seem to me like a better choice for my project. The Xylotex would not make the most of my choice of steppers (I think) :-)

I found the Breakout board from Campbell Designs quite interesting, especially with the Spindle Speed Controll add-on. This would probably aliminate the need of a relay to controll spindle on and off (more advanced though, I know.. and I like it :-) I have one question regarding the Breakout board. They say this board is designed with Mach2 in mind, would that mean that I can't use TurboCNC with this board? Am I stuck with Mach2 if I choose this solution?

I'm struggling with some technical terms. My native language language is norwegian, and my English is'nt that good. I hope someone can help me explain this for me:
1) What is a backlash nut?
2) What is a flexible coupler?
3) How do I convert oz/in to Nm or Ncm? (I don't even know how much 1 oz is)

Thanx,
...and thanx in advance!

Jan-Roger
-signing off

[ESjaavik]

1) What is a backlash nut?
2) What is a flexible coupler?
3) How do I convert oz/in to Nm or Ncm? (I don't even know how much 1 oz is)

Hei Jan-Roger,

1) I assume you mean an anti-backlash nut? That's a preloaded nut that have no backlash. (Forspent glappfri mutter. Finnes både for trapesgjenger og kuleskruer.)
2) A piece that goes between 2 shafts that are not perfectly aligned. It is (fairly) rigid in torsion, but allows some misalignment axially. It can be done in many different ways and prices. (Fleksibel kopling, prøv http://www.elra.no/).
3) Using this: http://joshmadison.com/software/convert/

[Al_The_Man]

[QUOTE=ESjaavik] (Forspent glappfri mutter. Finnes både for trapesgjenger og kuleskruer.)
Thats easy for you to say

[Jan-Roger]

Thank you mr. Esjaavik! I didn't know there where others from Norway in this forum as well! What a pleasant surprice! :-)

Nice SI converter by the way.. I'll archive it under "most usefull tools".

I don't think I quite understand what a anti-backlash nut is, or why it's been used, but I'll get back to it. (A search on google would probably get me on track.)

I had a question regarding the Breakout board that still is unsolved. Campbell writes on their homepage that the board was designed for Mach2. Does this mean that I can only use Mach2, and not e.g. TurboCNC with this board? Does the software have to be compatible with both the breakout board and the Gecko's? I would assume that since the computer has one interface; the breakout board, it doesn't matter what kind of driver I will be using.

BR
Jan-Roger

[ger21]

The spindle speed control will probably only work in Mach2, but I think you can use the breakout board with TurboCNC, but only for Gecko connections, limit and home switches and relays. All the special Mach 2 features the board has will not Work in TurboCNC. If you're not going to use Mach2, I'd get the Axxus board for half the price.

Backlash is when you turn a nut on a screw, then stop, and reverse direction. If the nut turns a little before it begins to move in the other direction, that is backlash. Anti-backlash nuts have no play in them.

[kevincnc]

If you're considering Geckos, you should definately also consider using brush DC servo motors instead of steppers with Gecko G320 or G340 servo drives. They also run from step & direction signals. You can get better performance, closed loop, and probably even less expensive. I don't know how much the stepper motors cost that you're looking at in US$, but you can find lots of DC servo motors on ebay and probably get better performance for less money. I regularly sell new ones for applications like yours on ebay, approx. 400 Ncm for $150 ea. You can also find used ones once in a while for even less.
Kevin