New Build 6 axis CNC first timer

[BarryB]

Hey folks, go big or go home right?  Anyway, I'm building a 6 axis cnc and would like advice and pointers as I order parts and what not.  I figured I'll order all the electronics first, make sure they work, and build the machine around them.

For the final machine, it's going to be a moving gantry system with an A/B head from doughty drive.  Initially the machine will be 5 axis.  The 6th axis will be added later to the table to revolve objects.  The cutting surface, I plan on being about 4' x 4' x 3'.  I will be primarily cutting wood, soft and hard.  Sometimes I'll be cutting metal as well.

Here's what I've ordered so far...

1.  USB Smooth Stepper
2.  7 Gecko G203V drives
3.  4 Nema 34 1250 oz motors
4.  Mach 3 (of course)

What I'd like advice on from here, would be:

1.  Power Supply (I need it to power each drive, which in turn will power the motors, remember there are 7.  The gantry will have two drives/motors to move it.)
2.  extra switches like limit switches, emergency cut-off switch (how many, and where?)
3.  wire (what's the accepted standard, how many colors etc)
4.  kit box to store everything neatly (Are there large locking ones?  Do we all make them by hand?)

Later on I'll ask questions about the frame.  For now, it's only electronics.

[BarryB]

I'm just ordered a B/C drive and about to order the spindle.  I do have a couple spindle questions though.  What is the difference between S1 and S6?  If this is in a home workshop, would that make a difference if you got S1 vs S6?  Is one more difficult to use than the other, more testy?

Let me know.

I figure I'm 1/2 way through parts ordering now, this gets a bit pricey huh!

Barry

[Tweakie.CNC]

Hi Barry,

For your wire - used screened cables for everything except the spindle (this will avoid any possible stray pickup problems at a later stage) and earth them at the controller box end only. For bipolar steppers you only need 4 core, for unipolar you need 5 core, not sure if you will be using encoders. Obviously the cores have to be man enough to handle the motor current. Limit switches only need two core but again make it screened cable.

Hope this helps.

Tweakie.

btw. When it comes to earthing - it pays to have one single earth point and earth everything to this single point within your control box. (do not earth the screen of your LPT connection - this is only earthed at the computer end).

[BarryB]

Thanks Tweakie, I didn't know that about the wire.  I thought screened cable was only for audio/video.  Good to know!  Btw, I plan on hooking up all the electronics first, to make sure that works, and can place it all in a lock box hidden away before making the frame.  Does that make sense?  I usually see others build their frame first.  Dunno, just seemed more appropriate to me this way.

Barry

[Tweakie.CNC]

Hi Barry,

I just stuck the box on the back of my router frame where it is out of the way and wired to it. If it didn't work first time I knew I would get it working eventually. But as luck would have it first time and rock'n'Roll.

Tweakie.

[BarryB]

Nice organized kit box you've got there.  I plan on mine being like yours too.  Your power supply is supplying power to everything?  How does that work?  I was thinking I'd have to get a separate one for each part for some reason.  Yes, that's the newbie in me;)

Barry

[Tweakie.CNC]

Hi Barry,

My machine here is a 3 axis router. Each axis motor is current limited to 2 Amps and the PSU is rated at 24 Volts, 6 Amps. The driver board gets its 5 Volt from the 24 Volt  PSU. This setup wouldn't work for everybody but it is fine for my needs.

Tweakie.

[BarryB]

A friend of mine has an emergency stop switch for each axis of his machine.  I didn't expect that.  I expected one switch for the whole machine.  What do you guys do?  One switch, or one per axis?  Is there a requirement for a commercial setup?

Barry

[Sam]

I have never heard of having one for each axis. Generally, you need an E-stop (too late button, as I call it) so that you can easily access it wherever your at. Typically, small bridgeport styles have one. The small lathe at work has 3. One at the manual controls, one at the interface, and another close to the door. A machine we're building at the moment has 5. I'm sure OSHA has guidelines.

[Tweakie.CNC]

Hi Barry,

It is essential that you can reach the EStop at any moment. If the EStop is out of reach then by all means add another. Having one for each axis doesent really make sense as EStop is EStop no matter which one you press it will still stop the process.

Tweakie.