Hobby CNC Mill Controller build. Request input...

[Headrock]

Hello everybody,

First of all I'm sorry for posting a way too long post. Especially since it's my first post here...

I'm about to buy an A2Z Monster Mill. This seems to be a better alternative then for instance
Sherline or similar products. Unfortunately A2Z doesn't do the control system only the "hardware"
parts.

So... this project is going to involve everything between the computer (not included) and the
stepper motors (including). I'd like to get help identifying suitable products to get a well
functioning and robust control system. The word 'system' is important to me as I think we
all know that just putting the latest and greatest parts together doesn't automatically make
them function well together. I do however like the latest and greatest geek as I am...

My level of knowledge in putting a system like this together is that I know how to use tools
but I definitely need a VERY easy to understand wiring diagram...

Help me get this working and we can use this thread to create a template for others to use also.
So please pour your knowledge into this.

I will be milling mainly soft steel and aluminium but also plastics like acrylic, POM and PC and
on occasion stainless steel.

What I'd like to achieve is three things:

1. Identify required parts.
2. Get knowledge of how to properly mount the parts.
3. Get knowledge of how to connect/wire the parts into the system.

The system should consist of:

• 5 axis control system
• As much control as possible from the computer. (In G & M-code)
  
  • Spindle on/off
  • Spindle speed
  • Cooling on/off
  • Tool change
  
  
• Limit switches
• E-stop
• Smoothstepper?
• Drivers
• Auto/Semi auto tool changer (this would be awesome to have)
• Touch off tool
• Power supplies
• Charging system
• Stepper motors
• Cables
• Connectors
• Enclosure to mount everything
• Anything else of vital importance that I have forgotten to list... You tell me!

My current thoughts and ideas (which you can completely ignore if you like) are:

* Mach3 on the laptop (has no par.port)
* Smoothstepper ESS
* Gecho G251X or G203V
* Steppers: Gecho has a 400 oz in. (points towards G203V)

* Spindle control. I can read spindle speed on the computer. I have no need for a box on the wall
to tell me what speed it's at unless the box has some other useful functionality as well that cannot
be controlled from the computer. (Many times it's a lot easier to push a button on the wall than it
is finding a mouse and click on a specific button you can't readily find on the screen. Everything has
it's advantages so I'm not ruling anything out...)

* Cooling system should be AIR or Mist. A flood system is way to messy for the amount of time I'm
going to use the machine. It's a hobby machine so I'm not going to be using it every day... And proper
cooling liquid is going bad after a while.

* Multiple e-stop buttons in a normally closed circuit.

* A tool changer would be very nice to have. I know there are at least one semi auto made for the
Sherline headstock. There are probably quite a few different ones in the DIY community.

* Sherline headstock. Is it the best for what I'm trying to do or are there others that are "better" or
more suitable in regards to computer control? Has to be equal or better in robustness too.

* Cables and connectors. Any particular brands that are better than others? Especially connectors can
be of varying quality to say the least. Wire gauges?

* I can always make a box myself or buy a big tower computer case. But sometimes it's not
worth it because someone somewhere is selling a purpose built enclosure for less than what it costs
me to buy materials... Any suggestions?


With this I hope you haven't fallen asleep trying to read all this and again sorry for the long post.

Cheers,
Headrock

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[awerby]

Are you modifying this mill to have a trunnion or something? Is that why you need a 5-axis controller? Do you have the software required to write 5-axis G-code? That's something you might investigate before plunging into hardware modifications.

Have you actually found an automatic toolchanger system for the Sherline? Which one? I've heard of some kits that used to be available, but I'm not sure they still are, and reviews on them weren't too favorable. The Sherline headstock is just fine for use as intended, but it's not the sort of thing that's generally used with automatic toolchangers.

If you don't really need a 5-axis controller, this all gets much simpler. I'd suggest the Geckodrive G-540 4-axis board, which has the cables and breakout board included and will control your spindle speed and the other outputs you want. 400 oz-in motors are overkill for a mill that size; ask Geckodrive for some that are more appropriate. Dan Mauch at Camtronics sells a box designed for the G-540, although you might get your own fans, plugs and switches for it. You can use a 50v supply with that board, which should be ample to get full speed from your 23-frame steppers.

Riunning Mach3 on laptops is not recommended. They have power-management functions built in which won't shut off that tend to kick in at just the wrong moments. I'd suggest getting a desktop instead. This setup should be able to handle mild steel if you take it easy, but I wouldn't count on being able to mill stainless very effectively, since it needs a lot of torque in the spindle to avoid work-hardening at the cut.

But good luck with this, and be sure to write back and tell us how it all works out.

Andrew Werby
www.computersculpture.com

[Headrock]

Hi Andrew,

As for the number of axis's let's just say that 99,99% of all hobbyists will only
NEED three. I WANT five for the education and experience it will give me but
do I NEED it? No, I don't but that is beside the point of this thread.

I'm fully aware of the G540 and that it would make life a lot easier. I've seen
the Camtronics box and it looks very well designed but it's designed solely for
the G540. Before I came here I actually was thinking about buying it but then
decided I want the 5th axis.

I'm also not only thinking about myself as I'd like to see at least one "generic"
model for how to build a more than off the shelf control system and in theory
we should build a 6 axis system. There are many build threads on the
net and they are all purpose built for one thing or another BUT the builders in
general show a video and/or some pictures but they rarely share any plans or
schematics likely due to they don't have any. Lets create some together.
From this anyone should get a good understanding of how things work and if
they only need 3 or 4 axis's they can go with the G540 and the Camtronics
box and easily set the rest up as needed because they will know howto from here.

There are many cool accessories to these hobby mills and a small trunnion
table is one of them. No need to modify the mill as it's a bolt on kit.
You can see it on youtube. watch?v=w0-tXDEvAqg

As for the tool changer I had this one in mind
Home Shop Accessories Inc.
but I'm sure there are others.

Thank you for the laptop info. I hadn't considered that. Maybe I'll get a
RoBoard NCBox-189 instead of the laptop for this.


Cheers,
Headrock

[Fastest1]

Joe Vicars tool changer as you linked to is not available as a kit anymore. There might be a few singular parts available but I doubt it. I have used the tool release from High Tech Systems but it slipped in the spindle and has since been discontinued. Regarding 5th or 6th axis, from my understanding as stated above, the price. Hoss had mentioned that too in his exploits.