My first CNC build (Micro Mark mini mill)

[neity]

Well I'm extremely new to this type of metal working, so please forgive me (and correct me) when I use the wrong words or am completely wrong! I am an electrical engineer with more of a background in woodworking and engine repair.

That being said, I recently picked up a micro-mark mini mill to do mostly aluminum work. I bought it intending to do the CNC conversion regardless.

I just bought CNC kit #2 with ballscrews for all 3 axis and mounts. I am waiting for that to come in the mail. I was following a build by as he seems to be the only person I could find with the micromark. I've been in touch with him and he has been extremely helpful!

So on to my current question...I need to order my motors, controller and power supply, and I'm not quite sure what the best thing to get is.


I emailed them asking about a custom package using (2) 270oz for the x/y and a 381 oz for the z with a G540 controller.

They suggested the following package:
NEMA23 381oz/in 3.5A 1/4” Dual Shaft Stepper Motor (KL23H2100-35-4B)
$49.00
NEMA23 270oz/in 2.8A 1/4" Dual Shaft Stepper Motor (KL23H276-28-4B)
2x $39 = $78.00
Gecko Diver G540 4 Axis Driver Module Gecko Diver G540 4 Axis Driver Module $234.95
48V/10A Switching CNC Power Supply (KL-480-48) 48V/10A Switching CNC Power Supply (KL-480-48) $109.00

Also on their site is this: [a kit with all 381 oz motors]

Which is a "kit" they have ready to go that includes all 381 oz motors. My question is will these be fast enough on the x-y? I don't have mass production runs planned, but I am going to do significant roughing of block aluminum which will take many passes, so it would be nice if I could bang simple operations out fairly quickly.

So since mhackney said that his knowledge might be a little outdated, he sent me here! I am wondering what the best package is that can get me through the milling I need to accomplish with the smallest amount of money. I guess my budget is around 500 and all the packages seem to be about that anyway, so that just adds to my confusion!

At the moment I don't intend to add a fourth axis, but I would like to have the capability.

Thank you!

Also, what type of clean-up and oiling should I use before I install the ballscrews. I've had the mill a couple months and been doing manual milling, trying to get the hang of it. I am almost certain my gibs are too tight. I need to rip this thing apart and get it fixed up. I didn't do much out of the box because it was a micro-mark, not a harbor freight. Everything from the freight needs the HF treatment, but a selling point on the micro-mark was that it didn't.

*had to delete all links because its my first post

[Winnfield]

You might be able to save yourself an afternoon or so by just buying a pre-assembled unit. It is bare bones, but would be more than adequate for a mini mill. The last time I talked to the seller, he had some 381oz. motors he was willing to substitute.
The 381oz. motors with a G540 can take the mini mill to its limits, so it will be plenty fast.

gecko 4 axis drive 4 taig maxnc sherline cnc lathe mill | eBay

[neity]

I have no problem soldering the db9 connectors or worries assembling the controller parts and im not in a rush so if i can save 100 bucks doing it myself i will.
To be honest i was kinda looking forward to that part!

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[neity]

Also i noticed hes using three 270 oz. Is a 270 enough umph for the z axis?

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[mhackney]

Hey neity. welcome aboard!

AS for cleanup, Simple Green is what i use and recommend but many others (and me on occasion) use WD40 too. I usually use Simple Green to get all the cosmalene off and then do a light wipe with WD-40 on a rag just to add a little surface protection.

cheers,
Michael

[hoss2006]

Go with the 381 oz/in motors, they are a better match for the g540.
Hoss

[neity]

Go with the 381 oz/in motors, they are a better match for the g540.
Hoss

Just curious as to what makes them a better match?

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[hoss2006]

They have amperage and impedance that will get great performance at the
amperage and voltage the g540 runs at.
More info here.
G0704 Electronics
Hoss

[neity]

So... this guy? G540 3-Axis NEMA23 381oz in PSU48V/10A | | Automation Technology Inc Automation Technology Inc

They have amperage and impedance that will get great performance at the
amperage and voltage the g540 runs at.
More info here.
G0704 Electronics
Hoss

[hoss2006]

There you go, you'll be very happy with that.
Hoss

[neity]

There you go, you'll be very happy with that.
Hoss

You hobby forum people are great! Nothing but the best help with no douchebaggery. This is really only the second hobbyist forum i've gotten involved in, but I the help here is great and fast! If anybody needs help with electronics, some day maybe I can help someone else out getting started.

Leads me to a quick question...Before I re-discover the wheel, anybody ever mess around and figure out what kinda data that DRO for the RPM is spitting out? If there is any interest I've got enough oscilloscope channels to figure it out. I mean LMC and others wanted like 100 something bucks for that simple LCD display. If it hasn't been done, the worst case is it takes a 5 dollar micro-controller to interpret the output and convert it to display on an LCD. I could easily make those things for 50 bucks in a nice enclosure.

So I have the machine completely apart (aside from the head) and am going to hit it with kerosene (Page 9) and then oil.

Hopefully my ball screws and then motor kit will arrive soon. I think I can have this thing up and running by next weekend.

I'm a little nervous sanding the tracks, dovetails, and gibs. Besides the tutorial I linked to, any suggestions? How do I know how much is enough...what about too much??? I read that it should be smooth, but still able to hold oil. What kind of oil do you guys suggest for the dovetails while in use? What about the ballscrews? Should I wait until the motors come (ordered ball screws first, waiting on motors) until I put this thing together? Or is it as simple as attaching the motors to the mounts and doing some easy soldering? (This should be a cake walk compared to doing SMT by hand). Also while it's completely apart, any suggestions that that article may have missed?

Should I add a counter weight or air spring conversion? mhackney (I think) said that with the ballscrew z axis, you no longer need any kind of counter support for the z axis, that the stepper holding torque takes care of that. That being said, I think of the thing as an elevator, and the less force needed to move an object in either direction, not just one, saves motor life, making me want to include some kind of stored energy mechanism to help returned the head upright (at least for commercial elevators this makes sense to me).

Anyway, I know I have a lot of questions in this post, but overall wanted to say thank you to you guys.



Thank you hoss for your advice on the drive/motors. I'm new to stepper motors.

[arizonavideo]

You really don't want to sand on the ways much at all. They don't sand well with oil but dry they will.

To remove high spots I use stick on 220 grit automotive paper onto a milled flat block.

400 or so might be better.

One thing you can do is to clean all the oil off the ways and by hand run the slide up and down and let them break in on themselves.