Mach3 and the spindle control

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MTBcrazy

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All the info I have gathered regarding mill conversions, lathe conversions, building a home CNC machine etc.. All describes controlling 3 or 4 axes using Mach 3 or similar software driving stepper motors and ball screws. I am really not finding answers about the detail on the spindle itself, which I would assume is the most important aspect of any machine. Videos on YouTube all demonstrate the steppers for x, y, and a axes, but nothing for the spindle.
initially I was of the impression that one could use a stepper motor for a spindle drive...although now I am no longer convinced.( I am talking for a milling machine or lathe specifically) engravers or routers is definitely not a consideration.
now I am trying to decide whether it is better to use a DC motor with controller or an AC motor with a VFD. If going for the AC option then does one still control the spindle speed with Mach 3 or manually on the VFD?
I have ordered a Nema34 stepper from China which I will use to try and drive a spindle with, but will change to AC with VFD if this is really unsuccessful. Once I have a spindle built I will carry on with the rest of the machine.
i guess I am going to build a machine around the spindle arrangement.

just waiting for the Chinese New Year to be over then hopefully I will get my first few goodies to start playing with.

i would appreciate comments on this....
thanks
Rob
 
Your spindle can certainly be controlled by Mach. The choice in spindle motor would be more dependant on machine size and what your work will be. DC motor with a speed control is one option, 3 phase motor with VFD is another. I don't think you will have much luck using a stepper for a spindle motor as it looses it torque at higher speeds. It's primary job is to position and then reposition.
Treadmill motors have been the latest fad for spindle motors, plenty of information out there on them. They can be had pretty cheap and torque is not an issue. Any speed control that can accept 0-10 Volt input can be controlled via Mach.
If you can provide us with more machine information I am sure someone will be able to suggest a path to follow based on experience and help get it running too. Most of the hobby machines have been modified to increase rpm and decrease noise using a belt drive replacing the built in gear heads.

Chris
 
Steve (Jumps5) may be able to help you get this figgered out. He has converted a couple of machines to CNC and uses Mach 3, Give him a shout and explain the issue you are having and he may be able to help you fix it right quick and pretty easilly. Hope this jelps get you going.
Bob
 
If you're doing a conversion on a G0704 (BF20, etc etc) - the motor controller in that is very easy to convert to Mach control.

You can get a board from (really hope I'm not violating rules by dropping company names!) CNC4PC.
I've got the C6 board,and it ties right onto the existing speed control. It interfaces with Mach, and you have direct control.

They have other similar solutions for different applications too.
 
Dr.Fiero said:
If you're doing a conversion on a G0704 (BF20, etc etc) - the motor controller in that is very easy to convert to Mach control.

You can get a board from (really hope I'm not violating rules by dropping company names!) CNC4PC.
I've got the C6 board,and it ties right onto the existing speed control. It interfaces with Mach, and you have direct control.

They have other similar solutions for different applications too.
Click to expand...

Hi, any chance you could be a little more specific with the connection of the C6 board to the existing controller? I have a G0704 that I will be eventually CNC'ing and would love to know the details on this.

Thanks for your time and info-
Dave
 
Thanks for the input so far.....essentially I want to build a machine to get some experience with computer control. The machine to be built will compliment my existing lathe, an optimum 280 x 700 vario. This is driven with a 1.5kW motor with a VFD. If I get the mill right then I will possibly look into upgrading the lathe as well to CNC. I will look out for a treadmill motor on eBay. Although not many of the sellers ship to South Africa, and to buy something here is going to be quite expensive. I'm sure I will find something soon.
 
After watching ebay for a few days I ended up buying this..
http://www.ebay.com/itm/360596501176?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
It is only 660W but might be more in line with what I have in mind and it was only $9.99 plus $60 for postage. Now I have to figure out what I need to drive the motor, and whether I can get something reasonably cheaply off ebay as well.:)):))
I see there is a web site http://www.automationtechnologiesinc.com that deals in these motors for CNC and offer a motor controller, if I can't find something slightly more affordable.
I will possibly use the Nema 34 stepper to drive the z-axis. this motor is quite heavy at 4 kg's
Any suggestions on an alternative speed controller... thanks
 
You weren't planning on using this motor as a spindle drive were you?

It's a stepper.
 
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