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Newbie
« on: March 16, 2011, 06:45:46 PM »
Like many I suspect, I have been thinking about building a CNC machine.
I started in the dead of the winter here in the Northeast.
I started by building a manual version, X-Y-Z wood mill, with hand cranks.
Worked out the bugs and I can etch-a-sketch on a sheet of plywood.
Repeatability is +/- 0.005 in each axis.
Next I calculated the torque I needed in each axis, then verified it using a gauge, the static break-away values anyway. The dynamic torques should be predictable given the frictional loads and mass.
I know the gearing so I know the torque and speed well enough to select the motors.
Simple so far, in retrospect anyway.
Now I need a bit of direction.
Somewhere between Mach3 and the motors we need a bit of stuff.
First a computer. I will get whatever computer makes sense. They are cheap and powerful by any measure. One problem though; most new ones don't have serial or parallel ports. They all have Ethernet and USB.
Next, I seem to see a plethora of motor drivers and some motion controllers. Not everyone plays nice with each other.
If anyone would be willing to suggest a path and products I would be grateful.

Mike

P.S. I am reasonably adept at computer stuff and software development in most systems and languages. I'm modestly capable mechanically.

Offline Hood

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Re: Newbie
« Reply #1 on: March 16, 2011, 06:54:14 PM »
First thing is serial is no use, has to be parallel port unless you use something like the SmoothStepper that can work from USB as it does the pulsing rather than using the driver in MACH.
Also worth mentioning is most modern computers do have parallel ports still, just it is a header on the mobo and you need to get the cable/plug.
Are you planning on steppers? If so what size?
G540 from Geckodrive might be worth a look if your motors will be under 3 amp each.
Hood
Re: Newbie
« Reply #2 on: March 16, 2011, 07:12:20 PM »
The X axis run about 1100 oz in - about 8A bi-polar, the Y is about half that and the Z is the same as the Y.
I'll take a look at the Geko line.  And THANKS!

Offline Hood

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Re: Newbie
« Reply #3 on: March 16, 2011, 07:14:45 PM »
You will need the G201X (or whatever they are designated) Other options would be the Chinese stepper drives that a lot sell, they are fine as well but I would say the Geckos have a slight edge.
Hood