Looking for parts to make CNC plasma table

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Farr0wn3d
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Looking for parts to make CNC plasma table

Post by Farr0wn3d » Sun Jul 05, 2015 9:40 pm

My brother picked up a home made cnc plasma cutting table setup, only thing is the stepper motors look old as hell, and they're rated at 4.5v @1.4Amp, and he doesnt have a controller for it. this table was made ten years ago, and I figured that there should be a pretty simple combo that could be had to run 2 stepper motors of a Rambo or something. Any suggestions for what parts would work would be awesome. I also dont know much about what software would work or maybe simplify3d would work for a 2d application.

All it really requires is 2 motors with enough torque to move a 100lb gantry back and forth, and a switched output for activating the cutter

wmgeorge
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Re: Looking for parts to make CNC plasma table

Post by wmgeorge » Mon Jul 06, 2015 11:30 pm

Having owned the Cadillac of plasma cutters the PlasmaCAM I know a little. It was neat to run but I got tired of the plasma dust and handling the steel. It seems that the Mach III controller is kind of the default for homebrew plasma cutters.
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pyronaught
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Re: Looking for parts to make CNC plasma table

Post by pyronaught » Tue Jul 07, 2015 5:54 am

Rambo is specific to 3D printing and the stepper drivers don't have the power to drive the larger motors you will want. Simplify 3D is also specific to 3D printing, you need a more generic CNC control software. Mach3 is a common one that hobbyists use and is reasonably priced. You can get decent prices on steppers, drivers, control boards, power supplies and all the other stuff you will need to rig your machine up to a computer and run it on Mach3 from this place:

http://www.automationtechnologiesinc.com/

There are many other places selling the same items, but the above company has the best prices that I've seen and that's where I buy mine from. You are also going to need CAM software to convert your CAD files into G-code that is then read by Mach3 and sent to the machine. I use CamBam, which is about the same price as Mach3 ($120 ish). Then there is the CAD end of things too, which is the most costly part if you don't already have a CAD program. So that's three layers of software you are going to have to deal with, none of them being trivial programs.

There's a pretty big learning curve on this subject if you know absolutely nothing about it. The better forum to use for CNC is cnczone.com
Experience is what you get when you didn't get what you wanted.

wmgeorge
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Re: Looking for parts to make CNC plasma table

Post by wmgeorge » Tue Jul 07, 2015 2:06 pm

Then there is the THC (torch height control ), you will maybe want to add. The other issue is the plasma cutter you will need to use with the table. Not all plasma cutters can be successfully be triggered remotely and then often they interfere with the electronics. Its a fun project, but lots of little problems to solve. And besides CNC Zone, you might look at the Machinist Home Workshop forum.
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Farr0wn3d
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Re: Looking for parts to make CNC plasma table

Post by Farr0wn3d » Wed Jul 08, 2015 1:13 am

Currently I use 123d for my 3d printer CAD designing, and it has an "send to CNC utility" option, do you have any experience with this? its free software that is well equipped for my skill level and i'm comfortable using it.

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Farr0wn3d
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Re: Looking for parts to make CNC plasma table

Post by Farr0wn3d » Wed Jul 08, 2015 1:36 am

would this kit work for my setut? What else would i need besides software?

http://www.automationtechnologiesinc.co ... it-small-2

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pyronaught
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Re: Looking for parts to make CNC plasma table

Post by pyronaught » Wed Jul 08, 2015 2:28 pm

Farr0wn3d wrote:would this kit work for my setut? What else would i need besides software?

http://www.automationtechnologiesinc.co ... it-small-2
I have no experience with plasma cutters so I don't know what else you might need that would be specific to that kind of machine, but I would think that since there is no tool head pushing against the part that NEMA 23 steppers should be more than strong enough. As long as you don't need a third Z axis then I would think that kit should work. You will just need to build a case to hold the electronics and you might want to pick up one of those big red stop buttons. If your machine doesn't have limit switches you'll need to get those too, and be sure to get shielded four wire cable to hook up the steppers, as well as shielded two wire cable for the limit switches. Without grounded shields you will have all kinds of noise problems. Build your control box so that the cable scan be easily detached using round, threaded DIN connectors too. You should be able to find pics of cases that others have made to use as a guide.
Experience is what you get when you didn't get what you wanted.

wmgeorge
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Re: Looking for parts to make CNC plasma table

Post by wmgeorge » Thu Jul 09, 2015 10:14 pm

I thought you already had some stepper motors? You will also need to either build or buy a pretty hefty power supply. Don't go by the motor voltage you need much higher voltage. You will need motor drivers and then usually a Mach III controller the older ones required a working parallel port computer but now the break out board can be had for either USB or Ethernet connection. Do some searching there are lots of people doing what you want to do and with milling machines, routers and lathes. This site here has so much good info and I have used their motor drivers and they are the best.
Link> http://www.geckodrive.com/

For just plasma cutting any good 2D program will work.
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pyronaught
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Re: Looking for parts to make CNC plasma table

Post by pyronaught » Fri Jul 10, 2015 1:41 am

Another thing you might want to consider, which is not mandatory but can get you some piece of mind, is a Smooth Stepper board. What it does is offload the stepper pulse generation to a dedicated processor on the board so you don't have to rely on the PC to supply that pulse train. This gives you a much more reliable signal to your steppers that is not prone to glitches when some background task hogs your CPU and it misses steps. The board costs around $120 and connects via Ethernet. You still need the serial port breakout board too, it just plugs into the Smooth Stepper instead of directly to the PC. So you have Ethernet from PC to smooth stepper, then breakout board between the smooth stepper and the stepper drivers. Mach3 has built-in support for using Smooth Stepper.
Experience is what you get when you didn't get what you wanted.

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Farr0wn3d
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Re: Looking for parts to make CNC plasma table

Post by Farr0wn3d » Fri Jul 10, 2015 6:47 pm

yes there are 2 old stepper motors with the table, but they're 15 years old and rather than run the risk of them not working I think he would rather start with new, working parts (especially ones that can be replaced easily) and go from there.

on that note, I should have asked up front what he could expect to spend to get this fully functional, as that may end up being a non-starter if it's excessive. thoughts?

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