CNC Plasma Table

[B&M Welding Inc.]

Just sharing one of my major projects of the year. Built & wired completely from scratch. End weight is approx. 4500 lbs. Has a 21" touch screen. Slag conveyor in the bottom for clean out. Downdraft fan for smoke control. Has a 80a. Hypertherm 1250 now but I have a used High Def. plasma to put on it now.

[B&M Welding Inc.]

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Here is a shot of the computer. I had a fiberglass enclosure now I have a TIG welded steel one that mount on 2 1/2" SS header pipes/elbows that I also TIGed together. Now the whole computer box can turn to any angle.

[Type]

Wow nice table. I was looking at building one but to do so I would need a new plasma cutter and can't afford to buy a plasma cutter and build a table.

[B&M Welding Inc.]

Thank you for the comments! This was my first attempt at building anything CNC. I tell everybody that now I would like to start over with a clean plan again, because I made all the mistakes on this one, now I know how I would like my next one to be built. ;-) It definitely has been a good experience I still make improvements to it every couple weeks.

[H80N]

WOW... First CNC Project..?? Impressive...!!

Really nice piece of work..!!!

Professionally done... big project..

could you share some construction and operating details??

Steppers/Servos,,?? racks/belts/ballscrews..?? travel speeds software..??

etc....

The scale and depth if it is amazing... smoke control?? slag conveyer?? computer environmental enclosure??...... WOW...

[B&M Welding Inc.]

Thanks! Some thoughts that went into the base design. With a solid welded boxed table with fork pockets this table can be picked up and moved to a new location any time with no worries about leveling/squaring when done. My shop floor is in poor shape so I wanted something that wouldn't depend on a solid level surface for structural integrity. I went with a T shaped single side drive gantry to keep the steel loading side minimalistic. I didn't want to have a motor or drive system vulnerable to damage when loading steel. The only downside to that concept is that I had to use a 4200oz. in. stepper motor for the Y axis and I get a little bit of flex in the T shaped gantry from being driven only on one side. The X&Y axes use a 4-1 gearbelt reduction that is enclosed in the alum. boxes on the steppers. At the bottom end of these boxes is a short jack shaft with a pinion gear that meshes with the gear rack welded to the frame. This type of drive seems work very well. I have had zero maintenance or backlash issues with this type of drive. I used 3/16" steel for the outside skirting. The inside skirting is 1/4" to minimize heat distortion and that slope inward from the cutting area which is 52" wide down to the conveyor at the bottom which is 36" wide this allows for about a 10" airspace all around the inside of the 3/16"skirting. Inside that airspace I have a fan to blow the smoke outside. The inside 1/4" skirting stops about 4" off of the conveyor so the smoke goes down to the bottom of the table then out. Hope that'll make sense!

[B&M Welding Inc.]

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[H80N]

Just slightly off topic...

Noticed you are running a PM1250 power supply.. great unit..
(I have a PM1000 on my PlasmaCam)

do not know if you are aware... but Hypertherm has a series of very good and free webinars on cnc plasma.... and Jim Colt is a super guy and resource on the subject..

http://www.hypertherm.com/en-us/Training_and_education/Webinars/

[B&M Welding Inc.]

More on the electronics!

Here is some pictures of my control box. When I built this I was on a budget so I just used the cheapest of everything I could find on eBay! That worked for some components, not to well for others. The steppers and drivers are Long Motors, seem to work very well and are cheap. The motion controller is an Ethernet Smooth Stepper mounted on a CNC4YOU breakout board. I originally used a cheap USB motion board but that didn't support the torch height control function very well so I switched to the ESS, love it too!! My computer is a Dell 2020 all-in-one w/touchscreen. Running Win. 8.1 with Mach3 CNC control software. The electronics all work great right now other than my THC needs to be upgraded to a higher quality system before I use the HD3070 unit that I'm installing. The steel scrap is 3/4" cut with the 80A 1250 Hypertherm.

[PlasmaGuy]

Nice work

When you said 4200 oz/in I had to take a double-take. That is a HUGE stepper.
Are you expecting any HF issues with the 3070 and your electronics?

Thanks for posting the pics.

Tom

[B&M Welding Inc.]

Yes that is a huge motor. I guess it weighs near 20 lbs. I am working on some grounding/filtering procedures to help combat interference. I'm open to ideas on how to deal with HF interference.

[B&M Welding Inc.]

Double post. This iPhone app ain't too up-to-date!

[H80N]

Yes that is a huge motor. I guess it weighs near 20 lbs. I am working on some grounding/filtering procedures to help combat interference. I'm open to ideas on how to deal with HF interference.

You might look at some split Ferrite beads and or torroidal cores on some of the lines to help attenuate some of that RFI

[B&M Welding Inc.]

Thanks for the reply! I have some ferrite choke that I am putting on. I also am working right now at putting in a couple 10' ground rods in the shop floor to ground the control console and plasma power unit separately.

[H80N]

a single point ground is a better idea,,,

multiple grounds encourage a difference in potential.... eddy currents and oscillation...

every piece of wire can look like an inductor when subject to an AC field...