Plasma/oxy/Router table build

[JT-fabshop]

Hello from Wisconsin

Just joined looking for opinions. First a little about me. I am a robot technician/programmer with 12years of fabrication experience in manufacturing ag and mining equipment. I very green when it comes to electrical side of robots and these CNC things learning but just not there yet.

I currently just finished installing 3ph 480v power in my shop to run equipment I acquired from my job and am going to try to start my own fabrication business. my goal is to have this table in operation by June of this year I travel globally for work so we will see how that goes lol.

I would like to build a 5x10 table that is capable of running plasma(hypertherm1000) oxy-torch and a 2.2kw spindle. so far my designed gantry by itself is sitting at 83lbs without motors or cables and hoses for gas and torch. I understand that its not ideal to mix plasma and router cause they don't play nice one is a turtle and the other is a spaceship but I don't have funding to build to tables currently.

Table is 5'6" long the X axis where the water pan will be 10'7" long along the y axis I also have a 16in over hang for the router for spindle turning and some other ideas I have I am not done modeling everything. but the gantry should be done minus the z slide was thinking supperz2 or avidcnc's z axis.

I was looking at the candcnc kits but am concerned the gantry will weigh to much for plasma cutting thinner metal?

what should I start looking at for motors, controllers and software to run this?

steppers vs. servo?

mach4 vs Linux ?

best z-axis to handle the weight of a spindle for 2.5d carving?

gear reduction ideas from what I read on here for servos I'm looking to be around 10:1 steppers 3:1

I'm using 23mm linear rails for x axis will be installing bellows on all linear rails to protect from dust and slag.

cross section of gantry is 3x6 aluminum extrusion with 5/8in thick 6061 up wrights.

I'm currently trying to learn fusion 360 and I'm getting my weight's from the software which I pretty close to spot on. The extrusion that I ordered the material weight from 80/20 was only 4oz off of what fusion says.

I've attached some pictures hopefully they come through.

Thank you for the help in advanced. And sorry for the long post.

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plasma table build (1).pdf

[adbuch]

Welcome aboard JT! It looks like you have a nice design. I am not a DIY plasma table builder, but I'm sure some of the more knowledgeable folks will chime in with some recommendations for you.
David

[cutnweld]

I think Candcnc rates their stepper system for up to 100 lbs gantry weight with 3:1 reduction. I'd by all means use servos, esp for a multi use table where you need broad torque band. I am just in the beginning steps of trying out clearpath servos with linux. Haven't even got my parts yet and I know I'm going to need a lot of help to get it going but I really want to learn. There's probably lots of options out there but they have a great selection of RPM and torque motors. For example if you dont want 10:1 gearbox(and I dont blame you, I have that currently) you can select a slower speed higher torque motor and just run a belt. Of course keep your resolution and speeds in mind. for example Candcnc 100 lb stepper system are rated at 620 ozin. Or you could buy an 1844 ozin from teknic with 840 max rpm with 6400 count per revolution. I'm in the middle of an engine rebuild right now and some reason cant get my brain to switch and figure out what speed and resolution that would give but I think with 2 of those on the gantry it would sling around OK.

[cutnweld]

But I shouldn't brag them up cuz I haven't even tried them yet

[Thor]

Where in WI? I'm about in the middle, more than welcome to come take a look at the one I built a few years ago.

A pic here:
viewtopic.php?f=3&t=16818&p=97535#p97536

Build log in my shop thread on Practical machinst, starts about post 16
https://www.practicalmachinist.com/vb/m ... op-298190/

[JT-fabshop]

I'm in Columbus (so probably not far from you) just read through your entire build. very nice build.

I'm leaning towards servos for the constant torque. I feel it would better suite the multi process table better than steppers I was looking at the clearpath 1700oz 34 frame motors. if I understand all this correctly (been planning this for 2 years now) being servos are constant torque if I gear them 10:1 and set my rack up correctly to get 1200ipm rapids. I should have enough torque to run the router at say 100+ ipm with a big enough spindle? or am I thinking about this wrong ?

As my understanding is that steppers loose torque as they speed up where servos don't run out of steam so I could run them wide open for plasma and slow and steady for router and oxy torch.

the part that I'm getting lost at is how to tie it all together so you have the servos and the servo amps/power-supply's. what THC do I run how do I tie it in. what is telling the servo amps to do what ? I learn best with physical things in front of me. but I don't want to order the wrong things and be out a bunch of money cause I didn't fully understand what I was doing/thinking.

my goal is to try and build it as best as I can without having to rework issues down the road.

Thor where did you get the gear boxes from I was thinking doing belt reduction 3 to 1 and then the remaining with rack and pinon everything on our robots is belt reduction and we hardly ever need to replace or sell replacement belts. unless a customer smashes the arm into something solid multiple times which usually ends in multiple other issues like a bent forearm and cracked arms.

[dodom]

If this is primarily a plasma table or even a router table the advantage of servos over modern steppers is marginal give the higher cost and complexity of the electronics. You might consider looking at hour G5XL bundle with the big 34 steppers and the updated LINUX based CommandCNC control software.
The G5Xl takes the place of the old Plazpaks and we will be offering a servo version of it using BLDC motors with embedded drivers .
Unless you have a 200 lb gantry or are doing heavy milling/routing you don't need a lot of torque . Some of the requirements for having high acceleration to keep velocity constant on turns and corners is a MACH limitiation. In CommandCNC we have real time access to the motion and the actual feedrate that allows us to do predictive antidive on corners sna sharp turns. Since CommandCNC is a better trajectory planner and is optimized for accuracy it follows the toolpath closer and adjusts its velocity to hoold the accuracy rather than the speed . Just like driving a road course it adjusts to the path and the VAD we have controls the DTHC on/off instantly .

[Thor]

I got the gearboxes off ebay, was a fluke really to find 3 identical zero backlash boxes for cheap.

I went with Dmm servos and DYn4 drives. Not sure I would do that again, maybe clear paths instead. Servos are nice for speed and accel, but running on Linux (Command CNC) there is no position feedback to the controller so the benefit of not loosing steps is not there. Still controlling them with step and direction signals. Unless you find a higher end control system that still has a nice THC and controls the servo drives with analog, which I doubt unless big bucks.

I'm probably 1.5 hrs North of you, but as I said if you want to come look mine over and talk about things I'd do differently etc let me know.

[JT-fabshop]

DoDom

With the G5XL package what would be my feed rate limitations on a 125lb gantry at I would assume 3 to 1 if they are stepper motors ? I would like to router solid wood doors but don't want to run at 20ipm with a 3/8 or 1/2in end mill like a lot of the home brew cheap router tables for the rough cuts.

90% of the time at this point it will be used for plaz/oxy for cutting trailer components and panels.

I have some big remodeling jobs wood working wise in my house I would like to do with a cnc router that's why I want the ability to be able to slap a spindle on since I have the expensive machine there already pretty much.

Thor
I sent a pm