This is a good idea. I too need to build a plasma, but since "all" the parts are already around I will need some adaptive design.
That rules a lot (all of them?) ready made "diy designs" that go like 1) buy this and that; 2) make someone do it for you 3) screw together 4) congrats, you are a builder!
I know that much can be done when you have more time and "stuff" than money. Maybe not all can be done, and I know there are still people who have more money than tools, time and stuff. They would need good *complete* plans, with drawings ready to send for laser cutting and the welder.
Because of the essentials I was thinking about the wide gantry - one linear rail with two THK carriages which are not the 6 circuit type but some that is much less rigid - i think this could use gravity and single wheel on flat surface parallel to the rail, otherwise it would rotate about the rail a little bit too much. The rail is a bit over 2m, and the ground flat thing even more. There is pair of something too for the shorter side, and being able to input bigger plate, or possibly having two ends of 2x1m of different thickness or kind laying on the table together is a favorable option.
I was considering some funky options, like a plasma frame that can be hung above the table/material to go up where not needed, or to be set 90deg on one side to be standing next to wall. Even some fantastic design where plasma is above the workplace, and pieces fall down on the floor (no, that may be too much. But I will upload an inspirational train-like photo).
Having this thing sliced into compatible modules, possibly that can be choosed from, like the kind of table to build would be great. With parametric design parts just need to be scaled correctly and the method of construction would be the same - like bolted or welded frame joints, with of course different tubing.
How many of You are using FreeCAD? If not, I suggest looking at it... This would make this "project" quite open source, easy to modify AND parametrical. This is one cool feature of freecad, there is a spreadshit (sheet?) thing, where you can input and calculate data. Later on with any operation you can pull in the dimensions from that. It takes a lot of patience waiting to recalculate a big project after a change but it is definitely the way to go. With the Techdraw module getting better we will soon have correctly auto-updated drawings and documentation, and this is propably the most important when trying the not-you to understand and recreate the project. Similar to rodw, I use "some" drawings with "some" dimensions that I at a time need for the detail machined. For anyone else that would be too little info.
I have had success using that to generate g-code "jobs" for machining a MDF front panels, it worked kind of cool when all that was needed was X and Y size and pattern type - all input as the shell script parameters, that would use FreeCAD (with no GUI needed!) to recalculate everything and spit out .nc file on the network drive. Can it get more CADCAM? Click I want my plasma.
Also I see one thing that is not very official common knowledge: the cut quality. "Go buy hypertherm and look up the table in the book" kind of answers. Both of You have a lot of experience and this thread could put some light on that. There is a number of things: air quality and what kind of quality and dross can we expect from a cheap chinese cut-40 plasma? DO I really need to hit that with hammer to make it go away, when it is good quality and grind off when it is not that good? Can a different kind of torch alone make a big difference, when using *just* pure air? How about stainless, generally? Other inert gasses? What about the plate immersed in water, and then about the torches with water injection? It may be a lot for this topic (maybe it can to other linked topic). I am quite sure that when I need more than 40 chinese amperes I can build a bigger power supply from free/scrap parts and that will be about 5% of a "great" plasma. Or use oxy-propane on the gantry if I'm not cutting alu/ss (I was wondering about using ultrasound/laser distance meter for alternative flame THC too).
Right now I would be happy to have nice 2mm thick parts with holes and some straight slots for bending.
Also, having THC directly in EMC as rodw first tested (positively?) would mean the cost can drop further and possibilities expand...
Thanks, I hope it is not too much.
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