Hello, its been great to connect with some of you so far the last few days in the hackerspace. I’d like to share with you my intent to create the Byron Bay Maker Space.
One of our goals is to collaborate with Open Source Ecology in designing an open source CNC oxy torch/plasma cutter.
Plenty of DIY systems like this have been put together, but many are from salvaged parts so there is no standard approach and it is not easily replicable. Replicability is important for progressive improvement from a baseline from version to version and for distributive enterprise.
My current approach is to learn from building a lasercutter and a router, and move from there.
The laser cutter I’m investing in is a Lasersaur. It’s a pretty expensive way of making an open source laser cutter, but it is a very solid and nice platform to work with.
The shapeoko 2 is an open source router. I hope to combine the best of both those systems after they are finished and made available to the byron bay maker space.
I’d love to here anyone elses thoughts if they are interested in this. We could also potentially do the builds of these systems in the Brisbane hackerspace potentially before moving them to Byron Bay.
Once you have completed a lazer cutter you should have no big problems doing a plasma cutter, as they are basically the same type of system but without lazer focusing issues. Unlike oxy\fuel gas cutting there are no risks with the tool becoming extinguished, nor any big dangers if the the tool pinches its own lines ect (even the electric shock you’ll get touching the tip isn’t a major issue unless you have existing heart conditions, same as a welder).
The biggest potential issue that CNC mills\lazer cutters won’t prepare you for is plate warping. This typically doesn’t happen when cutting out big shapes, but when you are either putting a lot of cuts into a very small area or cutting out smaller shapes (like letters\numbers) it can sneak up on you quite quickly. A simple fix is to have the torch head have “skids” that sit ~0.5mm off the plate your cutting, and ensure the plate is firmly secured to the bed. That way if it warps the head will keep it pinned down and thus at the right cutting height\angle. It also prevents it touching the tooling on anything, which avoids damage when something goes wrong. Unfortunately this also prevents you having any raised sections within the width of the skids from where you are cutting.
One other thing to note is you will need a very chunky air compressor as plasma cutting with anything that’s not a hobbyist toy has a fairly large air flow rate, and if pressure gets low it can destroy the cutting torch. Best of luck with your project, sounds like it’ll be good fun!
im guessing if you were relying on the pressure of the head to stop plate warping, that this wouldn’t work with very thick steel (1.3cm), but perhaps if its this thick warming caused by the plasma may not be as much of an issue either. I wonder if its only a problem with thinner material.
You basically guess correctly that warping is more common in thinner plate, its nice and intuitive so once you start to think things through it tends to fall into place very fast. If you start warping anything thicker than 3mm your either doing something crazy (which I fully support =p ) or you’ve got your settings wrong (normally too slow of an cutting speed, but it can also sneak up on you from incorrect cut order as well, particularly if your running low acceleration. But like I said before, its pretty intuitive so once you’ve done the lazer cutter you’ll figure it out really fast. Not that it’d hurt to build your system like a bulldozer anyway, but given the last plasma cutter system I worked with had 5 cutting heads working on a 40mm thick plate, for your application “overbuilt” will certainly vary.
Something I should have mentioned last time is the basic safety for the machine, again its very intuitive to work out, but given its something that can effect your health rather than just machine function I feel its worth being boring to spell it out anyway. Have a few accessible E stops, nothing is worse than being on the wrong side of the machine to reach one should you need it to prevent either injury or damage to the machine. The process of plasma cutting does produce metal fumes and large amounts of ozone, so ensure your ventilation is plenty, their is little drawback to having more than you need. The amount of light (especially UV) emitted in one small area is generally always high enough to cause permanent eye damage, so wear something like oxy cutting goggles, even the reflected UV isn’t great so it needs to be full enclosed before you can avoid needing this PPE. Obviously ensure there is nothing flammable near the machine.Lastly and most obviously, avoid contact with the plasma jet, sparks or hot metal, it hurts.
