This is a companion discussion topic for the original entry at http://maslowcommunitygarden.org/Help-me-with-a-design-to-convert-the-Maslow-to-a-CNC-Plasma-Cutter-for-metal.html
This is a companion discussion topic for the original entry at http://maslowcommunitygarden.org/Help-me-with-a-design-to-convert-the-Maslow-to-a-CNC-Plasma-Cutter-for-metal.html
There are already vertically mount flatbed Plasma Cutters, so converting a Maslow to function as a plasma cutter should be easily obtainable from where I sit. There will need to be some adaptations to the backboard so the metal that is being cut floats on strips of metal, along with a sheet to block sparks that pass thru the back during cutting. I have upload more photos showing examples of different plasma cutters for design ideas.
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A couple of questions:
What is the precision you are looking at? Looks like you make motorcycle parts?
What is your estimated total sled/z-axis weight?
What is the biggest part you will cut and what is the metal sheet size?
What is the time-frame you have in mind to build a proto-type?
At least one more on this Forum other then me has mentioned that he will attempt a more traditional X/Y machine with Maslow parts, in my case it will be a combination of aluminium and steel (frame).
I see possible matches in the general frame design and how X/Y moves will be built.
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- Precision - The most accurate as possible would be ideal.
- sled weight - Would be minimal just the weight of the handle and cable which would be couple pounds at most I would say.
- Size - I would say make it 4x8 so that full sheets of either wood or metal could be used allowing either a router or plasma handle to be used in either same sled or by swapping sleds out.
- Time-frame - I am in school right now and have access to a complete machine shop to build a prototype at.
I know very little about this type of stuff and am only a couple class into my precision machining certificate and being able to understand and program CNC machines. I tried to upload more photos to help show examples of what I have in mind but they only allow 1 photo to new users. Anyone serious about this project and talking to me should contact me directly thru email. I don’t often think about coming to this site to check for messages or progress on this project. By email I can show photos and give dimensions of the actual plasma cutter handle and trigger along with some similar designs for other flatbed plasma conversions.
There is a great YouTube video of a guy named " Made in Poland" who made his own table top plasma cutter for straight and angled cuts. It shows how he wired the controls so it turns on and off with either the stock trigger or with his jig. Something really similar to what he did could easily be combined with a Maslow mount to work as a plasma table instead of just being a hand plasma cutting unit. The thickness of the metal to be cut is just determined by the settings on the plasma machine and how slow the sled moves. Compared with the router that needs multiple passes requiring the machine to be very precise on each pass. The plasma cutter should be able to use the same controls and vector files as the router it just needs to have a new sled made to hold the plasma cutter handle or an adapter for it to fit in place of the router.
It may be easier to make just plain cartesian CNC driven by chains. Plenty of examples to follow.
If you are trying to save space you can hinge the table on a bracket attached to the wall and pull it up when not un use and bring it down to horizontal position for cutting. I have seen one such build on youtube.
Here is a rather innovative space-saving design https://www.youtube.com/watch?v=PhRQiRsL5oo
Shameless plug from an interesting company I’ve done business with…
If I ever get it up and running (hardest step is the first…) my long term goal with my Maslow setup is to have a plasma/router combo - something you can just walk up to, swap the sled and cut whatever you want. My current plan is to create a recess centered at the bottom of my wasteboard that I can cover with a plywood insert when I’m routing or insert a bed like this ^^^ for plasma. Bed doesn’t need to be ^that^ fancy, metal slats would likely suffice for much less $$$. Use a bungee and the the Z-axis control to pull the trigger and change your feed rate and it’d be off to the races.
Thoughts?
While this seems like it should be straight forward swap between the two (router vs. plasma torch) There’s a couple of key issues you’d need to sort out first. I will tell you this from experience, if you don’t start out with an Auto Torch Height Controller from the get go, you will hate life!
That being said, the way the Maslow functions is that the sled is weighted and rides on the substrate being cut. This is completely unnecessary for Plasma Cutting. In fact, it may cause more problems than it’s worth due to what’s called “Tip-Ups”. The sliding sled will catch dross and tip-ups, and therefore move your sheet. Also, the very same reason you’ll need Auto Torch Height Controller. As you are cutting along, especially anything thinner than 1/4" plate (I’ve seen 3/4" plate warp) the sheet will warp and rise all over the place from the heated cutting process. The ATH will keep the appropriate cutting distance between the cutting tip and the material, despite how much it starts to look like a Pringle.
So… when designing the machine, you really need to only support the weight of the torch. A weighted sled is unnecessary, as there’s no contact between the torch and the metal you are cutting. It won’t be a “walk up and cut whatever I want scenario” without some forethought and a convenient change-over method. A Cartesian X-Y-Z gantry is still the best for things like Laser, Plasma and WaterJet because there’s no contact with the work piece. But, that’s not to say that you can’t make the gantry out of something even fairly light weight, like 80/20 extrusions. And just have most of the rails bolted on the exterior of your Maslow frame, and all you’d have to do is pop on a light gantry that only has to hold the plasma torch.
One last thing to consider… Plasma Cutting makes a “Crap-Ton” of smoke… like a ridiculous amount. And it coats everything in your shop. Your electronics, your guide rails, your chain etc… Which is why most places opt for the water table. A vertical table will have only a vacuum system. (Maybe you can get clever, and do a waterfall behind the cutting grates
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this frame design looks like the best fit for plasma. 8020 is nice but plain old cheap square aluminum tube is about half the weight, depending on gauge is what I would recommend.