What we want is a Star Trek-style replicator. What we have are a bunch of different machines that can spew out various 2D and 3D shapes. For the foreseeable future, you’ll still need to post-process most of what you build in some way. [Stuff Made Here] had a challenge. He often uses his plasma cutter to create complex sheet metal items. But the cutter is two dimensional so the piece doesn’t look right until you bend it at just the right places. If you are doing a simple box, it is easy to figure out, but getting just the right spot on a complex bend can be a challenge. His answer? Attach a marker to the gantry so the machine can draw the lines right on the sheet metal.
Sounds easy and if you were willing to do a pen pass separately and then remove the pen and do the plasma cutting it would be relatively easy. However, that seems kind of crude. Mounting it permanently requires a way to raise it up when cutting — and it needs to survive the noisy environment near the torch. The pen would also dry out if you left in uncapped. The answer was using a permanent marker with a click retractor and let the mechanism extend and retract the pen point on command.
The torch uses an air system to raise and lower the torch. The mechanism for the pen uses two valve and two springs to allow the pen to go up and down appropriately. There don’t seem to be any exact plans, but your cutter will be different, anyway, and anyone who is using a plasma cutter ought to be able to figure it out from the explanation on the video.
The results look good and it is surprisingly useful to have marks drawn on the flat pieces, especially for bend lines. If you are lacking the cutter, we’ve seen many builds in the past. You might also get some ideas from pen plotter builds, just remember the unfriendly electrical environment around the torch.
Well done. I made a laser and pen plotter in the cheap version – action starts at 1:06 :
https://youtu.be/Ebe2kFlE058
Very nice but where are the sharks? :)
Well done. I made a laser and pen plotter in the cheap version – action starts at 1:06 :
https://youtu.be/Ebe2kFlE058
Neat. I am assuming you have shop air anyway for the plasma cutter.
That’s a sweet setup, Al. Do you ever plasma cut dash-lines along your bends to make it easier to fold parts? I imagine this would let you fold stuff that is too complicated to fit into a vice, etc.
when you do the dash lines do you go back an weld the dashes?
Now if you had a weld head on an X-Y machine, you might be able to make slits and patterns that bent itself to shape as it took various welds.
Is it possible to dial the power setting of plasma all the way down to the point where it just barely marks the steel sheet? Or use some kind of centerpunch (diamond scribe) to mark the steel instead of using sharpie to create weak point that will help bending? But hey. Dotted line will probably do, unless you need the structure to be manifold…
Pneumatics for the raise/lower do a good job of moving the electronics away from the noisy plasma cutter, like the electronics version of a bowden tube. It would be neat to calculate bend radius and mark with an offset for where the bend should start.
or dynamically vary the pen pressure, so that the stroke width corresponds to the bend radius
Very nice build but I’d add some cover for the pen tip, it may catch fire from plasma cutter sparks.
I’d still rather have it as I misread it, plasma cutter sharpie.
Spitballing… if we cram 20Ah in a large barrel sharpie, we might get it to cut through 1/8 thick stuff for a 15 minute run time, but our inverter efficiency won’t be better than about 90%, so it would be like holding the wrong end of a soldering iron for 15 mins as it dissipated through your hand….
Could you have use a Morse cable driven by a linear actuator or, a Flexible rotary/ tachometer cable? I don’t know if these play well with the energy chains and I’ve never really worked with pneumatic’s.