Ahh, yes. That would work too. Would want to make the slot length (along with material thickness) to complement the inclined angle to ensure the pin touches the bottom outside edge and top inside edge - to help keep it secured.
Crude and quick graphic…
These are the new pieces. The smaller ovals are for 1/4-inch x 3-inch bolts. The two platforms should be approximately 1.5 inches apart when assembled. I’m only feeling 50% confident it’ll work as the geometry may not pan out because I’m doing all the design in 2D and its truly a 3D object. Everything is 0.5 inch mdf/plywood. One challenge I discovered is that a sharpie tapers down toward the end, so the upper platform holes are smaller than the bottom platform holes. Hopefully will be able to play with it this weekend.
Though I’m still waiting on parts to arrive (stepper, mount, flange) I tried to cut the pieces last night… my first real cuts. Unfortunately, they (initially) came out horrendous. As it turns out, one of the zip-ties for one of the x-axis belt had ‘slipped’ and the belt was continuously slacking. I had to run up to the store to get more zip ties since the ones I had on hand didn’t fit through the slot. After that was solved, I restarted cutting and ran into problems with my tabs being too short. Easel apparently set them to 2mm high as default and I had set the depth of final cut to be ~ 2 mm past the depth of the board to ensure any z-axis height issue was mitigated. So pieces started to flop around and broke my bit. I think I need to wire up the emergency stop since it does not appear that the software stop works the same way as I’m used to with the Maslow. With that, I called it a night and have modified my gcode this morning to cut higher tabs as well as to cut out additional area in the pieces to try to lighten them up as much as possible. I’m not sure the two small mending plates I’m planning on using under the vac adapter screws is going to give enough rigidity to keep the hole assembly from drooping/bouncing/etc.
Yea, it’s going to finish whatever code is still in memory before the software stop take effect.
Looks like marlin would stop immediately on an M112 command but it only works if EMERGENCY_PARSER is enabled and it doesn’t seem like the firmware has it enabled. Well, the emergency button power switch would work… I’d want it to kill the router and controller, but not the RPI… got to figure that out.
If you use one of those IoT relays, cutting power to the controller will kill the spindle.
I’ve got mine set up like that. Two power strips, one always on and one connected through the E-stop button. The one wired through the E-stop button is also plugged into the always-on one so I could switch everything off with the one switch, equivalent to pulling the cord out of the wall. Although to this day I have never had a reason to do that.
To clarify, I don’t kill the 5V USB power to the controller, but I do cut the 12V power to the stepper drivers. I don’t think an emergency would need to fully kill kill the controller. Stopping the motors should be sufficient.
I don’t think that’s readily possible with the mini Rambo I have unless I actually put something in line with the stepper driver outputs or do something with the 5A motor fuse (like extend it off to a separate board with an relay in-line with it).
You wouldn’t want to cut the stepper outputs. That is bad for the drivers. Can you not leave the USB on (connected to pi) and cut the 12V input supply? On mine I cut upstream further: I cut the 110V to the 12V PSU.
Oh now I’m seeing the mini rambo doesn’t stay alive if the 12V power is cut. It doesn’t power from USB. So then I think that’s what you were asking, keep the Pi alive and kill the controller and spindle.
You can. The microcontroller will just also lose power. The rambo microcontrollers are not powered from USB.
Getting there… Really, really tight fit on everything, particularly the pens, but it turns rather smoothly so I expect the stepper will be plenty strong enough to handle it. I had to do a bit of sanding down of edges and such to make it all fit together. Having the pens slanted really shrinks the available space inside the carousel and I didn’t really want to make it bigger. I’m surprised just have well the brackets I used support the whole cantilevered assembly. I just replaced the 1-inch machine screws holding the vac tube assembly with 1.5-inch screws and used wingnuts to tighten everything up for easy disassembly, which was needed a few times. I’ve still got to build a wiring harness for it… after I take the twins to see Star Wars (promise to be kept)… and then write some gcode for it.
DUDE that is a beast!
It works, but probably not good enough. Here’s a video.
It’s clear that E0 can be used to select a pen. That part works well enough. The problem really lies in the calibration, and in part it might be related to the slanted design to allow pens to be vertical. In this design, a few items are critical and if they are off, even by a slight amount, getting accurate performance will be difficult:
Any slight variation, either due to cutting the pieces, or assembling them together will likely lead to difficulty getting everything lined up. Each of those three factors affect where the tip of the pen is. You can overcome some of the issues by modifying the gcode to account for difference in height of each pen tip (each time you pick a pen, adjust the z-axis so pen is touching the board), but you can’t readily account for x,y differences of where the pen touches down. I think the latter is the biggest issue with this design.
Perhaps by loading more markers and removing the 1/4-inch bolts things will line up better. Those bolts really should for a perfect triangle near where they meet and they don’t… so that tells me things are off a bit.
Love it!
I wonder if 3D printing the carousel would allow the pens to be inserted in a more consistent way? I can’t see making one of those for myself, but it’s awesome you did…
I tend to think so, but it would be good to have a means to readily adjust the height of the pens… maybe some kind of bolt adjustment. With what I cut, the pens are extremely snug. I have to remove the whole thing from the sled and grip it well to move the pens.
Great work! When working on my tool changer I used work offsets for the different tools. It would be a headache to have the CAM introduce offsets for the different colors but with a separate workspace for each color you can measure and set up the offsets ahead of time and the CAM is unaware of the difference. You would insert the appropriate G54 command at the same point you make the extruder move.
I hadn’t thought of that…that looks like a perfect solution since it appears to support all three axis… Can it also support E0? If so, that would be utterly awesome solution.
Doesn’t appear that E0 changes are tracked by work offsets. Not the end of the world, but would have made it much, much easier.
What about a third “layer” of wood above the pens, with no holes in it. The end of every pen could be firmly pressed against this third layer. Kind of like a stop block for the pens.
