I teach high school CAD and we 3D print student-designed parts a lot. Not keychain type things, but intricate, detailed parts that fit together in large assemblies, like student-designed geartrains for robots with true involute tooth shapes. Holding tolerances is critical to most of what we do. I have 4 Prusa MK3S+ printers and an MK4, and also a Lulzbot Workhorse and two Mini 2 printers. I have upgraded my Lulzbots to 1.75mm heads. All of my printers are on Octoprint, and my slicer is PrusaSlicer. I have it set up so I just select my printer, the print profile, and the filament and send it to any printer I choose. It is common for me to be printing 5 full print beds at a time.
Here are my issues:
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All 5 of my Prusas will make parts that are acceptably identical to each other. The outside and inside diameters of the parts are identical, and the gears all work well with our standard backlash parameters. But I just can’t seem to get the Lulzbots to match the parts the Prusas make. I’m not saying the Lulzbot parts are worse, they’re just different. Like, none of my parts make holes that are what I specifiy (because of the nature of 3D printing), so we design around that, but what’s a slight slip fit on all 5 Prusas might be a slight press fit on a Lulzbot. No amount of setting adjustment seems to help. I really wish there was an offical PrusaSlicer profile for these printers. I’m not switching to Cura for this. Thoughts?
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I have to monitor all three of my Lulzbots when they start prints because they fail to detect the washer touch so often. I’m using the same starting G-Code, and it seems to wipe, but it fails somewhere between half and one third of the time. I have cleaned those washers, and the connections to them, but I just can’t trust it. On the Prusas I hit print and walk out the door for the night, and come in the next morning to perfect prints every time. Thoughts?
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Speaking of bed leveling, it takes so long, every time. The Prusas just level the bed so fast, but the Lulzbots go through this heating and cooling process. Printing one small part takes forever because of it. Is there a way to skip that, or at least speed it up?
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OMG they are so loud. I can’t print with them in my classroom because it’s too loud. It’s like those steppers are hooked to speakers or something. My Prusas aren’t loud, even the MK3s. What gives? Tips?
As it is I just almost never use the Lulzbots because they are so difficult to integrate into my setup, and that’s a shame because they make the best prints. I print these big propellers in spiral vase mode, and looking at the prints that come off the Lulzbots you can tell how much stiffer the machines are than the Prusas when making the same print. They’re fantastic. I just need them to be easier to use.
Are your Lulzbots still using .5mm nozzles?
Prusa MK3S would have a .4mm nozzle, and if your print profiles are set to produce line width under .5mm, you’re asking for a line smaller than the nozzle opening, which is impossible to create with any sort of laminar flow. The result is inconsistencies in the walls that would easily account for your poor tolerances.
The washer-based leveling is atrocious, I agree. I’ve added BLTouch to my lulzbots to get around it. You can get knockoff versions for about $10, and I’ve done custom firmware for the Mini2 to use it. It can be added to the workhorse as well, but I since I don’t own one I haven’t build custom firmware for it.
Bed leveling time can be reduced by avoiding re-leveling. Swap out G29 in your startup GCODE for G29 O, and it will only level if needed. Or, if you go with custom firmware, you can use UBL as well, and it only needs to probe 3 points once the initial mesh is built.
Stepper noise is always going to exist with the 8-bit rambo boards. I swapped my boards to gain 32-bit steppers and the loudest part is the electronics case fan when it turns on.
I swapped the nozzles to .4mm when I changed the heads to 1.75mm filament optimized heads. I’m considering the BLTouch mod, but I’m just hesitant to do something non-stock because I don’t really have time to tinker with it or maintain it over the years. My time for this type of thing is limited, but it may be worth it. The new heads are also incredibly loud with the loudest fans I’ve ever heard on them. The noise isn’t my biggest problem though. Putting them in another room is fine.
It’s just frustrating how much money I have tied up in these for how difficult they are to use in the classroom compared to my Prusas, which were significantly less expensive and didn’t require upgrades. But, there they sit and I want to try to get them to work as easily as the Prusas.
Hi Brian, I have the sidekick 747, and the 2.84 feed. I had trouble with Cura, but it was my own rookie issue. I had sellected the wrong head. Once. I chose the correct one, it was much better. That. said, the initial dodo issue, was circumvented by using Fusion 360, I design in it any ways. The post processor setup for fusion was great, they included my machine, so I chose it and started sending jobs via Octoprint, I use a Pi 4b and have it setup on that, and can send Gcode from Fusion. to a iCloud folder, that I have the Octo connected to. Then just use the web site installed with octo to control and monitor, even with my iPhone…. still fiddling with accuracy. I”m building an enclosure for spools up above and filtered exhaust, lights camera etc. I hope you. have better luck with your Luzbot, I”m enjoying mine, and have made a lot of useful designs already. PS, the folks at Luzbot have been very helpful. to me.
Adding BLTouch to the mini2 is pretty easy.
Swap out the cooling shroud on the M175v2 with either of these LulzBot M175v2 BLTouch Toolhead Adapters by Wrathernaut | Download free STL model | Printables.com
The one that’s front-mounted can reach the whole bed, but requires x-twist compensation in the firmware run through. Takes about 3 minutes or so to do.
Side mount is more protected and is in line with the nozzle, so x-twist isn’t really necessary. The small bed on the mini2 means it’s not as important to probe the whole bed, but still is nice to be able to do.
Attach the BLTouch, run the wires along the cable chain for a clean install, and attach to the board.
I’m not sure the state of the Drunken Octopus firmware for BLTouch on the Mini2, but I’ve got a build I put together and have been running for a couple of years now.