The rubber can be replaced with a larger metal grooved wheel if necessary. The idea was to have a larger radius and increase the surface area that is in contact with the filament to avoid the grinding that comes with Mk8 or smaller direct drive mechanisms.by ipcalit - General
Even simpler, just get white filament and a set of Sharpie permanent markers. The you can make whatever color sequence you want without messing up with splitters. You can color the filament before it gets into the extruder and you can alter the shading by the amount of "painting" you do, such as on one side of the filament for lighter shades, two sided for deeper colors.by ipcalit - General
Quotematthock Yeah, the ideal would really be a brushless motor with encoder, but they're pretty expensive. My overall goal is lightweight dual direct drive with a Chimera, which will make the overall mechanism big enough that I was just going to stick a dedicated 40mm fan on top to cool the motors, at least for the time being. Maybe add one of the little sticky heat sinks for the stepper controby ipcalit - General
Quotenebbian Quoterklauco Well, for those that are lazy as me, I bought this. It's a bit expensive, but there was nothing similar I could buy in the shops nearby. I cut it using a normal saw and filed a "dimple" for the grab-screw of the MK8. You could have told me about that a couple of weeks ago!! Would have made life a lot easier. I cut a hole in that rod so that the mk8 set screw goes allby ipcalit - General
Quoterklauco I have trouble to believe it, but this stupid little thing just WORKS!!! "just WORKS" We just need to see now for how long. I'm playing with other motors as well to see how they compare. Found a tiny 10mm with planetary gearbox but that is struggling to push the filament, and a 16mm one that could be used as plan B if we find that the N20s have short lifespan. Quoterklauco I had tby ipcalit - General
Just got a couple more motors of eBay to test. The ZYM-16A050 models that are available for under $3 (search "gear motor pull wheel") are also good candidates. The gearbox is not planetary as one would think, but still all metal (took one apart) and slightly larger (16mm diameter). There's no encoder, so we have to resort to the same tricks as the cheap N20. The bushing for the 3mm output shaft iby ipcalit - General
Quotenebbian I'm not sure what the precious metal is, but I do know that in all the micro motors that I've disassembled (dozens), none of them had carbon brushes. They all had brushes that looked metallic to me. Also, from experience, putting them back together and having them work properly is almost impossible. You need to poke two small shafts through two holes in different directions to retby ipcalit - General
QuoteLoboCNC And here are a couple of videos: printer walk-around Nice little setup with all the heavy parts (motors, rails) sitting on the ground. Looks like a DLP with the model going up bridging test This is interesting. It seems that the pressure from the nozzle makes the extruded filament go up and create that reverse sagging motion. I'm wondering whether printing slower would alleviateby ipcalit - General
Quoterklauco QuoteipcalitIs this what you a have in mind? oO| - where "o" is the Mk8, O is the bearing, and | is the shaft for the encoder? I'm wondering whether having the encoder so far from the motor creates troubles for the PID loop. If I recall correctly most recommendations are to get the encoder as close as possible to the motor (generally on the motor itself), but here we are not dealingby ipcalit - General
Quoterklauco And keep in mind, that even now the code for the controller has a protection code implemented - should the bearing receive no movement (e.g. filament out or jammed), I'll know about it right then. Are you thinking about the filament detection code or something else? Quoterklauco However, I run out of pins, so I don't know how to get the information back to the RAMPS board. But I hby ipcalit - General
Quoterklauco To continue the original thread - I decided to go in a bit different direction. I'll make a tiny (2-3 mm) shaft with heatshrink that will be measuring the bearing movement by simply touching it. As there is virtualy no load, the added friction will be minimal. Is this what you a have in mind? oO| - where "o" is the Mk8, O is the bearing, and | is the shaft for the encoder? I'm wondeby ipcalit - General
Quotenebbian Ah OK, I see the bushing now. Didn't see it before. The reason I didn't go straight to your design was that I didn't have that tiny bearing handy, and your design doesn't have a lever to allow easy manual feeding / retraction. I got rid of typical springs as you don't really need them - the housing material is the spring. Attached is the latest design with space for the AS5600 inby ipcalit - General
QuoteLoboCNC Quoteipcalit Hmm, the frog looks nice, but... shouldn't the bridge be bending "upwards" if printed upside down? Yeah, it is actually kind of peculiar. As it printed the first bridging layer, the filament did sag down a little as you'd expect. But when the next layer went down (er, up), it pushed the bridging layer away so the net result looked very much like conventional bridging.by ipcalit - General
Quotenebbian Quoteipcalit Haha.. Not what I had in mind when going for the Pololu/N20 extruder. You might want to make a 10x12mm "tube" protruding from the plate that goes around the gearbox to secure it properly. The plate already has this. I would just make it a little bit longer. Also per JamesK comments, some bushing or bearing to support the other side would be beneficial. If you look atby ipcalit - General
QuoteLoboCNC I've got some initial printing results! Having watched miles of filament print over the last couple of years, so far, printing upside-down looks just like printing right-side up. The treefrog print, which has some steep overhangs, printed the same as on my conventional printers. Even my bridging test - ranging from 4mm to 34mm - came out pretty much the same. I'm sure longer bridby ipcalit - General
Quotenebbian And now for something completely different: From the "That looks ridiculous" department, I present to you the N20 to NEMA17 adapter. This allows you to use whatever extruder body you have lying around, without having to engineer a totally new solution. You can then concentrate on the electronics, while using a known-good extruder mechanism. Haha.. Not what I had in mind when goingby ipcalit - General
QuoteB4Me Quotenebbian I just received my geared motor with encoder today, and have been looking at the best way to turn it into an extruder. My goodness it's tiny! So small. Looking at the output shaft, it doesn't have a bearing, only a steel on brass bush. Are the side loads from the idler bearing considered low enough for this style of bearing surface? Would it be better to mount this motby ipcalit - General
Quoterklauco So, if I understand it correctly, the actual push on the filament is done using the sleeve, not the bearing, right? Not that I have anything against it, I am just wondering if the fit will be stable over time - at least ABS would wore out quite fast due to the friction of resisting filament (my opinion only). It should fare pretty well as it only has compression forces against it. Fby ipcalit - General
Quoterklauco I have a problem with the "just attach the encoder disk or magnet to the idler bearing" part of the sentence. As the idler bearing has to push the filament, I can't imagine something reliably be attached while not obstructing: the idler itself shaft for the bearing I thought about some mechanism to do it reliably, but I was not able to come up with something - limits of my imaginatiby ipcalit - General
Quoteo_lampe Why introducing another shaft for the filament encoder? Could you use the common idler gear for that as well? That is exactly what I proposed. Just attach the encoder disk or magnet to the idler bearing. I'll try to work out a design as I got the SOI8 adapter and magnets for AS5600.by ipcalit - General
Quoterklauco My problem with any of the gears like MK7/8 etc. is the diameter. To explain - for reasonable price I am able to get encoder with ~50-100 steps. By using the quadrupling code, I am able to get resolution of 400 impulses per revolution. Now, if I select my preferred width of 3mm shaft and add ~1mm of heat-shrink-like sleeve, I'll end up with 4mm diameter. That means 1 revolution willby ipcalit - General
Quotemisan I reckon putting the feedback on the filament and not on the output shaft is more useful for accurate printing. But I am afraid about the additional delay that might cause to the loop (which may make it unstable). How would this be different than backlash in the gearing if one adds the encoder to the output shaft? A mechanical error, such as a broken teeth, would manifest in the sameby ipcalit - General
Quoterklauco QuotemisanYour steel rod for filament motion sensing may have some teeth too, as we know this increases the grip, though in this case filament will be forcing rod rotation and not the other way around. I wanted to ensure the grip by shrink wrapping the rod using regular shrink tube for electrical isolation I don't like teeth on the rod, but if the shrink wrap will not work, I'll tryby ipcalit - General
Quoterklauco Major achievement here. Changing one word in the source file and all of a sudden, everything works!!! I had to define the target1 in source code as LONG, not INT - as the Zaxis has mental resolution. I am now able (while still having multiple of 10 steps) to do movement on Z axis with precision of 0.0025mm. I call it quite good - that's 2.5 microns Not really usable, but it's amazinby ipcalit - General
Seems that 2-3kg of force is enough to push the 1.75mm filament through the regular 0.4mm nozzle. I have a bowden setup with a similar large NEMA17 with Mk8 gear running at half its potential (i.e. 1A instead of 2A) to keep it cool. That's the reason for the current attempt to do tiny DC motor driven extruders:by ipcalit - General
Looks like Misumi 6 series or 8020inc 3030 series clones. [8020.net]by ipcalit - General
Quoterklauco That was my initial idea - just instead of Zero (due to virtually no availability) I plan to use Orange Pi One. Not familiar with this clone, but I got a couple Raspi2 and Odroid-C1s that I can play with. Awaiting on some SOI8 adapters for the AS5600 and the TB6612 and DRV8835s drivers to test.by ipcalit - General
Quoterklauco Well, I simulated 2 8-hour long prints with X and Y axis on a single TB6612 and it was as cool as it started. The motor got worm to touch, but the TB did not. I did not put any sort of heat sink on the A4953, I can try it tomorrow and report back the results. I would still like to make the A4953 work - I have a board in mind with ATtiny85, A4953, 2 capacitors and form factor that wouby ipcalit - General
Quoterklauco Well, I am disappointed. I tested the A4953 and while it works, it gets extremely hot even during position hold. And while doing back and forth 120mm movements it got so hot I could not put finger on it. I had to remove it and put back my TB6612, which works flawlessly. I had to admit, though, that my temporary board is WAY off the reference design - so probably the missing heat-distby ipcalit - General
Quotemisan No, I did not notice any relevant variation. However, I have not performed a dual-technology test (using a second optical encoder attached to the same shaft). So I might be fooled by my own perception. Recently I saw the project Mechaduino that does a big effort to compensate the errors of their magnetic encoder. Mecaduino I saw Mecaduino and the error compensation is valuable, butby ipcalit - General