Although one spring assembly went into place reasonably easily the other did not. Using a pair of long nosed pliers to compress the is NOT a good idea. If you slip you stand a good chance of trapping your finger between the jaws. I found a small rectangular plate (10cm * 2cm) with a cutout in the end just large enough with a bit of filing to fit round the set screw. Using this to either push down on the washer or fitted round the spring just below the washer is much easier and safer.
I think the model needs a little change there to assist in the build and to assist with compression when you're feeding new filament. Two blobs extending out here would be great:
Is it just me or is the spring really really tense? On my existing printer pressing it down to feed filament is easy, on the big box I can only just do it. I'm actually concerned it'll maul things like ninjaflex
If you tighten the screws it will decrease the force of the springs. I believe, I feel like I remember it being backwards of what I thought it should be.
Yep - it's a lot of force there; might well be an idea to tighten them further. I haven't done so far, but it's a good idea.
I agree that the tension is really high. I've tried tightening the screws as much as I can, but the hobbed gear is still really biting into my PLA. And compressing the lever by hand to load filament is difficult, and has me worrying about breaking things. I'm thinking about trying to find "weaker" springs, if anyone has an idea for where to source those.
An ebay search of "3d printer extruder spring" sure comes up with a lot of options. I wonder if a remorked idler arm with a bit more lenth for leverage would be sufficient. Its a cunning plan to make us all upgrade to a Titan
Hmm... I thought the assembly went together correctly, but it is waaaay too difficult to depress the levers, in my opinion. So maybe something is wrong. Are others easily (two fingers) able to depress the lever to move the idler away from the hobbed gear? On the other hand, there's not much more to this than a spring, so I'm not sure what could be all that different...
I don't know, I can push mine together with two fingers, it is a little tough, but not too bad. I do know at first it was very difficult, but I tightened the screw and it became much more manageable.
Okay what I've done is hand drill a shallow recess into the cable guide just to hold the tip of a screwdriver. Using it as a lever is fine, I can easily get enough on to do a filament unload.
Up to now, I've been doing a filament unload using GCODE (obviously this is after the hot end is up to temperature. T0 G1 E25 F50 G1 E-130 F100
I totally already posted my custom buttons, including this one By the way, I pulled those F numbers from nowhere in particular. It would be good to have some experienced person comment on whether they good or not. Too slow? Too fast?
Too slow/fast for what? Nothing really happens here. Filament which is down in the nozzle will not get out. Only thing you don't wanna happen here is stringing but on a direct drive it is not so important. On my UM2 I hate the unload mechanism because it heats the nozzle up then straight pulls the filament with high speed the full way back through the bowden. I always have a tiny string building in the bowden which can mix up with the new filament. So you have a color mix for about 30cm of material if you do not clear that out. I would probably go faster at least the second move. But the length you gotta move is pretty short. So as long as you don't have a problem waiting for the filament to go up you're fine on any speed...
I wondered about doing a full purge as per dual printing, which would be likely to get filament in the nozzle out, as, given that process, it probably doesn't have full time to melt.
