Marvin help

TheMeek · 2016-03-29T18:27:29.000Z

Are you releasing the idler arm by pulling it back while pulling up on the filament?

Lowfuel · 2016-03-29T18:30:40.000Z

I’m not sure what the idler arm means, but I’m not doing anything but pulling up on the filament (per Robo3D’s instructions).

TheMeek · 2016-03-29T18:36:14.000Z

The idler arm is the spring loaded arm that applies pressure to the filament against the hobble bolt that drives it into the extruder.

Lowfuel · 2016-03-29T18:53:39.000Z

Ah, okay. No, I’m not using that trying to remove, only when I load. Is that the correct method?

To remove I’m just heating the extruder to print temp, then tugging straight up on the filament. It doesn’t move at all.

Is it possible the screws are too tight on the idler arm?

TheMeek · 2016-03-29T19:04:02.000Z

No, your not doing it right! Take one hand and put your middle and index fingers on the spring screws, while with your thumb pulling back on the arm. Then you are releasing the pressure allowing you to use your other hand to pull the filament slowly up and out, so as to not pull molten plastic out with it!

Lowfuel · 2016-03-29T19:09:44.000Z

Gah, seriously!? I asked both techs I talked to what the proper procedure was, and specifically asked if I should be pushing the latch back like I do when loading, and they both said “no, just heat the extruder and gently pull up on the filament”.

Sigh.

TheMeek · 2016-03-29T19:18:21.000Z

Lol! There is the alt method of reversing your extruder stepper motor, but this would be more awkward and possibly pull molten plastic up with it!

Lowfuel · 2016-03-29T19:48:20.000Z

Okay, well… I will try changing filament again when this next print finishes. Thanks for the tips!

Lowfuel · 2016-03-29T20:13:58.000Z

It’s the weirdest thing. I push that tab back, and yeah the filament pulls out nice and easy UNTIL I’ve pulled about a 3" length or so out and then it just stops and refuses to go any farther.

Any thoughts appreciated!

Hilttech · 2016-03-29T21:41:06.000Z

3" sounds like the transition point between the hotend and the housing. Check alignment between the two. A good way to check is by removing the hotend. If its significantly galled by the threads then it wasn’t installed properly.

thormj · 2016-03-29T22:21:53.000Z

It’s on the high end, like nylon and ABS… If you have a grooved insulator tube, your chances are better. If you go from bed heat to head heat to print (not the other way around), your chances also go up… Otherwise heat will travel up the filament and melt the ptfe tube.

Lowfuel · 2016-03-29T22:49:33.000Z

What would the remedy be?

thormj · 2016-03-30T02:34:32.000Z

To reiterate - pull back on the extruder idler to release it from the motor. If you’re getting a hang after 3", it sounds like you need to unscrew the springs on the idler so you can get the filament out (it sounds like there’s a molten ball at the end of the filament that doesn’t want to go between the gap in the idler and the hobbed bolt).

If you unscrew the springs (and release the idler completely) and it still doesn’t want to come out, you have to cut it and remove it in 2 pieces:

Pull up the filament as far as it goes
Cool the hotend (just to make it easy for the next bits)
Remove the hotend.
Push the filament down and clip the ball off it so you can remove it.
Reinstall the hotend.

Generally, when I’m pulling used PLA out, I only let it heat to 100C or so before pulling, that way liquid PLA never gets in the teeth or gums up the mechanism.

If this happens a lot, I’d make a PTFE support tube for the Robo3D; see PTFE support for Robo3D | Atlanta3D (I’m adding pictures as I write); bonus is that now Flex won’t kink in your Robo3D!

thormj · 2016-03-30T02:37:20.000Z

PS. I recommend replacing the 2 Phillips head bolts that hold the hotend in place with socket-head-capscrews (Allen bolts) – available at McMaster or Home Depot. Trying to worm out a stripped head is really annoying.

TheWattsMan · 2016-03-30T03:02:02.000Z

It would depend on which version of the printer you have. The Post-Kickstarter R1 came with an all-metal Hexagon hotend that is perfectly capable of printing PETG. PETG requires the same temperatures that ABS does, so if your ROBO is stated to handle ABS, it will handle PETG as well. Mine has no mods and prints PETG better than it prints ABS most of the time.

thormj · 2016-03-30T12:53:16.000Z

Be sure to blow out the dust with canned air, and I remove the hobbed bolt and attack it with a wire brush (or a file card or a razor blade) to get all the plastic out of the teeth. Mine kept doing that after ~4 hours, so I replaced my bolt with one from eBay and it seems much better (still not sure why). I find that a coat of WS2 lubricant on the hobbed bolt helps a lot – at least the shavings from the eventual jam come out more easily.

Lowfuel · 2016-03-30T15:05:48.000Z

Mine has the quick release, though, unless you’re referring to something else?

Lowfuel · 2016-03-30T15:07:07.000Z

It’s brand new, the R1+. They say on the website that it can handle just about anything. Safe to try?

3dpGeek · 2016-03-30T16:35:29.000Z

What I do on my robo R1+ is hest to about 190c, turn the gear as if you are loading into I see filament coming out of the nozzle then turn the gear counter clockwise until the filament literally pops out the top.

3dpGeek · 2016-03-30T16:35:44.000Z

What I do on my robo R1+ is heat to about 190c, turn the gear as if you are loading into I see filament coming out of the nozzle then turn the gear counter clockwise until the filament literally pops out the top.