Replacing the hotend on my Max V2

[Stevolution]

Hi all
Long time since I have been around. I abandoned the V2 for a while for reasons of sanity.

[IMBoring25]

My recollection is it's .5mm but I don't have the manual in front of me.

If the filament has been sitting out all this time it might have absorbed too much moisture. There are various ways to try to dehydrate it. I've not had mine in a controlled environment and the opaque ABS is fine but the transparent ABS and speciality filaments are jamming like mad. Not sure if I'll try again to dehydrate them or just throw them out and get new.

Sometimes you can use PLA to clear a clog that doesn't go too far up the hot end. If you can get it down where it will melt you can heat it until it melts to the clog, cool it to around 160 where it's almost solid but will still pull out, and pull it out. I've also seen that method recommended as part of a routine maintenance schedule to clear small impurities out of the hot end.

Direct drive isn't usually used on deltas because one of their big strengths is having a lightweight effector that can be accelerated very quickly, and direct drive defeats that purpose. It also won't necessarily solve clogging problems but it should function if you want to try it. You'd have to solve routing for the filament without a Bowden and routing for all the extra wiring.

[Mac The Knife]

The stock nozzle supplied with the old hotends were .5 mm.

[thingismith]

In my experience, these are the ways my hotend would jam:
1. if the retraction setting was too high, the filament would solidify thickly at the top of the hotend (like a mushroom) between the ptfe tube and the passage in the hotend
2. The hotend got too hot and burned the filament in the nozzle or in the hotend
3. Too much filament got clumped and stuck on the bottom, exterior of the nozzle.

Whenever I have a jam, I first recommend the "cold pull" method http://bukobot.com/nozzle-cleaning. If you see the mushroom about 4 inches from the end, snip the filament above that and lower your retraction setting. You should still see the mushroom if you're unsuccessful in pulling out the entire filament out of the hotend.

If there's no mushroom and the cold pull didn't pull out the entire filament in the hotrend, take out the nozzle with the hotend hot. Carefully release the x and y arms from the hotend mount and look inside the hotend. Does the filament look black and charred? If so, straighten a paperclip (I use a piece of welding rod from my welding days) and poke it through the top, forcing the charred filament out the bottom. If it doesn't budge, stir the char from the bottom with the paperclip and try again. Note be careful not to scratch the inside of the hotend or threads when doing this!

If you're still convinced it's the nozzle, try using a spare nozzle to test your hypothesis. To clean, soak it in the acetone for a few hours, shake it in the acetone (you can use tweezers if you're afraid of using your hands) and lightly brush its exterior with a small brass brush (they sell them cheap at any hardware store), avoid brushing the tip too hard. Then let it soak a little longer in the acetone and swish it around again. Prusa hands out acupuncture needles for nozzle cleaning, I wouldn't know where to get one retail. But even then, it's never really helped me. GL

My prusa with a direct drive can retract more than my Rostock without jamming. But as long as I don't retract to much on the rostock, it can print just as well.

[Stevolution]

Thanks

[thingismith]

Sorry to hear you're giving up. Did you try lowering the retraction? Try turning it off altogether. Could it be the hotend's not getting hot enough?

[Stevolution]

[geneb]

I'm sure the tens of thousands of people that print with various models of Rostock MAX printers will be terribly disappointed to discover that all their prints don't actually exist.

g.