Makerbot Z18 with suggested mods problem

[Dan R]

Hello all,

So I have a Z18 that im stuck with. recently plagued by clogged extruders I decided to try both mods at once while waiting for my replacement. I created a hanging filament spool apparatus along with the cotton ball lubrication trick with housing. My new extruder arrived  arrived today and I was eager to see how it would work with my new makeshift mods.

I am encountering a problem that I hope someone can help me solve:

I attached the new extruder and loaded a brand new spool onto my hanging filament holder thing and attempted a print, 32 hour print since my place of employment is pushing me to get this project done - go big or go home with this piece of shit. Anyway, all seemed really good off the bat, my raft was sticking and the layers seemed uniform and perfect. After a time I decided it was safe to walk back to my office and check the print in an hour or so. When I came back, I discovered my worst fear. the hanging filament piece was off the ceiling and in pieces on the floor. it looked like the filament had came off the spool and started wrapping around the PVC pipe I set up for the hanging apparatus, creating more and more tension before it was finally pulled down by the machine.

Does anyone know of a way to not have the filament become so loose that it comes off the spool?

[Joseph Chiu]

You need to constrain the spool and the filament path so that the loose filament won't fall out over the flanges.  I'm afraid if you print long enough, you'll have this happen at some point -- the filament wraps itself around the spool holder like an alien facehugger.

[Jeff Davis]

Dan, can you tell me why you went with a different method to hold the spool rather than use the stock holder for the Z-18?  Were you seeing large friction from the stock spool holder?  You can see that when your filament is running fine through the extruder, it has a good amount of pull!  I would keep the oiler on but use the stock spool holder for now.  Grease the inside of the spool and hub to help keep it smooth running.

Jeff
http://homecnc.info

[Arafat Terron]

I can tell you that there is a lot of friction when you use the stock holder. I haven't run into any problems right now but I guess it would be better if used from the side feeding tube, I will try it once I print a side spool holder. I have used the Replicator Mini and you can easily pull the filament thru the guide tube without any effort, when I received the Z18 I was surprised by the amount of force required to pull the filament thru the guide, it was way more than what I experienced in the Mini.

[Dan R]

Used the over hanging method for two reasons

1) constant jams and holes in prints
2) the oiler does not stay on my extruder when the original feeder tube is used. The tension from the tube pulls the oiler to the side and it doesn't work.

This whole thing is a giant headache and its really pissing me off.

[Jeff Davis]

Hmm,   So your oiler body gets pushed to one side and then it does not work?  Is your tube too long maybe?  I guess with my door left up I basically have an over head system too.

So with your ceiling mount system, you must have held the other end of the tube somehow so it was fixed, but not too close to the filament spool because of the back and forth winding on the spool.

I'm pulling for a non-standard spool of PLA myself but when I keep the filament tight on the roll it does not spin off on it's own.  Maybe you need to get a shaft that is close to the same size as the spool ID.

Jeff
http://homecnc.info

[Lassi Kinnunen]

you could rig it with a guide, so the filament doesn't tangle like that.

(so that it leaves the hanging part at the same place) 

either that or add sidepieces to the filament spool to keep it on the spool itself.

also, some filaments like to jump off the spool more than others...

-lassi

[James Long]

I made a dead-simple U-shaped bracket (sized slightly larger than the spool, with a hole that the filament passes through, in the middle) that connects to the rod I use for my overhead mount, and effectively wraps around the filament spool.  It basically creates a minor pinch point so that the slack that naturally occurs from the back-and-forth motion of printing doesn't travel up to the spool itself, which keeps it from loosening, then unraveling and jumping off (which was the issue I had that spurred me into making it in the first place).    Might be worth a shot, based on what you're describing.

[TobyCWood]

+1 

I do the same...

Make it yourself. It should be VERY close to the same width as the spool and the filament goes through a hole which should have a rounded inner bevel to prevent friction. It is essential at the start of a spool when the filament wants OFF!