Makerbot Replicator 2 cant print for some odd reason

[CADstudent]

So ive been working on this printer for over a year and ive ran into yet another problem and this one i cant quite rap my head around how to fix it. So this is what its doing is either between prints (unsuccessful prints) or during long prints the filament sort of jams itself and the temporary solution is unload and reload filament but ive noticed a pattern of what the filament is doing it sort of bloats up from heating and stops itself from going through and with in seconds the drive gear just shreds and chips the filament making it unable to go through and you can see this from the photo this problem is just constantly occurring and it leaves prints a splotchy web mess( similar of what acceleration problems would do) or just stops altogether and air prints. I had a forum before on this issue but we concluded it was coding issue which now i notice it most definitely is not. Any help/input would be appreciated. ---DOWN WITH MAKERBOT!

[Feliks87]

I had a similar problem with my Replicator 2X...

the reason the feeding failed was the fact that my spools couldn't "roll" smooth enough to give enough filament to the extruder and the feeding motor shredded the filament while trying to pull it off the spool
that was because I use 1kg spools which are too large for the backside mounted filament holders which resulted in unsmooth "rolling"

there is also the problem of heat... due to the hood of the Rep2X a lot of the hot air vents to the backside and onto the spools which preheats the filament a lot during longer prints making it weak and stretchy.. another reason why I moved the spools from the backside to a place somewhere else to prevent the filament from preheating (see here)

I also printed without the hood and it still gets quit hot on the backside so mayber you have a similar problem

[Mouser]

What brand of filament are you using ? Makerbot or some of the cheap chinese stuff ? Does it act this way regardless of what type/brand filament you run through it ?

[CADstudent]

The Filament we use is from Gizmo Dorks, Prototype Supply, Makerbot, Deltamaker, its all PLA and are filament is off to the side so no preheat action is happening and it seems to roll fine and it all seems to be action the same but still it makes no sense cause as you see in the picture how the end bloats up, the heat block should melt it down but instead kinda just melts a tiny bit leaving that thread like end

[Feliks87]

you won't believe what happened to me today

after printing for almost 10h yesterday I returned to my Rep2X today with a new job and it messed it all up
it must have somehow clogged over night because it wasn't able to feed the filament correctly

after several tries of load/unloading the filament I decided to clean the whole extruder head
guess what I found, this looks a lot like your filament (it's ABS btw from NuNus)
clearly visable "bite marks" from the stepper motor on the filament


I then disassembled the feeding mechanism and it was all crammed with filament debris from the unsuccessful feeding tries
but after cleaning up this mess it still couldn't feed the filament (because of the clogging I guess?)


the problem here is obvious right? bad filament
wrong... I loaded the very same filament into my left extruder head and printed right away without any problems (for several hours now)

so it seems to me that there is a problem with the feeding mechanism itself but what could it be?
I guess you have checked your feeding mechanism already CADstudent?

[CADstudent]

Yah ive checked and cleaned it several times and we even had another motor and switched it out still the same I don't like these MK6 heads because the old ones you could adjust the plunger (tension on the filament) Im curious whether I can downgrade to one but anyways are you sure you couldn't feed through from a clog or were you feeding the filament in and it was hitting that nut right before the heatblock? I ask that cause I did that several times didn't make any difference though cause even if the filament fed in still the same issue

[Feliks87]

I'm pretty sure my right head nozzle is clogged
the filament string that came out of the nozzle first (now nothing comes out anymore) is way thinner than the string that comes out of my left head nozzle


as for the filament hitting the nut... I tried feeding the hot end by hand without the motor assembly and couldn't get filament through the nozzle easy enough... needed a lot of pushing just to get this thin string out of it
I just ordered some spare nozzles to see if that helps when I swap the right one with a new one

[CADstudent]

Well get back to me if that works out because that doesn't quite seem to work for me.

[CADstudent]

Just a little update apparently issues arise from cleaning out clogs with a wire or metal rod, you know when you jam like a wire throw the tube to unblock it, so were getting a new thermal barrier tube to see if that helps.

[CADstudent]

Believe we have found the issue its called "heat creep" look that up for more information on it and thanks for everyone's input