Makerbot - Filament Jams!

[blissiictrl]

Hey guys,

I just thought I'd type up this little tutorial for all you other Replicator 2 users!

Recently, I was having a huge amount of issues with my Replicator 2 jamming! I did a ton of tricks - Pulled the motor out and cleaned it, forced filament through the extrusion head - all to no avail!

What I eventually found through hours of scouring forums, was that there was a problem with my insulation on the top side of the extruder, which was causing heat soak into the filament guide tube.

This was causing pre-expansion of the filament (I got my digital calipers out for this - it was getting close to 1.95mm!!!)

So here is my fix-

Disassemble the machine as usual - take off the fan, the motor, the side fan, and the heater block.

Completely disassemble the extruder part.

Here's the next trick - re-insulate the extruder. I used a double layer of ceramic insulation tape, from my "local" i.e. Australian source BilbyCNC, then about 12 layers of Kapton tape to really help keep temps at bay.

The next trick was one that requires some extra gear.

Take the threaded tube - the one that the filament goes down, and apply a bit of thermal paste around the outside! Then, when you screw this into the aluminium block, it will coat the inside of that with the thermal paste as well. This acts as an extra insulation.

The final trick was to thermal-paste the bottom of the aluminium block.

Sorry for lack of pictures, I was so involved in getting my printer going again I plain forgot to take any!

But 30-40 hours on, I've still not yet had a better print! It may be the double layer of insulation tape that did most of the work, but it hasn't jammed, or skipped again!

[JohnA136]

Is this on a stock MakerBot extruder with the Delrin plunger or has it been modified with the bearing and spring lever upgrades?

[blissiictrl]

Is this on a stock MakerBot extruder with the Delrin plunger or has it been modified with the bearing and spring lever upgrades?

Mine is the model with the bearing and spring upgrade - it came with it from my supplier

[brackett27]

I wanted to make sure I understood your instructions correctly.

There is the heater block (the part that has the heater wires and thermal sensor and nozzle in it). Above that there is a an AL block that the filament passes through. You are saying wrap the heater block with ceramic tape and layers of kapton on top of that that. And to use heat sink compound (which is a thermal conductor) on the threads of the bit that goes into the upper AL block that passes the filament though it. This would make things more conductive in my mind (which might make that channel cooler).

Regards,
S.

Hey guys,

I just thought I'd type up this little tutorial for all you other Replicator 2 users!

Recently, I was having a huge amount of issues with my Replicator 2 jamming! I did a ton of tricks - Pulled the motor out and cleaned it, forced filament through the extrusion head - all to no avail!

What I eventually found through hours of scouring forums, was that there was a problem with my insulation on the top side of the extruder, which was causing heat soak into the filament guide tube.

This was causing pre-expansion of the filament (I got my digital calipers out for this - it was getting close to 1.95mm!!!)

So here is my fix-

Disassemble the machine as usual - take off the fan, the motor, the side fan, and the heater block.

Completely disassemble the extruder part.

Here's the next trick - re-insulate the extruder. I used a double layer of ceramic insulation tape, from my "local" i.e. Australian source BilbyCNC, then about 12 layers of Kapton tape to really help keep temps at bay.

The next trick was one that requires some extra gear.

Take the threaded tube - the one that the filament goes down, and apply a bit of thermal paste around the outside! Then, when you screw this into the aluminium block, it will coat the inside of that with the thermal paste as well. This acts as an extra insulation.

The final trick was to thermal-paste the bottom of the aluminium block.

Sorry for lack of pictures, I was so involved in getting my printer going again I plain forgot to take any!

But 30-40 hours on, I've still not yet had a better print! It may be the double layer of insulation tape that did most of the work, but it hasn't jammed, or skipped again!

[blissiictrl]

Yep, that fairly well sums it up. The ideal aim with the kapton and ceramic tape is to stop heat directly transferring to the AL block itself, and as the threaded section is directly connected to the heater block some latent heat will transfer through it, so the thread is coated in the thermal paste to help draw heat away from it. I'm unsure of what the material is in the thread but from heat transfer mechanics, aluminium is a much better conductor of heat that steel (assuming stainless steel is the thread) - stainless is bad at conducting so theoretically it would hold a lot of heat, which is basically why I used the thermal paste - it essentially helps to conduct excess heat away from the threaded tube

Hope that helps!