Bowden strength question

This is the sort of system I am running,
With my airtripper bowden coming from the top of the rostock.
However, I am not extruding. It only jams.
The hotend is getting to the correct temperature,
I just un-clogged the hotend also.
My hotend is a j-head mk5 .4mm nozzle with 1.75mm abs
Any ideas on what could be causing a jam?
If I remove it from the nozzle, it extracts and retracts the appropriate amount.
It just seems as if the stepper motor is not completely strong enough to push the filament through.
I was able to stick a .2mm strand of wire up the nozzle end without a problem.
And I can get filament extruded by pushing it by hand.

So the stepper motor doesn't have enough power. You probably need to turn up the amps on the stepper drivers. The procedure for which can either adjust the little trimpots on the stepper drivers, or through software depending on your board.

Is the J-head hotend a chinese clone? I've heard they can jam often, whereas the original j-heads from hotends.com do really well.

Edited 2 time(s). Last edit at 01/31/2014 03:12PM by TheTechnicalNoob.

I recently swapped my Jhead out for an e3d mk5. Pushing the filament through by hand takes much less effort now. My steppers are 4.4kg torque and both heads extruded ok but the Jhead oozed much more. The e3d is a really good product.

I might just take that advice and get a new hotend if adjusting the pots doesn't work.

Here's what I've been doing when my J-head Mk V starts to jam and it won't extrude easily when I push a filament by hand.

1. Remove it from the cold end (most people incorrectly call this the extruder)
2. Connect to the controller and heat up the hot end to operating temperature and pull out the filament.
3. Use an allen wrench to tighten the hollow set screw. You should feel just a slight resistance. Don't overtighten.
4. Turn off the heater and allow the hot end to cool down near room temperature. Remove from the controller/printer.
5. Mount an appropriately sized drill bit (for 3 mm, I use a 1/8 drill bit) on a drill set to run at very low speed. Adjust the length so that it won't drill into the brass nozzle.
6. Drill the filament hole out at very low speed. You need to pull the drill out a few times to clear the plastic from the drill bit flutes. Repeat until just before the bit hits bottom. You don't want to drill the nozzle.
7. Insert filament and heat the nozzle up to operating temperature and test by pushing the filament through.