Hotend Driving Bolt doesn't feed Material (Friction issue)

Hi,

I have issues with my hotend. The friction between the driving bolt and the filament seems to be too low. The hotend is hot enough, I can manually push down the filament until it's extruding. The motors are strong enough, all gears are moving. And I already tried to increase the force which presses the material against the driving bolt, but this doesn't help. The mechanism is pretty simple, the filament is between a driving bolt and a bearing, which are pressed together.
The contact surface of the driving bolt is plain. I thought about roughening it up with my dremel tool a little bit.

Any suggestions or ideas that could help?


Thanks

It's usual to use a hobbed pulley or insert to drive the filament. Here is an example: [reprappro.com]

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
It's usual to use a hobbed pulley or insert to drive the filament. Here is an example: [reprappro.com]

Thanks!

If you want to test your filament drive then....
Remove the filament from the extruder. Cut 100mm off the end to get a clean filament. Manually feed about 5mm of filament past the extruders hobbed bolt, then....Hold the filament with your fingers and then press "Extrude 10mm" in your host software - if you cannot hold the filament back from entering the extruder then your hobbed bolt is fine - the hot-end is your problem. However, If you can hold it back with your fingers during the test then, as you suspect, your hobbed bolt is not doing its job. Maybe upload a photo of your extruder.

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Waitaki 3D Printer

this is the same issue i am having while trying to print in ABS. my hobbed bolt just digs into the ABS and it stops all together...i can push the filament to make it extrude, but as soon as i stop pushing, the hoibbed bolt start digging in again...i think my ABS is too soft..this never happened with the PLA. ive tried aligning everything..increased spring pressure pinching the filament to the hobbed bolt etc, but to no avail...and yes, ve thouroughly clead the nozzle 3 times...it my be the china cheap filament i bought, so am buying some PLA to get me printing again and will buy quality ABS later on to get back to testing...but ya, 2 weeks and 40 or so hours of tinkering with no prints completing is annoying...and boring..so PLA for fun...ABS for testing my patience and getting past the learning curve...

Sounds like you guys havent tuned the stepper drivers.
Need to kick up the amps the maxify the torque.

Clockwise with a ceramic screwdriver until motor humms. Bring back slightly and test torque by holding motor shaft in hand. Shouldnt be able to stop with your hand strength. Unlessnyou are hercules.