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I think that my j-head is not working???

coreformula

I think that my j-head is not working???
March 28, 2013 11:13AM

Registered: 11 years ago
Posts: 24

I am using a j-head 1.75mm from hotends.com

250w power supply
RAMPS Board
Marlin firmware
Nema 17 motor (tested 4 + 5oz versions)

I have attached it to a makerbot minimal extruder setup as well as an bowden airtripper and am having the same problem. There is too much back-force on the motor and it is not extruding.

Any suggestions?

Thanks

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lazzymonk

Re: I think that my j-head is not working???
March 28, 2013 11:48AM

Registered: 11 years ago
Posts: 349

what type of plastic are you trying to print? and what temperature are you using??

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richrap

Re: I think that my j-head is not working???
March 28, 2013 11:49AM

Registered: 13 years ago
Posts: 818

Can you push it by hand when it's at temperature?

Do you have the thermistor calibrated? - if not see this post I just made here

And have you turned the Stepper motor POT up or down? to change power to the motor?

And if you have done all that, get a geared extruder, direct drive extruders are a pain.

[richrap.blogspot.com]

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coreformula

Re: I think that my j-head is not working???
March 28, 2013 12:24PM

Registered: 11 years ago
Posts: 24

I am using PLA at 180.

It is aligned and straight

I can push it through manually.

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lazzymonk

Re: I think that my j-head is not working???
March 28, 2013 05:05PM

Registered: 11 years ago
Posts: 349

try increasing the temperature a bit. Are you able to manually push it through the tube?

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bdcannon

Re: I think that my j-head is not working???
March 28, 2013 05:15PM

Registered: 12 years ago
Posts: 81

Check to make sure the idler on your extruder is applying enough pressure and that the hob (the part that looks like it has teeth to bite the filament) is lined up with the filament.

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richrap

Re: I think that my j-head is not working???
March 28, 2013 07:11PM

Registered: 13 years ago
Posts: 818

coreformula Wrote:
-------------------------------------------------------
> I am using PLA at 180.
>
> It is aligned and straight
>
> I can push it through manually.

Try it at 195 Degrees (if that is an already calibrated thermistor)

And did you increase the motor current? (turn the trim pot clockwise a little at a time)

Does the NEMA17 motor have a ~50mm long body or a ~40mm?