Hi,

I've got a badly printed MendelMax 1.5 with JHead Mk4b.

I was able to print exactly one part. Now it doesn't print any more, because the filament is not transported.
I removed it several times and inserted it again. No change.
I replaced the hobbed bolt with one that was made to transport 3 mm Filament. (the original would have fit 15 mm
Did not help either.

As you can see on the photo, the pla parts aren't in good shape any more.
So what solution should I try?
More or less pressure on the springs?
Print (buy) spare parts?

I already searched Thingiverse for some parts:
Would this one work with JHead?
[www.thingiverse.com]
But where can I get a geared stepper motor in Germany?

I really would like to use this one, because it looks as to cause far less trouble than the Gregs Wade etc...

thanks,

JPT

Edited 1 time(s). Last edit at 03/29/2014 09:03AM by JPT.

Sounds like the hot-end is blocked rather than there being an extruder problem.

Edited 1 time(s). Last edit at 03/30/2014 05:23AM by waitaki.

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Waitaki 3D Printer

Does it "dig" in to the filament, ie. does it try to feed the rod ? If it does, check the hot-end temperature and possible blockage. If not, try more pressure and check that the shaft is rotating when the extruder motor is running.

BR.
Ari

Thanks, that are good ideas.

Yes, it rotates and digs into the filament. Sometimes it transports, but as soon as it retracts the PLA on next extrude it's stuck.

Let me check somehting...

If I release the spring pressure and push the filament manually into the hot JHead it produes a nice output.
How do I know the manually applied force is more or less the hobbed bolt can apply?
Force required is a little bit less at 185°C than 160°C

you need to print hotter, 160C will never work and 185 is just about the bare minimum. try @ 195 -205C and see how things work.

If that problem comes especially when retracting the fillet, there might be a problem with the upper part of the hot-end getting too hot thus melting the fillet too much. The fillet will expand when heated. When the molten material is then retracted in to the colder zone, it will solidify and can get really stuck. Especially if there are any gaps in the channel where it can flow in to and "anchor" itself.

Heating up to 200°C did not help much.
I believe it's because of insufficient cooling. Haven't got any fans yet.

These are the parts that need cooling?
- The upper part of the Jhead.
- The printed part itself if the layer print time is below 30 seconds.

How would I achieve that?
Where do I connect the fans to the Sanguinololu?