Forcing the filament when its stuck

My filament stops feeding all the time. The feeding knurl just grinds a groove in the filament then the feed can not happen. I push on the filament to feed. The force is alot.
In Pronterface I: go z200 then extrude by 50. Filament extrudes continuously only after I push. I do not think its the hotend. Pronterface reports correct values.
The filament just doesnt feed correctly from the extruder end. I have Omerod extruders up on the top frame piece.
I cant tell if the filament is getting stuck. When it stops I push it through.
Dont know what else to try.

Edited 1 time(s). Last edit at 01/08/2016 12:06AM by Giantkiller.

Check the pinch roller spring tension- it should be very high, almost to the point of crushing the filament. Check the motor current. It should be 80-100% of the motor's rated current. Check the temperature of the hot-end- if it isn't hot enough the extruder won't be able to push the filament through it.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

There are no pinch springs on this type of extruder. It is just a narrow way between a knurl roller and a smooth bearing.
Omerod did send me a nice bowen extruder with clamp springs on it but I have no mounting for it.
The motor current is topped. The extruder gears spin like crazy while printing like they should. They are herringbone.

I catch any responses after this at next session.

Edited 3 time(s). Last edit at 01/08/2016 12:19AM by Giantkiller.

If the extruder is grinding away the filament, I'd say the tension is good.

Have you calibrated the extruder? Over-extrusion can cause back-pressure and jams.

What kind of hot end do you have? Under what circumstances do these jams occur? Is it always some time into the print? Or right from the beginning?

Frankvdh, if the extruder is chewing a divot into the filament, it means the pinchwheel tension is too low so the teeth of the drive gear aren't biting into the filament deeply enough. If the nozzle is clogged or the hot end isn't hot enough, the extruder motor should slip and click, it shouldn't chew a divot into the filament.

Giantkiller, there should be some sort of adjustment to control how tightly the bearing (the pinchwheel) squeezes the filament against the drive gear. If there isn't, you've got a poorly designed extruder and that's part of your your problem. Find the screw that adjusts the tension and tighten it.

Oh, I did some digging- that design doesn't have a tension adjustment. Ugh. See [www.thingiverse.com]

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Yes. I have to agree with poor design.
But I have found no spec file / bullet list to layout a good design items to look for when considering a purchase. And as I have seen in threads that all noob purchasers have a problem somewhere.
Plug and print is way over the rainbow but unfortunately an instantaneous affliction to anybody getting into this arena.
One can never or should say 'If I'd only known' or later 'Told ya so'. One is self cruelty the other victimization cruelty.

Back to the issue:
The other omerod that I have is screw tensioned. Swap out is easy. But...

I have attached the picture from a previous link to make a case:

My version has two screws and like this one has the hanging clip.
The breadth of that clip is a concern that should be noted by all.
Then attached motor protrudes out towards the viewer when correctly mounted way past the breadth of the hanging clip so that when placed on the top cross beam the whole extruder unit rotates down due the motor weight.
A saddle of some sort needs to be attached to the other side of the motor to suspend it horizontally, unless I am missing something.

But Omerod168, in his infinite wisdom sent me herringbone gear sets for my failing extruders and a herringbone wade bowen extruder assembly to switch to.
I will switch to this next and correct the suspension problem with a hack for now. An extended clip is on the list for the future.

Now for the idiocy:
I have not nor do I remember if I merged in the Replikeo config file. Oops and my bad. But I will check that also.
Remember I had a laptop crash and the new laptop had usb digitally assigned problems.
This would match the filament diameter with the filament speed with the hotend head.
So I at least have a couple of immediate options to try that don't cost money or shipping transit times.
And the Omerod bracket I have on at the moment has a slight warp to it. We learn as we go, no? After all, it is a kit.

But back to Dentist's comment. Yes, bad design. I hope enough prenoobs see this in order to make a patient and intelligent decison when purchasing a printer. They all have problems whether bad design, missing parts or price to value.

Edited 9 time(s). Last edit at 01/08/2016 01:06PM by Giantkiller.

Well, well, well, the Omerod Bowden with tension set did the trick!
Thanks go out to Omerod168!
I also used a Velcro strap to keep the motor horizontal.
But this points to the extruder holders supplied by Replikeo as of no use at all. There is no filament tensioning.
This test still has some rough spots but they are from the first layer not adhering to the print bed.
I raise the temp to 80d and try again.
I need to implement autobed leveling.

Any ideas?

Edited 3 time(s). Last edit at 01/09/2016 12:11AM by Giantkiller.

I am back with the previous error.
If I push the filament through with the head on it extrudes quite easily.
Through the extruder though is a different beast. It starts to feed to print the rail but fails at the same spot every time. The first layer of the arrow test print misses but then the next layers go down.
I put a sharpie mark on the filament to see the motion. When it withdrawals i see the mark go back but when on the forward motion the mark goes to the point in space where I made it and then the filament doesnt continue into the feed tube. It stays there. I have to push it in and then sometimes it will continue. I dont have any debris or jams because I push and it continues.
It is like the filament hits a stop in the feed line somewhere.
I ordered 2 e3d v6s and looking for a dual bowden tube feed adapter for the head mount.
In other words, I am stripping out all the Replikeo printed crap and replacing with high performance professional grade parts.

Edited 3 time(s). Last edit at 01/13/2016 11:33PM by Giantkiller.

What spring are you using in the extruder drive? Ball point pen springs are not strong enough. Springs from handwash dispensers work well in this design.

Regarding the extruder drive staying horizontal on the X arm, I think you may have a mix of Ormerod 1 and Ormerod 2 parts. The Ormerod 1 has a lip in each of the slots in the X arm to prevent the extruder from over-rotating. The Ormerod 2 extruder has a longer hook on the end, and the end of the hook locks into a rectangular cutout in the X arm.

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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].

See the length of the clip? This is not a problem. I just wrap a Velcro strap to keep the motor placement horizontal.

I have really good tension springs. In fact I can crush the filament.
I can push the filament through by hand and it flows consistently.
And see on this black one there is no tensioning at all. The orange one posted previously is like the one I have now.

Edited 1 time(s). Last edit at 01/14/2016 12:24PM by Giantkiller.