Re: Help! Filament jammed!
April 25, 2015 01:05PM
That picture is definitely not of a J-head. It's either an E3Dv5 or a clone. It does nor use a PTFE tube but requires a fan blowing across those fins at all time. Do you have it istalled? Is it aligned with the bottom fin?
Re: Help! Filament jammed!
April 25, 2015 05:00PM
Hi,

@QuackingPlums: Is your Mendel90 kit-built with a hotend wrapped in red tape?

If that is the case, the presence of the red tape is indicative of your printer having a hole in the fan duct to direct some airflow onto the J-Head (the mods were released at the same time around 09/2013).

I print PLA mostly at 185C, with the fan full-on after the first layer, at a speed of 40mm/s and first layer at 50% of this speed. Recently my workroom has been at an ambient of 26C and I have printed objects of one hour duration.

I do not allow the extruder to sit at working temperature any longer than the printing sequence requires. My start GCode pre-heats bed and extruder and end GCode disables both heaters after the print completes.

Regards,
Neil Darlow


I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.
Re: Help! Filament jammed!
April 26, 2015 12:23AM
i had this problem pop up with a spool of black pla. i reduced the extrusion multiplier down to 85 and increased printing speed. no more backups/clogs.
Re: Help! Filament jammed!
April 28, 2015 10:11PM
Wow, we're digging up some old threads now! smiling smiley

@Neil: No, my M90 pre-dated the red tape. It pre-dated a lot of cool stuff, which is why my x-idler end is still cracked and held together by a makeshift clamp that Chris sent me before the new revised x-ends were published. I tried making a small hole in my fan duct to ventilate the Jhead but it had no effect (my room gets above 30degC in summer with all the equipment powered up) so I had to switch to ABS.
I don't use PLA any more - in fact, I finally gave away all my Faberdashery stuff recently as I have a pretty extensive range of colours in ABS now to do everything I thought I'd need PLA for. ABS is much easier to work with in that regard, as silling things such as the small increase in temperature of a warm room in summer doesn't cause buckling of the filament inside the head. smiling smiley

@Pgringo: Does the print quality get affected when you mess with the extrusion multiplier and printing speed? I can't see how that wouldn't mess up your steps per mm calculations and cause issues with everything from perimeters to infill and first layer adhesion?
Re: Help! Filament jammed!
September 04, 2015 09:51AM
Hi,

the situation I am facing looks very similar to this :



I´ve been reading the replies, but I don´t understand what nophead means :

Quote

I assume it is PLA. If you have a heat gun then heat the top end of the extruder to about 70C. It then becomes like rubber and you can grip it with snipe nosed pliers and pull out the bit in the hex grub screw. It should then work again. It is only the fact that the hole through the grub screw is bigger than the normal filament path that is the Achilles heel of the JHead.

First, the top end is the end that is used to fix the JHead to the wades block? (the end seen in the picture?) I doubt that I could use the heatgun and only heat to 70°C, that thing gets very hot, very quickly, but I am willing to try, although I am worried about melting the black part (dunno what it´s called).
Second, I don´t see a grub screw?

Edited 1 time(s). Last edit at 09/04/2015 09:55AM by D4RK1.
Re: Help! Filament jammed!
September 04, 2015 10:28AM
Ok,.... after some thinking and looking I understood and managed to find and clear the grub screw and pushed the filament through the nozzle, seems to be working, I´ll be reassembling now and let´s hope no more problems occur.
Re: Help! Filament jammed!
September 27, 2015 04:29AM
Fixing this mess is rather easy, even when the printer was left unattended and forcefully pushed the filament into the melting camber. Just keep the hotend at temperature and remove it from the extruder like you did in the picture. Now use a soldering iron and push it at roughly 200 degrees all the way into the back of the hotend. Now pull it back out and grab a drill bit (2,5mm is fine) and push it inwards with a slight turning motion. This should force the drill into the soft filament and you should be able to pull most of it out.

It might help to insert a piece of new filament to check the extruder is free again. But don't push to hard, the j-head keeps blocking when pushing the filament to fast. The melting chamber gets full quickly and the soft filament gets stuck between the brass and the peek.

I had to do it three times. The root cause has always been temperature being to low or me feeding new filament to fast by hand.

Ingo
Re: Help! Filament jammed!
September 27, 2015 07:57AM
A drill risks damaging the soft PTFE liner. All you need to do is get the top of the hot end above 55C. You could dip it in a glass of hot water for a while.

The PLA is then like rubber so you can push needle nosed pliers into it and nip it and pull it out. It will stretch and come away from the sides. As long as you clear the bit in the hex socket of the grub screw the rest can be pushed forward by the new filament.


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