Hotend jams - not blocked

Post Reply
Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Re: Hotend jams - not blocked

Post by Hugues »

ok, i've machined my teflon disk, diameter 6 mm, inside diameter 2mm, and thickness 2.5mm

i've drilled my peek with 6 mm hole,

i have installed the teflon disk and screwed back both metal parts of the extruder,

but i did not manage to extrude any plastic with the disk in place

is my procedure ok ? is this the correct teflon part dimension ?

My filament does not really enter into the teflon part, maybe the holes are not aligned properly.

I have to try again tomorrow, too tired too think straight now.
IMG_20140228_204020.jpg
Hugues
Regards from Switzerland

Mayhem
Posts: 169
Joined: Tue Jan 08, 2013 4:15 pm
Location: Finland

Post by Mayhem »

its been like 6-7 months since i had block or jam so is your extruder coolin fan supplied whit 12v?
Felix 2.0----> 3.0
V4 hot end
Simplyfy 3D
Kisslicer
Autodesk fusion 360

Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Make a small bevel. The whole point is that the hole in the aluminum parts could have been made a wry, who knows what was the experience Turner. I have all the parts are machined on a CNC machine tool with a nominal dimensions. Perform a build with thread inside. ;)

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

i managed to align the hole of the teflon part with the hole of the extruder, and i could extrude some filament. But to my grand astonishment, this did not solve my problem. :shock:

But i did finally find the origin of my problem and now i'm printing again ! Feels good.

As you can see on the picture, part of the tensioner mechanism was fractured (this was a rather poor quality print job you'll tell me).

So there was not enough pressure on the filament anymore. Luckily i had an old spare part that was also fractured but not as much, so now i'm printing again, and the first part i'm printing is this print head base of course.

This has been a long journey, hopefully the "Saamec" mod will also make my printing more smooth.

thanks all,


IMG_20140301_163952.jpg
Hugues
Regards from Switzerland

Genaforge
Posts: 8
Joined: Thu Aug 29, 2013 6:20 am

Post by Genaforge »

Good to see people coming up with additional solutions.

I started having some additional problems with my filament feed. The extrusion motor, or the metal teeth attached to it, don't seem to be gripping the filament properly. I've tried all types of solutions, with the latest being printing a new housing unit; such as Hugues describes as the fix to the issue.

It's printing now, so I'm hoping this will be the end of my issues.


To explain the issue, for anyone else that's having similar problems:

I've managed to solve the temperature jamming issue (see the opening post). But the filament feed rate dropped off sporadically. I'd need to keep a constant eye on the printer, every 30 seconds, and manually assist the filament. Then it would be good to keep going for another 30 seconds to 5 minutes.

I knew the hotend wasn't jammed because I could loosen the tensioner and manually push filament through with no problems. It didn't matter what temperature I set it to... within reason, too high and I got got end jams again. The filament didn't seem to be the problem, although I did wonder whether I was having issues because the filament was poor quality, or if the teeth were biting down too hard and distorting the filament too much; causing excessive friction in the hotend.

I'll add that the filament seems ok, although I don't have a way to measure the diameter; which may also be a cause of the problem. If you're having problems with filament feeds, you may want to check your filament diameter; anything over 1.75 can cause sporadic jams.

I could tighten the tensioner up a high amount, but this ended up causing the bearing to make contact with the heatsink; which stopped the bearing turning and no filament went through. Outside of this I got no marked difference in print quality regardless of how tight or loose the tensioner was. I even had it barely touching (enough that I could still pull the filament out), and still got similar performance (or lack thereof).

I never needed to put much effort into the manual assistance of the filament. The tensioner just never seemed to do its job. The teeth on the motor aren't damaged at all, but I did move this slightly so an 'untouched' section made contact with the filament; no improvement.

It's only now that I've seen Hugues post above that the solution seems so obvious. And I hope this is the solution to my issues.

As a testament to my troubles; I've just spent the last two hours manually assisting this print job to get the new housing printed. It's late now, but tomorrow I'll be testing it out.

Genaforge
Posts: 8
Joined: Thu Aug 29, 2013 6:20 am

Post by Genaforge »

Update: Got the new PLA housing in place, and the first print is going off without any issues at all.

I was a bit disappointed to see that the bit of plastic that guides the tensioner wasn't damaged, so I'm not entirely sure if that was my issue, but; doesn't matter, it's working now.

I have an assumption that my past temperature tests may have warped things a bit, which led to a gradual decline in performance. I'm going to have to get a set of replacement parts printed in case similar issues happen again.

Anyone reading this would be well advised to do the same.

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

well i'm glad to hear you're back to printing.

I did go through a week of fighting with my printer, un-explained jams, cooling fan not working anymore. I assembled and dismantled my hot end zillions of time, and finally one night, without really knowing why, it started to print again. So i just don't touch it for now, but i don't quite like this, looks like black magic LOL. Never know when it will fail on me.

Can't say that i'm super impress with the Teflon mod proposed by saamec (with all due respect), it did bring some new headache, like having to center the little disk properly many times. THere are too many variables changing lately to say this mod is improving the reliability of this whole thing. But we'll see on the long run i guess.
Hugues
Regards from Switzerland

Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Mr Hugues. I am very sorry that you have not obtained. But I have already printed a half year with my new extruder. I forgot about the traffic jams just typing and all. It can print and ABS. Had to throw the cooling fan to 12 V, as Teflon was heated from the heating part. Let's see how my version of the extruder http://forum.felixprinters.com/viewtopic.php?f=9&t=729 I don't know how I convinced you, I really want you to enjoy printing. May be to sell you my extruder)))?

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

Saamec wrote:Mr Hugues. I am very sorry that you have not obtained. But I have already printed a half year with my new extruder. I forgot about the traffic jams just typing and all. It can print and ABS. Had to throw the cooling fan to 12 V, as Teflon was heated from the heating part. Let's see how my version of the extruder http://forum.felixprinters.com/viewtopic.php?f=9&t=729 I don't know how I convinced you, I really want you to enjoy printing. May be to sell you my extruder)))?
I believe in your mod. It's just that the one you show on your pictures is different than the one i made. I just made the teflon disk, 6mm OD, 2mm ID, 2.5mm thick, as precise as i could. But the teflon rod i bought is slightly less than 6mm OD, so my disk is moving in the peek, that could explain my problem.

Your picture is different, it's a disk and a tube together. I cannot machine this with my milling machine.

ACtually , that makes me think. Maybe i can simply use a long tube of 6mm OD, drilled with a 2mm hole. But then i need to drill a hole of 6mm ID in the upper part of my print head. I got an old one that I'm not using. Need to check if the OD of the print head is large enough. Oh wait, how i'm going to keep the teflon tube from moving upwards like this ? mmm...need to think a little more here...

I will see. For now I'm printing fine, but if it jams again, i will try it.
Hugues
Regards from Switzerland

Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Just cylinder PTFE, wedged inside, must fulfill the same function, it should work. The only problem is the alignment of the holes. You can fix making chamfer. I have no such problem, because everything is made with high-precision equipment.

Post Reply

Return to “Troubleshooting”