Possible reasons for extruder getting clogged

hello,
i am new to 3d printing and have a mendel90. been playing around with it and have been trying to sort out a good quality print.
it used to print fairly decent quality prints when i first bought it. i did notice the bed levelling was a bit off as the filament was not sticking to the bed at 2 corners. i tried levelling the bed and in the process, i ended up making the situation worse, and i also got the extruder clogged. trying to sort that problem, i ended up breaking the thermistor and eventually bought a new e2d-v6 hotend. i have altered the z position on the firmware and that is correct i think (as the extruder does not crash into the bed anymore). the bed levelling is also correct at the moment (done as per nophead's guide and advice given by e3d-online).

at the same time when all these things were getting sorted, i also bought PLA filament on ebay for like £14. it is a chinese product, but purchased from UK. visually, filament quality looked fine. i also measured the thickness with a digital vernier at various points on the filament and it was perfect 3mm dia. the filament itself was kind of a matt finish which was quite different from the faberdashery silky finish which i had earlier.
trying to use this new PLA filament, i ended up clogging the extruder again. removed it and managed to clean it thoroughly, and set up again. but the extruder has got clogged again. the temperature setting i am using just now - 200C for extruder and 90C for bed. (noticed it wasnt working at 185C and 60C as suggested for PLA).

what could be the reasons for the clogging?

advice please.

Here is a guide to extruder problems: [e3d-online.com] .
I am guessing that the filament is nominal 3mm. I found that anything over 3.07mm caused difficulties. I use nominally 2.85mm filament that is never over 2.95mm. Filament can be oval shaped so it is best to measure it from different angles.

I see persistent problems with PLA in the E3D hot end. I think J-heads are better for PLA because they have a PTFE liner (which PLA does not stick to). My own experience with all metal hot ends and PLA is that they require a taper in the transition zone.

Also J-heads will handle filament that is 3mm +/-1 0.1 as well as 2.85mm +/-0.1. Both are different definitions of what "3mm filament" means.

---

[www.hydraraptor.blogspot.com]

@ Ralph.Hilton, @ nophead - Thank you.
you reckon i change the filament? or change the hotend?
i have the original j-head which came with the printer. it is full of PLA inside
i am thinking of borrowing a small piece of filament from my university tomorrow and seeing if that will make any difference. shall keep you posted on how it goes.

I would go for 2.85mm nominal filament first and see how that works out.

Change your filament. The E3D prints PLA just fine. However, I did order a cheap spool of filament and have had it clog a few times. My solution was to disable retraction as the cheap filament would just get eaten up by the extruder. All my other spools I run through it never clog. I learned the hard way, DO NOT CHEAP OUT ON FILAMENT. What you save in money you will spend twice over in lost time and frustration.

Chris

Swirvbox,
May I ask where your bought your filament?
I just bought 1.75 from Maker Geeks.com?
and my extruder is clogging .30 small but still work!!
Thoughts?
Tayana

it has taken me 4 months to figure out what was causing the extruder to clog. in this process, i must have clogged the extruder at least 10 to 15 times; dismantled the 3d printer and understood how each part works; modified the firmware and understood how that works; and a whole lot more. over all a super experience; learning it the hard way. patience was key!!!

this is what caused the problem -
the e3dv6 hotend has a small cooling fan which i never used. so when this fan is not connected, the temperature from the nozzle starts to go up the extruder and pretty much the entire extruder (cold zone and hot zone) gets filled with melted PLA. this melted PLA does not get pushed down by the gear (filament feed) on the top, and the gear starts to grind on the filament.

Hi,

The standard J-Head is fine for good quality filament i.e. correct diameter and free of contaminants.

It does however require care in its use and there are a couple of situations that are best avoided:

1. Do not excessively pre-heat the hotend.
2. Do not print with excessively slow speed and lots of retraction.

The effect of these scenarios is that heat can creep up the filament, softening it in the process, leading to a jam occurring. Also, printing at the lower end of the acceptable temperature range specified for your filament helps.

I have had my Mendel90 for a little over a year now and used it for printing both ABS and PLA. Following these simple guidelines has meant that I have not experienced any jams at all.

All metal hotends (potentially) offer the opportunity to print materials beyond 240C but you really should understand any special requirements before attempting to use them. The small cooling fan supplied with the E3D hotends is not optional. It must be operational whenever the hotend is powered.

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.

It also needs to be on when the hot end is un-power but still hot, i.e. during cool down. And I still think heat can creep up the PLA if it is not in contact with cold the walls of the tube due to being a smaller diameter.

---

[www.hydraraptor.blogspot.com]

The main reason mine has ever got cloged has been Elmers Glue flakes.

I use it to cover the glass and when I scrape it off I have to wipe it with a damp cloth.

I was just blowing it off onto the floor and sweeping it up, but some flakes were flying up in the air and falling into the extruder.

So now I kee a paper tower over the exturder and wipe the flakes off easy and gently, I have not had a clog in 3 spools worth of plastic!

Edited 1 time(s). Last edit at 07/04/2015 08:53PM by ratdoghippy.