Actual filament width too thin for extruder?

Hi all -

I have a Mendel90 (3mm Wades Extruder, Repetier, Slic3r) and have been happily printing with PLA for a couple of years now.
Decided to branch out into ABS printing this month, so I purchased a spool of 3mm blue ABS.

I was using higher temps (230 C for the hotend, 110 C for the heated bed). The first warning was when I measured the actual width
of the ABS filament in a couple of places. 2.4mm, 2.6mm, 2.7mm... varying by 7%, and also consistently quite a bit smaller than 3mm.

I tried it anyway. My extruder worked for a short while, but quickly jammed. Just to confirm it wasn't anything else, I switched back to PLA
and everything was fine.

My theory: filament that is too thin can melt and fill in the space of the extruder hot end and jam up the works. Does this seem consistent with
anyone else's experience? If so, what is a minimum diameter for 3mm filament?

Thanks!
Rob

While the variation is a bit large it shouldn't matter that much, since it is all below 3mm.
In general all drilled parts will be larger than 3mm so the filament can move easily. While i used 3mm i usually drilled 3.1 holes.
Usually there is a large enough gap anyway to let filament go up in the hotend, it shouldn't cause trubble though since it should cool down sufficently before becoming criticle.
First thing i would check is that your hotend is cooled sufficently.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

This is quite frustrating! PLA works like a dream at 195 C extruder temp, but for the life of me I cannot get ABS to extrude at any temp up to 250 C (I don't go any higher for fear of burning something out).
I even have a cooling fan mounted on the x-carriage:
[www.thingiverse.com]

Am I missing something here? Does the Wades extruder not work with ABS?

Rob

I print ABS using a wade extruder for 2 years. It's a pretty much perfect extruder. As i wrote above, your problem is very likely in the hotend. Do a search on the forum, this kind of problem is popping up all the time and it has seldomly anything to do with filament diameter.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Does it jam on the first layer? You may have to adjust our Z height due to thermal expansion.