E3D heatbreak inner diameter question



  • I'm diagnosing an E3D Volcano+Titanium Heatbreak PLA jam in a print and, while cleaning it, found out that the lower section of the heatbreak is larger (2mm diameter) than the upper section of the nozzle (~1.75mm). What's the reason behind it? Wouldn't it just cause clogs? Is there something wrong/missing here like a PTFE coating? Confused.

    I can understand the upper section of the heatbreak being slightly bigger, but why would the lower section, which is screwed into a 200+ degree heat block, be larger?


  • administrators

    @Edgars-Batna here are the drawings:

    https://e3d-online.dozuki.com/Document/I2woGboCqjNEBkIx/V6.8-Heatbreak.pdf

    https://e3d-online.dozuki.com/Document/tPhOA1yXfxUjgBO3/VOLCANO-NOZZLE-(Edition-5.2).pdf

    You can see that the heartbreak and the top of the nozzle are 2mm, the reduction happens inside the top of the nozzle.

    As to why they did that you will need to ask them!



  • @T3P3Tony Thanks. In the nozzle drawing it says: inner diameter is D and D for 175 SKU is 2.0 +/- 0.1 mm. So, there's actually no reduction? Am I reading it wrong? Even more confused now, since I measured it using a caliper after burning the filament away and, since I didn't believe my eyes, tried to stick precision drill bits into the heatbreak and nozzle. 2mm drill bit did not want into the nozzle at all, while it moved easily but snugly in the heatbreak.



  • @Edgars-Batna
    How old is your E3D V6? I think old versions of the heatbreak may have been smaller in diameter.



  • Some wild guess .... filament expands ever so slightly as it gets hot. The extra clearance allows for that without causing issues.
    No, there is no ptfe coating in there.

    Last but not least re the heat break clog itself, There are several reasons for the issue such as too much retraction etc etc but if you use a Chimera setup there is a secret handshake which drove me nuts for a while with clogs. Just in case you run a Chimera and for the benefit of other people that might be ripping out their hair in disgust:

    Make absolutely positively sure that the sliding joint in the Chimera is in the heat sink the correct amount. If the upper setscrew doesn't properly grip, it is too far out and will always block up (but not consistently but rather whenever it feels like it, possibly related to lower extrusion speed) because the heatbreak section gets too hot. Note that the ptfe tube that carries the filament is supposed to seat against the top of the connector. If you push the tubing in a bit too much, it will prevent you from pushing the connector up enough. You feel that it is completely seated because the ptfe tube stops it but it's not in deep enough.
    Kinda hard to explain .....



  • FYI, I've had a lot of problems with Chinese knock-offs not working due to poor tolerancing. The best performance I've had has been when I ordered both the heat break and the heat sink together from E3D.



  • @bot said in E3D heatbreak inner diameter question:

    @Edgars-Batna
    How old is your E3D V6? I think old versions of the heatbreak may have been smaller in diameter.

    It's 2017/2018 ish. Also, it's the nozzle that's smaller.

    @jens55 said in E3D heatbreak inner diameter question:

    Some wild guess .... filament expands ever so slightly as it gets hot. The extra clearance allows for that without causing issues.

    But then why is there different clearance between nozzle and heatbreak? That's asking for trouble. I can imagine nozzle expanding at temperature, but I can't imagine inner diameter increasing up to 10% to match the heat break.

    No, there is no ptfe coating in there.

    Good to know, thought I might have burned or chewed it off somehow.

    Last but not least re the heat break clog itself, There are several reasons for the issue such as too much retraction etc etc but if you use a Chimera setup there is a secret handshake which drove me nuts for a while with clogs. Just in case you run a Chimera and for the benefit of other people that might be ripping out their hair in disgust:

    It's E3D Volcano with Titanium heatbreak.

    @TLAS said in E3D heatbreak inner diameter question:

    FYI, I've had a lot of problems with Chinese knock-offs not working due to poor tolerancing. The best performance I've had has been when I ordered both the heat break and the heat sink together from E3D.

    All genuine and from E3D directly, but not ordered together.



  • @Edgars-Batna I just meant that if you had an older heatbreak before you got the titanium one, it may have been smaller.



  • @bot said in E3D heatbreak inner diameter question:

    @Edgars-Batna I just meant that if you had an older heatbreak before you got the titanium one, it may have been smaller.

    I measured the old heat break and it appears to also be 2mm not counting the PTFE liner.



  • It's my experience that jams are often caused by cheaper filaments or over enthusiastic retraction - some of the defaults I found for firmware retraction when setting up my Duet (based on initial codes produced by the online tool) were excessive in the extreme (10mm) more suited to a bowden than a direct extruder - even then it's a lot.

    By retracting too far you pull molten plastic back into the heat break where it has no place being, it cools and bam ....



  • @Garfield said in E3D heatbreak inner diameter question:

    It's my experience that jams are often caused by cheaper filaments or over enthusiastic retraction - some of the defaults I found for firmware retraction when setting up my Duet (based on initial codes produced by the online tool) were excessive in the extreme (10mm) more suited to a bowden than a direct extruder - even then it's a lot.

    By retracting too far you pull molten plastic back into the heat break where it has no place being, it cools and bam ....

    Agreed. I just checked my config.g and indeed it's set to 2mm... Max practical retraction on my HEVO is 1.5mm or so due to high PA value. Nice pointer! I forgot to uncomment a line in the config.g as I was testing something the other week.


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