So I’ve been having the usual heat creep issues with the dual v3.1 toolhead, and got some 4020 fans for that and for the part cooling fans in an attempt to fix the problem. Thing was, the new fan was still putting out a pathetic amount of power. I checked the wiring in on the main board to see if there was a voltage adjustment that could be made or something.
Turns out the hotend fan was plugged into a 5v auxiliary port on the Rambo board. WTF? Is this the way all the machines are or did the previous owner of my machine do this (I doubt it)?
…Anyway I ran the fan wires straight to the power supply and now the fan is spinning really nice (yes, it is making more noise, but I’ll take it because the steppers on this thing are loud anyway, and the dual 3.1 hotend is useless with 5v power to the fan).
I searched for this issue and couldn’t find it in the forum. Anyone know what the deal is?
…And feel free to bugger your fan straight to the power supply like I did for some extra juice.
EDIT: the original fan was 5v, so I guess this was the way lulzbot intended it. Not super impressed.
First of all – Sorry for the snarky forum post. I haven’t done that in years. I’ve got a big project due soon and it’s kind turned me into an asshole this week.
So I’ve been running PLA (Polymaker polyterra PLA) under the polylite profile with just a few tweaks to retraction speed with ultimaker PVA as the support material, and no matter what I’ve done the PVA has clogged in the heat break after a maximum of 1.5cm of Z height of printing. PVA was also stock settings with various adjustments to try to diagnose the problem (increasing temperature to make sure filament was hot enough and not grinding, etc…noticing that the default PVA profile is rather colder than manufacturer specs for PVA, and surmising from inadequate evidence that this is an attempt to mitigate the heat creep issue). PLA-PLA printing has been ok, at least the one time I did it.
On the Dual Extruder V3, the shared heatsink had, IMO, poorly engineered cooling flow. V3.1 was an attempt to improve the cooling flow but, IMO, a solution that works better is https://www.thingiverse.com/thing:3213878. I was able to get the stock fan to attach with some careful rerouting of the existing wiring. There are also higher CFM 40mm fans that can be used if necessary.
If you need different temperatures on each extruder because you are using different filaments (i.e. PLA and PVA), then the illustration on Thingiverse shows why the air flow matters.
Thanks for the link. I think the 24v 4020 fan is already helping with the problem alright (first print is still going), but this shroud should definitely help with not having to cycle the hotends up and down in temp so much while printing, and might let me run the PVA a little hotter to help with layer adhesion where I’m having some issues.
I’m starting to really appreciate the support from FAME and the Lulzbot community. I suppose this is part of what people are paying for. I got my TAZ second hand, so I hadn’t done a ton of research.
EDIT: and to be fair, the chimera heatsink is kind of a crummy design to begin with.
Now if only the filament loading path could be as nice as with my bondtech extruder…I struggle to get the extruder loaded most of the time.