Upper fan issue.

[Padraicsdad]

I just discovered a small, odd piece of plastic wedged in a side crevice of my M200's base. After a lot of looking I realized it's a chunk off a blade from Fan 1, the upper extruder fan. In fact, I now see that four blades are either partly or mostly missing. I can't find any Zortrax info regarding this fan's function but my guess is it cools the extruder above the hot end to prevent heat creep that could cause filament to be delivered to the hot end at too high a temp. Question for those more experienced than me: is that this fans function? And since this damage has obviously compromised fan performance, how would it have affected this newbie's printing to date?

Fortunately, I already ordered three Noctua 40 X 10 12v fans, two for a double print fan mod and one spare. Two have arrived so I could move the lower fan to the upper (Fan 1) position and use the new Noctua fans for the print fans. Zortrax's directions are clear up to a point but why cut off the connector on the old fan? Is that just to get the wires back out through that shrink tubing sleeving? If so, does that mean they intend me to also cut off the connectors the new fans then solder them back on after threading the wires? They never say anything about cutting off or reattaching new fan connectors. BTW, I  realize the double fan mod requires me to make a parallel splice but thought I'd do that down near the fans.

Lastly, I'm wondering how this fan got damaged. I guess it could have come to me that way but in that case I've been printing like that since day 1. I use the OEM side covers and print in a 4th bedroom that only I use so misc stuff flying around is unlikely. The only thing I can think of is that during a filament change I let the tube droop down and get into that fan while waiting for the extruder to push out the old filament. I have that tube clipped to the flat cable so it doesn't want to do that but maybe I elbowed it clumsily or something. If so, the wire finger guard wouldn't have stopped it. Anyone else experience this?

Thanks in advance for any info on how to make this go easily and prevent it in the future.

Jeff

[Julia Truchsess]

Yowza. The extruder cooling fan is pretty critical, and your description of its function is correct - to keep the "cold end" cold. Since the ZT-HE has better heat-break properties than the Zortrax hot ends and also has a full-length PTFE insert, it's not quite as critical, but still you should have one! Operating without it could result in jamming due to filament expansion and/or softening in the cold end.

How it broke? Dunno. I've had 80 and 120mm fans that would break instantly when touched, but these little 40mm guys have always been pretty robust for me. In fact, my standard test to see if the right-hand print cooling fan is running is to stick a piece of filament in it.

Wire routing is entirely up to you. To feed through the block as shipped from the factory requires removal of the extruder heat sink, and as you note, probably removal of any connectors. You can also just run everything outside the block if you don't care about tidiness.

[Padraicsdad]

I guess this is the conclusion to the thread I started a few days ago:

I just finished (a) replacing my damaged upper fan with the OEM lower one and (b) installing ccc's double print fan mount with two Noctua 40 X 10 12vdc units. Happy days - my M200/Z-Temp/ZT-HE just delivered a very successful test print from the same PLA material that gave me fits before - rafts that were completely unremovable unless I printed at 190℃, no bed heat, 100% fan and even then I had to cut and peel them off. This time I printed at a more nominal 200℃ and the raft "snapped" off easily in one piece. WooHoo!

Since I did everything in one swell foop I can't tell if this improvement was due to replacing the cool-end fan or from adding an extra print fan but my spidey sense says the badly injured cool-end fan was the issue. Whatever, I'm a happy camper.

[Julia Truchsess]

That's great, Jeff, thanks for the report. I'm frequently asked "do I really need the dual fan mod", and I can never give a definitive answer because I've experimented with so many parameters over the past 18 months it's hard to keep track of the direct consequences of any particular mod. I just tell folks that it's unlikely to hurt performance in any case, and likely to help in many

[Padraicsdad]

BTW, ccc's dual fan mount does fit the ZT-HE with the insulating blanket on it. And with even a moderate amount of slack in its heater/thermocouple cables, the ZT-HE drops out easily for maintenance or replacement.