Fan shrouds melting too often  

RE: Fan shrouds melting too often

PC blend will help.  What temp are you printing?

RE: Fan shrouds melting too often

If you're not fond of ABS and some of the other high-temp filaments, Colorfabb HT has similar heat resistance and prints much like PETG with little odor. I use it for fan ducts. 

RE: Fan shrouds melting too often

I don’t know but it feels like something else is going on if your shroud melts after a few hour of PETG printing? I’m printing PETG for days and it doesn’t seem to affect my shroud at all.

I’d get on a chat with Prusa support, to see what they’re saying. 

RE: Fan shrouds melting too often

Posted by: @bobstro

If you're not fond of ABS and some of the other high-temp filaments, Colorfabb HT has similar heat resistance and prints much like PETG with little odor. I use it for fan ducts. 

Good product.  

RE: Fan shrouds melting too often

Sounds like you have a problem of some sort and printing the shroud in a different filament is likely to only temporarily mask it.

Just wondering what printer you are using as I was just browsing the forum and came across this note from @-2 on a different thread:

"The Mk3S fan shroud is quite a bit different than the Mk3 shroud, and PETg is sensitive to cooling, so you might start playing some more with fan speeds. Also, it wasn't uncommon to have the Mk3S shroud pointed at the heater block, causing thermal overshoot."

This isn't a subject I know about but thought could be worth mentioning.

RE: Fan shrouds melting too often

After printing a long run of ABS, I noticed that the stock fan shroud was indeed starting to droop.

I took the opportunity as an excuse to try the then-new PC Blend, and it worked out quite well.  Before I tore the machine apart I printed both the original and a remixed 'improved' one in PC Blend so I would have both and could decide in real time which to use.

I ended up using the remixed one, and it's held quite well with regular ABS prints and every-so-often PC Blend prints.

RE: Fan shrouds melting too often

PC or Nylon is certainly suitable for the fanshroud. With this material or similar from 3dxTECH you have no more problems in this aspect:

https://www.3dxtech.com/carbon-fiber-3d-filaments/carbonx-pa6-cf-gen3/

RE: Fan shrouds melting too often

Posted by: @hellbender-2

Anyone else have this problem?

I've printed them with PETG and ABS, and there seems to be no difference.   They deform after a single PETG temp print, and then get progressively worse until they are unusable after 8-12 hours of printing.

I'm interested in this topic as surely ABS shouldn't deform in such a short period of time when printing PETG?  Mines OK with PETG prints although admittedly they are relatively short ones.  I'm planning on some ABS printing so good to see suggestions before I run into problems.

RE: Fan shrouds melting too often

It took a LONG time and quite a few ABS prints for me to notice the shroud was starting to droop.  I'm sure many users of these print ABS prints and never even notice it.

A related question to those who may know.  Has the fan shroud on the MK3S always been printed in ABS from the factory?  I assumed mine was but I know that PETg is used for some of the parts on the machine.  I wonder if some machines have a fan shroud printed with PETg.

RE: Fan shrouds melting too often

@jsw

I guess this is a good reason to stick with Prusament PC Blend.  

RE: Fan shrouds melting too often

One thing to try is printing the shroud in white.  I use one of the shrouds off thingiverse and have tried it in a few different colors of PETG to help reduce heat absorption.  I thought clear would be the best but it did sag a little on 10+ hour prints, the shroud I currently have installed was printed in white and hasn't sagged at all even with some 15+ hour prints over the last few months.

I haven't needed to use ABS for anything so PETG at 230 is the hottest I print at.

RE: Fan shrouds melting too often

I have a short run product that I need heat resistance.  I was given a demo roll of PC with Kevlar.  I have been trying to get it to print.  It is pretty darn abrasive on the nozzle.  

RE: Fan shrouds melting too often

I've been printing them 4 at a time with ABS, but I'm tired of changing them out every couple of prints.  And if I try to get by with a droopy one, it will snag a print and mess it up.

I tore the entire print head apart today and checked everything, didn't see anything abnormal.

I'm trying a different design from Thingiverse and seeing if it might be better.  If that doesn't help, I'll try the PC blend.

Thanks for all the replies, I thought it might be a common problem with a simple solution I was overlooking.

RE: Fan shrouds melting too often

Do you have a photo of a droopy shroud? Is it droopy only on one side? Only the top outlets? Seeing how it is deforming might help better diagnose the issue.

RE: Fan shrouds melting too often

Posted by: @bobstro

If you're not fond of ABS and some of the other high-temp filaments, Colorfabb HT has similar heat resistance and prints much like PETG with little odor. I use it for fan ducts. 

I  don't have any problems so far with the stock fan duct. But liked what I could find about Colorfabb HT. 

Any tips on how to print with that? 

What sheet would work best. Smooth or textured? 

Do I need an enclosure? 

RE: Fan shrouds melting too often

@baklin

I printed them on either sheet.  I prefer the textured.  

RE: Fan shrouds melting too often

Just for comparison. This is my original MK3s fanduct. It is a little over 2 months old and I have printed over 3 kg of PETG with it and plenty of 5-10 hour prints. Some over 12 hours.

It is still fine. Only one corner is a little deformed but I think that happens when changing filament and forgetting to cooldown the extruder afterwards. Than it stays hot without cooling till the firmware times out the heating.

RE: Fan shrouds melting too often

Abs might melt a little.  I switched to ASA and PC Blend for my fan shrouds.  

RE: Fan shrouds melting too often

Everyone, thanks for all the replies.

I'm going to wait until I use up the last batch I printed with ABS, and then try the PC Blend. 

I'll let you know if it fixes the problem.