Drooping Extruder-Cover (New owner questions)  

RE: Drooping Extruder-Cover (New owner questions)

Posted by: mrbreton

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4. (Just so I don't have to create a new thread) Can I buy a silicone sock for my printer on amazon?  

Yes, but for some reason, they're expensive. You can get the regular E3D V6 socks in the US from FilamentOne for $7 with free shipping. I avoid the clone/knock-off socks because you have no idea what's in the materials they use that will outgas at printing temps. Be sure to avoid the Pro version with the tiny hole as filament can build up inside easily. Go for the version with the larger hole.

RE: Drooping Extruder-Cover (New owner questions)

1, Haven't tried it myself (yet - got the same issue), but https://www.prusa3d.com/prusa-i3-printable-parts/ states

Recommended print settings:

0.2 mm layer height, infill 20% GRID and material PETG.

 

RE: Drooping Extruder-Cover (New owner questions)

Posted by: mrbreton

3. Could parts be printed in ABS in the future as I will usually have that on hand?

For what it's worth, when I saw mine drooping I printed a copy in black ABS.  After installing the new one I noticed it too was drooping within a few hours when printing other things in ABS.  So I don't know that there's much point in reprinting it unless you can print it with a significantly higher temp material than you will ever print with afterwards.  Mine is now pretty much hanging straight down and doesn't seem to hurt anything so I haven't bothered doing anything else to it.

RE: Drooping Extruder-Cover (New owner questions)

Has anyone tried printing extruder parts for near the hot-end using HT-PLA and gotten the shrink during the annealing process compensated by strategic scaling of the stl file?

RE: Drooping Extruder-Cover (New owner questions)

Some folks have said they've made the fan shroud on an SL1 ... maybe the extruder parts can be made with that tech, too.  Temps no longer an issue with the resin used with the SL1.  I'll add I haven't looked at byproducts of outgassing at higher temps ... but seems a solution is at hand if some industrious persona were to step forward.

RE: Drooping Extruder-Cover (New owner questions)

Hmmm... maybe try tackling this from the other side: anybody knows which fan (model id) Prusa is using for the heatbreak cooler, and what would be the power limit of the fan control circuitry here?

If this is a Noctua NF-A4x10FLX, then it's high quality, low power and quiet. But my dealer also lists a few beasts that would, admittedly, be much more noisy and draw up to 350 ma (as opposed to the 50 mA for the Noctua), but also move 3.5 times as much air. Of course, bypassing the fan control and running the fan directly from a 12V (or 24V) supply could also work if you want to ignore the power issue.

RE: Drooping Extruder-Cover (New owner questions)

I am having form melting too.  I am replacing a couple with polycarbonate parts.  

RE: Drooping Extruder-Cover (New owner questions)

Can't edit any more.

😕

Checked the einsy documentation - the fans are run from 5V, with a tacho feedback. A) no significantly more powerful fans are available at 5V and b) replacing the Noctua with a 13,000 rpm blower would likely confuse the firmware that is expecting something like 5000 rpm.

RE: Drooping Extruder-Cover (New owner questions)

With the right extruder geometry, melting of extruder parts while printing equal temperature filament should not happen. You should be able to print PETG with a PETG composed extruder for an indefinite time. It also isn't a short body vs MK3 length body issue. BNBSX is a short body and tolerates printing equal level material without melting even with the noctua fan. Prusa has done better with the R3. Is the R5 still Mr. Melty?

You can also switch to the Bunny Science version of the R4 which lets gives you hot fins and more extensive PINDA support. Print the hot fins in higher temp material or at least print a couple hot fins. You can bolt on new hot fins should they deteriorate. https://www.thingiverse.com/thing:3645975

Special case is the fan shroud, that needs 1 grade higher on many setups. Do the fan shroud in ABS or best, PC. Then again BNBSX prints  polycarbonate for 100's of hours at 290C without destroying its polycarbonate fan shroud. There seems something amiss with the thermal handling on the Prusa MK3S extruder.

There are alternatives, but if you wish to stay with MK3S Prusa geometry, at least go to something with hot fins and reinforced PINDA mount.

RE: Drooping Extruder-Cover (New owner questions)

Posted by: Sembazuru

Has anyone tried printing extruder parts for near the hot-end using HT-PLA and gotten the shrink during the annealing process compensated by strategic scaling of the stl file?

To follow up, the reason why I asked was something I saw on CNC Kitchen's recent video about PolyMax PC, specifically this chart for temperature resistance at 12:05 in the video:

180°C of temperature resistance. Nice, but I've heard that the annealing process can change the printed part's geometry, though ProtoPasta claims only "x/y shrinkage of only 0.5% and negligible z change" under specific circumstances.

I'm thinking of picking up some ProtoPasta Black HT-PLA(v3) from PrintedSolid soon, but if anyone else has tried and failed I may skip spending that $50USD...

RE: Drooping Extruder-Cover (New owner questions)

Regarding the fan replacement - there seems to be a possibility: https://github.com/gregsaun/bear_extruder_and_x_axis/tree/master/optional_parts/hotend_fan

Off now to find a Sunon MF40100V1-1000U-G99