Mk3s Blower Shroud Improvement  

RE: Mk3s Blower Shroud Improvement

I just noticed that the original model got an update to fix the height issue for Mk3s a few weeks ago so I'll probably give it a try and see if the airflow is impacted by its asymmetry.

RE: Mk3s Blower Shroud Improvement

@msb64x

Is that odd section on the pinda arm supposed to be cut out?  I'm really tempted to try this.

RE: Mk3s Blower Shroud Improvement

@mtnmage

Yes that's just built in support so you can print without support settings.

RE: Mk3s Blower Shroud Improvement

Has anyone printed and tried this properly? I printed from PETG and fitted, then during its first print doing the same part (as a spare) it could see smoke from the hot end, stopped and removed and found badly warped & unable to be used. This was printing at 265 degree temp for PETG, any ideas going forward?

I know the standard shroud melts on PETG but I get much more prints out of shroud before its changed.

RE: Mk3s Blower Shroud Improvement

@jpeverley83

Which version did you use and what were your fan settings? The V3 sat too close to the hotend and would melt if I printed anything other than PLA. The V4 gives the heater block few more millimetres of space and I've been printing PETG with it for a few days now without issue at 245C 20% fan. 265 is really hot for most PETG and a little fan definitely helps. You also have to be careful that the heater block is centered between the sides so it isn't touching. I have had issues with my heater block wanting to rotate and contact the duct.

RE: Mk3s Blower Shroud Improvement

I used the V4, and the fan speed when printing the PETG items is at 76. I printed down to 250 when printing the item out of ABS and when printing a spare it also started melting. 

RE: Mk3s Blower Shroud Improvement

@jpeverley83

I just had a thought. You mentioned smoking before. That usually happens when you have a thermal runaway. Has your printer given you any warnings about that? When I was first trying to print with this shroud my printer couldn't keep up with the cooling so maybe your thermister is being cooled by the airflow and not reading the heater temp accurately. I had to drop my fan down to 60% for PLA or else the temperature wouldn't stay at printing temp. I'd suggest trying PETG with 20% fan and see how that goes. PETG usually likes less cooling anyway for better layer adhesion. I also use a silicone sock on my printer which could be keeping the thermister from being cooled by the airflow. Please let me know if that works. 

RE: Mk3s Blower Shroud Improvement

I'll try a lower fan speed, but I already use the E3D silicon sock on the hot end. I didnt know if that could be negatively affecting it. I've got one more printed in the ABS I'll try that tomorrow with less air flow, I've been running it at about 76 which seems to be 30%.

RE: Mk3s Blower Shroud Improvement

@jpeverley83

I thought you meant 76% not 76/255. I was running into heating issues at +60% so 30% shouldn't be a problem. The only think I can think of is to lower the temperature more but even 265 shouldn't be enough to cause smoking unless theirs something else wrong with the hotend. My printer has been running for 52 hours straight now and I haven't encountered any problems yet and minimal deformation. Also my stock blower shroud is in perfect condition despite a year of printing so it may stem from something weird with your hotend not the blower shroud.

RE: Mk3s Blower Shroud Improvement

I've had to modify the stock one slightly since fitting the sock, mainly the little wing on the front of the shroud, this had to be cut off as it was just deforming and catching the prints. 

RE: Mk3s Blower Shroud Improvement

@jpeverley83

Well if that's the case there's definitely something wrong with your heater or thermister because the stock shroud shouldn't deform under normal use. Maybe you should make a new post so more people more knowledgeable than me can see and help with that issue.

RE: Mk3s Blower Shroud Improvement

The little wing on the stock part is a support I think.    It's always melted off if I tried to print with it.  

I print PLA and PETG at stock Prusament settings with no deformation of any part.  You may have an older version.

Watching the evolution of this part closely!!

RE: Mk3s Blower Shroud Improvement

Just so you know, I reprinted the v4 in ABS again and fitted and its been ok when printing stuff this time. The only thing I found which was wrong was that I found a blob of filament on the top if the not end, looks like the hot end had unscrewed a little. I removed the blob and cleaned it all up and refitted the silicon cover and its been ok since.

RE: Mk3s Blower Shroud Improvement

Adding one to the print queue Like how you have gotten the nut trap in and successfully added print in place support. Also likes you flow channels for the air that it does not have any blocked part.

What i have even with stock shroud is some heat safe tape as insulation material.

Noted that its little to little material at upper part of the intake on a 0.4mm nozzle print but that can be fixed afterwards for now. (MK2.5S 0.4mm)

RE: Mk3s Blower Shroud Improvement

I just printed your versino 4 of the print shroud. I just had to cut away maybe 0.5 mm on the left end as it collided with the hot end power cable but afterwards it was just fine.

I should have tested the stock shroud as well but instead I went straight for the modified shroud. The result is puzzling me a bit. Ok, the back overhang ist performing worse than the others, makes sense as it is cooled the least. However, the further up one goes, the better the back side overhang actually gets. At 3 cm height actually all overhangs look fine.

Why ist that? the worse overhangs still look somewhat ok, but show visible "upcreep". Is there anything one can do about that, other than simply printing slower?

RE: Mk3s Blower Shroud Improvement

PS: Here is a link to my remix. I am not sure others see the point in it, but I just wanted to have the modified flow pattern without modifying the mounting and without interfering with the PINDA socket.

https://www.prusaprinters.org/prints/31766-mk3s-blower-shroud-remix-without-support-arm