Improved Rep 2 Fan Duct

by MakeALot, published

Improved Rep 2 Fan Duct by MakeALot Feb 17, 2013


My original model was OK, but I felt it needed better direction. This one is a noticeable improvement over the previous one in terms of bridging and fine detail.

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Any results from the air flow analysis?

You should look at MinLayerDuration, mine is set to 5 this should mean that a layer cannot complete more quickly than 5 seconds, which should give it time to cool. Maybe you could try a longer time to make sure each layer at the top cools before moving on, Alternatively, print something else alongside that will give the layers time to cool while the other item prints. Glad you got it working in the end!

I made this yesterday on my Rep 2 and can definitely see a difference in the quality of my prints after installing and trying it out. However, I tried using these settings twice and both times the print got way too hot at the top and became uneven and warped. The settings that worked for me were:

Quality: Medium
Infill: 10%
Number of shells: 1
Layer Height: 0.15 mm

Printed in about 50 mins.

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loosen the bolts, remove old duct, slip in new.

I've included the model for anyone with Alibre Design that wants to play/improve.


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DeadCatDot on May 16, 2013 said:

Hope this works. My original fan duct got knocked off a few times by big blobs and it's kind of loose. I'll let you know.

MakeALot on May 17, 2013 said:

Good luck!

Scott216 on May 7, 2013 said:

I just printed this, but it hangs too low. I think it would hit the print.

MakeALot on May 8, 2013 said:

Shame, some nozzles seem lower than others, make sure it's at the top of the travel in the screw slots. Unfortunately, I can only go on my printer and the damaged original duct for guidance as there are no released drawings.

funkshin on Apr 8, 2013 said:

I'm enjoying this. Thanks for sharing the source. I'm using it w/ a modified assembly and the tolerances are real tight. The fan touches the extruder w/ my setup so I added a little HVAC tape till I can CADapt it to fit and when that thing kicks in on layer 2 my thermister temps drop 20c in about 10 seconds. nuts

MakeALot on May 8, 2013 said:

You're welcome!

MarkTecWizard on Apr 6, 2013 said:

What is the physics of the air flow that minimizes the bridging and improves the fine detail? Mine melted too when a piece came off the build plate and dragged a lump of PLA all over the place.

MakeALot on Apr 6, 2013 said:

In a perfect world, the PLA would leave the nozzle, stay liquid long enough to adhere to the previously extruded layers or bed and set solid immediately after that. The fan helps the PLA cool to speed up the solidification process, but it mustn't blow too hard in one direction otherwise it pushes the molten PLA away from its intended target. So really, the nozzle should push cool air to the tip of the extruder equally from all directions enough to cool it as soon as it has joined to the previous layers. I do have another model that brings the air in from 3 sides 120 degrees apart, but it's not ready for Thingiverse yet ;-)

Nagano on Apr 5, 2013 said:

Why is it that one of the two of a duct is buried?

MakeALot on Apr 5, 2013 said:

I'm sorry, I don't understand your question. Could you rephrase it?

Anonymous on Apr 5, 2013 said:

Why is it that one of the two of a duct is buried?

Andychn on Apr 4, 2013 said:

Does it work OK in PLA or does it get too hot by the nozzle?
Thank you for this!

MakeALot on Apr 4, 2013 said:

Yes, it's fine in PLA, I've been using one for Months.

michaelladt on Feb 27, 2013 said:

This is a great mod for sure but are you guys having issues with it coming in contact with the nozzle? and melting...

MakeALot on Feb 27, 2013 said:

I've been using mine for a couple of weeks and it is a little glossy right at the tip where it is closest to the nozzle, but it hasn't changed the overall shape.

gmeghani on Feb 25, 2013 said:

Just melted mine, thank you for making this!

camstuff on Feb 19, 2013 said:

what did you model this part in?

MakeALot on Feb 19, 2013 said:

Alibre Design

fullandc on Feb 19, 2013 said:

made it like it - works like a charm! - the first one melted at the extruder because i didn´t now that the extruder fan is not running always! - You have to start it manually - while printing -> left button -filament fan ON!
makealot - you are genious!

MakeALot on Feb 19, 2013 said:

Thanks, glad you like it.