Done some updates to my fan duct for Tevo LM. I wanted to direct the air more towards the nozzle as well as raise the bottom of the ducts as I was getting a little bit of catching on prints that were curling. I also raised the IR sensor mount up a little for the same reason as the ducts and set it a few mm back from hotend as it was getting a little hot when the hotend was at 400*C. I also set the 40mm fans back another 0.5mm so they don't overhang on ABS prints that shrink a little. The other changes are less noticeable as they have been made to prevent layer lamination/warping issues with super high temp plastics like Polycarb and Peek.
Printed in Polycarb seems to be holding up to constant bed temps of over 150C (up to 175C so far) no problem
BLTouch mount for this duct
Additional add on's for Tevo LM to go with duct here
Hobbyking Polycarb in Translucent Blue
Bed 160C (measure on bed surface not temp sensor)
No cooling fans
Thin smear of PVA on Printbite when bed is cold then let it bake off at 55C then heat up to 160*C before printing (auto pops off when done), 4 walls, 30% infill to make it nice and strong in case your Tevo decides to smash it into a print. It is not recommended to print Polycarb on PEI as it will microfracture the surface and pull the PEI away from the glass bed on cooling.
For best printing results on the Tevo LM, rotate the object 45 degrees (so the IR sensor side faces to front right), then set you stat stop points for printing (tab 2 in S3D) to X50, Y-50 to get all the seems to line up on the IR sensor side where you can't see them when installed and it will also put the seems on corners where they are nearly unable to be seen to begin with.
Suggest printing in Polycarb but ABS works well as long as you don't heat the bed above ABS print temps (if you want to print polycarb then you will need to make it out of polycarb due to the bed temps being high enough to warp and melt the duct if made from ABS after about 10mins).
Remember to sand the tops of you fans a tiny bit at and angle to match the angle they sit against the effector (only like 0.5mm to remove).
Add some additional supports on top of the auto generated ones in S3D around the 40mm fan ducting to ensure all the supports are joined together to make it easier to remove.