K40 stock exhaust fan mod (suck vs blow)

thingiverse

This is my first design uploaded to Thingiverse, and I'm a complete beginner when it comes to CAD software - TinkerCAD was the tool of choice for this project. I'm a firm believer in keeping hobbies as budget-friendly as possible, which forces me to rely on my creativity rather than my wallet. My goal with this design was to repurpose the subpar exhaust fan that comes with a K40 laser instead of buying a new one. I wanted to modify it so that it draws fumes and smoke out of my K40 and hose, rather than blowing them through the hose. The hose will press fit onto the adapter, which has flat sides instead of a perfectly smooth surface - I could have smoothed out the sides, but this design works incredibly well, so I haven't made any changes. To mount the fan flush with the board in my window, I used a razor blade to trim some excess plastic from its housing. If you'd like to remix this design, please feel free to do so - just give me credit for the original idea and we'll call it square. You could even send me a dollar if you're feeling generous, but I'm guessing most of you are as frugal as I am, so I won't be holding my breath. To attach the fan duct to the inside of the original fan, simply glue it in place - meanwhile, the bracket uses the holes found on the wiring cover of the fan. I did use supports inside the screw holes, but they're probably not necessary. For inspiration, check out czmorris' excellent fan duct design, which can be found attached to the back of my K40: https://www.thingiverse.com/thing:2485649 As an aside, I also conducted some experiments to see if I could boost the output of the stock fan by moving its squirrel cage closer to the outlet - I achieved this by adding washers to the side of the fan nearest the motor. Unfortunately, this mod actually decreased the fan's CFM rating. To visualize the effect, I created a weighted "flap" out of a sheet of copy paper and heavy washers, which I've included in the pictures for your reference. Don't forget to check out my other fan mod: $17 K40 laser quad smoke assist fan project: https://www.thingiverse.com/thing:3629269