jcdammeyer
Senior Member
I've been trying to figure out how to make this in Alibre. It seems like extruding the grid upwards and rotating it 30 degrees. But can't seem to achieve this.
Extruding a fan cover
- Thread starter jcdammeyer
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jcdammeyer
Senior Member
No. I only have an STL file so if you were to load it in Repetier or any other slicer you'd see the type of part that has been designed. The idea is that instead of a fan screen with just holes the 30 degree twist results in less turbulence and actually better air flow. The designer has verified this with an air flow meter. More work is required. I wanted to play around with some of my own ideas. But for the life of me I can't figure out how to curve the holes. Silly....
jcdammeyer
Senior Member
Apparently this is the basis for the special fan covers.
www.thingiverse.com
Very powerful once you figure out how to use it. OpenSCad is free.
Customizable Fan Grill Covers by OutwardB
TOO MANY FAN GRILL COVERS!Latest update - 31th May 2021 -7 new patterns (i'll update the zip files eventually)Mutli-color options (layer change or multiple STLs) for text/SVG files!Check the change log at the bottom for more infoI've uploaded .zip files with nearly 4000 pre-built STL files! They...
www.thingiverse.com
Bazzer
Member
Best of luck making that in volume, looks like a 3D print job to me and the Chinese will have it ripped off and in a print farm in no time at all.
Bazzer
Member
Would just working on pair of holes and extrude cutting them through the parent block and then to array the cut holes be less intensive on resources?
It looks like there is a good repeat pattern of those holes.
jcdammeyer
Senior Member
Fascinating. I'd have never thought of doing it that way. Time to play with some dimensions.
Thank you so very much.
Thank you so very much.
jcdammeyer
Senior Member
David, Wow! I just spent the last couple of hours redoing your drawing from scratch to get a feel of what to do and how to do it. I would never have thought to do it the way you did. I used 2mm wide for the thickness along with 10mm spacing and tried 400, 800 and 1200mm pitch.
So cool. Thank you for teaching me how to do this.
Busy printing one now to see what it looks like.
John
jcdammeyer
Senior Member
Yes. Adding script to make it more turnkey would obviously make it easier to use. I've created several part drawings now each time starting from scratch as an exercise to learn how to make better use of Alibre. I've used a lot of dependant parameters so changing the diameter isn't a big deal. The number of fins and spacing before rotating is more difficult.
Aside from that though I did talk to a mechanical engineer and ask his opinion on this type of computer fan cover. He mentioned that like a garden hose, having an exit tube quite often does more than enough to straighten the airflow and keep efficiency (CFM) high. I think thought when it comes to computer or other equipment cases room for an exit pipe may not be feasible so a fan gover that improves efficiency might still be the best solution.
I'm in the process of writing up a document that describes how to create the drawing you passed on to me and yes, I've given you credit in the introduction. I suspect, but more tests are required, that the angle of the helical form should match the angle of the fan blades. As thin as possible fins, as large as possible holes without allowing fingers to get inside onto spinning fan blades and hoepfully some CFM tests to verify how well it works.
I'll post my document here when it's done.
jcdammeyer
Senior Member
bolsover
Senior Member
Looks good to me
jcdammeyer
Senior Member
I think 20mm gaps are adequate for adult fingers as I can't get mine through the holes but a kid with small fingers might so likely this is a bit large yet.Looks good to me
I'm trying to decide if I want to buy an impeller type flow meter or hot wire anemometer and calculate CFM from the supply side.
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bolsover
Senior Member
Looks great! Would be interesting to know how changes to the pitch restrict or aid the flow. Pity Alibre doesn't have built in simulation tools.
jcdammeyer
Senior Member
That would be nice but I think too complicated. My Mech Eng friend said that something as simple as a straight exhaust pipe, like a garden hose does with water, would allow the flow to straighten and reduce back pressure. Possibly even a flared outlet. But they all take extra space. I think HandsOnKatie's original goal was to make a minimal screen. In her video she discusses how surprised she was at the efficiency of the flow was modified by the twisting fan cover. She's an Electrical Engineer so not just a pretty face doing YouTube videos.
Ex Machina
Alibre Super User
Wow, David's part is really cool and a great approach to this. I think that adding the "Patterned Vane" technique and a boolean intersect would create wonders! I don't know if you have booleans available but if you do, check out this vid on what I'm talking about. It would create parts of amazing complexity and beauty.
jcdammeyer
Senior Member
Cool. I'll look into that. I have the Pro version so yes I have booleans. I think you've just verified what David said that there are other ways to do this.