Bladeless Fan Final Report Part 1

Recap

I am building a bladeless fan, similar to the Dyson fans but on a smaller scale and it is wireless and handheld. The whole frame will be 3D printed. The head piece will be removable and different designs will be made.

Progress

My prints have come completed and I am quite happy with the results. Unfortunately the fan is not powerful and actually inhibits the flow of the internal compressor. However, since this is a first prototype and I am mainly focusing on aesthetics I think it came out quite nicely. I achieved one of my main goals which was to have an interchangeable head so that I can create multiple different designs and readily change them.

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Another issue is the cap at the bottom is extremely difficult to remove and requires pliers to get off. So it is currently extremely difficult to replace the batteries right now. To fix this I would have to print a new cap with a textured outside, perhaps with large bumps, so that it is easier to grip. I am currently running out of money in my budget so this may have to be something I fix in the future.

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To fix the issue of the reduced flow I printed another head piece with a reduced outlet area to attempt to accelerate the flow more so some pressure can build up. After printing the modified head piece I tested it with the fan and it actually performed worse than the larger outlet area head piece. I may have to go to a lower area, or I must rethink how the technology actually works and analyze how air flows through the channels.

Design

So in this post I am going get more detailed about the actual design. I will be covering everything from the flow profile to the circuit and wire routing.

One of the most critical parts of my design was the flow profile of the head piece. The way I created the head was by making a sketch and then sweeping it around a profile. Using this method the flow profile would always stay constant and to get a different design I could change the sweep sketch.

HeadPieceProfile

Notice the 0.06 dimension on the far right. This is the dimension that controls the area of the outlet.

ProfileCutout

The above picture shows how the profile is swept around a heart shape to create the final part. This rendering successfully captures the aesthetic I was going for in this project. Due to the manufacturing method (3D printing) I was not able to get a glossy finish, but if this were to be a product I would like to get it molded so I can achieve the glossy finish. Another idea would be to make it out of a clear plastic so you can see the internal channels in the fan this could help visualize how air flows through the piece by using a fog generator or smoke.

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Another major design challenge in my project was developing a way for the head piece to be removable while still sealing to prevent any leakage. In the photos above you can see the base of the head piece and its mating feature in the middle section. There is a hole cutout in the middle section to allow for the headpiece to slide in, but there are also slots cutout within the hole to allow for the tabs on the headpiece to slide into and lock. This makes it a really easy two step process to remove and install the head piece, just insert into the hole and rotate to lock. You will notice that there is a raised ring on the middle section, this gets inserted into a pocket on the headpiece to create a nice seal. After testing with the fan I did not notice any leakage coming out of the interface.

The next challenge was finding a way to mount the fan, and routing the wires down to the bottom structure without them being overly visible.

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To mount the fan I simply drilled and tapped the holes I needed. Originally I tried to print the holes, but due to the tolerance on the printer and the tendency of plastic to warp I had to open the holes a bit to get the tap to fit. To rout the wires I wanted them to be hidden from view. The black and red wires really stand out even though they are confined you can still see them through the inlet holes. To mitigate this issue I created rings on the side of the the middle structure to hold the wires up against the wall.

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You can also see in this photo that middle structure and the bottom structure are mated to each other using printed threads. This was an interesting task as I had to take into account the tolerance on the 3D printer and how much the threads would expand. Basically I looked at an image of a thread and modeled it after that while getting my dimensions for major and minor diameters.

ThreadImage

The circuitry for this project was pretty simple, I did not need to use a bread board, but it probably would have made it neater. Below is a diagram of my circuit provide by the manufacturers of the latching push button. I had to wire it up so that the LED only turns on when the device is turned on.

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I wasn’t able to get 12V DC with any reasonable amount of capacity, so I settled for 9V DC with two batteries in parallel. This gives me double the capacity. 9V batteries hold around 500 mAh of charge, and my fan only takes up around 285mA at 75% power. So with two batteries providing 1 Ah of charge my fan can run for 3.5 hours continuously. This seems pretty reasonable to me for a handheld device. Unfortunately the cost of replacing the 9Vs over and over would add up with the fan is used often, so if I can find a way to run it off AA or AAA batteries and step up the voltage that would be best. I did not want the device to require 8 AAs as that adds a lot of weight and takes up space.

Conclusion

This has been a fun project overall and I think I learned a lot along the way. I may continue to improve on the design down the road, but for now I am running out of money and 3D printing gets expensive. Getting the opportunity to learn about bladeless fan technology, and then implement it into my own design was incredibly fun. Even though I didn’t get the performance I desired I still ended up with a product that demonstrates the technology while also capturing an aesthetic.

 

 

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8 Comments. Leave new

  • Joseph Graff
    May 4, 2016 11:56 pm

    This looks so good! Do you feel cheated at all by Dyson for their “bladeless” fan design, now that you know how it works? The 3D printed parts look surprisingly good (not surprising based on this project or your ability, just that 3D printed parts don’t always have the best fidelity). Did you use ABS or PLA for printing your parts? Regardless, it looks awesome! A job well done indeed.

    Reply
  • I really like the aesthetic of the final product. It looks modern and professional. Nicely done, you clearly put in a lot of work into this.

    Reply
  • Sorry I couldn’t make it to the presentation. I hope all went well. Your fans are nicely polished. Are you thinking of coloring it (with spray paint for example) or would you rather have the original color of the 3D printed material? Can you print on a cheaper printer while maintaining the same resolution you have?

    Reply
  • Meridith Richter
    April 27, 2016 3:13 pm

    I love the idea of the changeable heads. Very sleek and cool (literally) design. Nice job!

    Reply
  • Samantha Maierhofer
    April 27, 2016 3:11 pm

    I love the clean finish and thought that went into this to make it interchangeable and removable. Good work!

    Reply
  • The whole project looks extremely clean, I did not realize that you had a lot of difficulties with the tolerance. The uprint was an excellent choice for its 3-D printing capabilities. The functionality is supreme because of the manufacturability, its versatility with the head attachments, and the overall quality. The heart was a nice touch to increase the aesthetics of the project, by making it more “cute”.

    Reply
  • The fan and its blades really look nice. I remember looking at your post thinking that the fan base is going to be big for the hand to grab, but when I held it in the expo it was comfortable. I like the white material you have and the finish. Your blog post is a good summery of how you built it. Since the battery lasts for 3 hours I won’t get too caught on replacing the cap. I understand it is difficult to have more prototypes before the final build due to the 3D printing cost. My suggestions for improvement might be a shot in the dark but, I would have the fan closer to the base if possible and have the base be the air intake or have bigger vent holes might help the air flow. It is great to see you considering any air leakage in the design, and your design around that definitely worked. Good job! Enjoy your fan.

    Reply
  • I really like seeing the details and thoughts behind the project. Very insightful. It’s good to see that you took leakage into consideration. Would you possibly think about moving the fan closer to the heads to help with flow? Would making the head opening’s smaller help with your flow? What other options do you think could be included for more customization in the future? I really like the clean modern look of your designs. Very simple. Great work on this project.

    Reply

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