Unbeelievable Flowers

If you have been in the HMC Student Makerspace lately you may have seen a bunch of small, vaguely flower-shaped 3D printed pieces. You may have been annoyed by their multi hour print time (and for that I am sorry) and confused about who needed so many of these oddly shaped bits. If you are totally confused by all of the words I have just written out then I highly recommend coming to the bottom floor of Harvey Mudd College’s McGregor building to come check out the 3D printers, laser cutter, welding station, and crafting areas in the student Makerspace! I am currently using the space to build an artificial flower patch for use in Prof. Carr-Markell’s research on honey bee foraging behavior and these little flowers are for the bees to drink from. Follow along as I walk you through our design process over the last few months!

[1] A bee drinking from the wick on one of our 3D printed flowers

If you have not already realized, my name is Liza Gull and I am a Harvey Mudd sophomore majoring in engineering. I am working in the Bee Lab on a subteam with Sydney Cornell, a junior physics major. Sydney and I were tasked with fully creating the artificial flowers and a way of displaying them to make the bees treat them like a flower patch but allow us as researchers to carefully control their spatial arrangement. Our original idea that we have mostly stuck with is a series of large trays of sugar water that will have lids on them with holes drilled in a regular grid pattern. We will fill each of the holes with an “open” flower or a “closed” cap, completely controlling the density of rewarding sites. 

[2] The author, Liza Gull, (left) and research partner Sydney Cornell (right) wearing our bee suits on a field test day

The open flowers have a hole built into them that we thread a wick through. The wick sits with one end submerged in sugar water and the other end poking out of the top of the open flower where the bees can drink from it. We have conducted a series of field tests with different colors to make sure the bees have deemed our flowers acceptable for consumption. 

[3] An example of an open flower with a bee trying to gather sugar from it (the gray cylinders are closed caps)

Now because Sydney and I have been making most of this from scratch we have run into quite a few problems, the first of which being how exactly we make these flowers, let alone 1000 of them. 3D printing seemed like the easiest solution for both prototyping and scalability and we luckily have access to many resources that make designing something to 3D print quite easy.  I threw some stuff together in Solidworks (a Computer Aided Design modeling program) and we immediately started using the 3D printers to actuate our prototype. Solidworks is a great program to use for creating both singular parts and assemblies, however, it is hard with any program to make very organic shapes so we had to approximate “flowers.”

[4] A view of the open flower in Solidworks

The idea behind 3D printing is that you take a spool of PLA (polylactic acid) and heat it up to around 200 degrees Celsius and extrude it in vertical layers into a desired shape. Image 5 shows our lab 3D printer (an M2 MakerGear printer) extruding the first layer of filament on the textured print bed.  

 

[5] The lab 3D printer working hard on the first layer of an open flower

Sydney and I first used the Prusa i3 MK3S+ 3D printers that are available to all students in the Makerspace and were quite happy with the quality of the 3D print. We then realized that using the Prusas might not be the most viable option because other students using the Makerspace need access to them and we were going to need hundreds of hours of print time to make all the flowers. 

[6] A printed open flower from a Prusa

[7] A tray of flowers in the PrusaSlicer software getting ready to print

Our supervising research professor then told us that the Bee Lab did have its own cranky 3D printer and we were welcome to try to troubleshoot it. Sydney and I gave a valiant effort for almost 3 weeks before deciding we could not figure out the optimal speed, temperature, and extrusion size to get comparable 3D prints to what we could get on the Makerspace Prusas. Ideally you make your 3D printer operate at a pretty high speed so that your parts get done faster but at a certain point you begin compromising quality in favor of speed. The outside edges of our flowers need to be pretty high quality and waterproof because we really do not want the sugar water turning into mold inside them. Usually when you 3D print parts that are not undergoing a bunch of stress you do not make them completely solid and instead have an “infill” much lower and closer to 15-25%. Different infill patterns are better for different stress applications and if you are trying to print a particularly tricky part I recommend looking into this.

[8] Some of our first attempts with the lab 3D printer

We eventually decided we are going to give our .stl file of the flowers to a company that specializes in bulk 3D printing to save ourselves many hours of managing the Makerspace Prusas. We have currently printed about seventy-five open and closed flowers for prototyping and testing purposes which already took a lot of strategic timing over spring break on my part.

[9] Most of our flowers at the moment. The gray ones are “closed” flowers that essentially plug up the hole on the array to reduce the density of rewarding sites.

[10] The lid of our test array filled with open (pink and blue) and closed (gray) caps

[11] One of our tests with just open flowers

That is about it for the flowers! I have greatly enjoyed learning more about the prototyping process this semester and how as an engineer I can help other departments with their research projects. I have become a lot more comfortable with testing things on a really small scale and iterating really quickly through different designs. Our next steps are to finalize the CAD file of the flowers and send it to a 3D printing company. Check out our other blog posts for more information on the artificial array and its use during the summer!

Media Credits:

[1] Photo by author

[2] Photo by author

[3] Photo by author

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Helpful Links:

• The Harvey Mudd College Makerspace! https://www.hmc.edu/makerspace/ 

• Solidworks! https://solidworkstutorialsforbeginners.com/solidworks-basics/ 

• 3D printing infill https://the3dbros.com/3d-print-infill-patterns-explained/ 

Further Reading:

O'Connell, Jackson, “3D Printing Infill: The Basics – Simply Explained.” All3DP. Updated February 24, 2022. https://all3dp.com/2/infill-3d-printing-what-it-means-and-how-to-use-it/. 

Tonasam, “Solidworks Tutorials.” Solidworks. Published May 22, 2015. https://solidworkstutorialsforbeginners.com/solidworks-basics/.