DIY Bike Frame

This is a bike frame that consists of metal tubes and 3D printed components to join the tubes together. I am a student at the College of San Mateo and am designing this for the 3D printed student design challenge presented by Autodesk.

The idea originally started off with "what if I build a bike frame out of PVC pipe" and turned into "what if I 3D print a bike frame". When the 3D printed student design challenge came around and I came in for design review, one of the Autodesk ambassadors suggested that this is a great opportunity to try out generative design.

One point of inspiration I had was my experience in robotics. At competitions I saw teams use 3D printed bearing blocks and gearboxes to save time and money in production. Seeing how other teams implemented 3D printing, I wanted to try incorporating 3D printing in structural and functional parts. Although 3D printing isn't as scalable as subtractive processes, it's a powerful tool for creating low cost one-offs.

After doing some research, I was inspired by the Dream Stem from CW&T and decided I would try out generative design for this challenge.

Depending on the kind of bike you want to make, the parts will vary. These are the parts I used for a brakeless fixed gear road bike. Some specific products I used are linked.

Tools:

• Fusion 360
• 3D printer
• Pipe cutter
• Screw driver/ T handles
• PPE for handling chemicals
• Chain Breaker

Bike Frame Parts:

• Tube set
• 30.4mm to 27.2m seat post shim
• The seat tube included in the tube set is an uncommon size, used the shim so I could use more available seat posts.
• Head tube (36mm?)
• Had to get a separate head tube since the one included in the tube set doesn't work with the 1-1/8 fork i had.
• Road rear dropouts
• flux and brazing materials
• To mount rear dropouts
• 2k epoxy
• Clear coat to prevent rust
• PF30 bottom bracket
• If you want to make your own I suggest using BB30 and a pre-made shell. I wasn't aware at the time of making this but PF30 is a relatively new mounting system, as a result it is far more expensive and harder to work with than BB30.
• 1-1/8 threadless headset bearing
• XTC-3D
• For finishing the 3D printed parts
• 1/4-20 screws of various lengths and nuts

To Finish off the Bike

• 700c wheelset (rims + tires+ tubes)
• Fixed gear cogs
• Handlebars
• Stem
• PF30 single speed crank set (or BB30 if you design for BB30)
• Pedals
• Seat post and saddle
• 1-1/8 fork and star nut
• Grip tape
• Single Speed Chain

I started with a frame sketch using dimensions from this. I used the layout as sweep paths later on.

A rough model was also made so I could think about the order of operations for the final model.

Initially, I considered using two top tubes parallel to each other however, I figured it would be less work for me to have one since I was planning on ordering a tube set that had one top tube.

As of right now, the plan is to have the tubes joined with clamping style printed parts.

Using what I learned from the first iteration I made some updated models and put this version into generative design.

I just figured out how to get a usable model from generative design (12/12/2021). I have been playing around with the force placement and obstacle geometries for the last two weeks.

Above are some screen shots of how I set up the model for the generative design process. I also did a rough force analysis to figure out what forces I should enter for the generative design portion.

Here are some videos that I wish I found earlier that helped me get through generative design:

https://www.youtube.com/watch?v=LaG9uVj_grE

https://www.youtube.com/watch?v=XfKQ8AKjQMo

https://www.youtube.com/watch?v=1e8WSHZmE_U

https://www.youtube.com/watch?v=sHRiF2y50Ac

https://www.youtube.com/watch?v=LI9v8P25c8s

https://www.youtube.com/watch?v=wevpii0J2bU

https://www.youtube.com/watch?v=yu0q_asyfvE

https://www.youtube.com/watch?v=BCshgXvci38

Unfortunately, I wasn't able to figure out how to use generative design in time to print all the parts before the deadline. I could only print one part that didn't use generative design.

Although I couldn't complete the project in time, I was able to create a usable version of the model before the deadline and I will be printing the parts after 12/13/2021.

All parts ready except for the 3d printed components.

In the future, it would be cool to make a version printed in metal that can be brazed on.

Additionally If this version goes well, I will be making a multi speed version.