[Interaction 1] Flower-Blooming Mechanism Development Challenges

I have encountered multiple challenges when developing the structure for the flower-blooming mechanism. It took me one whole month++ to iterate the design and the whole structure for the flower-blooming mechanism to ensure it is doable for future production. 

Design Development

Output Arm

For my initial design for the output arm, it is just a stick. My thought on the structure is by attaching the wires on the petals and wire around the output arm. However, it is not doable enough as it will be very troublesome for future mass production. Thus, I was advised to create a clamp for the output arm to increase the stability of the overall structure. At first, I don't get the idea. I just extruded a triangular shape from the output arm, and it looks horrible and serves no purpose. 

I sought help and get some advice from experts on the clamp who specialize in engineering. I also further modified the model on the length and shapes to evaluate the best design for the mechanism.

For this design, I was criticized for the triangular shape of the clamp. According to my lecturer, the clamp should be designed aesthetically in order to fit together with the flowers. I was suggested to design it in a curvy pattern like the buds of the actual flowers.

This is the final version of the output arm. In my opinion, I feel it's ready to go as it grips the petals tightly without attaching the screws.

Development Challenges

As the motor vibration will cause the nut to drop off easily, I was suggested to attach spring washer on the nut. However, it turns out to be a disaster as it breaks the PLA due to the extra force exerted on the PLA. I felt tired and disappointed because I had to reprint all the broken components again and it took several days for the printing. The iteration progress had undergone for several weeks.

I had made experimentations for both the design of the chassis. Seems like the spring washer is a bad choice to lock the nut as it uses too much force on the PLA. Another problem that I've discovered is the infill settings for the 3D print. The wall thickness and infill settings should be increased to make it stronger so that it is not easily broken due to vibration. At the same time, I have replaced the options of using spring washer to self-locking nut. 

Resin Printing

For the output arm, I also experiment with different materials, like PLA & Resin and 3D printing settings. Initially, my printing line direction is horizontal. However, I was suggested to print it vertically for a stronger structure. However, I think it should print horizontally as it is cleaner for the bottom part of the output arm, and it seems stronger than the ones printed vertically. 

Other than that, I think it's not flexible to open the clamp for resin printing. Thus, I will be using either PLA or PETG. The bottom part of the output arm easily breaks after a long run of testing. Thus, it should be increased on the infill settings, and the design should be thicker.

Chassis

The design for the chassis (5 & 6 petals) has been finalized and amended to the same design. For this 3D print, I have used PETG instead of PLA. I have tested it and replaced the spring washer with self-locking nut. It seems quite stable during the motion. 

Test on one output arm

Test on three output arm

As I have mentioned before, the output arm will break after a long period of time. Thus, I will finalize it with a thicker version.

Final Design Plan

Comparison between the old version and the latest version

Carriage

Added more holes to insert petals

Output Arm

Thicker output arm so that it won't break easily

Joint

Chassis

Conclusion

With all the 3D printed parts, I will try for the final setup of the mechanism. The final prototype will be demonstrated in the next slide.