18.6 - Conclusions and Future Work
Our team successfully created a large-scale AFM probe that accurately mapped changes in elevation through the use of a 4-bar geneva drive slider crank. As seen in our project demonstration, this was verified by measuring the height of two towers constructed out of 3D printed cubes, as seen in the figure below. Each cube height was correctly mapped relative to the floor of the conveyor belt (which was a height of zero in our plot).
Future Work, Lessons Learned, and Tips:
An issue we ran into with the system is that the mechanism was moving downwards in a very rough motion as it slid down the rail. The main concern with this issue is that the aggressive motion could damage the whole system or the object that the probe is trying to map. To prevent this from happening in future iterations, we could epoxy the shafts into the bearings to prevent any play, which is what we believed to be the cause of this issue.
Additionally, it would be beneficial to have additional gearing to break down the motion into even more steps from the Geneva mechanism. This would allow for us to map many more distinct heights as we increase the number of steps traveled. This drastically improves the accuracy of our design since the heights are determined based on the number of steps traveled, and we are unable to map values in between steps.
Finally, another major limitation of our design is that we cannot measure gaps between objects that are smaller than the probe width itself, since the probe has to be able to fit between the space in order to record data. As a result, future iterations would greatly benefit from reducing the width of the probe to be as thin as possible, which would significantly improve the ability of our design to measure small gaps.
Some general issues we ran into were poor adhesion from our epoxy and poor wire management. Our main issue with adhesion came from the fact that we would try to epoxy plywood to acrylic, which was not working effectively. Future teams should try to avoid mixing materials when using epoxy and should opt for bolting these connections like we eventually did, and only use epoxy on homogeneous connections. As for wire management, teams should consider adding slots in their baseboards/components to allow for wires to pass through and be hidden underneath the assembly.
Acknowledgements:
We would like to thank the teaching team, Dr. Symmank, TA Min-Geun Park, and TA David Gutierrez Moreno for their instruction and support throughout the project, as well as for the advice given during crucial progress checks with our team. We would also like to extend our gratitude to the TIW student staff for provided resources for manufacturing as well as additional training and help with fabrication. Finally, we want to show appreciation to the TIW machine shop manager, Joe, for helping us cut our metal components.