Automated Petri Dish Filler Machine

Abstract

In research, plates (petri dishes) are used to contain and study various processes under controlled conditions. For instance, Dr. Truttmann's lab uses petri dishes to breed Caenorhabditis elegans. The research conducted on these organisms is used to study neurodegeneration under a range of controlled conditions, so having a ready supply of prepared and petri dishes filled with a growth medium (agar) to breed these worms is paramount for the lab ecosystem. Usually undergraduate lab assistants are tasked with manually filling the plates for the lab, but automating this process would free them up for more rewarding work and would produce a steadier flow of filled dishes for the lab. For 2 semesters of ME 450, students have worked on developing a low cost alternative to the prohibitively expensive automatic plate fillers that would usually find their way into a lab like Dr. Truttmanns, albeit for operations with a much higher throughput. The developed prototype was able to reliably work on 3 sizes of plates, until the lab switched to plates with ridges on the lids, which prevented the mechanism inside the machine which pushed the plates into a feeder from removing the bottom plate in the stack. The goal of our project is to modify this existing machine to minimize the time the undergraduate assistants spend on the plate filling process by making the existing prototype compatible with the different lid profiles. Our team has gone through the concept creation, concept selection process, as well as performed engineering analysis and testing to develop a solution to the machine's compatibility to different plates problem. We developed two alpha designs and after some analysis created a finalized wedge system that would enable the machine to separate the bottom plate from the rest of the stack and push it through to get filled up with medium and continue on to the next subsystem of the machine. The next steps are verification of our engineering specifications and validation of our implemented solution. The verification process was successful in that all eight requirements were verified through cycle testing of the machine, engineering analysis, and working closely with the project sponsor, Dr. Truttmann, throughout the whole process. The verification process was physical testing heavy as this project was small scale with there not being intense load cases involved and it being easy to prototype and physically test the machine. Validation process was not fully completed but the team looked for Dr. Truttmann's feedback all throughout the design process to ensure he was satisfied with the results and the design problem was fully addressed. The team feels confident delivering the design implementation to Dr. Truttmann's lab. The fully functional machine will directly compete against the industry standard and indirectly against prefilled plate companies. The main goal is to have a positive impact on the experience for undergraduate researchers and increase the efficiency and productivity of the lab with the machine's reliability being the top priority to avoid waste of agar.