Blog Post 7 GRBcelL BioPrinter

This week the bioprinter was finalized, and a lot of cables and wires were reorganized and re-soldered. First, I ran a test of the X, Y, and Z axis using a temporary Arduino circuit board to ensure that each component’s mechanical aspects were fully operational. Next, I did the same mechanical analysis with the plunge axis and a stepper motor testing that the aluminum plate grasped the base of the syringe while the triangular lip holder moved with the motor on the linear rail as planned. While this second step for the most part went well, one of the bored holes in the aluminum plates was about 2 milometers off and had to be completely re-drilled. Knowing that all the motors were working, the Arduino circuit boards were replaced with the Tiny G circuit board. The old Arduino model used a firmware known as GRBL, but the TinyG board used a program with the same name “TinyG.” I spent a good part of the week learning the differences between the 2 G-code languages. By the middle of the week, the bioprinter, now with all four stepper motors properly rigged and wired to the central TinyG circuit board, had full movement in the X, Y, and Z directions along with a vertical plunge of the syringe pump. All of the axes worked with remarkable speed and accuracy, a testament to the use of lead screws instead of a belt method (Initially a design for the bioprinter used ball-screws to move in the X, Y, Z, and plunge which would have provided even more speed and accuracy than the lead screws we ended up using). After this movement was achieved, limit switches were properly attached to the frame of the gantry such that overstepping pieces that would collide against metal parts instead hit the limit switches and killed detrimental motion. As another safety protocol, a large red kill switch was attached to the front of the machine to kill power if anything were to go wrong. By the end of the week, as rats nest of wires were cleaned up, the wiring was well documented. Although the project may still require a custom firmware and way to send code and could use slightly better insulation and polish, I am overall extremely satisfied with the progress made over the course of these seven weeks, and I look forward to continue working on the bioprinter as time progresses! This whole project has been a fantastic opportunity that has helped me learn a lot about engineering, design, physics, and biology, and, hopefully, will one day benefit the school with a new tool for various departments.

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