This week, I discussed designs with the team and helped look for parts we could use in our project. I helped in discussions which weighed alternatives in how we will procure the parts for the 2D gantry system, such as considering the tradeoffs of 3D printing some parts. I helped 3D print a modified pulley part that originated from an Ultimaker CAD file. Inspecting it and experimenting with it, we found it to be fairly durable. However, it was noted to have some imperfections.
The part is shown in the picture above, and the 3D printer printed it from bottom to top in the orientation shown in the picture. The bottom of the middle ring is notably not flat, due to there being no support underneath which caused the material to drip when the ring was initially being created. In contrast, the top of the ring is flat and smooth. The topmost part of the pulley in the picture orientation is also more rough and less even than the bottom piece, again due to lacking support during the printing. We brainstormed a method of rectifying this, which involves creating a structurally weak support underneath these components so that the material will not drip down while being printed. However, our overall assessment was that the part is sturdy enough and the defects are not significant (as well as probably being eliminated in the future), which makes 3D printing a viable solution to our securement of parts for our gantry.
For the rest of the physical robot, our team also did research and brainstorming for the bottom part of the base, as well as how the 2D gantry component would be stabilized. My personal research was looking into the type of beams we would use to hold the gantry up. I looked into aluminum beams, specifically the T-slot beams that our team first considered using during preliminary research. I compared alternatives from different vendors, as well as considered buying separate beams or longer ones that we would then cut down.
I also spent time preparing for the hardware component of our project, which was the primary division of the work that was assigned to me. I researched and read about the different raspberry pi libraries for Python that we are considering using, namely gpiozero and RPi.GPIO. Comparing these two options, I have found opinions online that point to gpiozero being the superior library due to simplicity and other advantages. I looked through documentation for both libraries and studied some examples. In addition, I looked into the hardware parts that we plan to buy, such as the stepper motors and servomotor. We are considering buying the same stepper motors that are found in Ultimakers due to using many other Ultimaker parts in our design, unless we can find a cheaper or significantly better alternative.
My progress is generally on schedule, although our initial schedule has making power and control schematics finished tomorrow, which we may need more time with. In order to catch up to our schedule, my team and I will primarily focus our efforts on the power schematics and hardware designs in the next few days, as we have mostly wrapped up the design for our 2D gantry system.
For the next week, I hope to finalize decisions for hardware parts we plan to use, finalize power schematics, and start performing calculations for the motor control. As a team, we will also work on finalizing the design for our frame.