Max Khatsenko   |   Engineer

2016

I've been very busy the past two weeks completing the rest of the design for John SteinBot. Refer to the slideshow above for the design notes which are broken into three parts. In this post, I complete the X axis for John SteinBot and use the lessons learned to evolve the design loops for the Y Axis. Then, I finish the design and CAD the rest of John SteinBot. Finally, I have a final review and make sure I can acquire materials and manufacture John SteinBot by the deadline 05/11/16. I was able to get a peer review early on in the topic, but we were busy manufacturing and traveling after that.

"I finished my X axis actuator system and figured out why my carriage wasn't sliding. Since I used a drill bit to bore my rail holes in my bearing blocks, the holes were way oversized. This pushed my rails in and the carriage couldn't accommodate the misalignment. Additionally, the drill bit, used to machine the sleeve bearing press fit holes in the carriage, had walked in the hole when I machined the carriage and created misalignment as well. Still, machining these parts for the X axis was a good experience and helped me evolve the design for the Y Axis. I was committed to not repeating the bearing misalignment error by being extra careful when machining the Y carriage.

"I reviewed my requirements once more to make sure I was on track. I refined what type of performance I wanted: repeatability to 0.1 mm over a 1/2" x 1/2" space and accuracy to 1.65 mm over the entire workspace. I used these new requirements to refine my error budget and settled on 1/2" diameter rails for my Y axis. I then used the lessons learned from the X Axis MCM to design the rest of my machine. I finished the entire machine CAD.

"I began to have my final reviews. I ensured John would be electrically safe through wire guides and wires management. Since no one was going to be using John except for myself and my friends, I didn't worry about the machine pinch points. I will definitely take care of these if I ever make a followup that I intend to distribute. I also made sure I had enough time next week to build, assemble, and test John SteinBot before the due date. Finally, I drafted a bill of materials and a plan to acquire all the extra materials I needed. I ordered off McMaster and may end up under budget depending on the shipping costs."

I will use the design from the past two weeks to build the rest of John SteinBot next week. I also have to assemble and test him before the showcase on 05/11/16. Wish me luck.