Results/Lessons Learned

• Successfully designed a 4-axis conceptual milling machine that met all specs, functions, and objectives as judged by the course teaching assistant. 

• In a system with lots of moving parts, the accuracy of the system is determined by the least reliable mechanism. Therefore, we need to weigh the tradeoffs between reliability, performance, and cost of a mechanism/part in regard to the whole design.

• Rack and pinion may reduce the overall accuracy/precision of the system, but ball screws are more prone to buckle under vertical loads.

• The ball screw mechanism was chosen over other mechanisms that can translate rotational motion to linear motion, such as a rack and pinion, due to its high accuracy and low backlash. As the ball bearings are contained within the nut, they are self-lubricating, leading to very low friction. Furthermore, as the bearings are enclosed, no debris can interfere with them, making them low maintenance. 

• Reverse engineering when choosing motors: based on the gear used, we can calculate the torque and required speed, and then check if specs are within the range of stepper motors. If a higher torque is needed, then look at servo motors. A gearbox is not required for any motors that can provide the speed and torque required. A gearbox can be used to reduce/increase speed. 

• When researching different mechanisms, it is super helpful to watch videos on existing systems.

• When working on a group project, it's extremely important to communicate any issues that are preventing progress. Because our team didn't do this on time, it led to many delays in progress and rushed work towards the end.