2024/2025 Mechanical Team Onboarding
- Yu-Ming He
This fall we have one official and one yet to be confirmed coop students, this document will serve as a general outline for onboarding them onto the team.
Note: Timeline used here is flexible, can be adjusted as we go
Goals for onboarding:
Teach mechanical engineering skills which include the following:
DFM/DFA when designing new mechanical systems
How to make drawings for manufacturing
Manufacturing on commonly used machines, CNC, lathe, bandsaw, drill press, etc.
Sourcing and speccing component
Teach the basics of mechanical design to get started on designing simple parts, before moving onto project and system level design
Week 1: General Onboarding Training
Goals: Introduce the main systems of the rover, complete the mechanical training. This should focus on getting the members familiar with the systems they will be working on, while going over mechanical design choices and documentation.
Set up confluence, kenesto, discord, solidworks
Leads will introduce the main systems of the rover and how they work. This should feature an inperson overview showing the system, going over the CAD assembly and subassemblies, and going over important documentation to explain design choices and quirks of the system:
Drivetrain: rocker bougie suspension, carbon fiber tubing with aluminum joints for weight and manufacturing reasons, 3D printed TPU wheels, BLDC motor and gearbox actuator
Arm: 6DOF robotic arm, BLDC motor and gearbox actuators, aluminum manufactured parts
Communications: radio anthenas, gimbal (TBD)
Ebox: sheet metal welded container, removable interface for ports, fans for cooling, general layout of ebox components
Mechanical Training
@Yu-Ming He thinks the training is pretty solid, as long as it is done properly and the important lessons from each part is taught. Here are notes from each section of the training that should be mentioned as they complete it
Manufacturing: 3D printing
Easy for prototyping components
Use for checking tolerances/assembly
When designing for 3D printing, consider print orientation. Bottom of the print is always the smoothest, so if the part has to be flat on one side you would want to print it with that side facing down
Use of supports
Holes might be distorted if printed in the z direction
CNC
Lathe
Laser cutting
Solidworks training
Design practices: there are an infinite different ways to design the same part in solidworks. It is important when creating a part to make it easy to understand, easy to change select features if needed, and keep the feature manager organized
Creating Drawings: The purpose of a drawing is different depending on what it is being used for. The drawing given for the part earlier in the training is made for the purpose of having it remade in CAD, so the part needs to be fully defined. When manufacturing a part, however, the drawing should fit the needs of the manufacturing process it is being used for. For example:
This drawing is good enough for the part to be manufactured. This is because for laser cutting, the only dimensions important to the operator is the overall width and length of the part to specify how much material is needed. The holes and outline of the part would be specified in the DWG file that is converted into code for the laser cutter to run, so although those dimensions are important to you as the designer, it is not important to the manufacturer making the part. The same goes for the thickness of the component, as it is specified at the top that we are using stock material of aluminum with a set thickness of 1/8th. A special consideration for sheet metal laser cut parts are the edges have to be straight and the thickness can’t vary. Important note that different manufacturers will have different requirements for drawings, so in general its a good idea to talk to the technician for the machine you are trying to use to make sure your drawing is correct.
Making the assembly: make sure to go through documentation on how to make large assemblies. How to mate parts together is very important
Make sure coops read over the how to guides, they can start doing the training and understanding all the documentation as they do it if it helps to retain the knowledge
Week 2-4: General Mechanical Tasks
Goals: At this point we will assume the coops have enough relevant base knowledge as a mechanical team member and understanding of the rover subsystem to do simple mechanical tasks for the team. At this milestone we will start treating them as a mechanical team member.
Introduce them to simple, well defined mechanical tasks to get understanding and experience with manufacturing, reading and making engineering drawing for parts, designing simple mechanical components for projects.
Leads need to make well defined tasks with detailed descriptions. The members should not have to figure out too many constraints for the tasks, they should be pretty straightforward and focus on getting applying some of the skills and techniques from before
Possible projects:
Drivetrain reassembly and revision
Teaches manufacturing with aluminum and carbon fiber, DFA, 3D printing/additive manufacturing, drawings, etc.
Allen key tool set for the arm
If Josiah finishes arm simulation and we have the workspace, this will be a great project to introduce key considerations for the arm. Will also teach 3D printing skills
3D printed mounts for the camera
Manufacture arm weight reductions
Wire management for the ebox
During this time they can also shadow the leads on the arm simulation and testing, smaller tasks in that system will likely pop up that we can assign.
During this time can also focus some attention on understanding other subsystems, for example for camera mounts try to work with software to understand the range of motion on the camera, what angle they have to face for optimal visibility, or working with electrical to design mounts for components/figure out better ebox layout
This will help give better understanding for system level design projects
Week 5-6: Larger projects with more research and design
Goals: At this point hopefully the coops have a good foundation of mechancial knowledge and understanding to take on a larger design project. The biggest difference here is these projects require more research and design on their part, where parameters and constraints have to be set by them. Leads will be there to provide guidance and regular check ins for design reviews, and to make sure the projects can integrate into the system properly.
Projects:
Gimbal
Sensor skeleton
Science
Drone