This is a page for @Tommy Tran to make note of investigations that should be fully carried out and verified.

Short Note of Things to do:

Goal for June 27th Sync Up:

Short Recap

The problem definition and analysis has been completed.

Conceptual Ideation and Concept Evaluation has been completed. A concept has been selected.

First iteration of detailed design using 6061 Aluminum Alloy showed very low stresses.

What is left to do is to: (in the recommended order)

• complete detailed design of the screws and placement

  • along with appropriate simulation and calculations

• perform weight reduction and Design for manufacturing and assembly (DFMA)

• drawings

  • GD&T - I am wondering how flat and parallel it has to be. And to create the correct datums so it can be manufactured properly using a mill. Also proper tolerancing.

• bill of materials and supplier interfacing (from E3 store or from our resources on the shelf)

Things to do

Detailed design of screws and placement (1.5 weeks)

**We are going to be ordering screws from E3 Machine Shop. See the section below regarding supplier interfacing so you can find more information regarding your variety of screw choices.

I did very basic hand calculations and simulation to verify that the support pillars are strong enough as it is.

It has yet to be detailed where and how the screws would be inserted. I would advise using only one screw on one side of each support pillar. You would have to justify why one screw on one side is better than having one on each side of the support pillars

The only particular detail that needs to be verified might be:

• how the tightening of your screw would add to the “combined loading scenario” of the tightened screw + the applied mass of the machine/test specimen

• checking if the normal force/friction provided by the tightening screw is enough to counteract any forces in the horizontal direction that might be generated.

• checking that the inclusion of the screw will prevent the support pillars from rotating, e.g. is the support pillar thick enough to prevent torque? how would this effect geometry of the support pillars, accuracy of the parts, flatness of the support base, etc.?

• how the screw quantity and placement might affect certain flatness or geometry requirements of the base component and/or support pillars. This would be carried over into DFMA and tolerancing.

• If the support pillar needs to be a certain width for the selected screws. Or the selected screws should be small enough to fit onto the support pillar width. But then the screws need to still apply enough force to fulfill its purpose of holding the support pillar in place. Interesting thought: Is there a way to design this so that you can the support pillars afterwards (e.g. make the thread hole/size bigger) in the case that a calculation or assumption was incorrect? The other case might just be that you have to machine again the support pillar with the new geometry requirements lol. Who knows. I haven’t looked into this too deeply yet.

Note: I don’t expect you to fully understand what I’m saying or know the answer. I do expect you to do some research and show up with questions so I can teach them to you or at least give you better hints.

Notes on simulation:

There are specific ways to increase accuracy of your simulation in regards to simulating your fasteners

There are also ways to increase accuracy by customizing placement of loads, etc. on surfaces or bodies.

Also conduct a mesh convergence study to ensure your simulation results are accurate.

Another interesting resource is:

Shigley’s mechanical engineering design textbook

but this is a 3B course textbook so uh idk. it might be more useful to just google around to find what you might be looking for.

Weight reduction and design for manufacturing and assembly (DFMA) (1 day)

Once your design is robust and you have a very accurate simulation, it would be useful to see how you can reduce any weight/volume/mass, etc. to reduce costs. The only consideration is that it should still be rigid and robust so that it does not deflect, fail, or is no longer easy to handle.

This is also a good plan to do research on limitations of your manufacturing process (i.e. milling). Create a manufacturing plan that accommodates the limitations and best practices of milling in order to increase accuracy of your part. Your manufacturing plan could be consulted with the E5 Student Machine Shop Instructors including the people listed on this page: Contacts | Engineering Student Shops | University of Waterloo (uwaterloo.ca). They have helped me a lot in all my previous projects. They prefer speaking in-person to review your work and also to take a look at your raw materials (if you have them). They’ve been doing this for a long time.

Drawings (1 day)

See resources on confluence for some tips on making drawings.

This is a useful resource for learning GD&T and how to apply it. There are many more resources online, too.
GD&T Symbols | GD&T Basics (gdandtbasics.com)

I imagine this would be solely machined using a mill. If I recall correctly, it is rather easy to machine to +/- 0.01 mm of tolerance. This is assuming you have decent experience and decent control over your hands.

I imagine your datum and tolerances will reflect:

• how important that surface is, i.e. if it doesn’t matter how flat or accurate it is then take note that you can loosen the tolerances, and vice versa (if the flatness matters a lot then…)

• your DFMA - it would be good if you planned out your machining steps so that you minimize number of setups, machining steps, and therefore chances of error.

Bill of materials and supplier interfacing (1 day)

We are going to be sourcing our materials for this project from E3 machine shop.

Online E3 Machine Shop Reference: EMS Stores (ems-stores.herokuapp.com)

Note: You would most easily discuss details of availability of resources and purchasing by visiting the E3 machine shop in person. You would have to talk to Jorge (Jorge Cruz | Engineering Machine Shop | University of Waterloo (uwaterloo.ca)). If necessary, you can email him to ask about your material and purchasing inquiries.

For bill of materials, please create a list of the raw materials and hardware required for your final design. Please also give a cost estimate based on the Online E3 Machine Shop Reference. I would like you to get an updated and more accurate cost by meeting Jorge in-person once lockdown lifts. We would very soon after confirm purchases so we can immediately begin machining it.

Onsite Manufacturing

Beginning June 7th preferably