Machine Class / Mechanical Design

Welcome to machine class! Designing machines requires a breadth of knowledge that is difficult to master in its entirety. In practice, you should hope to find teams of folks collaborating across the disciplines of mechanical design, electrical design, and software design, and we can each try to understand enough of our colleagues’ domain in order to work collectively alongside them.

A Machine’s overall performance will always be coupled to multiple domains: a great mechanical design with bad control is just as good as a poorly designed

It is worth noting at the outset that this is (in many ways) a design class: we are not often interested in precise or exact answers to problems - instead, we want complete systems that work, given limited time and expertise.

For the hour and a half, I’ve tried to break this down into a few sections but I want to qualify at the outset that none of this is exhaustive and whenever the time does exist it’s awesome if you can take things down to first principles.

Principles

Stiffness, backlash, alignment, angular error, flatness, and resolution vs. accuracy.

Kinematics

Layout, transform matrices, mounts and perfect constraint.

Transmissions

Belts, gears, screws, etc.

Parts

What’s available COTS (commercial / off-the-shelf), where to find them, and how to qualify them.

Materials

What to make it with, and how to make it.

Approaches

Design patterns from the field.

Tailing Notes:

Learn to Love the XLSX

A spreadsheet can take 20mins to build and tell you things it might take two weeks of design and assembly to learn first hand. They also help tie your intuition together with real data, and are useful communication tools.

Specialization

A perfect machine that follows all of these principles to the letter doesn’t exist, so the exercise is often about finding a medium between each that suits the task at hand. In the world, ‘generalist’ machines seldom do anything very well: the more specific our design criteria

On Sketching

Draw it before you CAD it.

Spiral Development

Probably Neil’s best piece of advice; make something that does something first, then improve.

External Resources

Slocum: FunDaMENTALS of Design
Hyperphysics Table of Tables: HyperPhysics

Reference Machines

Clank
Jubilee
Fabricable Machines

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