Assignment 14: Mechanical design and final project update.

After a lecture on mechanical design we were given the choice to either make a set of gears, or to work on the final project plan. In the end we had to do both. I wanted to make a set of involute gears, since these type of gears provide smooth transmission of power without speed or torque variations.

In an involute gear, the profiles of the teeth are involutes of a circle. The involute of a circle is the spiraling curve traced by the end of an imaginary taut string unwinding itself from that stationary circle called the base circle

(source: wikipedia).

There are various open source tools that can help designers to draw good working gears. I followed this handy tutorial based on a plugin for SketchUp. After installing Sketchup you can download the plugin here. For making the gears it is best to use an exact gear ratio. I chose 1:2 and used 13 teeth for the small wheel and 26 for the big one. The next step was to download MeshLab, in order to convert the Sketchup model file into a CAD file that could be edited in Rhino or illustrator. Once this was done the gears could be given holes for the centre and spokes. This is a test in acrylic - I had to scale the small gear a bit, so it would not be too small after melting away the kerf width of the lasercutter:

Weird square wheels

When looking for interesting mechanical principles I came across non-circular gears. I made a set of square gears in Illustrator.

Furthermore, I updated my idea for the final project.

Starting point
At the moment many people come here, engrave some nice patterns with the lasercutter, and then they go home without realizing that other possibilities are within reach for them as well. I think they can be triggered do more if we would explain the other machines and techniques in a simple way. And I believe that if we can empower people from other-than-technical disciplines to work in the lab, they will come up with unique cross-over projects.

Goal
I want to make 'something' that inspires newcomers in the fablab what they can do and learn. I want to encourage them to start making things by offering some open example projects that people can copy and change.

Concept
The projects should always start with something that people can relate to, or already know, combined with some new challenging elements. As they execute the project they become more skilled, and step by step they can increase the complexity of the project and create something new and unexpected.

There will be a coffee table interactive inspiration book with examples that combine a traditional craft and a new technique. Inside the book people can find little inspiration cards to take out. On the cards there is a URL to a website with step-by-step tutorials and more open project ideas.

Content
The book will first contain only 6 pages, and the idea is to add more later on. At least there will be a press fit construction kit and an interactive 3D paper structure, and hopefully an embroidered circuit or a canvas painted with the shopbot.