Week Fourteen: Mechanical Design, Machine Design

Goal

do the mechanical design for your final project

Week Fourteen: Mechanical Design, Machine Desing

• Chose a package to design in
• Design a mechanism

Chose a package to design in

Ok, back in familiar territory. Since, I used to design mechanisms and machines through out undergrad and grad school. The assignment was fairly, straight forward. I wanted to design a rotatory/linear mechanism and a flexure. I have had the pleasure of learning directly from one of the world leaders in flexure design, Stuart Smith. He is actually coming to see the CPCC Fablab this week.

Rotary/linear design was designed in Solidworks. I felt, I could get more complex and effiecient design using the software. Furthermore, I am still not as comfortable designing with kokopelli moving parts as of yet.

For the linear flexure, I used kokopelli. I wanted to see how well I could design a mechanical object in it.

Design a Mechanism

Rotary Linear Translation Design

The first design is a linear stage when the base rotate the top and bottom linear displace to one another. This is to be used for short travel. The connection between the arm and the base is a ball joint and is limited in travel. There are different ways of joint connection. For example a flexure would limit travel more, however, the device would be more precise. You can make this flexure on the 3D printer. However, it is intended to be made of different materials. For instance, the balls should be made of stainless steel. The base and arms could be made from annonized aluminum. More annalysis would have to be considered.

Arm

Base

One unfortunate feature of SWs is the file size. Therefore, I will not put them up. If you would like to download them please email me at tjfagan (at) gmail.com

Mechanism Video

Simple Flexure Design

Ever since, I saw the first flexure design for precise movement I have been fascinated with them. I wish I got to do more design with them, however, I have so many other interest. The flexure is a simple precise mechanism.

Kokopelli

Flexure.ko file.

Note Worthy

On a side note, I fixe my navigation using a command line in the terminal. This is new to me and worthy of noting. Replace 'txt' with the file extension you want. This little command saved me a ton of time.

perl -pi -w -e 's/SEARCH_FOR/REPLACE_WITH/g;' *.txt

http://lifehacker.com/5810026/quickly-find-and-replace-text-across-multiple-documents-via-the-command-line

Below is after the week and assocated with the final project. Pictures show the 3D 
model of the case for "The Little Bro"

Solid Model in Solidworks

imprint

electronics case

 

Flexures

1. http://web.mit.edu/mact/www/Blog/Flexures/FlexureIndex.html
2. http://www.jonathanbhopkins.com/#!
3. http://ocw.mit.edu/courses/mechanical-engineering/2-72-elements-of-mechanical-design-spring-2009/lecture-notes/MIT2_72s09_lec08.pdf
4. http://engineerblogs.org/2011/05/flexure-design/

Errors

1. http://fab.cba.mit.edu/classes/863.12/people/laia.mogassoldevila/projects/p6.html

Pin layouts

1. http://www.instructables.com/id/How-to-drive-a-character-LCD-displays-using-DIP-sw/?ALLSTEPS