Hello World!
For our Additive Manufacturing class group project we will be 3D printing a desktop trebuchet. We have self selected a few basic design requirements.
1) We will be throwing peanut M&M’s because:
a) They are commonly available
b) They are round (fly better)
c) Peanut M&M’s weigh more (fly farther) and are more round that regular M&M’s
d) Should cause less damage and hurt less when being flung around the office
e) Fairly in-expensive
f) Can eat the non-flung pieces. (You can eat the flung ones if you are ok with your office’s sanitary conditions.)
2) Max throwing arm length 25cm
A max length of 25cm was chosen because it is a little under the max diagonal of the TAZ5 printer we are using. We decided it would be easier for the groups to not have multiple piece arms since assembly would be difficult. Limiting the arm length should also limit the max distance the projectiles can fly, keeping the machine at a slightly more reasonable scale.
3) Max counterweight 0.5kg
With the mass of a peanut M&M being in the 1.5-3 gram range (http://stat.pugetsound.edu/hoard/datasetDetails.aspx?id=1) and phsstpoks rule of 100:1 ratio CW:Projectile ( http://www.northernelectric.ca/medieval/siege/phsstpoks_rule.htm), somewhere around 300g would be enough counterweight. We then rounded that number up to 500g just to be sure the amount of counterweight is not limiting our distance.
Our printing goals are:
1) Print as much of the machine as possible
2) Reduce build time
3) Have a good looking machine