Class Assignment 7: Make it Big!



Class Assignments

Final Project 1.0

CAD

CCC

Electronics production: FabISP

3-D Print

Electronics Design

Make it Big

Programming

Mechanical Design+Machine

Input Device

Molding + Casting

Output Device

Composite

Networking

App/Implications

I n I n I

Final Project

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for this assignment, i again looked to my life to inform what i would do. we own a child's rocking chair that is falling apart. so i decided to create a press fit rocking chair.

sketchmodel 1

i began by employing the same principles as in lesson 3: starting with a sketch and then translating it into a small cardboard press-fit kit including chamfers, cut on the laser cutter. the model is on a 1/10 scale, and my thought is that once i get it how i want it- i will scale up by simply moving the decimal point, and resizing slots.

recycle 3

i approached the design aiming for simplicity and including elements that my daughter likes (butterflies and hearts). after hand sketching, i went into CorelDraw and created the kit based on the sketch and measurements slightly larger than her other chair. i re-used pieces of cardboard that i used before on the press-fit kit to create the tests. i ended up creating 3 models. the first (i am holding) did not have enough clearance between the seat and back and didn't come together. i tweaked the design, and made the second- which was ok but tipped backwards really easily when rocked. i then created the third design, which adds weight to the front with the arm rests, as well as has a bit more flattened curve on the bottom. it rocks really well.

new model

after creating a model that i was happy with, i sized the file up by one order of magnitude. i then measured a piece of plywood that i wanted to use, and resized the slots to match the thickness (.5 in). i then saved as a dxf file, to then open in Partworks which will create the toolpath for the Shopbot.

click here for the 1/10 model cdr file

click here for the chair dxf file

click here for the chair crv file

Shopbot Workflow:
1. check all safety precautions.
2. clamp and screw material to sacrificial layer as flat as possible.
3. select and insert chosen endmill.
4. turn on machine, and engage, turn on air vent.
5. press reset button so that the computer recognizes the machine.
6. in shobot software use command C5 to begin warm up sequence (important to do once per day that the machine will be in use).
7. while machine is warming up take out the manual and look up the suggested speed and feed for the selected material and endmill, adjust in software.
8. once warm up routine is complete, use command C2 to zero endmill (z-axis), and then using command JH zero the x and y axes by manually adjusting in the control panel so that the middle of the endmill is directly over the front, left corner.
9.use the 'load part' command and load the tool path, press the green button on the machine and then click ok.

bot 1

for this project we : zeroed it form the top, and slowed the Shopbot down to 1.2, 12,000 rpm, 3 passes- stepping down .183 inch each time.

bot 2

the Shopbot gave a very clean cut, only slightly cutting into the sacrificial layer a tiny bit, and no need to re-cut. all of the pieces broke away from their tabs cleanly. the peices fit together nicely with the help of a rubber mallet. the only thing that i would add would be two braces along the bottom rockers for more stability. other than that it is a pretty strudy chair, and after sanding thoroughly, i will give it to my daughter.

chair 3

chair 2