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###Week6: Computer-Controlled Machining
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###Design
For this week, I just want to make something that is not crazy, but functional. Apparently, some furniture is still missing at my place. Between the high chair for the terrace and the side table for my bed, I chose the latter for now, since I may spend more time on my laptop, even on the bed, rather than relaxing at the terrace....
The side desk should have just one side leg, so that the table can protrude into the bed area. I'd like to make it multifunctional, with one side functioning as table, the other side hanging whatever you like, such as a plants, wire holder, or light bulb strings!
I measured all the dimension of me sitting on my bed, the height of the desk, and the length/width of my laptop. I just want to make it a very marginal, minimal space area so that I won't spend too much time on it.
For design, I always start from sketching. Then, going to 3d. This time, I picked solidworks rather than rhino, since it can easily generate each part in 2d drawing mode, as opposed to rhino, which could be a pain translating 3D to flat fabrication.
<img src="01_Design/d1.jpg" alt="strandbeest" width="1000"/>
<img src="01_Design/d2.jpg" alt="strandbeest" width="1000"/>
<img src="01_Design/design1.JPG" alt="strandbeest" width="500"/><img src="01_Design/design2.JPG" alt="strandbeest" width="500"/>
<img src="01_Design/dxf.jpg" alt="strandbeest" width="1000"/>
###Toolpath
Before executing the full scale CNC, Joon (our amazing TA)suggested that I do the joint test. I cut off a small section of my design for a joinery test. Then we realized that all my curves were not joint, but still gave it a try. The end-mill ended up moving back and forth in one curve, which led to dog-bone like corners (as shown in figure#1).As for the tolerance, we first tested it out without any adjustment,
and it ended up very tight, even needing a hammer to assemble it. Then we ran a second trial, which we followed Joon’s test result, set the tolerance of the 'hole length' to 'joint length+1.588mm', while the width of both joint and hole remains the same as OSB thickness, 11.8mm (as shown in figure#2). We decided to run the full scale with this setup, however, the result was not very pleasing, I still needed to polish the rough edge and used a hammer to assemble.
<img src="02_Aspire_Shopbot/cc_rules-01.jpg" alt="strandbeest" width="1000"/>
In the video, I documented the test of 1)aircut 2)non-joint curves, and 3)joint curves.
<iframe width="1000" height="600" src="https://www.youtube.com/embed/xnPS5ngTztc" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
Following <a href="https://fab.cba.mit.edu/classes/863.21/Harvard/people/harvard-group-work/joon/index.html">Joon's documentation</a>to set up the toolpath
in <a href="https://www.shopbottools.com/products/software">Aspire</a>, it was very cool to see how the machine generate the tool path by differentiate inner(holes)
and outer(boundary), and the tab function helps the cutted pieces stay on the platform to avoid flying in the air.
<img src="02_Aspire_Shopbot/t1_holes.JPG" alt="strandbeest" width="500"/><img src="02_Aspire_Shopbot/t2_holes.JPG" alt="strandbeest" width="500"/>
<img src="02_Aspire_Shopbot/t3_outline.JPG" alt="strandbeest" width="500"/><img src="02_Aspire_Shopbot/t4_ouline.JPG" alt="strandbeest" width="500"/>
<img src="02_Aspire_Shopbot/t3_toolpath.jpg" alt="strandbeest" width="1000"/>
###Shopbot
Finally, shopbotting! We used the desktop shopbot to do a test run before going to the full scale. Here I want to clarify how to set up the origin in both machines.
For the small shopbot (desktop):
x-y positioning:
If you start from the left bottom, you would like to avoid the end-mill hitting the nail,thus setting the origin (x,y) position to (25.4,25.4)mm.
If you start from a resumed work(aka, somewhere in the middle but not left bottom of the board),then you can set the origin to (0,0), and manually set x and y to the wanted position.
z positioning:
Manually set the end-mill z position, and use a slightly thicker paper or cardboard to test the tightness between platform and end-mill. Once you feel good about the tightness, set the z as origin, and we are good to go!
<img src="02_Aspire_Shopbot/cc_rules-02.jpg" alt="strandbeest" width="1000"/>
For the big shopbot:
We started from moving x-y position to the center of the board as the standard for material thickness.
Then we used the conductive plate to touch the end-mill to link the mill to the shopbot, place the plate on to the OSB board,
and the shopbot will automatically set the Z origin with the end-mill touch upon the plate.
<img src="02_Aspire_Shopbot/cc_rules-03.jpg" alt="strandbeest" width="1000"/>
<img src="02_Aspire_Shopbot/b6.jpg" alt="strandbeest" width="500"/><img src="02_Aspire_Shopbot/b7.jpg" alt="strandbeest" width="500"/>
###Final Product
A 24-hr working-nonstop bed-desk!
<iframe width="1000" height="600" src="https://www.youtube.com/embed/wjbgtmnDfwQ" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
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