Week 5

Computer Controlled Machining

Materials: C.R Onsrud | 4x8 ft OSB | Fusion 360 | Rhino 3D | Mastercam

Design: inspired by low tables, shelves, and the lack of storage in my 90 sq-ft MIT dorm room, I designed a compact, visually interesting shelf.



The next step in my design process was hammering out the details. Functionally, as this piece will live under my bed, I decided to prioritize functionality over aesthetics and chose the model version that maximizes storage space without frills.





After playing around with measurements, I was ready to plug my design into AutoCAD. Some dimension considerations included leaving the depth of the shelves and supports at .5' to minimize tooling. Tetris-ing my pieces into a 4x8 sheet of OSB wasn't due difficult due to my rectangular components, but there was a significant amount of wasted space I could've used.





As a safety check, I created a quick 3D model to check dimensions, proportions, and assembly. At this point in the design I haven't included a method to fasten upper tables to lower tables, but I am hoping this will not be necessary as the structure should be statically stable and stacking the shelves vertically should suffice.

Machining

Before sending my file to the CNC, I had to add account for kerf. I did this by adding a .5' gap between all of my parts in Rhino using the trim and extend commands.

To set the toolpaths, I had to make the points a seperate layer before importing the file to Mastercam. From there, the toolpath was sorted 'point to point', defined on the outside of of the cut (countour remachining).

   

Once the file was sent to the C.R. Onsrud, I could relax, put on my noise-muffling headphones, and watch the machine mill the OSB for me.

   

Post-processing took some time because OSB is so flakey, and I had to remove the onion layer. An hour of sandpapering did the trick.

Learning note - in the future, I will need to improve how I take in information for this class. With so much new information, much of it unfamiliar terminology, it's hard to categorize what is relevent and what's extraneous for my applications. This week, I could've saved 2 hours of time if I did my background research on kerf.