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      Week 7: Computer-Controlled Machining    
    • Learning Objectives (Week 7):
    • 7.0. Notes during the class and workshops:
    • 7.1. Generate ideas of something big
    • 7.2. Design something big
    • 7.3. Test the design of something big
    • 7.4. Mill something big
    • 7.5. Assemble something bigt
    • 7.6. Possibilities and Improvements moving forward
    • 7.7. Debugging (March 16th recitation)
    • L.O. (Learning Objectives) Week 7:¶

      ¶

          
            •	Generate ideas of something big
            •	Design something big
            •	Test the design of something big
            •	Mill something big
            •	Assemble something big
            •	Reflect on Possibilities and Improvements moving forward
          
            
        

      7.0. Notes during the class and workshops:FABLAB¶

       
            •	Tooling:
              o	Coatings
                  	Uncoated endmills are cheaper than the coated ones
              o	Up/Down cut
                  	Start with Up-cut
                  	Finish with Down-cut
              o	Flat/Ball end
                  	Start with Flat End
                  	Finish with Ball End
                  	But it makes sense only when working on hands
                  	Flat end mill can make smooth surfaces
                  	On the bottom, Flat Endmill gives a flat surface, while Ball Endmill gives a curvy surface.
            •	Speeds and Feeds:
              o	Cut depth
                  	how far the path is
              o	Step over
                  	Vary the Step Over, trading over time on how good/smooth the surface is
            •	Toolpaths:
              o	Three main toolpaths:
                  	1. Profile: cut
                  	2. Pocket: cut with wings
                  	3. Drills: engrave circles to drill (fixture role) 
              o	+Joint, Routing(3d cutting)
            •	Sacrificial Layers, Squaring
              o	From the bottom: 1. Sacrificial Layer -> 2. Layer that will be used
              o	Making sure the machine is “square” (?)
                  	In order to do so, the machine needs to be updated periodically.
                  	 Making sure the angles are accurate
                  	Especially important – when it comes to making joints that need to be assembled after the cut.
            •	Joint Test (Prototyping)
              o	Make sure the tolerance and the structure of each joint is great enough.
              o	Cut out the portion that has joints, rather than the whole design.
              o	Please test.
              o	We shouldn’t need nails 
              o	Glue
            •	Limits of CNC Machine (ShopBot)
              o	Cannot cut in Undercut (angle of the cut)
              o	Cannot cut Thin material (thickness)
              o	Cannot cut Internal design e.g. captured part
              o	Cannot cut something bigger than bed size
              o	Cannot cut an object/design that is smaller than the diameter of the endmill 
              (4mm)
              o	Cannot cut “square” holes
            Safety is much more important this week!!!
            •	You need to know what to do when emergency occurs.
            •	You never do this alone – EVER! 
            o	There needs to be people who can keep an eye on you.
            •	You don’t do it when you’re rushing
            •	You need to do it when you can work sanely
            •	You’ll go through safety training. Safely. Properly.
          
            
        

      7.1. Generate ideas of something big:¶

      Outcome:

      • This is a drawing of an updated version of my final project. It shows the bones of the structure. For this week, I intend to make the top part, except the bottom, because I think it is important to see if the curve shape – which requires kerf structure – works and if it is what I want in actuality.
      Process to reach this point:
      • In order for me to think of the design that has an entrance where a person can go through, I had to go deep in terms of which visual image, as well as which flow of human movement, I want for the design.
      • Abstract thinking was highly stimulated in the process.
      • Essentially, I wanted an “egg” shape.
      • However, I had to change into a flower or lotus flower shape, because it is “makeable” on the CNC machine (Shopbot).

      • Portable Structure.
      • I wanted the “wall”s that surround the whole shape to be foldable to be portable.
      • Nevertheless, it was too challenging for me for this week’s work and my current knowledge in engineering and design. I just decided to several parts that I can assemble anywhere I go.

      • Instead, I came up with the idea of using a sheet of cotton, like those used in a camping tent, to increase the sense of comfort for the user who will go inside the structure and sit down.

      7.2. Design something big:¶

      Outcome:

      • Four petals – three with a hole inside it, and one full board. • I will put a cotton sheet on each hole.
      Process to reach this point:

      • I will need to find a way to attach a cotton sheet on each petal shaped wood.
      • Craig later advised me to think of using stapler and/or glue.

      7.3. Test the design of something big -- 1:¶

      Outcome:

      • I made a small version using a piece of cardboard and a laser-cutter.
      Process to reach this point:

      • “Invalid color code” warning message appeared (blue) even when I set everything correctly. This issue was resolved by using green instead of blue. I do not know what the exact problem was with the software, but everything went fine after that.

      • The kerf part – which is required for the curve shape – took quite a long time. I am not sure if it is a great idea to solve this at all, so I did not attempt to change anything about the time duration for cutting. (laser cutting)


      7.4. Test the design of something big -- 2:¶

      Outcome:

      • I just finished cutting the test version for various shapes of kerf for the curve shape.
      Process to reach this point:

      • Problem that I faced: the time estimate for cutting the whole test joints and kerf shapes was over 3 hours. Therefore, after asking Craig, I decided to increase the "pass depth" from 2 to 3, as well as increase the overall speed from 6000 to 9000. I would not do this for my final version because there would be a high risk of getting a rough finish on the wood after the cut. Since this version is just for testing the angles of bending each kerf shape and testing the joint shape, I have decided to less priortize the quality of cut. (I did consider the safety part though :))

      • This is the result of this test.

      7.4. Mill something big:¶

      Outcome:

      Process to reach this point:
      •

      7.5. Assemble something big:¶

      Outcome:

      Process to reach this point:
      •

      7.6. Possibilities and Improvements moving forward:¶

      Outcome:

      Process to reach this point:
      •

      7.7. Debugging (March 16th recitation):¶

      Outcome:

      Process to reach this point:
      •

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