L.O. (Learning Objectives) Week 15:¶

¶

    
      •	Participate in the group assignment project
      •	Review the safety data sheets for each of my molding and casting materials
      •	Make and compare test casts with each of the materials mentioned above
      •	Design my 3D mould and create my rough ++ finish toolpaths for machining (&& machine setting)
      •	Make my mould and cast the parts
      •	Trouble shooting along the way: HI TROUBLE!!!
      •	Upload design files and ‘hero shot’ of the mould and the final object
      •	Keep perspectives?

15.0. Notes during the class and workshops:FABLAB¶

 
    •	Drystone:
        o	Beautiful surface finish
        o	But terrible flexibility
        o	Very inexpensive
    •	Plaster cement
        o	Frequently seen in art studios
    •	Materials have lifetime
        o	Need to make sure they are in good condition
        o	Need to be mixed in a right ratio
    •	Preventing bubbles
        o	One of the key processes of this week
    •	Exothermic reaction
        o	Releasing heat
    •	The larger the volume, the longer the time it takes to release all the heat and be completely made.
    •	‘Health and Safety’
        o	Clean
        o	Should not mix two materials accidentally in one container.
        o	“Safety Datasheet”
        o	Need good ventilation
        o	Protection – gloves 
        o	Disposal
        o	Pro-tips: Don’t Eat Things!
    •	Endmill
        o	Flat vs. ball ends
    •	Cut-depth
        o	One of the limitations of this week
    •	You want to design after knowing what endmills you have in the lab and which one you will be using for your design.
    •	Ideas for this week:
        o	Fusion 360 brain
        o	Fusion 360 heart
    
        --
        Workflow for molding:
        •	1. Safety gears on
        •	2. Extraction on
        •	// Read 1) safety datasheet, and 2) datasheet for each material/chemical
            o	https://www.smooth-on.com/products/smooth-cast-326/
            o	https://www.smooth-on.com/msds/files/Smooth-Cast_326_327.pdf
            o	https://www.smooth-on.com/tb/files/SMOOTHCAST_325_326_327_COMBO_TB.pdf
        •	3. Measure the two parts (by weight)
        •	4. Mix ‘em (add color before/during this mix process)
        •	5. //De-gasing = Remove air bubbles
        •	6. Wait
        •	7. (alongside the step 6) reset and clean up
        
        •	Q. How do we know how much one chemical goes in?
            o	Measure the volume by using water first
        •	Mix Ratio_01: 115A:100B
            o	5.348A:4.651B
            o	Smooth-Cast 326
        •	The clock starts after mixing the two materials
            o	Not racing the clock until we mix them together.
        •	Q. How do we know whether or not it is mixed well?
            o	Increased viscosity
        •	Start_01: 10:30PM Hawaii or 5:30PM Korea
            o	End: 
        •	Useful to wear two pairs of gloves, one on the top of the other
            o	
        •	Q. How much pigment/color/filler do we add?
            o	Generally, 0.5% - 1% of the whole thing
            o	 
        •	Mix Ratio_02: 100:93
            o	Total: 30g
            o	100:93
            o	15.54:14.46g
        •	Start_02: 10:41PM Hawaii or 5:41PM Korea
            o	End: 
        
        Tooling
        •	Wax/Aluminum/Composite materials
            o	3mm flat endmill w/ 4 flutes
            o	Give all that depth (long endmill)
            o	E.g. ‘Long-series mill’
        •	Round endmill
            o	For better finish (마감용)
        •	Unicorn horn shaped endmill (‘taper’)
            o	Friction
        •	When putting two blocks together:
            o	1) air holes
            o	2) locators (lego-shaped parts)
            o	3) “DRAFT ANGLE” – w/ unicorn endmill
                  	Should not be 90 degrees
                  	Add tiny little angle at the edges, etc.
            o	Alternative 3) brush some oil on the mold 
                  	HOWEVER, oil can be reactive to the material that you use (and put into the mold)
            o	Q. What do we have to consider while the Design Process?
                  	Size
                  	Min size, max size – matching tooling e.g., which endmill, etc.
                  	Enough clearance
                  	Locaters (having little markers, where you’re gonna pour in and out from)
                  	Extra holes
                  	IMPORTANT: Hard tooling vs. Soft tooling
        •	Hard tooling: -  +  -
        •	Soft tooling: +  -  +
        •	We are learning ‘soft tooling’ this week.
                  	Fusion 360
        •	Component vs. Body in Fusion360
                  	Pouring hole – the bigger the better usually – e.g. 4 or 6 mm
                  	Air hole – e.g. 2mm
                  	After finishing the design process, use the ‘manufacture mode’.
                  	Big to Small – Tiny Robo for this week
        •	Unlike Bantam which is Small to Big.
                   	
            o	Viscosity of the material that you use affects how detailed your design result is.
        
        •	Material name: Mold Max 60
            o	Ratio: 100A: 3B by weight
        •	Vacuum machine (for removing air bubbles)
            o	Do everything slowly.

15.1. Participate in the group assignment project:¶

Link to week 15 group assignment
http://fabacademy.org/2020/labs/seoulinnovation/tag/group-work/
(Update on my final project:

)

15.2. Review the safety data sheets for each of my molding and casting materials:¶

We read 1) safety datasheet, and 2) datasheet for each material/chemical

o https://www.smooth-on.com/products/smooth-cast-326/
o https://www.smooth-on.com/msds/files/Smooth-Cast_326_327.pdf
o https://www.smooth-on.com/tb/files/SMOOTHCAST_325_326_327_COMBO_TB.pdf

15.3. Make and compare test casts with each of the materials mentioned in the section 15.2 above:¶

The content of this section is in the group assignment page ->
http://fabacademy.org/2020/labs/seoulinnovation/tag/group-work/

15.4. Design my 3D mould and create my rough ++ finish toolpaths for machining (&& machine setting):¶

Workflow of my design process for this week:
1. Search examples from the previous year students.
2. Decide which design I will make.
3. Find relevant tutorials on the internet.
4. Design + - +
5. Make toolpaths for roughing and finishing
6. Simulate all toolpaths, and check and fix errors
7. Save the file(s) as a g-code.

1. Search examples from the previous year students:
I found this documentation and example cam files useful ->
http://fab.academany.org/2019/labs/kannai/students/kota-tomaru/assignments/week10/

2. Decide which design I will make:

I wanted this design because this is the logo of the Laboratory for Visual Learning at MIT, which I love so much. Although this lab has been closed one or two years ago and the professor/founder, Dr. Matthew H. Schneps, has retired around one year ago, I respect the existence of this lab deeply because it is one of the few laboratories that extensively research on neurodiversity and/or dyslexia in the world. The world needs more researchers in this fields! (Plus he recently guided me to connect one of the postdoctoral student in Italy who researches neurodiversity and dyslexia, and I learned how I could find such labs and prepare to apply for the research internships (professionally, academically, etc.)

3. Find relevant tutorials on the internet:
I found some useful CAM Fusion 360 tutorials on youtube ->
(a) https://www.youtube.com/watch?v=whGKwsEY4Vo&feature=youtu.be
(b) https://www.youtube.com/watch?v=Do_C_NLH5sw
But be mindful not to use 2d toolpath. 3d toolpaths should be used.

4. Design + - +:

5. Make toolpaths for roughing and finishing:

6. Simulate all toolpaths, and check and fix errors

7. Save the file(s) as a g-code:

8 gcode files saved, for each toolpath.

15.5. Make my mould and cast the parts:¶

Moulding began -

video here

Casting starts -

>

15.6. Trouble shooting along the way: HI TROUBLE!!!:¶

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Problem 6

Problem 7

The machine randomly stopped as well as the software.
I am guessing that it would be because I separated my toolpaths into several files, and loaded them in the TinyRobo software each time.
The software version seems really old, apparently, in our lab, and I think it could be a trade-off of using seperating toolpates into several gcode files. Albeit heavily depends on the the machine condition and the software version.

I saved my toolpages in several files in order to prevent a probable problem of using only one gcode file that contains several toolpaths. (e.g. hitting and/or breaking something after changing an endmill - the machine might move to a place where we have not predicted it to move.) In our lab, the student who first tried using the CNC TinyRobo broke an endmill due to this cause/problem, and I wanted to prevent the same mistake, as well as losing an endmill.
If I break an endmill, I might affect your classmates's plans and toolpaths settings, which might make them take longer time editing their fusion360/CAM filies.

Problem 8
Trust your intuition when using a machine! When you feel like something's wrong, you're right (probably)!!
Problem 9