15. Wildcard week¶
For this wildcard week we needed to design and produce something with a digital fabrication process (incorporating computer-aided design and manufacturing) not covered in another assignment, documenting the requirements that our assignment meets, and including everything necessary to reproduce it.
Vacuum Forming¶
Vacuum forming is a simplified version of thermoforming, where a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mold, and forced against the mold by a vacuum. It is an easy way to make molds of CNC or 3D printed objects. We have some DIY vacuum forming machine. You can see it in a picture bellow.
We have a vacuum, box for vacuum mold and heat gun as a heater. Design files for vacuum forming machine are included bellow to download.
First thing I needed to do is to design a piece. From that piece we make a mold. I started design in Fusion 360. I made a 2 pieces that I wanted to do a vacuum forming. Since I like basketball, I wanted to design a Kobe Bryant Mamba logo. You can see it in a picture bellow.
In Fusion I inserted picture as a canvas by going to Insert -> Canvas. I moved to the center and calibrated for measurment.
I traced the outline of the logo and got the following shape.
Then I made an offset plane 12mm above. On the offset plane I traced the second part of the logo. I got the following results.
Now I have two sketches, one above other. I used command Loft to connect two sketches. The result was no so good, so I manually arange point to get the desired shape like in a picture bellow.
I wanted to design another piece, simpler piece for vacuum forming. I made a simple box with the text FabLab. I rounded the edges with fillet commands.
All the files I exported as stl so I can print them. In Cura I set layer height to 0.2mm and because we working with heat it’s important for the infill to be 100%. By doing that the piece should be stronger and more heat resistant.
The print time is little more than 1 hour. This is how the pieces turned out.
Next thing is to make a mold from printed pieces. We used two materials, plastic transparent foils and plastic plates. Plastic plates are made of Polypropylene. I put the first piece on a vacuum box and then turn on the vacuum. I put a plastic plate on the piece and turn on heat gun. First I heated the outer part of the plate and then the middle. Ou can see in a video bellow.
This is how the first mold turned out, front and back side.
I repeated the steps for the other piece and this is how it turned out. Here is the front and back side.
I also tried plastic transparent foil to make a mold. I used the same steps like before. First I heated the outer end of the foil and then the midlle. These are the final results.
Next thing I wanted to make a soap. We sliced glycerine into thiny pieces. Then we added pieces into a small plastic bowl and placed in a microwave. We then got a liquid substance.
Then we poured the glycerine into the molds. I also tried some other pieces to vacuum form. I tried to experiment by adding differnet colors. These are the final results.
And this is after cooling.
I wanted to make chocolate molds also, so I poured molten chocolate into the molds and left them overnight in the fridge.
