Week no.12
- Molding and Casting
Assignments :
- Design a 3D mold
- Fabricate by Machinning it
- Cast parts from it
CAD Design
For this week assignment I planned to make a mold for a bottle opener I once saw, which is actually a skull form (cool!). Since I was making it from zero, I looked the internet and found a reference image of the model:
![Images](images/week12/skull_2.jpg)
And so I began to draw the 3D model in CREO Parametrics "sculpting it" in flexible modeling (FreeStyle) until I was satisfied with the part design:
![Images](images/week12/FreestyleCAD.jpg)
The resulting 3D model :
Mold Design
![Images](images/week12/Draft.jpg)
Before creating the Mold I ran a draft analysis looking for "Negative angles" that could potentially stuck parts inside the mold.
After a few surface adjustments I manage to get a clean mold part.
The next steps for creating the mold cavities were:
- Create the "Blank" to be machined
- Create the mold "split-line" based on the draft analysis
- Create the split surface
- Split the mold in two cavities
- Define and create the cast openings and guide pins.
The splitted mold cavities are now ready for CAM.
![Images](images/week12/Mold.jpg)
Machining the Mold Cavities
![Images](images/week12/Fanuc.jpg)
So the CAD model is assembled in manufacturing workspace and all the parameters like physical parts, cut strategies, speeds and feeds needs to be filled in CAM simulation. The output is a G-code file with the CNC machine instructions. More detailed steps are:
- Define the CAD part to be machined (reference Model)
- Define and assembly the "Blank" - Aluminum (100x100x50mm)
- Define Fixtures
- Create Work Center - FANUC 3 axis CNC
- Create Cutting Tools - Plunge, End Mill, BallNose
- Create operations - Facing, roughting, finishing x3
- Define cutting parameters
- Create tool path - machining time
- Simulate surface finishing
- Export machine G-Code
![image](images/week12/CAM1.jpg)
![image](images/week12/CAM2.jpg)
![image](images/week12/CAM3.jpg)
![image](images/week12/CAM4.jpg)
![image](images/week12/CAM5.jpg)
FAIL : Choose carefully your strategy and cut parameters! It was a difficult part to make in Aluminum, since it demanded a tiny mill tool (2mm diameter) for finishing and cut the detail of the small choosed part. As the 2mm end mill broke, the strategy shifted to make a mold from a softer and milling safe material like Polyacetal to preserve my last 2mm tool !
Mold Machining - second attempt !
Ok, it is not a injection mold and I´m not looking for durability. So I cutted 2 blocks of Polyacetal and ran the manufacturing again !
Finnaly I got the jobb done and could cast some polyurethane resin parts from my mold. I also 3D printed the design CAD for comparsion.
![image](images/week12/Mold1.jpg)
![image](images/week12/Mold2.jpg)
![image](images/week12/Mold3.jpg)
![image](images/week12/Mold4.jpg)
![image](images/week12/Mold5.jpg)
![image](images/week12/Mold6.jpg)
![image](images/week12/Mold7.jpg)
![image](images/week12/Mold8.jpg)
And here is a video of the milling process: