3D printing (updated)
3D Printing
Since it's during the holidays, I decided to challenge myself a little in creating a 3D printable design. I have obtained the original design in Thingiverse and I decided to tweak the design a little to make it suitable for this project as well as make it simpler to make. The catapult design I tweaked could be made easily subtractively is because I made the latch for the catapult to be a joint instead of a flexible piece as the material used to 3D print is different from the recommended ABS but the stiffer PLA. From the embedded design below, it can also be seen that the starting position of the catapult is lowered and therefore needed supports when 3D printing. This can be seen in Figure 14.
Figure 1: Original design of catapult
Instructions to make catapult
Step 1: To make the basket of catapult, using Create form, make 2 Spheres and a Torus. After removing half of each sphere, and half of the torus, weld edges together.
Figure 2: The finished result of 'basket'
Step 2: Create the base sketch as shown in Figure 3 and 4 using the parameters provided. 
Step 3: Create Sketch for latch
Figure 3: Base sketch 1
Figure 4: Base sketch 2
Figure 5: Sketch for latch
Step 4: Extrude base sketch according to height in Figure 7. (2mm and 5mm) Fillet all edges to 2mm.
Figure 6: Base body extruded
Figure 7: Side-view of base
Figure 8: Front view of stand
Step 6: Fillet all edges 1mm. Rotate stand by required amount from Figure 9.
Figure 9: Rotated and Fillet stand
Step 7: Extrude latch by as shown in Figure 10. Fillet edges afterwards
Figure 10: Image of Extruded latch
Step 8: Make a hole at the side for the joint as shown in Figure 11.
Figure 11: Hole for joint
Step 9: Make cylinder for joint, as shown in Figure 12.
Figure 12: Cylinder as a component.
Step 10: Using the reference link below, create joint
Figure 14: After slicing design time required is 1hr
In Figure 14, you can see a light blue base at the bottom of the product, and this light blue portion is actually your Brim!
I found this activity quite challenging but fun as I got to use my creativity to tweak the design to suit the requirements of this project. I felt that this practical also gave me a chance to improve on my designing skills in Fusion360 and also boost my confidence in using the software. However, the 3D printer could not print out the joint part of my catapult because of the lack of resolution in the printer. The joint was fused with the design of the body! I was told by MR Ting that if the size of the catapult was larger, my design would be successful.
Hero shot
Figure 15: HERO shot of finished product.
Video of 3D printer in action!
The embed below is the same catapult but with my group's logo (Body 13)