How to Build a Foam Ball Launcher Using Laser Cutting and Simple Materials

Have you ever wanted to combine the precision of laser cutting with a fun, hands-on project? In this Instructable, I'll guide you through the process of designing and building a foam ball launcher using laser-cut acrylic and simple household materials. This project not only demonstrates the practical applications of laser cutting but also delves into basic mechanical principles like tension, force, and motion. Whether you're a DIY enthusiast or a student looking to apply fabrication skills, this foam ball launcher offers an engaging way to explore design and engineering concepts.

Materials:

1. Eco Medium Clear Acrylic Sheet (12" x 20")
2. Wood Glue or Acrylic Adhesive
3. Popsicle Sticks (2-3 pieces)
4. Rubber Bands (2-3 strong ones)
5. Toothpick (for the trigger pivot)
6. Cardboard
7. Foam Ball (or any soft projectile)
8. Hot Glue Sticks
9. Tape

Tools:

1. Laser Cutter (e.g., Glowforge)
2. Computer with Design Software (for SVG files)
3. Hot Glue Gun
4. Drill with small drill bit
5. Ruler or Measuring Tape
6. Sandpaper (optional, for smoothing edges)
7. Scissors
8. Utility Knife

The main body of the launcher is crafted from laser-cut acrylic sheets.

1. Prepare the Design Files:
2. Download or create the SVG design file for the launcher body (attached below).
3. Ensure the design fits within a 12" x 20" sheet.
4. Set Up the Laser Cutter:
5. Open the Glowforge (or your laser cutter's) software.
6. Upload the SVG file into the software.
7. Draw another stick about 8.5 inches in length and 1 inch width (will act as the bolt).
8. Adjust the settings according to the material specifications (usually provided by the manufacturer).
9. Cut the Acrylic Sheet:
10. Place the acrylic sheet into the laser cutter.
11. Execute the cut to produce three identical pieces of the launcher body and the bolt.
12. Assemble the Body:
13. Stack the three acrylic pieces precisely on top of each other.
14. Apply wood glue or acrylic adhesive between each layer.
15. Clamp them together or place a weight on top to ensure a tight bond.
16. Allow it to dry for about 30 minutes.

Tip: Using multiple layers adds strength and durability to the launcher.

The bolt is the moving part that propels the foam ball.

1. Attach the Hook and Stopper:
2. Cut the wooden popsicle into 2 small blocks measuring approximately 0.4 x 1.2 inches.
3. Position the 2 blocks about 1.5 inches from the backside of the bolt.
4. Glue a block above the bolt and another one below the bolt using hot glue.
5. The top part acts as a hook for the rubber bands.
6. The bottom part serves as a stopper to prevent the bolt from shooting out unintentionally.
7. Enhance the Bolt Tip:
8. Glue a small piece of cardboard to the front end of the bolt.
9. This increases the surface area to effectively push the foam ball.
10. Attach the Rubber Bands:
11. Loop the rubber bands around the hook at the top of the bolt.
12. Stretch them to the front end of the launcher body and secure them.
13. Glue the bands to the top part of the bolt

Note: The tension in the rubber bands will determine the force of the launch. Adjust accordingly but ensure safety.

The ramp guides the bolt smoothly, and the trigger controls the release mechanism.

1. Create the Ramp:
2. Use the utility knife to cut a popsicle stick to form a ramp
3. This piece helps guide the bolt and keeps it in place after pulling the trigger.
4. Hot glue the ramp to the launcher body towards the backside of the launcher, before the trigger cutout.
5. Build the Trigger:
6. Take two popsicle sticks and shape them to resemble a trigger.
7. Glue them together to form a sturdy piece.
8. Install the Trigger Mechanism:
9. Drill three holes. One through the center of the launcher body where the trigger will be placed, one through the gun (above the trigger cutout), and one through the trigger itself.
10. Ensure that the gun and trigger holes align inside the launcher.
11. Insert a toothpick through the hole to act as a pivot for the trigger.
12. Trim the excess ends of the toothpick.
13. Test the Trigger:
14. Pull the bolt back and engage the trigger to hold it in place.
15. Ensure the trigger releases the bolt smoothly when pulled.

Tip: Sanding the ramp can improve the overall feel of the launcher.

We'll create and attach a cylindrical piece to the front of the launcher to keep the foam ball in place.

1. Prepare the Material:
2. Measure and cut a rectangular piece of cardboard.
3. The piece should be 5 inches tall and wide enough to form a cylinder with a 3-inch diameter.
4. Form the Cylinder:
5. Place the rectangular piece on a flat surface with the longer side horizontal.
6. Tightly wrap the material around any thin cylinder piece to form a smooth cylinder.
7. Apply tape along the overlapping edge to hold the cylinder shape.
8. Modify for Easy Reloading:
9. Using a utility knife, carefully cut out a vertical section from one side of the cylinder.
10. This cut-out will face outward when attached to the launcher, making reloading convenient.
11. Attach the Cylinder to the Launcher:
12. Place the cylinder at the front end of the launcher where the bolt exits.
13. Ensure it aligns with the bolt's path for smooth operation.
14. Apply hot glue along the edges where the cylinder meets the launcher body.
15. Press firmly and hold until the glue sets.

Now, we'll test the launcher.

1. Load the Foam Ball:
2. Place the foam ball at the front of the bolt, resting on the ramp.
3. Test the Mechanism:
4. Pull the bolt back until the stopper engages with the trigger.
5. The rubber bands should be stretched, storing potential energy.
6. Pull the trigger to release the bolt and launch the foam ball.
7. Safety Check:
8. Ensure all parts are securely glued and there are no loose components.
9. Test the launcher several times to confirm consistent performance.

Note: Always point the launcher away from people or animals during testing.

Building this foam ball launcher was an enlightening experience that combined principles of physics, engineering, and digital fabrication. Here's what I learned:

1. Laser Cutting Precision: Utilizing the laser cutter allowed for precise cuts, ensuring that the components fit together seamlessly. This reinforced the importance of accuracy in design and fabrication.
2. Mechanical Principles: Constructing the bolt and trigger mechanism provided practical insights into kinetic and potential energy, tension, and force distribution.
3. Material Properties: Working with different materials like acrylic, wood, and rubber bands highlighted how material choice affects the functionality and durability of a design.
4. Problem-Solving: Converting measurements between metric and imperial units emphasized the need for careful calculation to maintain the integrity of the design.

Overall, this project was a valuable hands-on application of concepts learned in coursework, bridging the gap between theory and practice.