Cajon Clapper with no supports: Instant Percussion

🥁 Cajon Clapper with Rattle: Your Next Rhythmic 3D Print!
 

Introduce a sharp, distinctive "clack" and a vibrant, dynamic rattle to your musical arsenal with this innovative 3D-printed cajon clapper. Engineered for percussive clarity, expressive sound, and effortless printing, this model is a fantastic addition for musicians, makers, and anyone looking to expand their sound.

The design features two rigid PLA clapper bodies seamlessly connected by two flexible TPU joints, providing excellent durability and the perfect resonant "clack" when struck. A clever addition, a PLA ball attached to a TPU stem, connects to the top clapper body, creating a lively rattling effect that activates with every slap. Best of all, this comprehensive model is designed to print without the need for any supports, making it a straightforward and satisfying project even for beginners.

Whether you attach it to your cajon for integrated rhythm and texture or use it as a versatile standalone instrument, this clapper promises to bring a new dimension to your jam sessions and creative soundscapes.
 

🔨 Build Instructions

Assembling your cajon clapper is a quick and easy process, designed for minimal fuss after printing.

Identify Components: You should have two identical PLA clapper bodies, two identical TPU flexible joints, and one separate rattling assembly consisting of a PLA ball attached to a TPU stem.

Orient the Clapper Bodies: Take one PLA clapper body. You'll notice slots on its side where the TPU flexible joints will connect, and one additional circular hole on the top surface where the TPU stem of the rattling ball will attach.

Insert the TPU Flexible Joints: Carefully align one end of a TPU flexible joint with a side slot on a PLA clapper body. Gently push and wiggle the TPU joint into the slot until it seats securely. Repeat for the second TPU flexible joint on the other side slot of the same PLA clapper body.

Connect the Second PLA Clapper Body: Take your second PLA clapper body. Align its side slots with the exposed ends of the two already-inserted TPU flexible joints. Push the second PLA body onto the TPU joints, ensuring a snug fit into both slots. You might need to apply gentle, even pressure to seat both joints fully.

Attach the Rattling Ball Assembly: Take the PLA ball with its attached TPU stem. Locate the circular hole on the top surface of one of the assembled PLA clapper bodies (this will be designated as your "top" clapper). Gently push the TPU stem into this hole until the ball assembly is securely seated. The flexibility of the TPU stem should allow it to fit snugly and hold the ball in place while still allowing it to move freely for rattling.

Verify Assembly: Once all components are connected, the clapper should feel sturdy but have a slight flex between the two PLA sections, and the ball should rattle freely when the clapper is moved or slapped. The assembly is now complete!
 

🖨 Print Tips

Achieving the best results for your cajon clapper involves understanding the unique properties of PLA and TPU for each component.

General Tips:

No Supports Needed: The entire design, including the rattling ball assembly, is optimized for FDM printing without any support structures. Ensure your bed adhesion is good.

Printer Calibration: Ensure your printer is well-calibrated, especially for consistent extrusion, as this impacts both material types.

PLA Clapper Bodies & PLA Ball:

Material: Use standard PLA filament for the main clapper bodies and the rattling ball.

Nozzle Temperature: Typically between 195°C - 215°C (refer to your filament manufacturer's recommendations).

Bed Temperature: 50°C - 60°C is usually ideal for PLA.

Infill:

Clapper Bodies: 15-25% infill (e.g., cubic or gyroid) should provide sufficient rigidity and sound for the clapper bodies.

Ball: For the rattling ball, 10-15% infill is often sufficient, ensuring it remains lightweight for better rattling. You can experiment with very low infill or even hollow for maximum rattle, but ensure structural integrity.

Perimeters/Wall Thickness: Use at least 2-3 perimeters (or 0.8mm - 1.2mm wall thickness) for good strength and a solid feel for both the clapper bodies and the ball.

Print Speed: Standard PLA speeds work well (e.g., 50-80mm/s).

TPU Flexible Joints & TPU Stem:

Material: Use a flexible TPU filament (e.g., Shore Hardness 95A).

Nozzle Temperature: TPU generally requires higher temperatures than PLA, typically 220°C - 235°C (check your specific TPU's recommendations).

Bed Temperature: A heated bed around 40°C - 60°C often helps adhesion for TPU.

Print Speed: Crucially, print TPU SLOWLY. Speeds of 20-40mm/s are common. Printing too fast can lead to filament stretching, inconsistent extrusion, and clogs. This is especially important for the thin stem of the rattling ball to ensure it prints cleanly and remains flexible.

Retraction: Minimize or disable retraction. TPU's flexibility makes it prone to tangling in the hotend with aggressive retraction settings. If you must use retraction, keep the distance very low (e.g., 0.5mm - 1.5mm) and the speed slow (10-20mm/s). This is critical for both the joints and the stem.

Cooling: Reduce cooling fan speed, especially on the first few layers, to improve layer adhesion. Too much cooling can prevent layers from bonding properly.

Filament Drying: TPU is highly hygroscopic (absorbs moisture). If your TPU filament has been exposed to air for a while, consider drying it in a filament dryer before printing to prevent stringing, bubbling, and poor layer adhesion.

First Layer Adhesion: Ensure your print bed is clean and level. A thin layer of glue stick or blue painter's tape can help with adhesion.

Test Print: If you're new to printing with TPU, print a small test piece (e.g., a single joint or the stem) first to dial in your settings before printing the final parts.

By following these tips, you should achieve a high-quality, functional cajon clapper with a satisfying "clack" and lively "rattle," ready to add some percussive flair!