Reaction Ball v2.0

Reaction Ball v2.0 — Printed in Siraya Tech Roamr 85A

Train your reflexes. Outsmart the bounce.

This 3D printed reaction ball is a multi-lobed training tool designed to produce unpredictable, erratic bounces. This forces athletes to track, react, and respond in real time. Whether you're a hockey player, martial artist, tennis player, or just want a serious coordination challenge, this ball will keep you on your toes.

What Makes This Design Different

This model is sliced with zero perimeter walls — a deliberate design choice that replaces rigid shell layers with pure infill structure. Combined with Siraya Tech's Roamr 85A foaming TPU, the result is a ball with outstanding energy return and a natural, rubber-like feel on impact.

Supports have been tuned for clean, easy removal — no digging required.

The no-wall approach is critical. Adding walls will make the ball too stiff and kill the bounce response. Trust the infill.

Material: Siraya Tech Roamr 85A (Recommended) - Any High Rebound Filament Will Work

Roamr 85A was originally engineered for high-performance 3D printed footwear midsoles — and it turns out that makes it a near-perfect reaction ball material. Here's why it works so well:

• 48% rebound resilience — a snappy, responsive bounce that mimics the feel of professional athletic equipment
• Up to 57% weight reduction via active micro-foaming, giving the ball a lightweight, "air-infused" feel without sacrificing toughness
• Variable hardness from 68A to 85A — dial in the feel by adjusting your print temperature for a softer or firmer response
• Premium matte finish — the micro-foaming creates a fine, non-glossy texture that hides layer lines and eliminates the typical "plastic" look of TPU prints
• Excellent abrasion resistance for repeated high-impact use on floors, walls, and hard surfaces

Other high-rebound materials that work great: PEBA 90A, standard TPU, or any foaming/high-rebound flexible filament in the 85A–95A shore hardness range. The key is energy return — the bouncier the material, the better the ball performs. Avoid PLA, PETG, or any rigid filament.

Print Settings

⚠️ Zero walls is intentional. This is the defining feature of this print — do not add perimeter walls or you will significantly reduce flex and rebound performance.

Printing Tips for Roamr 85A

• Dry your filament before printing — Roamr is hygroscopic and moisture negatively impacts both print quality and foaming performance. Dry at 70–80°C for 4–6 hours. Siraya Tech
• For best results, print directly from a dry box or filament dryer, maintaining humidity below 15%. Siraya Tech
• Do not load through an AMS — feed directly to the extruder.
• Use my settings!

Use Cases

• Hockey, soccer, and lacrosse agility training
• Hand-eye coordination and reaction time drills
• Wall bounce training and solo catch drills
• General athletic conditioning

A genuinely high-performance training tool that proves great material selection matters as much as great geometry. The Roamr's foamed structure and energy return bring this closer to a commercial rubber reaction ball than anything a standard TPU print could achieve. Happy printing! 🏒