From CAD to Competition: Top 10 3D Printing Tips for Robotics Teams

Welcome to Build Season! If your shop is anything like ours, the 3D printers are already humming 24/7. In modern robotics, 3D printing has evolved from a tool for making pretty prototypes into a critical manufacturing method for competition-ready parts. However, there is a big difference between printing a desk toy and printing a complex mechanism designed to survive the rigors of the field.

To help your team maximize performance, minimize downtime, and make the most of your filament budget, we’ve assembled our top 10 engineering-grade tips for integrating 3D printing into your robotic design process.

1. Orient for Strength

3D printed parts are weakest along their layer lines (the Z-axis). When designing and slicing a part, always consider the direction of the forces it will experience on the robot. Orient the part on the build plate so that the structural loads run perpendicular to the layer lines, not parallel to them.

2. Wall Thickness Beats Infill

If you need a stronger part, don't just crank the infill up to 100%. Increasing the number of outer perimeters (wall thickness) adds significantly more strength and rigidity than increasing infill density, and it often saves material and print time.

3. Use Heat-Set Inserts for Threads

Never tap threads directly into plastic if the part will be disassembled or take a load. Instead, design your parts with slightly undersized holes and use a soldering iron to melt brass heat-set threaded inserts into the plastic. This gives you strong, reusable metal threads inside your 3D printed components.

4. Match the Material to the Application

Don't print everything in PLA!

• PLA: Great for rapid prototyping, electronics mounts, and low-stress parts.
• PETG: Good flex and impact resistance (great for intakes).
• TPU: Excellent for custom rollers, bumpers, and grippers.
• Polycarbonate (PC) / Carbon Fiber Blends: Essential for high-stress structural parts, gearboxes, and brackets.

5. Design for Additive Manufacturing (DFAM)

A 3D printer isn't a CNC router. Avoid designing parts with massive overhangs that require a ton of support material. Use 45-degree chamfers instead of rounded fillets on the bottom edges of parts to prevent "elephant foot" and improve bed adhesion.

6. Prototype Small Before Printing Big

If you are printing a massive, 15-hour mount that interfaces with an aluminum extrusion, don't print the whole thing just to check the fit. Slice and print a small, 10-minute cross-section of the mating feature first to verify your tolerances.

7. Dry Your Filament

Engineering materials like Nylon, PETG, Polycarbonate, and TPU are highly hygroscopic (they absorb moisture from the air). Wet filament causes stringing, poor layer adhesion, and brittle parts. Keep your spools in a dry box and actively dry them before printing structural components.

8. Mind Your Tolerances

3D printed holes usually shrink slightly. As a rule of thumb, add a 0.2mm clearance gap for parts that need a snug fit, and a 0.4mm to 0.6mm gap for moving or sliding fits. When designing holes for bolts, always make them slightly oversized.

9. Combine 3D Printing with COTS Hardware

3D printing is amazing, but it shouldn't replace everything. The strongest 3D printed part is often one that serves as a custom bracket holding together Commercial-Off-The-Shelf (COTS) aluminum tubes, hex shafts, and standard bearings. Let the metal handle the heavy structural loads, and let the 3D printer handle the custom geometry.

10. Fail Fast and Iterate

The biggest advantage of having 3D printers in your shop is the ability to iterate rapidly. If a design doesn't work, figure out why, update the CAD, and get the next version on the printer before the meeting ends.

Conclusion

Integrating 3D printing effectively is no longer just a neat trick; it’s a competitive necessity on the modern robotics field. By focusing on design for strength, correct material selection, and strategic use with hardware, your team can build a more robust, sophisticated, and successful robot.

Don't be afraid to experiment, but always remember to test your 3D printed parts under load before they get onto the competition field. Good luck this season, and happy printing!