Injured Biathlete Still Shooting with 3D Printed Rifle Part

According to Clement Jacquelin, the CEO and founder of Athletics 3D, most of their professional athlete clientele require personalized sports equipment to help improve their performance. The French company then uses its farm of Zortrax 3D printers to fabricate a personalized product. But recently, the company was faced with a different challenge—3D printing a custom, modified rifle hand stop to enable an injured biathlete to continue their Olympic training. Zortrax technology and BASF filaments were used to get the job done.

At training camp ahead of the Winter Olympics, the French biathlete, who’s one of the best in the world, crashed on the way to a cycling session and fractured the ulna and radius bones in his left arm, which he’d extended to cushion his fall. A metal stabilizer was used to surgically secure the bones, but the recovery would last a few months, and modifying his rifle was the only way to ensure effective training. It would be tricky, because the biathlete would be unable to aim a standard biathlon rifle in a prone shooting position.

Professional biathlon rifle with a custom hand stop attached, 3D printed with BASF Ultrafuse PP GF30.

“3D printed sports equipment can be customized to accommodate limited movements an athlete has to deal with during the recovery period after an injury,” Jacquelin said in a Zortrax case study. “In this case, our client had trouble with forearm supination and his ulnar deviation angle was severely limited.”

A rifle’s hand stop is the part where a sling is attached to the bottom of the stock, and it needed to be modified in such a way that the biathlete could shoot with his limited ulnar deviation angle, compensating for his movement restrictions. First, Athletics 3D used a Zeiss 3D scanner to make a digital model of the original hand stop. Once this was done, the team began to tweak the design using Z-SUITE software.

“The first thing we changed was the angle at which the hand stop was held to enable aiming without twisting the wrist. This way we solved the problem of limited ulnar deviation angle,” Jacquelin explained. “In the second step, we increased the area of contact between the hand stop and the palm to provide more stability in a position our client had not trained for.”

Digital model of a modified hand-stop visualized in Z-SUITE software before the 3D printing process.

The software includes pre-defined print profiles for supported materials. In order to achieve the necessary mechanical properties and performance in freezing temperatures, the team used BASF Ultrafuse PP GF30 filament, which had been tested by Zortrax engineers. Most polymers become brittle in sub-zero temperatures, but this polypropylene-based composite, reinforced with 30% glass fiber, performs well in the cold, and also offers excellent surface quality.

“World Cup biathlon races are done in temperatures as low as -25 °C. This is the winter sport after all. And such low temperatures tend to degrade the mechanical performance of most polymers. Materials such as PLA or even ABS tend to become brittle when it’s freezing. That’s why the French team coaches insisted on choosing the material that could perform in low-temperature conditions,” Jacquelin said. “Thanks to BASF Ultrafuse PP GF 30 we had no problem with that. The material’s exhibited the same, excellent performance in both freezing cold and relatively mild temperatures just below 0 °C.”

BASF Ultrafuse PP GF30 is often used for automotive applications due to its thermal stability and mechanical strength, and the material is also resistant to UV light and several chemicals and exceptionally stiff. It was selected for the modified hand stop because it is impact-resistant, holds up well under stress, and could give the part a grippy surface.

The hand stop 3D printed with BASF Ultrafuse PP GF30 was modified to provide stability while aiming the rifle with a fractured hand.

“Professional sports are very often used as a testbed for new, innovative technologies. 3D printing is no exception,” stated Zortrax CEO Mariusz Babula. “We are proud that Zortrax 3D printers working with materials coming from world-leading manufacturers such as BASF Forward AM can deliver the performance necessary at the very pinnacle of disciplines like biathlon.”

Athletics 3D chose the Zortrax M300 Dual because it helps deliver the necessary surface quality, can create the complex, organic shapes seen in ergonomic designs, and is factory-calibrated to work with BASF Ultrafuse PP GF30.

“This easily translated into excellent printed parts,” Jacquelin said. “Moreover, this also meant that we could expect consistent results in case spare hand stops were needed.”

Zortrax M300 Dual working with side covers and HEPA Cover keeps the temperature stable in the build chamber which ensures consistently high quality of prints made with BASF Ultrafuse PP GF30.

The resulting modified, 3D printed hand stop was impressive, and helped the injured biathlete get back to shooting in less than two months after his injury. Its grippy surface enabled a secure hold while aiming the rifle, without twisting his wrist. However, while he was making more precise shots with the 3D printed hand stop, his shooting rate went down. So when he regained full wrist movement two months after he began training with the modified version, the team decided to have him go back to the regular hand stop.

“The main reason was that the coaches together with our client decided that increased accuracy did not offset the slower shooting rate,” Jacquelin explained. “However, getting back to shooting and competing in World Cup races was made possible at least two months before it normally would have without our 3D printed hand stop.”

The hand stop 3D printed with BASF Ultrafuse PP GF30 could be held without twisting the wrist.

While he didn’t continue using the modified version for further training or in competition, without 3D printing, the biathlete would almost have surely have been unable to compete in the Winter Olympics.