BLT’s metal Additive Manufacturing helps OPPO build thinnest foldable smartphone
March 11, 2025
Xi’an Bright Laser Technologies Co., Ltd (BLT), China, has highlighted the role of its Additive Manufacturing technology in producing OPPO’s new Find N5 foldable smartphone. The Find N5, released in February this year, features a ‘Flexion Hinge’ with additively manufactured titanium alloy casing and wing, helping make it the first book-style foldable smartphone less than 9 mm thick when folded.
Manufacturing issues in foldable phones
A key issue in the design process of the Find N5, reports BLT, was screen creasing caused by an insufficient bending radius when the phone folds and unfolds repeatedly. Durability was another concern, as most conventional metal hinges struggle to survive 200,000 folding cycles without some level of deformation.
Weight was also an issue; in many foldable models, the hinge alone accounts for over 10% of the phone’s total weight, making it difficult to achieve a truly lightweight design. Reliability can also be an issue in hinged phones, because dust intrusion and mechanical wear are common hinge failures, something unacceptable in high-end devices where users expect smooth performance over years of use.
To solve these issues, OPPO needed to redesign its hinge from the ground up using stronger materials and more advanced manufacturing methods. This is when OPPO reached out to BLT to check the suitability of its metal Additive Manufacturing and proprietary powders.
Titanium for a stronger, lighter hinge
To help OPPO achieve its goal for the Find N5, BLT applied aerospace-grade titanium Additive Manufacturing to the phone’s hinge system. Titanium offered an ideal combination of strength, lightness and durability, while metal AM allowed for precise structural optimisation that is impossible to achieve with traditional manufacturing.
Through extensive testing and adjustment, the BLT team was able to reduce the hinge thickness by 50%, from 0.3 mm to 0.15 mm. The final design is also said to have resulted in a 120% increase in structural strength, making the hinge far more resistant to mechanical wear. BLT also noted that screen deformation was also reduced due to a 36% increase in hinge rigidity.
To test the hinge’s durability, the design underwent 100,000 folding cycles in extreme temperature conditions, ranging from -20 to 50°C, ensuring that it could withstand real-world use without failure. The Find N5 currently has two TÜV Rheinland certifications.
OPPO was said to have also been impressed by the efficiency of BLT’s multi-laser Additive Manufacturing, which enabled the production of 300 hinges in twenty-five hours, a pace that would have been difficult to achieve using conventional methods.
Precision engineering: the Skyfold hinge
As well as its role in material selection, BLT played a role in optimising the hinge design to achieve durability while remaining lightweight.
One of the most complex parts of the hinge is the wing plate, which shapes the droplet-like bending radius when the phone is folded. This component supports the smooth unfolding of the flexible screen while reducing stress on the panel, helping to prevent visible creases over time.
Another key part is the outer rotating shaft middle frame, which plays a critical role in absorbing energy from accidental drops or impacts. This enhancement is intended to improve both long-term reliability and contribute to the phone’s overall structural integrity.
