Smart Molding International 2-2025

38 smart_molding international 2/2025 additive manufacturing Replacing metals with 3D printed polymers PEEK and ULTEM™ offers between 50-60% weight reduction, while maintaining high strength and high heat resistance. AON3D Hylo, a large, high temperature industrial 3D printer, was optimized to make 3D printing high performance materials like PEEK and ULTEM™ 9085 easy and accessible. R eplacing metals with poly- mers is not only possible but becoming increasingly more prevalent. The current generation of high-performance polymers and composites has similar mechanical properties to aluminum at a fraction of the weight. In addition, the ability to additively manufacture parts from these polymers, with high tempera- ture 3D printers like the AON Hylo, has driven further adoption by reducing the complexity, lead times, and cost constraints of traditional manufactur - ing methods. What differentiates metals and polymers? Before we address which polymers are suitable for replacing metals, we need to set the right expectations. Some companies may inflate the capabilities of high-performance polymers and fail to consider that metals and polymers are fundamentally different. Here’s how the differ: Polymers 3 D p r i n t a b l e p o l yme r s a r e thermoplastics, made up of polymer chains that are chemically separate from each other (no molecular bonding between chains). These chains are physically entangled which provides mechanical integrity to the overall material. The chains can also organize and fold into a crystal structure which are harder to pull apart due to greater intermolecular interaction forces. This is why semi-crystalline polymers are better in strength and stiffness compared to amorphous polymers. Metals If you were to put a common metal under the microsco pe, you’d see a structure similar to image A below. Metals are made up of small grains, where each grain consists of a crystal lattice (image B). These crystals are made of an array of metal atoms that are connected through strong metallic bonding. The bonding and the organization of atoms into crystals is why metals are naturally strong and stiff. Often these grains differ from each other by the size and orientation both of which influence the bulk properties of themetal. In conclusion, semi-crystalline polymers are partially made of crystals while metals