AM Polymers & Composites

AM Polymers

• Polymers in AM refer to a class of materials, primarily thermoplastics, that can be melted, extruded, and solidified layer by layer to produce a 3D object. Polymers in AM are preferred due to their ease of use, versatility, cost-effectiveness, and the wide range of properties they offer.

• Types of AM Polymers:

  • Thermoplastics: These can be repeatedly melted and solidified. Common examples include PLA, ABS, and PETG.

    • PLA (Polylactic Acid): Biodegradable, made from renewable resources, low warping.

    • ABS (Acrylonitrile Butadiene Styrene): Strong, durable, and heat-resistant, but can produce fumes during printing.

    • PETG (Polyethylene Terephthalate Glycol): Combines the best of PLA and ABS - durable, with good layer adhesion.

  • Thermosets: These set into a solid form when cured and cannot be re-melted. Epoxy-based resins in SLA/DLP printing are examples.

• Printability and Material Properties:

  • Factors Affecting Printability:

    • Temperature: Ensuring proper extruder and bed temperatures for optimal adhesion and reduced warping.

    • Shrinkage: Some polymers shrink upon cooling, leading to warping or cracking.

  • Properties:

    • Mechanical: Tensile strength, flexibility, and durability.

    • Thermal: Melting and glass transition temperatures.

    • Chemical: Resistance to solvents, acids, or bases.

AM Composites

• At the intersection of strength and flexibility lie composites. By weaving in reinforcements, composites amplify the properties of polymers. From the high-strength and stiffness of carbon fiber to the economical strength of glass fiber and even to the sustainable potential of natural fibers like hemp, the possibilities are vast. There are even metal-filled polymers that mimic the appearance and weight of solid metals.

• Printing with composites isn't without its challenges. The added fibers can wear down printer nozzles, and sometimes these materials have difficulty adhering to the print bed. Yet, with innovation, solutions emerge. Nozzles made of hardened steel or embedded with ruby tips can resist wear, and with the right bed surface or adhesive, even the trickiest composites find their grip.