Navigating the 3D Printing Landscape: Comparing High-Performance Polymers and Metals
In the dynamic world of 3D printing, material selection is a pivotal factor shaping the outcome of manufacturing processes. The choice between high-performance polymers (HPP) and metals introduces a fascinating debate, as both offer unique advantages for advanced end-use parts. Delving into their properties, characteristics, 3D printing processes, and applications provides a comprehensive understanding of the considerations involved in this critical decision-making process.
Unveiling Distinctions in Properties and Characteristics
High-performance polymers and metals originate from distinct realms – one crafted through chemical synthesis, the other extracted from natural sources or engineered as alloys. Notwithstanding their diverse beginnings, certain HPPs, such as ULTEM, PEEK, and PEKK, exhibit properties that rival those of metals, especially in terms of strength, purity, stiffness, and resistance to wear and chemicals. The term "high-performance" refers to engineering-grade technical polymers, distinguished for their superior qualities.
Metal varieties span aluminium, steel, copper alloys, titanium, cobalt-chrome nickel-based alloys, and even precious metals like gold and silver. Each metal type offers unique properties, such as aluminium’s lightweight strength, copper's conductivity, and titanium's biocompatibility. The forms of metals – powders, filaments, wire, and nanoparticles – provide a diverse range of choices, influencing 3D printing processes.
Comparing Properties
Both HPPs and metals exhibit exceptional mechanical, thermal, and chemical properties. High-performance thermoplastics like PAEK and PEI rival metals in chemical resistance, temperature stability, and mechanical strength. Notably, HPPs boast an outstanding strength-to-weight ratio, surpassing even aluminium by being 60-70% lighter.
Metal strengths lie in their variety, offering tailored solutions for specific applications. While aluminium excels in a superior strength-to-weight ratio, copper stands out for conductivity. The wide range of available metals allows users to select materials aligned with their specific requirements, from strength and stiffness to thermal conductivity.
Exploring 3D Printing Processes
3D printing processes for HPPs primarily involve extrusion, with filament and pellet options, along with selective laser sintering (SLS). Metal 3D printing, on the other hand, encompasses a broader spectrum, including laser powder bed fusion (DMLS, EBM), directed energy deposition (DED), binder jetting, and metal extrusion. The choice of process significantly impacts material compatibility, offering greater flexibility for metals.
3D Printing Challenges
Despite their exceptional properties, both material families pose challenges in the 3D printing realm. High-performance polymers demand specialized printers with closed chambers, high-temperature capabilities, and a controlled printing environment to counteract their propensity for warping. Metal printing introduces additional complexities, requiring closed chambers filled with inert gases like argon to prevent reactions with oxygen. Safety measures, including respirators and protective clothing, are essential during metal 3D printing processes.
Post-Processing Considerations
Post-processing further distinguishes HPPs and metals. High-performance polymers offer advantages with evolving support solutions, making removal more manageable. Metal post-processing involves sintering, heat treatment, machining, and surface finishing to achieve the desired final part characteristics.
Applications
Applications for both material families overlap across industries such as aerospace, automotive, and medical. HPPs demonstrate their worth in aerospace with a superior strength-to-weight ratio, while metals continue to be crucial for structural integrity. The automotive sector benefits from both materials, with HPPs contributing lightweight solutions and metals providing strength. In medical applications, titanium and certain HPPs like PEEK and PEKK find use for their biocompatibility.
Manufacturers & Price
Manufacturers for HPPs are primarily chemical companies like Arkema, Solvay, and SABIC, along with 3D printer providers like INTAMSYS. Metal 3D printing materials are predominantly supplied by 3D printing solution providers such as EOS, 3D Systems, Trumpf, Sciaky, Desktop Metal, and HP. While the price points for both HPPs and metals are higher than standard polymers, metals tend to have a wider range of material choices, offering cost advantages, especially in bulk.
The comparison between high-performance polymers and metals in 3D printing unveils a nuanced landscape, where material selection intricately aligns with specific requirements and application nuances. Both material families contribute to the ongoing evolution of additive manufacturing, each bringing its unique strengths and challenges to the forefront.