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How to make metal powder for 3D printing?

Published in Metal Powder Production 4 mins read

Metal powder for 3D printing is primarily manufactured through various atomization processes, which transform molten metal into fine, spherical particles suitable for additive manufacturing technologies.

How Metal Powder for 3D Printing is Made

The production of metal powder for 3D printing is a specialized process, with atomization being the leading method due to its ability to create high-quality, consistent powders.

1. Atomization: The Primary Method

Atomization is the most common and effective technique for producing the high-quality metal powders required for 3D printing. This method involves forcing molten metal through a small opening in a nozzle or orifice. The metal emerges as a spray of fine droplets, which rapidly cool and solidify into powder particles. The specific characteristics of the powder, such as particle shape, size, and purity, depend on the type of atomization process used.

Types of Atomization

  • Gas Atomization: This widely used method employs high-velocity inert gases (like argon or nitrogen) to break apart a molten metal stream. The rapid cooling by the gas jets results in highly spherical powder particles with excellent flowability. This is crucial for powder bed fusion processes like Selective Laser Melting (SLM) and Direct Metal Laser Sintering (DMLS), where uniform spreading of powder layers is essential for part quality.
    • Example: Producing spherical stainless steel (e.g., 316L) or nickel alloy (e.g., Inconel 718) powders for aerospace and medical applications.
  • Water Atomization: In this process, high-pressure water jets are used to disintegrate the molten metal stream. Water atomization typically produces more irregular or jagged powder particles. While these particles may have lower flowability compared to gas-atomized powders, their irregular shape can be beneficial for applications requiring high "green strength" (the strength of an unsintered, compacted part), such as in binder jetting or metal injection molding (MIM).
    • Example: Producing iron-based powders for binder jetting processes, where the subsequent sintering step consolidates the irregular particles.
  • Plasma Atomization (e.g., Plasma Rotating Electrode Process - PREP): This advanced method involves melting the tip of a rotating metal electrode using a plasma torch. Centrifugal forces from the rotation, combined with the plasma's effect, throw off molten droplets that solidify into extremely clean and highly spherical powder. This method is particularly well-suited for producing powders from reactive metals (like titanium and its alloys) and refractory metals, offering exceptional purity and morphology.
    • Example: Manufacturing spherical titanium alloy (e.g., Ti-6Al-4V) powders for biomedical implants and high-performance aerospace components, where contamination must be minimized.

2. Other Methods (Less Common for General 3D Printing)

While atomization dominates, other methods exist for specific applications or powder types:

  • Mechanical Alloying: Involves milling powders together to create composite materials or nanocrystalline structures. Less common for primary metal powder production for 3D printing, but used for specialized alloys.
  • Chemical Reduction: Involves reducing metal compounds into metallic powder using chemical reactions. Offers high purity but is often more complex and less scalable for the volumes needed in 3D printing compared to atomization.

Key Characteristics of Metal Powder for 3D Printing

Regardless of the production method, the quality of metal powder for 3D printing is paramount. Key characteristics include:

  • Particle Size Distribution (PSD): The range and distribution of particle sizes are critical. For laser-based systems, typical ranges are 15-45 µm or 45-105 µm, optimized for proper layer spreading and laser absorption.
  • Particle Morphology (Shape): Spherical particles are generally preferred for powder bed fusion technologies due to their superior flowability and higher packing density, leading to denser final parts.
  • Flowability: The ease with which powder flows and spreads across the build plate. Good flowability ensures consistent layer thickness and prevents defects.
  • Purity and Chemical Composition: The precise elemental composition and low levels of impurities (especially oxygen and nitrogen) are vital to ensure the final part's mechanical properties and prevent defects like porosity.
  • Bulk Density & Tap Density: These properties affect how densely the powder packs, which influences the final part's density and shrinkage during processing.
  • Recyclability: The ability to reuse unfused powder from a print job is important for cost-effectiveness and material utilization.


Powder Production Method Typical Particle Shape Primary 3D Printing Applications Advantages Disadvantages
Gas Atomization Spherical SLM, DMLS, EBM High purity, excellent flowability, high sphericity, wide material range Higher cost, lower yield of finer powders
Water Atomization Irregular Binder Jetting, Metal Injection Molding Lower cost, higher yield, can produce finer particles Poorer flowability for powder bed fusion
Plasma Atomization Highly Spherical Reactive metals (Ti), aerospace, medical Extremely high purity, highly spherical, minimal contamination, consistent Very high cost, slower production rates

Choosing the right metal powder and its manufacturing method is crucial for achieving desired part properties and optimizing the 3D printing process.