What is 3D printing metal powder?

3D printing technology, although not yet common in public life, has already opened a new chapter in the manufacturing industry. It is a typical representative of additive manufacturing technology, which can easily construct complex three-dimensional objects, unlike traditional manufacturing methods.

The outstanding advantages of 3D printing are reflected in the manufacturing of complex structures and achieving personalized customization. In the automotive industry, those intricately designed and structurally complex components, which used to require cumbersome manufacturing processes, can now be efficiently completed with 3D printing technology; the aerospace field has extremely high requirements for the precision and complexity of components, which 3D printing technology can fully meet; in the medical field, 3D printing also excels in creating customized prosthetics and implants for patients. In summary, in these industries, many complex structures that were previously difficult to manufacture can now be easily realized through 3D printing.

For 3D printing technology to gain higher popularity in the manufacturing industry, the development of emerging materials is one of the key factors. The technical level and product richness of 3D printing materials play an important supporting role in the development of the entire 3D printing industry. Currently, the most widely used 3D printing materials in the market mainly include two categories: plastics and metals. The plastic category includes ABS, PLA, nylon, photopolymers, etc.; the metal category includes pure metals such as steel, silver, gold, titanium, aluminum, and their alloys. These materials typically exist in forms such as powder, filament, sheet, and liquid.

From the current market situation, in the field of consumer products manufacturing, plastic materials dominate. The materials involved in its production mainly include ABS, PLA, nylon, and photopolymers. However, from the perspective of market demand and large-scale industrial and high-tech industries, metal materials produced through 3D printing have a broader development prospect. Especially in the aerospace field, metal 3D printing can manufacture complex and high-performance components, meeting the stringent requirements for lightweight and high strength in aircraft; in the military industry, it can achieve rapid customization of weaponry and timely replacement of components; in the automotive industry, it helps create more innovative body structures and engine components; in the medical field, it can customize personalized implants and medical devices for patients. Therefore, the application of metal materials in these industries shows great development potential and upward space.

Currently, the global 3D printing consumables market is expanding rapidly, with an annual growth rate exceeding 20%. In this booming market, various materials have their own strengths. Although plastic 3D printing materials still account for nearly 50% of the market share and have wide applications in the 3D printing field, their growth rate is not as strong as that of metal powders. In recent years, the demand growth rate for metal powders, especially those represented by titanium alloy powders, has far outpaced that of plastic materials. From the development trend, in the next few years, metal powders will, with their strong growth momentum, completely surpass plastic 3D printing consumables, dominating the market and becoming the core driving force for the development of the 3D printing industry.

1、金属3DBasic principles of printing technology:

When performing metal 3D printing, the first step is to use CAD design software on a computer to carefully construct a three-dimensional model, which is then exported in STL file format. Subsequently, this three-dimensional model will be sliced into multiple layers. The 3D printer uses the generated digital three-dimensional data to control a high-energy laser beam or electron beam, allowing them to melt the metal powder layer by layer, gradually constructing a three-dimensional and complex workpiece.

According to the different processes used for metal powder materials during processing, the common types of metal 3D printing technology mainly include the following:

1. Laser selective melting (SLM) technology: This technology uses a high-energy laser beam to irradiate the uniformly spread metal powder material, causing it to melt, layer by layer.“Printing”, ultimately forming the required workpiece.
2. Laser near-net shaping (LENS) technology: Its working principle is to use a high-energy laser to melt the synchronously supplied metal powder according to a pre-written printing path. This technology is suitable for printing and manufacturing various metal powders such as stainless steel, titanium, and titanium alloys.Co-Cr-MoAlloys and other metals.3D Electron beam selective melting (
3. EBSM: This technology uses an electron beam to irradiate the pre-spread metal powder material, which is similar in form to the) technologytechnology.SLMNanoparticle jet metal forming (
4. NPJ: This technology uses high-temperature liquid iron, which contains nanoparticle alloys. These metals enter the) technologyprinter in liquid form, and the printer achieves forming by spraying a mixture containing metal nanoparticles.“、”Printing metal powder materials3D Metal powder materials are key raw materials for metal 3D printing processes, and their basic properties are closely related to the quality of the formed products. In metal 3D printing, there are strict requirements for the powder in terms of chemical composition, particle morphology, particle size distribution, and flowability. Currently, mainstream methods for preparing 3D printing metal powders include gas atomization (GA), plasma rotating electrode process (PREP), plasma atomization (PA), and radio frequency plasma spheroidization (PS), among others.“、”来实现成型。

2、3D打印金属粉体材料

金属粉体材料作为金属 3D 打印工艺的关键原材料，其基本性能与成型制品的品质紧密相关。在金属 3D 打印中，对粉体在化学成分、颗粒形貌、粒度分布、流动性等方面有着严格要求。目前，主流的 3D 打印金属粉末制备方法包含气雾化法（GA）、等离子旋转电极法（PREP）、等离子雾化法（PA），还有射频等离子球化法（PS）等等。

The working principle of the gas atomization method is to use high-speed flowing inert gas to spray liquid metal. In this process, the liquid metal is atomized, then condensed, ultimately forming spherical powder. The powder produced by this method has some significant characteristics, such as a wide particle size distribution range, a smaller average particle size, and relatively easy control of impurities. However, due to the characteristics of the gas atomization process, the produced powder also has some drawbacks. For example, bubbles can easily form inside the particles, the powder shape may not be uniform, and conditions like satellite particles may occur, which can affect the performance of the powder in metal 3D printing to some extent.

Ideal state of powder

ASatellite particlesBIrregular, internal bubbles (defects)

In the technology of producing high-purity spherical titanium powder, the Plasma Rotating Electrode Atomization (PREP) method is a commonly used centrifugal atomization technique. Its uniqueness lies in the abandonment of the high-speed inert gas atomization of the liquid metal flow, which effectively avoids the problems of hollow powder and satellite powder particles caused by the "umbrella effect." With this advantage, the powder produced by this technology has a very high sphericity, reaching over 99.5%. However, this process also has certain limitations, as the particle size distribution of the produced powder is relatively narrow, mainly concentrated in the range of 50 - 150μm, with a larger average particle size.

The radio frequency plasma spheroidization process is another method for producing spherical powder. This process applies an electromagnetic field to various gases (mostly inert gases) through radio frequency, inducing heating and generating radio frequency plasma. Utilizing the ultra-high temperature of the plasma zone, non-spherical powder is melted. Subsequently, the powder experiences a significant temperature gradient, rapidly condensing into spherical droplets, ultimately obtaining spherical powder. The particle size range of the powder produced by this process can reach 20 - 50μm. In China, some well-known companies have already successfully applied this process. For example, the AlSi9Cu3 printing powder produced using this process has excellent high-temperature and corrosion resistance. Practical verification shows that under the SLM process, its mechanical properties are outstanding, with a tensile strength of up to 480MPa and a yield strength of up to 300MPa.

In summary,3DThe performance of printed metal powder is closely related to the particle size distribution and particle morphology. At the same time, the existing various production processes for powders have issues related to particle shape and size. This makes the detection of particle shape and size distribution, as well as the control of the production process, an important aspect in printing technology.3DIntroducing advanced particle size and morphology detection equipment to provide scientific data for process improvement, production control, and product quality inspection is imperative.

3. Common3DPrintingMetal powders

and titanium alloy powders

• Performance: High strength, low density, high specific strength, meaning a high ratio of strength to weight; good corrosion resistance, not easily corroded in various harsh environments; excellent biocompatibility, good affinity with human tissues, and does not cause significant immune reactions.
• Application: In the aerospace field, used to manufacture key components such as engine blades and landing gear, which can reduce the weight of aircraft and improve performance; in the medical field, widely used to manufacture artificial joints, dental implants, orthopedic fixation devices, etc.

Stainless steel powder

• Performance: Good corrosion resistance, can resist the erosion of various chemicals; good strength and toughness, can withstand a certain degree of deformation without breaking while ensuring structural strength; relatively good processing performance, easy to3Dprint and form.
• Application: Commonly used to manufacture mechanical parts, such as gears, shafts, etc., meeting the usage requirements in general industrial environments; in industries such as food and chemicals that require hygiene and corrosion resistance, can be used to manufacture components like pipes and reaction vessels; can also be used to manufacture architectural decorative components, such as door handles and decorative moldings.

Aluminum alloy powder

• Performance: Low density, lightweight, can effectively reduce the weight of components; high specific strength, can maintain a certain strength while reducing weight; good thermal and electrical conductivity, excellent heat transfer and electrical conduction performance; high processing efficiency, fast forming speed.
• Application: In automotive manufacturing, used to produce engine blocks, body structural components, etc., achieving lightweight vehicles and improving fuel economy; in aerospace, can manufacture components such as aircraft wings and fuselage frames; in the electronics field, used to manufacture heat sinks, casings, etc., facilitating heat dissipation and reducing weight.

Cobalt-chromium alloy powder

• Performance: Extremely high wear resistance, can maintain surface integrity during long-term use and friction; strong corrosion resistance, can stably exist in complex chemical environments; good biocompatibility, non-toxic, and does not adversely affect the human body.
• Application: Mainly used in the medical field, such as manufacturing artificial joints, capable of withstanding long-term wear and corrosion from physiological environments; in dental restoration, used to make crowns, bridges, etc., providing good support and chewing function.

Nickel-based alloy powder

• Performance: High strength at elevated temperatures, can maintain good mechanical properties in high-temperature environments; excellent oxidation and corrosion resistance, can operate stably under harsh conditions such as high temperature and oxidation; good thermal stability, with minimal performance fluctuations during temperature changes.
• Application: In the aerospace field, used to manufacture high-temperature components of engines, such as turbine blades and combustion chambers; in the energy sector, can be used to manufacture high-temperature reactors and gas turbine components in petrochemical processes, capable of reliable operation in high-temperature, high-pressure, and highly corrosive environments.

Copper and copper alloy powder

• Performance: Excellent electrical and thermal conductivity, making it an ideal material in electrical and thermal conduction fields; has certain corrosion resistance, can remain stable in specific environments; good plasticity, easy to process and form.
• ApplicationIn the electrical field, used for manufacturing wires, cables, electrical connectors, etc., it ensures efficient current transmission; in electronic devices, used for manufacturing heat sinks, chip packaging, etc., it can quickly dissipate heat; in the art field, it can be used for3Dprinting art sculptures and other works, utilizing its good formability and unique color.

Iron-based alloy powder

• PerformanceCost is relatively low, with high strength and hardness, meeting the strength requirements of general engineering structures; it has certain wear resistance and corrosion resistance, maintaining stable performance in conventional usage environments.
• ApplicationWidely used in the mechanical manufacturing field for producing various mechanical parts, such as gears, cams, shafts, etc.; in mold manufacturing, it can be used to make injection molds, stamping molds, etc., capable of withstanding certain pressure and wear.

Precious metal powder

• PerformanceHas unique physical and chemical properties, such as gold's high chemical stability, making it difficult to oxidize; silver's conductivity and thermal conductivity rank among the best of all metals; platinum has good catalytic performance.
• ApplicationIn jewelry manufacturing, used for printing complex and exquisite jewelry styles; in the electronic packaging field, utilizing its excellent conductivity and stability, it can be used to manufacture packaging materials for high-end electronic components; in the chemical catalysis field, precious metal powders like platinum can be used as catalysts to accelerate chemical reactions.

Magnesium alloy powder

• PerformanceHas an extremely low density, being one of the lightest common metals, with high specific strength and stiffness; has good shock absorption performance, effectively absorbing vibration energy; however, it is chemically active and easily oxidizes in the air.
• ApplicationIn the aerospace and automotive fields, used for manufacturing structural parts with extremely high weight requirements, such as internal structural parts of aircraft, dashboard supports of cars, etc.; in electronic devices, it can be used to manufacture lightweight shells, providing certain strength and shock absorption performance while reducing weight.

Tungsten alloy powder

• PerformanceHas an extremely high melting point, being one of the most difficult metals to melt; has a high density, reaching16 - 19g/cm³, high strength and high hardness, maintaining good mechanical properties under high temperature and high pressure.
• ApplicationIn the aerospace field, used for manufacturing high-temperature resistant parts of engines, missile warhead weights, etc.; in the defense field, can be used to manufacture armor-piercing projectiles, shielding materials, etc.; in the electronics industry, can be used as high melting point electrode materials and electronic packaging materials.

3D printing metal powder details