At present, metal 3D printing technology mainly includes "powder bed selective melting" technology and powder/wire feeding "melting deposition" technology. Among them, the "powder bed selective melting" technology is suitable for the manufacture of small and complex components, while the "melting deposition" technology is suitable for the manufacture of large key load-bearing components for major equipment, but its technical difficulty is greater.
In order to achieve better results for 3D printing finished products, it is critical to accelerate the development and upgrade of materials supporting 3D printing technology. In-depth research on the basic issues of the preparation and forming of meta-materials such as molten pool metallurgy, solidification, thermophysics, solid phase transition, etc. in the melting deposition printing process is of great significance to the promotion and application of 3D printing technology.
Generally speaking, the metal powders used in metal 3D printers at home and abroad are: tool steel, stainless steel, martensitic steel, pure titanium and titanium alloys, aluminum alloys, nickel-based alloys, copper-based alloys, cobalt-chromium alloys, etc. Below, let us understand the next few types of subdivided materials together.
Titanium is a strong, lightweight, heat-resistant and chemical-resistant metal. Generally speaking, titanium is very challenging in processing, leading to its high cost. The common 3D printing titanium is Titanium 64 (Ti-6Al-4V), which can be used for parts processing with very high strength and weight ratio, such as applications in the aerospace field.
Nickel plays a key role in the electronic functions of mobile phone batteries and devices. It is the main component of the electronic circuit component of the mobile phone-the capacitor. It is reported that the new generation of capacitors abandon the expensive old technology, no longer use precious metals such as gold and palladium, but use multi-layer ultrafine nickel powder, which reduces the construction cost of components. The shape memory, electrochemical and magnetic properties of nickel can directly promote the development of science and technology. In innovative applications, the characteristics of nickel alloys also make it compatible with other elements and materials.
The characteristics of stainless steel are high mechanical strength and strong corrosion resistance. From the early industrial manufacturing to the application of 3D printing technology, the metal material is widely used in the production of various industries. 3D printing stainless steel materials mainly include heat-treatable 17-4 PH stainless steel and extremely corrosion-resistant 316L stainless steel. Among them, tool steel is used for various manufacturing tools. Any item on the cutting, stamping, molding or forming production line may be made of tool steel.
Pure titanium currently used in the market, also known as commercial pure titanium, is divided into grade 1 and grade 2 powders. Level 2 is stronger than level 1, and it is also corrosion resistant for most applications. At present, the main titanium alloys used in metal 3D printing are titanium alloy grade 5 and titanium alloy grade 23. Based on its excellent strength and toughness, combined with low specific gravity, corrosion resistance, and biocompatibility, it has broad application space in aerospace and automobile manufacturing.
Currently, aluminum alloys used in metal 3D printing mainly include AlSi12 and AlSi10Mg. Al-Si 12 is a lightweight additive-manufactured metal powder with good thermal properties and can be used in thin-walled parts. For example, heat exchangers or other auto parts can also be used in aviation industry-level prototypes and parts manufacturing.
The precious metals that can be 3D printed include silver, gold and platinum. These materials are usually soft, high gloss, and low chemical activity. In many cases, their conductivity is also very good. In addition to Concept Laser, Cooksongold is also one of the few companies that provide gold (yellow, white, pink) and platinum 3D printing. These materials are mainly used for jewelry and handicrafts.
There are relatively few types of refractory metals, including tungsten, rhenium, niobium, molybdenum, and tantalum. They are known for their high heat resistance, with melting points generally exceeding 2000°C, inactive chemical reactions, high density, and high hardness. Among them, tantalum has high corrosion resistance and very good conductivity, which has broad application prospects in the electronics industry. According to the Los Alamos National Laboratory, 60% of this material is used for vacuum furnace parts and electrolytic capacitors. In theory, tantalum can increase the radioactivity of nuclear particles.
The application fields of metal 3D printing materials are quite extensive. In general, aerospace, automobile manufacturing, injection molds, food processing, medical and health, electric power, light metal alloy casting and other fields are included. Of course, the classification of 3D printing metal materials is not limited to these, other printing materials also include rock, cement, paper and so on. With the continuous development of 3D printing materials, processes, and equipment, 3D printing technology will more effectively support my country's steady progress toward a manufacturing power.