Additive manufacturing— 3D Print

I. Industry Overview

         3D Print (3D Printing) , also known as additive manufacturing (Additive Manufacturing , abbreviated as AM) , which emerged in the 1990s. Unlike traditional “material-removal” machining methods, 3D 3D printing is a computer-aided manufacturing process that creates three-dimensional models through design, scanning, and other methods, then builds up the object layer by layer using discrete materials. ( Powders, wires ) A manufacturing and forming technique. 3D Most printing processes use spherical powder as the feedstock, which is selectively melted by a focused heat source and then solidified during subsequent cooling to form the printed part. 。

                      3D Print                                 3D Print product

  3D One of the main areas of printing is Aviation In the aerospace industry, modern jet engines comprise thousands of components, some of which—such as turbine blades—figure 1 ) Must comply with strict specifications and use a single material. Mold Manufacture. Use 3D Some of the engine components that have been printed include turbocharger impellers, blades, fuel nozzles, and other parts.

                                                                            (Figure 1)

II. 3D Printing technology Compared with Manufacturing Advantages of Traditional Manufacturing Technologies

      Current metal Compared with traditional precision machining, 3D printing technology still lags behind in terms of machinable materials, machining accuracy, surface roughness, and processing efficiency. However, its entirely new technological principles and manufacturing approach offer significant advantages that are unmatched by conventional precision machining, as evidenced by the following:

（ 1) Shorten the R&D and time-to-market cycle for new products. The 3D printing process is directly driven by a 3D model, eliminating the need for molds, fixtures, and other auxiliary tools. This significantly reduces product development time, cuts costly mold-making expenses, and accelerates the pace of product R&D and iteration.

（ 2) It enables the efficient fabrication of more complex structures. The principle of 3D printing is to decompose a complex three-dimensional geometry into two-dimensional cross-sectional shapes and then build up the part layer by layer; thus, it can produce intricate components that are difficult to achieve through conventional precision machining, thereby increasing part yield and improving product quality.

（ 3) Achieve integrated, lightweight design. The application of metal 3D printing technology can optimize the structure of complex components; while maintaining performance, it enables the transformation and redesign of intricate geometries into simpler forms, thereby reducing weight. Furthermore, 3D printing can realize the monolithic formation of components, enhancing product reliability.

（ 4) High material utilization. Compared with conventional precision machining, metal 3D printing can significantly reduce material waste, particularly for high-cost metal materials, thereby achieving substantial cost savings.

（ 5) Achieving excellent mechanical properties. Owing to the rapid solidification characteristic of 3D printing, the as-built parts exhibit uniform and dense metallurgical quality throughout their volume, with no other metallurgical defects; moreover, this rapid solidification results in a fine substructural microstructure, enabling significant strength enhancement in the fabricated components without compromising ductility.

III. 3D Current Status of the High-Temperature Alloy Powder Materials Industry for Printing

The preparation methods for spherical powders used in 3D printing include gas atomization, plasma torch atomization, rotary electrode atomization, and carbonyl processes. Among these, gas atomization is the most widely used.

1. Overview of the Mechanism for Producing Spherical Metal Powders via Gas Atomization

According to See and Dombrowski Research has shown that the gas atomization process is divided into three stages: primary breakup, secondary breakup, and spheroidization and solidification. These stages primarily encompass airflow distribution, alloy melting, melt breakup, spheroidization, and solidification, among others, as well as the gas atomization process itself and spray photographs. (Acquired by a high-speed camera) as shown in Figure 1. First, the airflow is accelerated through the atomization nozzle to form a stable flow field. When the molten metal stream comes into contact with this airflow, the high-velocity, high-pressure gas impinges upon and breaks up the liquid stream, converting the kinetic energy of the gas into surface energy of the metal droplets and thereby generating fine droplets. Under the drag force of the airflow, these droplets are propelled at high speed; during flight, surface tension causes them to assume a spherical shape, and they rapidly cool and solidify within the high-speed atomizing airflow to yield spherical powder particles.

                       Schematic diagram of the atomization process (a)                                                       Spray photo (b)

2. Metal Powder Materials

At present In the 3D printing industry, metal 3D printing accounts for a substantial share, and as the technology continues to mature and costs drop significantly, its scope, depth, and scale of application are constantly expanding. For instance, in the aerospace sector, metal 3D printing has progressed from producing test prototypes to full-scale batch production; in dentistry, 3D-printed metal crowns have become a standard practice in dental laboratories; in orthopedics, 3D-printed metal implants are now being deployed on a large scale; in mold-making and heat sink manufacturing, it is increasingly replacing traditional processes; and in the automotive industry, vast untapped application potential remains to be explored. 。

Metal Powder Materials

3. High-temperature alloy materials

Superalloys, also known as high-temperature alloys, exhibit excellent oxidation and corrosion resistance, superior tensile, creep, and fatigue properties, and long-term microstructural stability. They were developed to meet the demanding requirements of modern aerospace technologies under a wide range of high-temperature service conditions and have demonstrated remarkable viability in advanced aerospace engine applications.

Powder metallurgy superalloys are high-temperature alloys prepared by powder metallurgical techniques. Compared with conventional cast and forged superalloys, they exhibit a more uniform microstructure, absence of macrosegregation, and superior yield strength and fatigue performance, thereby overcoming the segregation issues inherent in traditional processing methods. (Non-uniformity) is eliminated because each particle of the pre-alloyed powder used functions as a “microscopic steel ingot,” allowing alloy segregation to occur only within the fine-scale structure of individual powder particles. This approach enhances the overall performance of the alloy, reduces the amount of machining required, and improves alloy utilization. In particular, as the compositions of high-temperature alloys become increasingly complex and component sizes continue to grow, powder metallurgy–based high-temperature alloys demonstrate even greater advantages. 。

IV. 3D printing Industry Development Trends

1. There is an urgent need for industrial financing, and the scale will exceed RMB 7 billion. According to statistics, in 2021 global additive manufacturing financing totaled RMB 65 billion, representing a growth rate of 66%. In China, total financing for additive manufacturing companies reached approximately RMB 4.8 billion, up 33.3% from 2020; however, both the overall investment volume and the investment growth rate still lag behind those in overseas markets. It is projected that in 2022, financing demand in China’s additive manufacturing sector will exceed RMB 7 billion.

2. Mid-range equipment components are poised for full domestic substitution. In recent years, Chinese additive manufacturing component manufacturers have steadily increased their R&D investment, and domestically produced components from companies such as Han’s Laser Technology and Wuhan Raycus are now in stable use in dental laser powder bed fusion and photopolymerization equipment. As demand continues to grow, the localization of component supply is accelerating, positioning mid-range equipment components for complete domestic replacement.

3. Industrial-grade additive manufacturing equipment is trending toward larger build volumes, higher efficiency, and greater specialization. Driven by technological advancements, process innovations, increasingly stringent application requirements, and the continuous expansion of use cases, additive manufacturing systems are progressively evolving to meet these demands. Meanwhile, in response to the distinct needs of sectors such as healthcare, construction, and cultural heritage preservation, domestic manufacturers have already introduced laser powder bed fusion systems for dental applications, stereolithography equipment specialized for replicating cultural artifacts, and robotic-arm-based material extrusion systems for construction.

4. The service market continues to expand, with sectors such as casting poised for explosive growth. According to data from the Wohlers Report, the share of international additive manufacturing service providers has been increasing year by year. In 2021, the global additive manufacturing services market was valued at approximately US$6.25 billion, accounting for 41% of the total market—underscoring the pivotal role that services now play in driving industry growth. By contrast, the number of domestic additive manufacturing service providers remains relatively small, representing only about 21% according to survey data from participating companies. Several domestically based service providers, such as Xinjinghe and Kangshuo Group, have already commissioned newly built facilities, and the domestic services market is expected to expand substantially in 2022. According to statistics from the China Foundry Association, China has roughly 26,000 foundries, with the sand-mold casting market valued at around RMB 120 billion; the adoption of additive manufacturing can streamline the casting process from 15 steps down to 8. Against the backdrop of the “dual carbon” goals, additive manufacturing technologies continue to empower the casting industry, and demand for sand-mold additive manufacturing equipment is projected to exceed 2,000 units over the next five years.

                                                                                         Revenue Performance of China’s Additive Manufacturing Industry, 2018–2021

V. Conclusion and Outlook

         Since its emergence in the 1990s, 3D printing technology has evolved from initially focusing on polymer materials to increasingly emphasizing metal powder-based printing, leading to the development and application of a wide array of new technologies, equipment, and materials. Today, driven by rapid advances in information technology, industrial production is entering a new era of intelligent and digital transformation, with 3D printing poised to serve as a powerful enabler of this shift. In recent years, significant progress has been made in high-temperature alloy powder-based 3D printing, which now finds extensive applications in aerospace, biomedicine, and the automotive industry. The 3D printing sector is expanding at a fast pace, with domestic industry revenue reaching RMB 26.5 billion and an average annual growth rate of 30% over the past four years; the number of enterprises above designated size has surpassed 100.

Currently, China’s high-temperature alloy powders 3D printing technology still faces numerous challenges: on the one hand, these include powder flowability and particle-size distribution, interaction with the heat source, the resulting layered microstructure, defect reduction, and more precise quantification of metallurgical characteristics; on the other hand, they encompass process-parameter optimization, real-time monitoring, establishment of qualification standards, high-throughput testing, and the fabrication of scaled-up components. The design of high-temperature-alloy powders for 3D printing must strike a balance among manufacturability, mechanical consistency, stability, and cost. Material bottlenecks will inevitably impede the widespread adoption of 3D-printing technology, which in turn places increasingly stringent demands on materials. The development of 3D-printed high-temperature-alloy powder materials is primarily oriented along three main axes: first, building upon existing materials to strengthen the correlation between material properties and microstructure, further optimize process parameters, increase printing speed, reduce porosity and oxygen content, and enhance the surface quality of printed parts; second, developing new materials specifically tailored for 3D printing, such as novel high-temperature-alloy powders that exhibit superior corrosion resistance, high-temperature resistance, and well-rounded mechanical performance; and third, revising and refining the technical standard system for 3D-printed powder materials, thereby institutionalizing and normalizing the standards for high-temperature-alloy printing technologies.

Six 、3D Precautions for Printing Compared with Traditional Manufacturing

Nanjing Jianchuanshi Industrial and Trading Co., Ltd. is a specialized provider of cutting tools and fixtures for mechanical machining and manufacturing, boasting an outstanding technical service team and a robust supply service system; targeting 3D The company boasts extensive experience in post-printing processing and conventional precision machining, with an excellent reputation and comprehensive technical service solutions in the μm-level machining field. 3 D The disadvantages of printing compared with traditional manufacturing, as well as the precautions for subsequent processing, are summarized as follows:

    1) Project Comparison

  2) Precautions for 3D Printing

    1. It is recommended to tap threads rather than print them directly (including both internal and external threads).

2. Wall thickness, groove width, and font size below 0.5 mm cannot be guaranteed to print successfully;

3. For assembled components, please be sure to request the assembly drawing; we will fully assemble the items before shipping. If no such request is made, we shall not be responsible for assembly.

4. For assembled products, a 0.15 mm gap must be maintained on each side.

5. For parts with stringent local assembly requirements (such as bearing bores, diameters, and planar mating surfaces), machining allowances shall be provided in advance, followed by secondary finishing to achieve proper fit.

6. After high-temperature sintering, certain slender, thin-walled, and shell-like structures produced via metal 3D printing may deform. The primary advantage of metal 3D printing lies in its ability to fabricate complex geometries; however, its dimensional accuracy and surface finish are inferior to those achieved through machining.

7. Natural surface with pitting (Ra approximately 7);

8. Post-processing of metal 3D-printed materials: Like conventional materials, they can undergo subsequent secondary machining and finishing processes.

9. For parts with dimensions within 50 mm, the printing tolerance is ±0.1 mm; for larger parts, the printing tolerance shall be determined on a case-by-case basis according to the engineering drawings.

10. For large components that require part-by-part printing, the parting lines must be carefully planned to avoid hole locations, account for deformation, and provide sufficient clearance for alignment during welding.

Nanjing Jianchuanshi Technical, Industrial and Trading Co., Ltd. May 10, 2023