# Academic Insights and Perspectives in 3D Printing: A Bibliometric Review
###### Abstract  
Research interest in three-dimensional (3D) printing has been greatly aroused since 1990 due to its outstanding merits, such as freedom of design, mass customization, waste minimization and fast prototyping complex structures. To formally elaborate the research status of the 3D printing field, a bibliometric analysis is applied to evaluate the related publications from 1990 to 2020 based on the Science Citation Index Expanded database and Social Science Citation Index database. The overview with detailed discussions is cataloged by keywords, citation, \(h\)-index, year, journal, institution, country, author, patent and review. The statistical results show that the United States plays a dominant role in this research field, followed by China and the UK. Singapore is the most productive country with the highest average citations per publication (ACPP), and the second most cooperative country. Among all the institutions, Chinese Academy of Sciences is most productive, and Harvard University has the highest ACPP and \(h\)-index. Among all the journals, _Materials_ ranks first in the number of publications in this field. The most attractive research area is \"Materials science, Multidisciplinary\", with 4053 publications. Moreover, the major hot topics derived from authors' keywords are \"3D printing\", \"additive manufacturing\" and \"tissue engineering\". Commercial and medical applications appear to be the initial driving force and end goal for the development of the 3D printing technology. 3D printing; multidisciplinary; bibliometric; additive manufacturing; Web of Science +
Footnote †: journal: _Applied Sciences_  
sports [23; 24], toy industries [25; 26; 27], food supply chains [28; 29; 30], agriculture [31], earth science [32] and robotics [33; 34]. The 3D printing manufacturing process was initially developed by [PERSON] in 1984 in a process named as stereolithography [35], which is the pioneer of all 3D printing technologies [36; 37], and one of the most popular rapid prototyping technologies for plastic fabrication. Technologies like powder bed fusion [38; 39; 40], fused deposition modelling (FDM) [41; 42; 43], inkjet printing and contour crafting (CC) [44; 45; 46] direct energy deposition (DED) [47; 48; 49] and laminated object manufacturing (LOM) [50; 51; 52] subsequently appeared with more advancements in this field after the stereolithography technology. Current 3D printing technologies are able to combine different materials in precise positions to achieve the multifunctional properties of the manufactured parts [53]. However, it faces a lot of challenges such as limited materials, high cost, inconsistent quality and regulatory issues [54]. The limitations of the exiting techniques spur the promotion of more advanced methods in 3D printing field. For instance, the multi-jet FDM method attracies increasing attentions in bio-printing of the complex hydrogel scaffolds with cells [55]. Moreover, multi-material manufacturing processes and multifunctional applications are achieved by the assists of the computer-aided design and optimization techniques [56]. The 3D-printing process concerning various novel materials, methods and equipment has been developing rapidly over the years, which reformed the traditional manufacturing processes that involve material removal or energy-intensive process [57; 58; 59; 60]. And it is quite an achievement that 3D printed prototypes or products have been commercially utilized in various industries [61; 62; 63]. A wide range of materials from cereal to advanced multifunctional materials in diverse forms of filaments, wire, powder, paste, sheets and inks can be fabricated thanks to the 3D printing technologies [64; 65]. Polymers like polyamide [66; 67; 68], polylactic acid [69; 70; 71] and polystyrene [72; 73] are among the most common composites in the 3D printing applications. Plentiful pylemetric materials are continuing coming forth for 3D printing with excellent mechanical properties by synthesizing other matrix material.