# Academic Insights and Perspectives in 3D Printing: A Bibliometric Review
## 3 Results  
### Global Contribution and Leading Countries  
As a result, 17,505 publications were collected from InCites data set, in which English is the most used language (99.18%), then German and Chinese. Since 1990, there are more than 118 countries involved in the 3D printing research field with 16,022 publications in article and 1483 in review, among them, 394 publications are Essential Science Indicators (ESI) highly-cited articles and 13 publications are ESI hot articles. Although 3D printing is a young industry, it has grown to almost $3 billion in value in 2012 [1]. As shown in Figure 1. The number of total publications per year was relatively small but quickly increased from 51 to 474 during 2009-2014, suggesting that this research domain started to attract more scientists and engineers during that time. The publications had more than doubled in the following year of 2015. Since then, the rising rate of yearly publications has been decreasing, but retained high percentages of 71%, 59%, 46% and 37%, respectively, in 2016, 2017, 2018, and 2019. The urgent needs of the industry and interests of the researchers has led to an enormous growth in this field in the last few years, which is reflected in the number of publications. The total number of published articles on this topic in the last three years is more than that in the first 27 years since 1990. \"3D printing\" has been widely adopted as a keyword in scientific articles since 2009, especially after 2014, as shown in Figure 2. The second most frequently used keyword is \"additive manufacturing\", followed by tissue engineering, bioprinting and rapid prototyping, which also to some extent indicates the popularity of 3D printing technology in the medical or biology. The top 10 countries contributing most publications in this field are shown in Table 1, and their proportions are presented in a pie chart, as shown in Figure 3. The United States, with 5546 articles, is the most productive country, followed by China (3914 articles) and the UK (1469 articles). The national development programs, research fundings and institutions played an essential role in the arena of 3D printing technology. For example, the National Science Foundation (NSF) in the United States has supported most influential researchers, roadmaps, conferences, networking events, patents, and manufacturing firms. It awarded almost 600 grants worth over 200 million dollars by 2005, promoting the emergence and development of 3D printing [106]. The National Additive Manufacturing Innovation Institute (NAMI or America Makes) [107], which was funded with $45 million in 2012, is the first national network of institutes that focuses on the development of the 3 Dprinting. The reasons for the mass output increase from China are the launching of initiative projects like \"Made in China 2025\" (108) and \"National Additive Manufacturing Industry Development Plan 2015-2016\", which have motivated the development of the domestic 3D printing manufacturing industry. An earlier development program launched in 2008, i.e., the Comac C919 aircraft (109), also needs massive parts from 3D printing and has presented tremendous technological demands. Moreover, China surpassed the UK and has occupied the second place in the number of publications since 2014, as shown in Figure 1. 3D printing in Europe, including the UK, has received European Union (EU) funding since the first Framework Programme (FP) (1984-1987). During 2007 and 2013, a total budget of around \(\upxi\)225 million spent on this field in EU, in which over \(\upxi\)160 million successfully supported more than 60 3D printing technology projects (110). Among the top 10 countries' publications, a large number (>39%) involve international cooperation, especially for France (56.11%), Australia (54.18%) and Singapore (53.69%). However, Singapore has the highest ACPP (23.00) that indicates its non-negligible influence in this field. Therefore, scientists and engineers involved deeply in the aspect of communication and cooperation in the 3D printing field.