Impact of additive manufacturing on maritime transportation: a review

Abstract

Purpose

Although additive manufacturing (AM; 3D printing/3DP) is presently in its infancy, once it becomes economically viable for mass production, it would revolutionize the operation and supply chain network of traditional businesses and manufacturing industries. To this end, approaches for ensuring a smooth transition of the economy, businesses, manufacturing centers and related services are being investigated. This review paper assesses the existing literature on the impact of AM on the maritime transportation sector.

Design/methodology/approach

This paper provides a systematic literature review through three methodological phases: (1) a comprehensive review of the number of English language literature studies published on the topics of AM or 3DP (1970–2021); (2) a bibliometric analysis of selected keyword combinations and (3) a detailed review on the impact of AM on different sectors.

Findings

The key findings are that existing studies do not attempt to forecast shipping volume and ton-miles that can be affected by the mainstreaming of the technology. Additionally, existing literature that focuses on the impact of the technology on different shipping categories is limited to studies on container ships.

Originality/value

The review identifies some potential areas of research that since maritime transportation will be affected by mainstreaming AM, it will have economic, social and environmental impacts on global trade that require future assessment.

Citation

Teweldebrhan, B.T., Maghelal, P. and Galadari, A. (2022), "Impact of additive manufacturing on maritime transportation: a review", Journal of International Logistics and Trade, Vol. 20 No. 4, pp. 190-209. https://doi.org/10.1108/JILT-06-2022-0017

Introduction

With the increase in investment, technological advancement and mainstreaming of additive manufacturing (AM) (3D printing/3DP), foreseeable future changes will be observed in the structure of many traditional businesses, manufacturing processes and transportation industries (Attaran, 2017a; Gao et al., 2015; Huang et al., 2013; Mashhadi et al., 2015; Niaki and Nonino, 2017; Oettmeier and Hofmann, 2016). Many scholars consider the technology as having the power to question the state of existence of many industries, whether annihilating or massively disrupting their processes (Abeliansky et al., 2020; Boon and Van Wee, 2018; Kubáč and Kodym, 2017; Leering, 2022). Particularly, the world's trade network, supply chain and logistics, and cargo transportation industries will be greatly affected (Abeliansky et al., 2020; Attaran, 2017b; Birtchnell et al., 2012; Boon and Van Wee, 2018). New industries and businesses will emerge due to the mainstreaming of this novel technology (Gao et al., 2015; Gupta et al., 2012; Niaki and Nonino, 2018). To understand the transition from traditional manufacturing systems to AM technology and to minimize the adverse effects it can create, advanced studies on its impact are necessary (Gao et al., 2015; Gupta et al., 2012). One of the industries highly affected by the advancement of AM is the supply chain network of traditional manufacturing industries (Attaran, 2017b; Birtchnell et al., 2012; Durach et al., 2017b; Thomas, 2016). Of all the transportation systems, maritime shipping is responsible for the transportation of the majority of the goods and raw materials globally (Rodrigue, 2020).

Currently, AM is in its infancy stage. Once this novel technology becomes viable, it will lead to future changes in the structure and supply chain operation of businesses (Attaran, 2017a). There are numerous acknowledged studies on the topic of AM technology. Until the last decade or so, almost all of the studies were focused on the technology's applications, such as producing functional parts and finished goods in many industries (Caviggioli and Ughetto, 2019; Durach et al., 2017b). Many scholarly publications have dealt with the impact of the technology on traditional manufacturing systems and their supply chain networks. Specifically, the studies on the impact of the technology in different sectors such as spare parts industries, supply chain systems, business models and its numerous social, economic, geopolitical, security and environmental consequences have substantially increased (Caviggioli and Ughetto, 2019). The maritime and shipping industry, one of the streams of logistics and supply chain networks, is expected to be revolutionized by the mainstreaming of AM. It is reported that the industry is serving more than 90% of global trade and providing employment to an estimated 1.65 million seafarers worldwide (ICS, 2022; UNCTAD, 2021). A recent study showed that AM has the potential to reduce the transportation of finished products and increase the shipping volume of raw materials (Teweldebrhan et al., 2022). Consequently, it can significantly impact maritime communities (shipping owners, manufacturers and operators), traditional manufacturing industries and businesses. Hence, a study that summarizes the existing literature on the impact of AM in maritime transportation and identifies potential ideas for additional research is vital. To date, limited studies have focused on the maritime industry, and to our knowledge, no study has reviewed the present knowledge on the impact of AM on the maritime industry. To fill this gap, a systematic literature review is conducted. An approach with three methodological phases is used. In the first phase, the trends on the record of articles, reviews and conference papers on AM are presented. This phase provides the overall picture of the evolution and significance of the technology. In the second phase, a bibliometric analysis of the relevant keywords is conducted. In the last phase, an exploration of the existing literature on the impact of AM on manufacturing industries, global trade, transportation and specifically the maritime transport industry is conducted.

Review context

Maritime transportation is a derived demand that corresponds strongly with supply chain management (SCM), and AM is likely to identify several key parameters of this demand; as more products are printed locally, changes in the demand for container shipping and their routes will occur (Chen, 2017; Teweldebrhan et al., 2022). Currently, the world's largest ten seaports are in Asia, seven of which are in China, as global manufacturing is making use of economy of scale. Since AM will disrupt the economy of scale for certain products, their supply chain will be impacted (Chan et al., 2018).

According to the International Maritime Organization (IMO, 2022) and the International Chamber of Shipping (ICS, 2022), maritime transportation is vital for trade and international commerce (Sanchez-Gonzalez et al., 2019). It is estimated to cover over 90% of the world's trade and is responsible for the most cost-effective approaches toward transporting goods and raw materials globally on a large scale (ICS, 2022). Moreover, the IMO and United Nations Conference on Trade and Development (UNCTAD) report that there is continuing growth in maritime transportation demand contributed by factors such as population growth, increased standard of living and rapid industrialization (Ortiz-Ospina et al., 2018). Considering these facts, maritime transportation remains the lifeline of global trade and is one of the most globalized industries in terms of ownership and operations (Anheier and Juergensmeyer, 2012). The 2019 UNCTAD report indicates that there are approximately 95,402 registered ships, which account for 1.97 billion dead-weight tons of capacity (Sirimanne et al., 2019). Nonetheless, the industry is experiencing challenges due to significant economic disruptions, geopolitical instability, environmental regulations, pandemics (such as COVID-19) and uncertain customer demands (Millefiori et al., 2021; Panayides and Song, 2013).

Owing to these global requirements and constraints, the industry's operators undertake efforts to increase their capacity and lay a strong foundation of sustainable practices in their operations. These new challenges fast-track the need for economic restructuring, management reorganization and technological innovation. In turn, this reorganization and restructuring can profoundly affect various industries including maritime transport (Panayides and Song, 2013). The future of maritime transportation is imperiled by the emergence of novel technologies such as AM, drones, rockets (e.g., SpaceX) and hyperloop tunnels (Boon and van Wee, 2018; Laplume et al., 2016; Teweldebrhan, 2020). According to Manners-Bell and Lyon (2012), AM technology could reverse the trend of globalization, which has benefited maritime transportation, airlines and freight forwarders because large quantities of consumer goods are being transported on a global scale.

Although experimenting with AM technology dates back to the 1960s, its commercialization began with the invention of technologies such as CAD, lasers and controllers during the 1980s. Since then, different manufacturers experimented with AM technology and witnessed its potential to revolutionize the way products are designed, manufactured and distributed (Gao et al., 2015). Despite its benefits, however, the technology is compounded with several challenges that would require further research and technological development. Size limitations, slow fabrication speed, and high machine and production costs are some of its current challenges (Attaran, 2017a). Moreover, the limited number of AM materials, lack of knowledge and skills, poor quality and cybersecurity risks are some of the challenges to the implementation of the technology (Gao et al., 2015; Malik et al., 2022). Moreover, the fabrication of weapons, drugs for criminal activities and high energy consumption are considered as some of the negative aspects of the technology on the society and environment (Gao et al., 2015; Ford and Despeisse, 2016; Malik et al., 2022). The adoption of AM depends on technological improvements in the field, and hence, it is difficult to predict the share of 3D printed items in the manufacturing industry (Attaran, 2017a). At present, data on the value of goods and services produced by AM machines are unavailable (Teweldebrhan, 2020). However, the technology is likely to replace traditional manufacturing and international trade once it becomes economically viable, and mass production is performed using high-speed printers (Leering, 2022). Furthermore, it can disrupt and restructure the current global supply chain (Abeliansky et al., 2020; Birtchnell et al., 2012; Boon and Van Wee, 2018). AM technology can eliminate the need for high-volume production facilities and the number of assembly workers, thereby eliminating at least 50% of the supply chain (Kubáč and Kodym, 2017). Accordingly, this technology would be a game-changer and would introduce a new industrial revolution by transforming production processes. Consequently, with the current increase in investments, technological advancement and the acceptance of the technology, new businesses would emerge and well-established businesses would fail (Kubáč and Kodym, 2017). Manufacturing plants would be located nearer to customers, which would decrease the degree of complexity of the supply chain networks (Janssen et al., 2014). This would, in turn, severely impact the transportation system, which is the main backbone of the traditional supply chain and logistics industry (Galadari, 2008).

Review methodology

This paper attempts to provide a systematic literature review that encompasses three methodological phases (Figure 1), similar to those used in some reviews (e.g. Chopra and Meindl, 2007; Durach et al., 2017a; Mouschoutzi and Ponis, 2022; Wamba et al., 2015). This multi-phase system provides a comprehensive overview of literature related to a research question and efficiently enables the filtration of a large number of articles in each phase of the review process (Williams et al., 2021). Reviews using this method have proven to be explicit and transparent, reducing biases (Briner and Denyer, 2012; Williams et al., 2021). In the first phase, to have a bigger picture of the number of annual publications related to AM or 3DP, supply chain and maritime, a broad search is conducted using the SCOPUS database of which a larger number of journals are indexed when compared to other databases, such as Web of Science (Mouschoutzi and Ponis, 2022). A timeframe ranging from 1986 to the end of 2021 was considered to represent the period covering the emergence of AM or 3DP. This phase analyzes the overall significance of AM technology and industries. Furthermore, it gives a clear picture of the annual trend of publications for the past 35 years.

The following search strategies (or steps) were conducted: (1) filter papers (mainly articles, conference papers, reviews, book chapters and conference reviews) that have the exact phrase of selected keywords (discussed in the subsequent section) within the paper's title, abstract and keywords; and (2) present a graphical and tabular summary of the key highlights of the search. In the subsequent phase, additional search terms were used to identify literature discussing the impact of AM. The search terms are based on certain keywords that are selected to lead the search from the broader search in phase 1 into a targeted and in-depth search in phase 3. Finally, a review is conducted on the impact of AM on areas related to the topic of interest such as the traditional manufacturing industry, global trade, supply chain and logistics, and maritime transportation.

Results and discussion

Descriptive statistics

This section describes the descriptive statistics and provides an overview of the trends in the annual number of publications of the three most important keywords of this study: AM/3DP, supply chain and maritime (shipping). To gain a better insight into the screening procedure of the review, it is deemed appropriate to provide statistics on the initial search results of these three keywords. This initial analysis result shows the distribution of documents by year, document type, country/territory and subject area.

The actual search in SCOPUS database was performed by using the following search string (for the 3DP): TITLE-ABS-KEY (“3D printing” OR “Additive Manufacturing”) AND (EXCLUDE (PUBYEAR, 2023) OR EXCLUDE (PUBYEAR, 2022)) AND (LIMIT-TO (PUBSTAGE, “final”)) AND (LIMIT-TO (DOCTYPE, “ar”) OR LIMIT-TO (DOCTYPE, “cp”) OR LIMIT-TO (DOCTYPE, “re”)) AND (LIMIT-TO (LANGUAGE, “English”)). The same searches were made by changing the term “3D printing” OR “Additive Manufacturing” in the above search string with “Supply Chain” and “Maritime” OR “Shipping.” Documents (mainly articles, conference papers and reviews) that were published between 1986 and 2021 are filtered. It can be seen from the string that the search limits the documents that are published in English languages and neglects those articles that are still in press. Based on this search string, a total of 59,580, 101,563, and 71,187 documents are recorded for 3DP, supply chain and maritime keywords, respectively. Out of these records, almost 99.25% (58,778 records), 76.26% (77,457 records) and 64.91% (46,205 records) of the studies on the topic of 3DP, supply chain and maritime (respectively) were made over the past 11 years (2010–2021).

Figure 2 illustrates the distribution of the published articles over the selected period. As can be seen from the figure, no records were found before 1986 for 3DP. The paper published in 1986 discussed the AM process of wiring boards and evaluated its performance (Akahoshi et al., 1986). A clear rise in the number of publications has been recorded since 1986. In the past seven to eight years, the annual number of publications on AM (3DP) has sky-rocketed and the maximum is observed in 2021 with a record of 14,001 articles. In fact, Figure 2 shows that the study on AM (3DP) is significantly increasing noting the popularity and importance of the studies in this technology in the past few years. The study on the maritime industry, one of the oldest and most critical transportation systems (Teweldebrhan et al., 2022), had 548 records in 1986 when 3DP had only 1 record. Since then, the study on the maritime industry has shown a relatively slower growth compared to the study on 3DP. The record on the study of supply chain showed significant growth, albeit rather still slower than the study on 3DP.

Figure 3 presents the share of document types (articles, conference papers and reviews) from the search. Almost 62–66% of the recorded documents are articles, while conference and review papers cover the remaining 29–32% and 5–6%, respectively. Approximately, the same proportion in percentile of document types is observed for the three keywords. The United States, China, the United Kingdom and Germany are among the top five contributors to those studies. Almost half of the studies on 3DP have been made in the US and China, which contributes to 31 and 18% of the total records, respectively (Figure 4). Documents in the field of engineering are dominant in all of the three topics. Materials science, business and social sciences are the second top contributors to the study of 3DP, supply chain and maritime, respectively. Table 1 shows the list of the top (1–14) leading fields of study.

Analysis based on selected keywords

To narrow down the review, certain keywords are selected and used to filter the relevant papers. Table 2 illustrates the keywords added in the TITLE-ABS-KEY search box (in combination with the string used in the previous section). For each added keyword, Table 2 presents the number of documents filtered along with the provision of the top three most cited documents in the obtained list. Most of these studies focused on the application of the technology to produce functional parts and finished goods in many industries (Durach et al., 2017b). For example, the three most cited papers in AM are related to the potential application of the technology, particularly in the medical and metal industries (DebRoy et al., 2018; Frazier, 2014; Murphy and Atala, 2014). The most cited topics considering the keyword “Impact of 3DP” are mainly about the impact of the technology on the aircraft spare parts supply chain (Liu et al., 2014), business model innovation (Rayna and Striukova, 2016), numerous social, economic, geopolitical, security and environmental consequences (Pîrjan and Petroşanu, 2013), and the international supply chain (Zhen, 2016) (Table 2).

Advantages of additive manufacturing

Table 3 summarizes the significant advantages of AM over traditional manufacturing and its supply chain, as identified from the reviewed literature (Attaran, 2017a, b; Chan et al., 2018; Gao et al., 2015; Khajavi et al., 2014; Kubáč and Kodym, 2017; Mohr and Khan, 2015).

Challenges of additive manufacturing

Despite its benefits, the technology has a few drawbacks that would require further research and technological development. Table 4 summarizes some of the barriers as listed in Abdulhameed et al. (2019), Berman (2012), Chen et al. (2015), Ford and Despeisse (2016), Gao et al. (2015), Huang et al. (2013), Malik et al. (2022), Ngo et al. (2018), Petrick and Simpson (2013), and Petrovic et al. (2011).

Impact on manufacturing technology and industrial strategies

The First Industrial Revolution started during the late 1700s and early 1800s (Ashton, 1998). Manufacturing processes were transformed from mechanical production to mass production in the late 1800s (Second Industrial Revolution) and then to automated manufacturing in the 1960s (Third Industrial Revolution) (Hudson, 2014; Jamwal et al., 2021). Throughout the past 250 years, the manufacturing industry has played a significant role in the enhancement of the global economy and job market (Jamwal et al., 2021). According to an International Monetary Fund (IMF) report, the manufacturing sector accounted for almost 16% of the global gross domestic product (GDP) in 2018 (UNCTAD, 2019). The manufacturing industry is presently on the verge of the Fourth Industrial Revolution, driven by novel technologies such as AM, artificial intelligence, advanced robotics and smart devices. The predicted impact of AM on the global manufacturing industry would vary from industrial transformation to an alteration of certain aspects of production processes (Gao et al., 2015; Laplume et al., 2016). Based on the present and future diffusion of AM technology, these manufacturing industries can be classified into either of three categories (Table 5): (1) those that cannot adopt the technology, (2) those that presently utilize it and (3) those that are likely to adopt it (Laplume et al., 2016).

Leering (2022) indicates that 3DP is presently used in five industries: aerospace and defense, automotive, medical and dental, consumer products (electronics) and industrial machinery. These industries are the largest buyers of 3D printers and related services. According to the report, medical and dental devices and aerospace are the leading industries in terms of the use of 3D printers. Thus, various papers have reported studies on the suitability (feasibility and cost-effectiveness) of AM technology in these industries. Reports predicted that the global market for AM products will reach USD 23.75 billion by 2027 (Luniya and Chimata, 2021). One of these studies identified the potential benefits of AM in the automotive market by providing individualized spare parts without requiring expensive tooling (Beiderbeck et al., 2018). Another study identified the limited effectiveness of 3DP for spare part industries under the conditions of high-demand and multi-item scenarios wherein printing is performed in-house (Arbabian and Wagner, 2020). Other studies explored the potential of 3DP technology in maritime spare part manufacturing (Kostidi and Nikitakos, 2017; Kostidi et al., 2021; Taş and Şener, 2019; Vujovic et al., 2018).

Impact on global trade

Globalization is the process of integrating national economies into a global economic system (Feenstra, 1998). This integration enables the continual growth of trade between countries. Unlike the first wave of globalization, where trade was driven by colonialism, the second wave was driven by technology and a decrease in transportation costs (Feenstra, 1998; Ortiz-Ospina et al., 2018). Between the periods 1930 and 2005, international trade recorded a 32-fold growth (Ortiz-Ospina et al., 2018; UNCTAD, 2019). A report published in 2018 also indicates that contemporary exports are more than 40 times larger than those in 1913 (Ortiz-Ospina et al., 2018). UNCTAD broadly distinguishes international trade as trade in goods (merchandise) and services (UNCTAD, 2019). Approximately 77.3% of the international trade in 2017 was in goods (Ortiz-Ospina et al., 2018). Global trade in goods increased dramatically over the past decade, mostly driven by the global manufacturing industry. However, the advancement of AM and the cross-border trade in intermediates and final goods would reduce significantly (Drake-Brockman et al., 2020). Leering (2022) predicts AM technology could be the source of 50% of manufactured products either by 2060 (assuming continuation of the current growth rate of AM) or 2040 (assuming accelerated growth). Furthermore, it could result in a 22% (40%) reduction in the overall world trade in goods (services) compared with world trade without 3D printers, as AM enables more local manufacturing (Leering, 2022). In addition, the quantity of raw materials required would be reduced because it results in less wastage (Leering, 2022).

Abeliansky et al. (2020) indicate that the mainstreaming of AM could counteract the ongoing globalization trend, and it could reduce the importance of shipping parts and components at the global level and result in what is known as “glocalization.” Chen (2017) indicates that the broader adoption of 3DP would reduce the total demand for crude oil by approximately 10%. In contrast to the above studies, Freund et al. (2020) indicate that AM has resulted in an increase in the trade of hearing aids (an industry that transformed its production to AM in less than 500 days in the mid-2000s) by 58% relative to the baseline, over nearly a decade earlier. The study is based on 35 products that are increasingly using AM. The conclusion drawn by additional literature indicates that the universal application of AM technology has the potential to reduce the volume of goods transported and, hence, emboldens the reduction in international trade by reconfiguring the supply chain (Chen, 2017; Khajavi et al., 2014; Kubáč and Kodym, 2017; Mohr and Khan, 2015; Zhen, 2016).

Impacts on global logistics and supply chain

Logistics and supply chains are becoming highly complex and challenging in the contemporary global economic system, where the exchange of goods is practiced in terms of inter-industry and intra-industry trade (Gibson et al., 2021; Ortiz-Ospina et al., 2018). The global logistics and SCM industries are the circulatory system for traditional manufacturing and international trade (Galadari, 2008; Gibson et al., 2021) and, hence, will be impacted by AM. With the adoption of AM, manufacturing sites would shift to locations near customers and eliminate traditional supply chain facilities, such as manufacturing, assemblage, distribution, warehousing and retail sales facilities (Kubáč and Kodym, 2017; Sanchez-Gonzalez et al., 2019; Akbari and Ha, 2020). This would compel existing supply chain networks to restructure and, thus, result in a decrease in the total freight volume and cost of the chain (Chan et al., 2018; Chen, 2017). The logistics industry would be restructured extensively causing the involvement of fewer suppliers upstream of the supply chain. Furthermore, it can introduce build-to-order (customizable) production strategies downstream of the supply chain. This would result in a fusion of sectors of the logistics industry and the evolution of a new type of logistical organizations (Xiong et al., 2022).

Certain studies indicate that AM technology would reduce the volume of goods transported and alter the existing supply chain network (Chen, 2017; Khajavi et al., 2014; Kubáč and Kodym, 2017; Mohr and Khan, 2015; Zhen, 2016). Chen (2017) demonstrates that the total freight volume and cost of the international supply chain would be substantially reduced. Kubáč and Kodym (2017) indicate that the technology has the potential to contract the supply chain by at least 50% and, thereby, eliminate the need for high-volume production amenities and low-level assembly workers. Thus, the implications of AM technology include (1) a reduction in the trade volume and the cost and complexity of the supply chain network, and (2) an alteration of the direction of flow. For instance, the technology may cause manufacturing activities to move from Asia to North America and Europe, which could lead to a drop in the volume of shipping and air cargo in both tons and ton-miles (Manners-Bell and Lyon, 2012).

Mohr and Khan (2015) observed that although the future development of 3DP technology is uncertain, it could emerge (in the shorter rather than longer-term) as one of the most disruptive innovations in the global supply chain and logistics industry. Bhasin and Bodla (2014) illustrated that AM technology has the potential to reduce the cost of the supply chain by 50%–90%. However, Chan et al. (2018) argued that 3DP technology is not ready for mass-scale applications and concluded that the technology has not been as widely deployed as many studies had predicted. Nonetheless, this does not preclude a wider use of the technology in the long term.

Durach et al. (2017b) demonstrated that the five leading AM processes (powder bed fusion, directed energy deposition, material jetting, material extrusion and vat photopolymerization) are likely to play a leading role in the impact of AM on the supply chain, thereby indicating that the other two processes (sheet lamination and binder jetting) are not significant for the present or the future. Khajavi et al. (2020) analyzed the changes in the supply chain before and after the implementation of AM. Their study was conducted based on interviews to analyze the supply chain complexity in the case of three companies. Other studies focused on the impact of AM technology on the supply chain structure. For example, Mohr and Khan (2015) identified the seven key areas of the supply chain that are most likely to be affected by the technology: mass customization, resource efficiency, decentralization of manufacturing, complexity reduction, rationalization of inventory and logistics, product design and prototyping, and legal and security concerns. Kunovjanek and Reiner (2020) investigated the impact of AM on the raw material supply chain process and observed a reduction in raw material inventory by approximately 4%. Arbabian and Wagner (2020) identified and quantified the economic and competitive benefits of the technology in a simple supply chain comprising manufacturers and retailers.

Other studies focused on the impact of AM on the supply chain network of specific industries (merely those presently affected by AM technology). Khajavi et al. (2014) quantitatively analyzed and compared the impact of 3DP on the supply chain of spare parts based on the total cost of new and traditional supply chain systems. Liu et al. (2014) investigated the impact of AM on the supply chain of aircraft spare parts based on quantitative data and a supply chain reference model. The results of the investigation of three scenarios (conventional, centralized and distributed AM supply chain) indicate that the technology would play a substantial role in the reduction of the required safety inventory of aircraft spare parts in the supply chain network. Chen (2017), for example, analyzed the likely deviations in the supply chain of sneakers. The outcome of the study indicates that the supply chain of sneakers would be altered significantly in terms of flow direction, speed and volume.

Impact on the maritime transport industry

Scholars are becoming increasingly interested in integrating logistics and SCM concepts to address the rapidly changing role of seaports to solve contemporary challenges (Panayides and Song, 2013). However, the evolution and mainstreaming of the promoters of the Fourth Industrial Revolution questions the future of the manufacturing industry, whether it shall be evolutionary or revolutionary (Boon and Van Wee, 2018; Laplume et al., 2016). AM and other modes of digital production will promote the realization of the upcoming industrial revolution that could disrupt the future maritime, air and land freight transport (Gao et al., 2015; Kostidi and Nikitakos, 2017; Mckinnon, 2016; Sanchez-Gonzalez et al., 2019). Nevertheless, the existing literature on the impact of AM on the maritime transport industry is limited. Studies that incorporate the two key terms “AM (or 3DP)” and “maritime industry” were focused on exploring the potential of AM technology in supplying spare parts to the maritime industry rather than the future of the world trade network (Jha, 2016; Junghans et al., 2021; Kostidi and Nikitakos, 2017; Kostidi et al., 2021; Sanchez-Gonzalez et al., 2019; Taş and Şener, 2019; Vishnukumar et al., 2021; Vujovic et al., 2018). As for the automobile and aircraft industries, AM technology has the potential to transform the industry's operation and introduce a new approach to manufacture the required spare parts (Cunningham and Marro, 2014; Kunovjanek et al., 2022).

With the advancement of digital production where goods could be sent to one of the operational units closest to the customer, it will eliminate the need for hardware to be shipped from afar (Szymczyk et al., 2018). However, little research is done in the assessment of the impact of AM on maritime container ships (Chen, 2017). Chen (2017) predicted that the total demand for global maritime transport would decline after the application of AM. Exports of finished products would decline in the traditional manufacturing countries, while digital manufacturing would increase in consumer countries, which could potentially affect the state and flow of maritime transportation (Manners-Bell and Lyon, 2012; Sanchez-Gonzalez et al., 2019). Recently, the impact of AM on car shipping supply chain logistics in the Middle Eastern region has been quantitatively studied predicting a 26–39% reduction in ton-miles of shipping by 2040 (Teweldebrhan et al., 2022). Moreover, the same study predicted a 29–45% shift in shipping volume due to swapping car carrier (roll-on/roll-off) fleets to bulk cargo fleet types.

Review summary

AM is currently used in the aerospace and defense, medical and dental, automotive, consumer products and industrial machinery industries (Kunovjanek et al., 2022). Although the first two are the leading industries in terms of the use of 3D printers, these are smaller in scale than the other three (automotive, consumer products and industrial machinery) (Leering, 2022). Most of the existing studies focus on the application of the technology in producing final products and do not focus on its impact on freight types and shipping volume.

Additionally, studying the future economic, social and environmental impacts is vital to achieve higher operational efficiency and better regional regulations to control seaport pollution (ESCAP, 1992; Hiranandani, 2014). The shipping industry has increased in size and now generates trillions of dollars of economic activity, whereby it employs over 1.65 million people and transports over 11 billion tons of cargo (UNCTAD, 2019). However, the scope and type of services gained from maritime transportation would be altered with the wide adoption of AM. This would, in turn, alter the economic and social advantages of this global industry. However, the existing literature barely explores this anticipated wave.

From the literature reviewed, it can be inferred that future studies that plan to investigate the impact of AM on maritime transportation should consider the following aspects: (1) the impact on each shipping type and evaluate the reduction in shipping volume (in tons and ton-miles); (2) swapping between different shipping types (e.g. roll-on/roll-off for shipping automotive vehicles might need to be swapped to container shipping for automotive raw materials instead); (3) future demand for transportable materials or goods; and (4) economic, social and environmental impacts.

Conclusion

AM or 3DP technology enables manufacturing companies and customers to produce final goods in a novel, convenient and efficient manner. Many industries would be transformed by the continuous increase in investment, technological advancement and acceptance of the technology. In particular, world trade, supply chain and logistics, and cargo transportation industries would be considerably affected. Currently, the technology is considered to be in its infancy from an industrial perspective. However, once it becomes economically viable and starts mass production, it would revolutionize the operations of traditional businesses and manufacturing industries and their supply chain networks (Attaran, 2017a). Hence, there is a primary need to develop scientific models that optimize the supply chain and construct life-cycle costing models for the affected industries (Teweldebrhan et al., 2022). Accordingly, the main objective of this literature review is to participate in the ongoing studies and assess the current level of research on the impact of AM on the maritime transportation industry.

Although the wide adoption of AM would considerably affect the global trade, supply chain, traditional manufacturing and transportation industries, the review reveals that most published papers on AM (or 3DP) mainly focus on the application of the technology in several industries (e.g. Durach et al., 2017b; Caviggioli and Ughetto, 2019). Some studies investigated its effect on traditional manufacturing processes (e.g. Attaran, 2017a; Szymczyk et al., 2018), and a few others emphasized its impact on the global supply chain (e.g. Abeliansky et al., 2020; Boon and Van Wee, 2018). The transportation of finished goods would be reduced irrespective of whether the technology is adopted in manufacturing industries or used directly by consumers. Products would be directly printed rather than being assembled from dozens, hundreds or thousands of globally procured parts. The scenario would be aggravated further when customers would start to produce (print) the desired product in their own homes.

Qualitative and tentative estimations from different studies indicate that AM would be able to eliminate half of the supply chain and would increase the risk for the businesses of air cargo, ocean container and truck freight transportation (Kubáč and Kodym, 2017). In particular, as the maritime transportation industry is currently responsible for over 90% of the global trade (ICS, 2022; UNCTAD, 2021), the mainstreaming of AM could affect its operation in terms of shipping volumes, routes and types. However, the existing literature that reports the studies on the impact of AM on maritime transport is limited (in terms of both quantity and scale). Studies are needed to determine the expected impact on shipping volume due to the mainstreaming of AM technology.

Furthermore, considering the different types of goods and their future demands, studies need to focus on the effect of the technology on different shipping fleet types. In addition, future expected trade partnerships and shipping routes should be identified and developed. The economic, social and environmental impacts of AM's influence on maritime transportation are another potential research area identified. The outcome of the proposed studies would contribute significantly to the maritime transportation industry in evaluating the potential advantages and losses from restructuring the supply chain network in terms of both volume and shipping types. Additionally, the studies would help shipping owners, manufacturers and operators to reconsider the future demand in terms of the quantity and type of fleets they need to own and manufacture.

Figures

Figure 1

The three phases of the review

Figure 2

Trend on the annual number of publications (1986–2021)

Figure 3

Records by document type

Figure 4

Number of documents in the top 10 countries

Table 1

Popular fields of research on the topic of AM (3DP), supply chain and maritime (Shipping)

No	Research field	3DP or AM		Supply chain		Maritime or shipping
		No. of records	Rank	No. of records	Rank	No. of records	Rank
1	Engineering	35,893	1	41,715	1	29,216	1
2	Materials science	27,131	2	4,378	11	3,639	12
3	Physics and astronomy	13,526	3	2,220	14	4,154	9
4	Computer science	11,393	4	30,454	3	10,137	5
5	Mathematics	4,128	5	10,034	7	3,946	11
6	Medicine	3,896	6	2,967	13	2,851	14
7	Energy	2,246	7	7,875	8	4,132	10
8	Business, management and accounting	1,539	8	35,974	2	4,842	7
9	Environmental science	1,428	9	11,087	6	14,143	3
10	Social sciences	1,286	10	12,437	5	16,636	2
11	Decision sciences	1,125	11	22,599	4	2,978	13

Table 2

Research summary based on keywords

No	Keyword	No. of records	Top 3 cited papers
			References	# of citations (resp.)
1	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”)	19,303	Gu et al. (2012), Thijs et al. (2010), and Gao et al. (2015)	1961, 1759, and 1,335
2	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND (“traditional manufacturing” OR “businesses”)	446	Ford and Despeisse (2016), Attaran (2017a), and Zocca et al. (2015)	677, 547, and 523
3	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND (“globalization” OR “global”)	336	Attaran (2017a), Klerkx et al. (2019), and Strange and Zucchella (2017)	547, 217, and 214
4	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND (“transportation” OR “transport”)	377	Thompson et al. (2015), Kim et al. (2018), and Uriondo et al. (2015)	615, 313, and 245
5	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND “Supply chain”)	218	Huang et al. (2013), Attaran (2017a), and Ivanov et al. (2019)	1,070, 547, and 474
6	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND (“maritime” OR “marine” OR “shipping”)	121	Thakur and Gangopadhyay (2016), Kreiger and Pearce (2013), and Liu et al. (2014)	337, 155, and 143
7	(“3D printing” OR “Additive Manufacturing”) AND (“international trade” OR “cargo” OR “freight”)	77	Ceylan et al. (2019), Bozuyuk et al. (2018), and Mohamed et al. (2016)	153, 146, and 111
8	(“3D printing” OR “Additive Manufacturing”) AND (“maritime transport” OR “marine transport” OR “shipping” OR “Containership”)	41	Kreiger and Pearce (2013), Liu et al. (2014), and Tang and Veelenturf (2019)	155, 143, and 137
9	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND (“maritime transport” OR “marine transport” OR “shipping” OR “Containership”)	13	Kreiger and Pearce (2013), Liu et al. (2014), and Varsha Shree et al. (2020)	155, 143, and 24
10	(“Impact” OR “Influence” OR “Effect”) AND (“3D printing” OR “Additive Manufacturing”) AND “international trade”)	8	Khare et al. (2017), Hertle et al. (2016), and Voet et al. (2021)	42, 39, and 19

Table 3

Advantages of additive manufacturing

No	Values	Major advantages
1	Cost-saving	Eliminates economies of scale
		Eliminates the need for high-volume production facilities
		Reduces transportation cost
		Eliminates the need for low-level assembly workers
		Reduces requirement of tools and machine centers
		Eliminates penalty for redesign
		Reduces the size of an economical lot
		Adopts more economical and effective packaging solutions
		Offers customized designs at a lower cost
		Eliminates the need for bulk inventories (Bullwhip effect)
2	Shorter delivery time	Models a highly straightforward supply chain
		Eliminates the time lag between design and production
		Shortens the lead time with a flexible production process
		Enables on-demand (custom) manufacturing
		Reduces supply chain inter-mediation
3	Production efficiency	Reduces production waste
		Enables rapid alterations to the design
		Improves product quality
		Incorporates customer feedback
		Eliminates excess parts that cause drag and adds weight
		Uses an appropriate digital file
		Manages demand uncertainty by collecting real-time information
		Offers a higher degree of freedom that yields an accurate and precise final product
		Ensures customer satisfaction
4	Reduced environmental impact	Reduces material and resource consumption
		Reduces carbon footprint
		Reduces waste generated (possibility as much as 90%)
		Increases efficiency (by reducing weight)
5	Miscellaneous	Minimizes accidents, ship hijack, and causalities encountered during shipping
		Eliminates scrapping and damage of finished products during transportation
		Enables supply during pandemics and wars
		Eliminates losses and wastage
		Allows for the emergence of new businesses
		Opens up new avenues for further technological advancements

Table 4

Challenges (barriers) of additive manufacturing

No	Constraint or barrier	Consequences or challenges
1	Material constraints	A limited number of AM materials; development and standardization of new materials are difficult and expensive
2	Lack of knowledge and skills	Deficits in designers and engineers, low manufacturing efficiency, divergence from design to execution
3	Quality constraints	Difficulty in regulating final AM products made by novices, poor accuracy, warping, pillowing, stringing, void formation, under-extrusion, layer misalignment, over-extrusion, elephant foot, the existence of anisotropy in microstructure and mechanical properties, low surface quality, staircase effect
4	Software barriers	Cybersecurity risks to design files, limited availability of digital designs
5	Environmental barriers	Support structure materials cannot be recycled
6	Cost barriers	High machine costs, high cost of acquiring new digital designs, and uncertainty regarding where AM is cost-effective
7	Machine barriers	Development of multi-material and multi-color systems, automation of AM systems, limited applications in large structures and mass production, limitation on the building of overhang surfaces
8	Time constraint	Fabrication speed is too slow and often requires post-processing
9	Others	Fabrication of weapons or drugs for crime purposes, intellectual property issues (particularly regarding patents)

Table 5

Manufacturing industry categories based on the present and future diffusion of AM

Manufacturing industries
Unlikely to be affected	Currently being affected	Likely to be affected in the future
Products made of natural materials such as solid wood, cork, leather, natural textiles and paper	Products such as jewelry, musical instruments, hearing aids, sports goods and toys, and medical instruments	Food, apparel and medicine
Production of most industrial raw materials such as petroleum products and basic metals	Products composed of a single raw material such as plastic, ceramics or a metal	Applications in synthetic textiles and wearable clothing
Industries that break down or fragment materials	The manufacture and repair of machinery and equipment	Manufacture of fabricated metal products
	Spare parts for machines	Computers, electronics, conductive materials and electrical equipment
		Motor vehicles and other transport equipment