leads to the advancements of 3D printing in biomedicine. Around 2005, the open‐source 3D printing project RepRap developed the first 3D printer capable of producing its part named RepRap Darwin (DIY 3D printers). RepRap introduces the word fused filament fabrication (FFF) that replaces the term FDM.
With the innovations of AM, the first 3D printed car was developed by Urbee in 2011, and then in 2013 3D printable gun was released (3DSourced 2021). Gradually the 3D printing moved from polymers to foods as National Aeronautics and Space Administration (NASA) experimented with 3D printing the foods for aeronauts in 2014 (Lipton et al. 2015). Meanwhile, the emergence of flexible new software enhances the mass production of 3D printers in 2017 and until to the present date. Beyond fashion jewellery and aircraft, 3D printing allows for the construction of affordable houses for the developing world. Still, many advancements are happening, and much research is going on in exploring the potential applications of 3D printing in different sectors.
1.5 Prospects of 3D Food Printing
The concept of 3D printing encompasses three key criteria: universal, practical, and efficient. With the development of information and technology, it becomes possible to print foods (one of the essential components for life) in the desired form by uploading a digital file to printers that deliver printed food (Bandyopadhyay and Heer 2018). The main purpose of applying this AM technology in food printing relies on the advantage of designing foods with newer texture, consistency, flavour, and taste with enhanced nutrition (Figure 1.3). A synergistic combination of material properties, chemical interactions, and binding mechanisms assist in achieving a stable 3D food constructs (Sun et al. 2018a). However, understanding material behaviour is cumbersome that stands to be a challenge in the food printing process since food is a complex substance with a wide variations in its physiochemical characteristics. Globally, several research works are going on in exploring the potential applications of 3D printing in the food sector. Researchers of the Netherlands Organisation for Applied Scientific Research (TNO) have explored the application of food ingredients for 3D printing and converted them to tasty, printed food products because of the health issues due to busy lifestyles and environmental concerns from depletion of resources. Similarly, NASA is exploring and developing 3D printed space foods for astronauts (Sun et al. 2015b).
The idea of customization aids in the delivery of food items as per the requirements and needs. Researchers have customized foods like pizzas and cakes with the idea of incorporating complex shapes and intricate designs using 3D printing technology. Nowadays, the consumer perception towards diet is gradually changing due to changing lifestyle, and different age grouped people require a varying degree of nutrients. Formulating a balanced diet as per individual needs and preferences is the need of the day. This technology allows for personalized meals based on age groups and helps in reduced calorie intake. Thus, the concept of ‘personalized nutrition’ comes into focus which makes possible the delivery of ‘digitalized food’. 3D food printing reduces the multi‐step process into a single step which has the potential to revolutionize the future food industry. The supply chain of 3D food printing allows consumers to have a prime role in the value addition of the end products based on their requirements which is very minimal in the case of a conventional food supply chain (Figure 1.4) (Jayaprakash et al. 2019).
Figure 1.3 Prospects of 3D food printing.
1.6 Design Considerations of 3D Printer
1.6.1 Printer Configurations
Food printing is a synergistic combination of incorporating digital culinary skills with 3D printing techniques. 3D food printers are machines that have the potential capability of reproducing 3D edible constructs from a designed digitalized 3D models. In a broad sense, 3D printers are classified as cartesian, delta, polar, and selective compliance assembly robot arm (SCARA) based on the movement of printing arms (Figure 1.5) (Sun et al. 2018a).
A simple configuration of a 3D printer is a cartesian type. The movement of these printers is configured in a linear straight‐line path (coordinate axes) whose movements are controlled by moving printing nozzle, printing platform, and/or both simultaneously for respective movements in X, Y, and Z direction (Horvath 2014b). Based on the motion of coordinate planes, cartesian printers are grouped as XY head printers, XZ head printers, and XYZ head printers. In the former type of XY head printer, the print head moves in the XY plane, and the print bed moves in the Z plane. Another variation in print head is ‘XZ head printers’ where the print head moves in XZ plane and the print bed moves in Y plane, respectively. An example of this type of printer is Choc creator, a commercial 3D food printer specifically designed for the customized fabrication of 3D constructs from chocolates. The third case is ‘XYZ print head’ where the print bed remains stationary and only the print head moves in all directions as in the case of Foodini, a commercial 3D printer developed by Natural Machines (Derossi et al. 2019). Comparatively, the motion of XY and XYZ head printers remains faster than that of XZ head printers. However, this type of cartesian printer requires accurate and regular calibration before printing.
Figure 1.4 Value chain of 3D food printing. (a) consumer buying 3D printed foods; (b) consumer buying 3D food printer.
Source: Jayaprakash et al. (2019) / With permission of Elsevier.
Figure 1.5 Illustration of printing movements in various printer configurations. (a) Cartesian; (b) Delta; (c) Polar; (d) SCARA.
Source: Sun et al. (2018b) / With permission of Elsevier.
The second type is the delta 3D printers works on the triangular coordinate mechanism based on the Pythagoras theorem with relative movement of printing arms in three co‐ordinate axes (X, Y, and Z directions) (Sun et al. 2018a). These types of printing system consist of three pairs of carriages (arms) that moves simultaneously up and down and aids in printing with a stationary print bed. Here, each pair of arms form the diagonal of a triangle and makes an angle to other planes namely X and Z. Likewise, all the three carriages move at the same time thereby aids in simultaneous printing. The major advantage of the delta type over the cartesian is its higher printing speed because of less physical loads and its ability to print bigger‐sized objects especially in the Z direction (Horvath 2014b). However, this suffers from the limitation of low precision in printing smaller objects.
Another configuration of the 3D printer is polar which is the rarest that works based on the polar coordinate system. Here, the motion of printer arms is defined by an angle of 360° with a pre‐defined centre point along radial direction while printhead moves vertically up and down thereby forming a 3D construct (Sun et al. 2018a). An example of this type of configuration is the XOCO 3D printer, a commercial chocolate printer equipped with a rotating build plate with a single supporting pillar that holds a print head and glass covering (Ontwerp 2018). Another example for polar configuration is the TNO food printer that consists of three rotating arms provided with
