# A Review on Recent Trends and Applications of IoT in Additive Manufacturing
## 2 IOT-Enabled 3D Printing Applications
### 3D Scanners  
3D scanning is the process of studying an object or environment in the real world to acquire data about its shape and even its appearance (e.g., color). The collected information may subsequently be utilized to create digital 3D models. Dark, reflective, glossy or translucent objects can provide several challenges for 3D scanners. Utilizing 3D scanning technology, a physical model is converted into a digital 3D computer-aided design (CAD) file. This digital output is utilized effectively for the design and fabrication of bespoke components using AM technology. Figure 13 illustrates the distinction between conventional manufacturing and 3D scanning. Apart from the social sectors, 3D scanning supports a range of conventional technical industries. Figure 14 depicts the widespread potential applications of 3D scanning, including scientific and education sectors, design and manufacturing domains, reverse engineering professions, art and design industries, etc. Additionally, technology provides various benefits. Specifically, enhanced workflow processes, correct resolutions, an automated system as a whole, quality services, research views, etc., make this instrument a more particular quality service for the engineering industry at present [84]. 3D scanning technologies are utilized to scan physical components that frequently lack drawings or CAD data in order to digitally copy the data. Using the scan data, quality managers may measure and compare the actual design with digital information. The accuracy of the component's dimensions may be rapidly computed and verified. Precision and construction quality analysis, including fitness checks, gaps, and alignment, is helpful for components with complicated geometry and old or broken instruments. However, the engineers are trained in the utilization of robust models scanned by this technique. This information is stored as a feature in the logical measure and specifies the necessary format of an object. Changes to the dimensions of a single element may be made in the solid CAD, and the other model updates will accommodate the modifications. Workflows utilizing scanning technology are easily extensible to reproduction and reconstruction, reverse engineering, and metrology [84]. Figure 14: Potentials of 3D scanning for real-life domains [84]. Figure 13: Conventional Vs 3D scanning process. In earlier days, the modelling of a complex part is difficult due to complex structures, curves, and irregular shapes. Due to this, the final 3D Model varies from the original product. To overcome this problem, 3D scanning technology was discovered. The first 3D scanning technology was created in the 1960s. The earlier scanner uses light, cameras, and projectors to perform the task. Due to this limitation of this equipment, it often took a lot of time and effort to scan objects accurately. After 1985, there was a replacement with scanners that used white light, lasers, and shading to create a 3D model of a given object. With this advancement, it was possible to build up highly complex models. Some of the manufacturing components required very high accuracy but modeling these components with conventional modeling software made the model somewhat inaccurate due to the complex curves. So, for these highly accurate components, we use 3D scanning technology. Scanning makes it possible to create a 3D model of an existing part or its environment. The digitized part can be used for producing a replacement part or creating a better-optimized entity in design. 3D scanning is also used for inspection purposes; that is, 3D scanners are used to inspect the final product of additive manufacturing. Figure 15 shows the 3D scanning process used in the inspection. Therefore, additive manufacturing with 3D scanning using the Internet of Things (IoT) makes the process very easy. The IoT monitors the scanning process very accurately. It will suggest the best method of scanning for the best result and integrate the 3D scanner and 3D printer by generating the STL file.