Introductory Chapter: Rapid Prototyping – Trends and Opportunities

1. Introduction

Since their advent, Rapid Prototyping technologies, nowadays known also as Additive Manufacturing or 3D printing methods became widely used in different applications that are used both, in industrial and medical domains [1, 2]. The benefits and advantages of using such modern manufacturing methods based on adding layers of materials, instead of removing (subtracting) material are multiple, consisting in the efficiency in producing parts more rapidly and with a minimum waste of material in the end [3]. Besides the advantages of these methods, there are also some disadvantages that consist in the performances that are reached using these types of technologies in terms of accuracy, roughness, and density in close correlation with the type of materials that are used in the additive manufacturing (Rapid Prototyping) methods and complexity of the parts that are required to be manufactured [4].

2. General presentation on the main Rapid Prototyping and Rapid Tooling methods

The manufacturing processes (most of them) are still quite expensive and the range of materials that can be used is still quite limited, even if in the last year’s lot of progress has been made and quite new types of materials that are suitable to be used on the 3D printing technological methods occurred on the market [5].

Diversity of Rapid Prototyping methods is really impressive. The methods that are using molten plastic material that is heated up and extruded through a nozzle are the most spread and developed nowadays on the market [6]. Manufacturing of parts made of resin material by Vat polymerization (curing of the material using UV light) or manufacturing of different parts by Material Jetting or Binder Jetting, methods that are based on the use of different binders or fusing agents that are being sintered or cured by light are also 3D printing technological variants that are used on a larger scale in this field in the world [7]. Powder bed fusion or direct energy deposition methods are widely used to produce different types of metallic parts made by sintering or welding metallic powder grains in order to materialize one part made by 3D printing technologies [8, 9]. The parts can be made from a different range of metallic materials using these methods, starting with light materials like aluminum alloys or nickel alloys and ending with materials that have much higher strength like titanium alloys, tool steel alloys, etc. [10, 11, 12, 13]. In the last year’s lot of researches were reported in this field regarding new types of metallic materials that were developed and tested, like copper-alloys, gold, tungsten, carbide, or diamond 3D printing [14].

Rapid Tooling methods, such as Vacuum Casting, Metal Spraying, Investment casting, and other similar technologies were also quite well developed in the last years for producing different types of molds that were used to conceive, develop, and test new types of materials that are not suitable to be used by 3D printing technologies [15, 16, 17].

3. Trends, challenges and existing opportunities in the 3D printing domain

There are different types of materials that are still very difficult to be printed, like PMMA, Hydroxyapatite, or chitosan if we are referring to the medical domain or different types of materials that are easier to be made by casting instead of 3D printing, such as different types of Irons, so, therefore, these methods are considered to be also very important in this field in close correlation with the 3D printing technologies [18]. Rapid Tooling methods are using 3D printed parts as master models for the realized molds and, therefore, it is one real challenge to produce master models made of different types of materials that are suited to the Rapid Tooling method that is used for producing the molds in the end [19]. New types of materials mixed with new types of 3D printing or rapid tooling methods that are more and more used in the last years are really encouraging, are very promising, and represent one strong proof that there is still one wide open room in this domain, as there are still lot of things to be investigated in this field, in order to provide one quick response to the medical or industrial sector needs [20].

Life cycle of the products became very short, developing and personalizing of products are highly demanding also, need for standardization in the field of 3D printing is also one very important challenge as new types of additive. Manufacturing (3D printing) methods are still under development and are launched every year on the market [21].

The use of subtractive technological methods (like CNC cutting) in combination with additive manufacturing technologies in so-called “Hybrid manufacturing” technologies represents one of the most important trends on the market and provides lot of research topics for the researchers all over the world [22]. Whether we are referring to metallic, ceramic, or plastic materials, in principle, the trends, challenges, or opportunities are the same in the field of Rapid Prototyping technologies. Using of robots integrated with these methods, integration of “in-line” quality control systems in the manufacturing chain jointly with 3D printing methods, application of different types of heat treatment or coating methods in the rapid development process of a new product, and use of “digitalization” or “optimization” procedures or software programs correlated with the new developed 3D printing methods are just few of the most important examples of the opportunities in this field, both, for industrial or medical sectors [23, 24, 25, 26].

Topological optimization or bionic design methods are quite well correlated with the additive manufacturing technologies, being also quite well integrated with specific software programs that are usually used to optimize the shape and redesign some components in order to decrease their weight, this trend being highly seen in the industrial sector (aerospace or automotive), but also in the medical sector, when such methods are used to enhance the biocompatibility of different medical implants, by designing the models with specific lattice structures in which bioactive materials can be inserted or integrated [27, 28]. Biomimetic structures, which refer actually to structures that imitate nature or biomimetic materials that can be used on 3D printing equipment are on top interest in the medical domain as well [29]. Bioengineering, biomedical, or bio 3D printing are new domains in which progress that has been made in the last years is really impressive and remarkable. Vessels, tissues, personalized bone structures, or even organs can be now realized or produced using 3D printing or 4D printing methods [30, 31].

Last, but not least, possibility of using multi-materials in the process of 3D printing and the possibility of using composite materials that are suitable to be used by 3D printing have enlarged the domains of applicability of these methods even more, by providing access to different applications, such as building constructions, textile and fashion, and consumer goods industry, etc. [32, 33, 34].

4. Conclusions

In the context of the trends and challenges that were presented in this chapter and based on the opportunities that exist in the Rapid Prototyping (3D printing) domain as were presented in this chapter, the current book aims to present few of the most important results that were reached in the 3D printing domain by researchers coming from different prestigious universities all over the world. The character of the researches presented in the book is inter and transdisciplinary, providing anyone who is looking to develop new researches in the field of 3D printing (PhD students, researchers, engineers, etc.) a good starting point for this purpose. The applications presented in this book are very large, covering a wide spectrum of 3D printing methods that were successfully used for the developing, testing, and producing different components that were further successfully used in the industrial and medical fields in the last years.