Analysis of various additive manufacturing technologies

Introduction

Additive manufacturing represents a crucial breakthrough in the manufacturing industry by redefining its processes through the elimination of traditional molds and tools. This method allows transforming digital models into three-dimensional objects quickly and accurately, optimizing production lines in terms of efficiency and costs.

In recent years, its adoption has grown significantly, consolidating itself as a pillar of the fourth industrial revolution. The ability to produce items on demand and with high accuracy makes it a key technology for the evolution towards more agile and adaptable logistics, with a profound impact on the optimization of industrial processes and the competitiveness of the manufacturing sector.

What is additive manufacturing?

Additive manufacturing is an advanced manufacturing process that involves the creation of three-dimensional objects by the controlled addition of material, layer-by-layer, from a digital model¹. Also known as 3D printing, it is a method distinguished by its ability to produce complex, customized geometric shapes using materials such as thermoplastics, metals, and resins, without the need for molds or tooling.

Unlike subtractive manufacturing, additive manufacturing minimizes material waste and significantly reduces production times, making it an efficient and sustainable technology for modern industry.

Fundamental types of additive manufacturing technologies

Selective Laser Sintering (SLS) technology

Selective Laser Sintering (SLS) is an advanced additive manufacturing technique that uses a laser to sinter, i.e., bind and fuse particles of fine powdered material, creating a solid, three-dimensional object.

This process works by precisely focusing the laser on specific points in the powder bed, which causes an atomic-level reaction that binds the particles together, resulting in a piece with high precision and isotropic strength, i.e., with equal strength in all directions. Despite its technical advantages, SLS requires expensive equipment, specialized maintenance, and skilled operators, which implies a higher operating cost compared to other additive manufacturing technologies.

Fused Deposition Modeling (FDM)

Fused deposition modeling (FDM) is a technique that consists of the controlled extrusion of a thermoplastic filament, deposited layer by layer on a platform to build a three-dimensional object2. This process, also known as fused filament manufacturing (FFF), is characterized by its ability to produce parts with high strength, low weight, and dimensional stability, in addition to offering heat tolerance, which makes it economical and efficient for various industrial applications. One of its technical challenges is the anisotropy of the parts, where the strength varies depending on the direction of the deposited layers.

Stereolithography (SLA)

Stereolithography (SLA) uses an ultraviolet (UV) laser to cure successive layers of a liquid photopolymer, forming a three-dimensional object with high precision and level of detail. Each layer of the light-sensitive material solidifies instantly upon exposure to the laser, adhering to the previous layer until the part is complete.

Although this is a technique recognized for its ability to produce complex and detailed shapes, it has limitations in terms of object strength and the risk of deformation in larger parts. This technique is appreciated for its accuracy, but the equipment and materials required involve cost and durability considerations.

Direct Metal Laser Sintering (DMLS)

Direct Metal Laser Sintering (DMLS) is an advanced additive manufacturing technique in which a high-precision laser completely melts metal powder particles to create three-dimensional objects layer by layer. Unlike other methods such as Selective Laser Sintering (SLS), where particles are partially sintered, DMLS achieves complete melting, resulting in parts with stable and reproducible mechanical properties.

This technology is capable of using a wide variety of metallic materials, providing high precision and consistency in the parts produced. However, the process requires specialized equipment, skilled operators and careful handling of the metal powder, making it a complex and expensive technical option.

Fused Metal Filament Fabrication

Fused Metal Filament Fabrication uses a filament composed of metal powder agglomerated with plastic, which is deposited layer by layer to form a part. The part is then subjected to a debinding and sintering process in a furnace, where the plastic is burned and the metal particles fuse together, creating a metal object.

This method is notable for its material availability, accuracy and lower cost, as well as offering greater safety and ease of use compared to other metal additive manufacturing processes that use loose powder. However, the resulting parts are not completely solid, which reduces their weight, but may limit their application in certain contexts.

Digital Light Processing (DLP)

Digital Light Processing (DLP), similar to stereolithography (SLA), uses light to cure layers of photopolymer material. However, unlike SLA, which uses a laser to cure point-by-point, DLP projects an image of light that solidifies the entire layer of material simultaneously.

This key difference enables DLP to offer higher speed in part production, as well as high precision in creating complex designs. Despite this, the process can generate a strong odor during printing, and larger parts can experience warping.

Direct Energy Deposition (DED)

Direct Energy Deposition (DED) is an advanced additive manufacturing process that uses metallic raw materials, such as metal wire or powder, combined with a laser or electron beam to create or repair parts. This method uses a nozzle mounted on a multi-axis robotic arm, allowing material deposition at almost any angle and the creation of large components.

While DED offers certain advantages such as the ability to manufacture large parts and perform repairs, it also presents challenges, including the high cost of the equipment, the need for specialized technicians, and the post-processing required to achieve the desired accuracy.

Electron Beam Melting (EBM)

Electron Beam Melting (EBM) uses a high-energy electron beam directed by a magnetic field to melt and solidify successive layers of metal powder in a vacuum environment. This technique enables the precise and rapid manufacture of high-strength metal parts.

This process is distinguished by its ability to achieve excellent surface quality and robust mechanical properties in the parts produced. An important aspect to highlight is that its optimal use requires specialized technicians due to the complexity of the equipment and the operating conditions in the vacuum chamber.

MultiJet Printing (MJP)

MultiJet Printing (MJP), also known as material jetting (MJ), is an additive manufacturing technique that uses printheads to deposit fine droplets of photoreactive material layer by layer. Each layer of material is solidified by the application of ultraviolet (UV) light, enabling the precise creation of three-dimensional objects.

This technology stands out for its ability to produce parts with multiple materials and colors in a single print, thanks to different printheads that use different materials simultaneously. However, despite its versatility in composition, parts produced with MJP can have limitations in terms of strength and durability.

Benefits of additive manufacturing technologies

• Internal production control: Additive manufacturing allows companies to produce more parts in-house, reducing their dependence on external suppliers². This, in addition to reducing the costs and lead times associated with outsourcing, gives companies greater control over the quality of the final product.
• Significant cost reduction and accelerated ROI: Compared to traditional subtractive manufacturing methods, industrial 3D printing is much more economical, especially in cases such as the production of tools and prototypes. Thanks to this, companies can save considerably on material and labor costs, which translates into a return on investment that can be realized in weeks or months.
• Elimination of traditional constraints: Additive manufacturing breaks through the limitations imposed by traditional production methods, such as the need for specific molds and tooling for each design. With industrial 3D printing, complex and customized geometries can be created without the restrictions imposed by subtractive techniques. This design freedom not only improves the functionality and aesthetics of parts but also enables continuous innovation in product development.
• Accelerated lead time and speed to market: One of the biggest benefits of additive manufacturing is the drastic reduction in the time required for the transition process between the design and production phases. While traditional methods can take months to produce a part, 3D printing can complete it in hours or days. This not only speeds up design and prototyping cycles but also enables companies to bring products to market faster, giving them a significant competitive advantage.

The future of additive manufacturing

Referring to the latest advances in 3D printing technologies, bioprinting is an additive manufacturing innovation that enables the creation of three-dimensional structures similar to natural tissues by printing bioinks, which combine biocompatible materials and living cells. This process has emerged as a crucial tool in fields such as tissue engineering, bioengineering, and drug development.

Unlike traditional 3D printing, bioprinting uses bioinks to build structures layer by layer. These bioinks, composed of natural or synthetic biomaterials mixed with living cells, are arranged in precise patterns that mimic the structure and function of natural tissues. In this way, three-dimensional structures are created that more closely replicate biological functions compared to conventional in vitro studies³.

Among the main advantages of bioprinting are the ability to generate personalized medical treatments, reduced need for animal testing, and greater biological compatibility with human tissues. However, bioprinting also faces significant limitations, such as its high cost, the complexity of the process, ethical challenges, and its high energy demand. These barriers must be overcome for the technology to reach its full potential in medicine and the pharmaceutical industry.

Conclusions

Additive manufacturing is emerging as a key technology for the industrial future because of its ability to optimize production processes through its ability to create complex, customized objects without the need for traditional molds or tooling. This manufacturing modality has great potential to transform the manufacturing industry, especially when considering the speed and precision with which it converts digital models into physical products.

This technology not only generates efficiency improvements and cost reductions but also drives logistics development toward a more agile and adaptable framework. As additive manufacturing continues to advance, it is expected to play a crucial role in different sectors, opening up new opportunities and concepts in various industries.

References

1. https://www.mecalux.com.co/blog/fabricacion-aditiva
2. https://markforged.com/es/resources/blog/additive-manufacturing-101-guide-the-basics
3. https://www.upmbiomedicals.com/solutions/life-science/what-is-3d-bioprinting