What Is Additive Manufacturing?

Additive Manufacturing, also known as 3D printing, is a process of making three-dimensional solid objects from a digital file.

In an additive manufacturing process, an object is created by printing successive layers of material until the entire object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.

3D printing is the opposite of subtractive manufacturing, which is cutting or hollowing out a piece of metal or plastic with, for example, a lathe.

3D printing enables you to produce complex, functional shapes using less material than traditional manufacturing technologies.

The term “3D printing” covers a variety of processes in which material is joined or solidified under computer control to create a three-dimensional object, with the material, such as plastic or liquid resins, being added together.

What Is The Additive Manufacturing Process?

The additive manufacturing process starts with a computer-aided design (CAD) file or 3D scanners. The CAD file is uploaded to a 3D printer that reads the data and lays down successive layers of material, building up the object. The object is then finished with post-processing, such as heat treatment or surface finishing.

3D printing technology has been around since the 1980s, but it was not until the late 2000s that the technology became more widely adopted. Today, many different types of 3D printers are available on the market, each with unique capabilities.

The most common type of 3D printing technology is fused deposition modelling (FDM), in which material is extruded through a nozzle to build up the object layer by layer. Other common 3D printing technologies include stereolithography (SLA), selective laser sintering (SLS), and polyjet 3d printing.

3D printing technology is used in various industries, including aerospace, automotive, healthcare, and consumer goods. In recent years, there has been a surge in the use of 3D printing for prototyping and low-volume production due to its ability to produce complex shapes quickly.

Types of Additive Manufacturing

While we often think of additive manufacturing as a single technology, it’s an umbrella term that encompasses various processes. Each process has capabilities and limitations, so choosing the proper technique for your specific application is essential.

According to the American Society for Testing and Materials (ASTM), which is referenced by the BSI, there are seven main types of additive manufacturing processes:

1. Directed Energy Deposition-Arc (Ded-Arc)
2. Material Jetting
3. Binder Jetting
4. Material Extrusion
5. Powder Bed Fusion
6. Sheet Lamination
7. Vat Polymerisation

Each type of additive manufacturing process is suited for different applications. To help you choose the right process for your project, we’ve compiled a brief overview of each type below.

1. Directed Energy Deposition

Directed energy deposition is a type of additive manufacturing that deposits material onto a substrate layer-by-layer using a directed energy source, such as a laser, electric arc, or an electron beam.

DED is well suited for repairing or modifying existing components and fabricating new ones from scratch. The process can be used with various materials, including metals, ceramics, and polymers.

DED is often used in the aerospace and automotive industries for fabricating large-scale components, such as turbine blades and engine parts.

The process works by heating the material until it melts and then depositing it onto the substrate. The molten material then cools and solidifies, bonding with the substrate to form a strong bond.

DED is a relatively fast process and can be used to fabricate complex shapes with little to no post-processing required.

2. Material Jetting

Material jetting builds objects by selectively depositing material from a print head onto a build platform. It works similarly to an inkjet printer, but instead of jetting ink onto paper, it jets material onto a build platform using Drop-on-Demand (DOD) or Continuous Inkjet (CIJ) technology.

DOD uses a print head with small nozzles that stores material in chambers behind the nozzle. When a droplet is needed, a piezoelectric element inside each chamber selectively deforms, ejecting a material droplet through the nozzle and onto the build platform.

CIJ technology uses a print head with a continuous flow of material. This technology uses pressurised air to break the material stream into tiny droplets. These small droplets are then deposited onto the build platform.

The two main benefits of material jetting are its accuracy and the wide range of materials that can be printed. Material jetting can print tiny details and features with high accuracy. In terms of materials, material jetting uses polymers (ABS, HDPE, polypropylene, HIPS, etc.) and plastics.

One of the main applications of material jetting is prototyping small plastic parts, such as those used in the automotive and consumer electronics industries.

3. Binder Jetting

Binder jetting is considered the fastest AM technology for producing parts at industrial scales. In this process, two materials are used: a build material and a binder. The build material is typically a powder, such as metal, ceramic, or plastic; while the binder is a liquid that adheres the build material together.

Using a method similar to Selective Laser Sintering, a build platform is lowered into a powder bed. However, an industrial print head moves across the powder bed instead of a laser and selectively deposits the binder material. The build platform is then lowered again, and another layer of powdered material is deposited on top. This process repeats until the desired part is built.

Once the binder jetting process is complete, the part needs to be cured in order to solidify the binder material. Curing can be done via heat, ultraviolet light, or both. After the part is cured, any excess powder is removed, and the part is ready for use.

Binder jetting is different from other AM technologies in that it doesn’t use heat to fuse the build material during the printing process. Instead, the binder material is used to hold the build material together until it can be cured. This makes binder jetting ideal for printing large parts or parts with very intricate details.

Binder jetting is also one of the most versatile Additive Manufacturing Technologies. It can be used to print parts made from metals, ceramics, and plastics.

Some typical applications for binder jetting technology include:

• Creating prototypes
• Aerospace components
• Jewellery
• Casting patterns
• Sand moulds

4. Material Extrusion

Material extrusion is the most popular type of 3D printing technology. In this process, the material is pushed through a nozzle to create the desired shape. The most common type of material extrusion is Fused Deposition Modelling.

FDM works by extruding a thin layer of material, typically plastic, onto a build platform. The print head then traces the cross-section of the desired part, building it layer by layer. Once the part is complete, it’s removed from the build platform, and any support material is removed.

FDM is a versatile technology used to create parts from various materials, including ABS, PC, AB, and nylon. It’s also one of the most affordable 3D printing technologies, making it a good choice for hobbyists and schools.

Typical applications for FDM technology include:

• Low-volume manufacturing
• Prototyping
• Education
• Dental models

5. Powder Bed Fusion

Powder bed fusion is a 3D printing technology comprising various Additive Manufacturing processes, including Selective Laser Sintering, Direct Metal Laser Sintering (DMLS), Electron Beam Melting (EBM), Multi Jet Fusion (MJF), Direct Metal Laser Melting (DMLM), and selective heat sintering (SHS).

In powder bed fusion, a laser or an electron beam is used to melt and fuse small powder particles, layer by layer, to create three-dimensional objects. The laser or electron beam is directed at a powder bed, usually made of metal, ceramic, or polymer.

Powder bed fusion is often used to create prototypes and small-scale production runs of parts and products. It’s also used for industrial production, where it can be used to create complex parts for various industries, including aerospace, automotive, and healthcare.

Powder bed fusion is a flexible technology that can create parts from various materials, including metals, ceramics, and plastics.

6. Sheet Lamination

Sheet lamination is a type of Additive Manufacturing technology that uses sheets of material, usually metal, to create three-dimensional objects. The sheets are bonded together using adhesives, ultrasonic welding, or friction stir welding.

Sheet lamination is further divided into two subcategories:

• Ultrasonic Additive Manufacturing (USAM)
• Laminated Object Manufacturing (LOM)

In USAM, the thin metal sheets are bonded together using ultrasonic welding. This process uses high-frequency sound waves to create friction and heat, which melts the sheets together.

LOM is a similar process but uses paper as the build material. The paper is bonded together using adhesives or heat and pressure. Once the object is complete, it’s removed from the build platform, and any support material is removed.

USAM and LOM are similar in that they both use sheets of material to create three-dimensional objects. However, there are some key differences.

USAM can only be used with metals, while LOM can be used with various materials, including plastics and composites. USAM is also much faster than LOM, making it the preferred choice for applications where speed is a factor.

LOM is typically used for visual prototypes or models, while USAM is used for creating functional parts. USAM is also well suited for mass production, as it can quickly produce large numbers of components.

7. Vat Polymerisation

Vat polymerisation uses a liquid resin to create a three-dimensional object. The build material is a photopolymer, a type of plastic that changes properties when exposed to light.

There are three types of vat polymerisation:

• Stereolithography (SLA)
• Digital Light Processing (DLP)
• Continuous Direct Light Processing (CDLP)

In SLA, a laser is used to draw the desired shape of the object onto the surface of the liquid resin. The object is then built up, adding layer upon layer until it’s complete. DLP uses a projector to project the image of the object onto the resin. The object is then built up in a similar way to SLA.

CDLP works the same way as DLP, but the object is built up continuously rather than in layers. This makes CDLP much faster than both SLA and DLP.

Vat polymerisation is an excellent option for creating objects with intricate details and smooth surfaces. These objects can be very strong and precise, making them perfect for applications such as jewellery, dental implants, low-run injection moulding prototypes, and medical devices.

Additive Manufacturing Techniques

The technologies and processes used in Additive Manufacturing can be broadly categorised into three main categories:

• Sintering
• Laser Sintering
• Stereolithography

Sintering

Sintering is a type of Additive Manufacturing process that uses heat to create a solid mass without melting the material.

The build material is typically a powder placed into a mould or build chamber. The build chamber is then heated to just below the material’s melting point. As the build chamber heats, the powder particles stick together, or “sinter.”

Once the build chamber reaches the desired temperature, the build material is allowed to cool and solidify. The final product is a solid, three-dimensional object.

Laser Sintering

Laser sintering uses a laser to combine the metal powder layer by layer. It’s one of the most commonly used Additive Manufacturing processes for metals and can be used to create metal alloys that traditional manufacturing techniques cannot.

With Direct Metal Laser Sintering (DMLS), the laser is focused onto the powder bed, fusing the particles to form a solid layer.

The build platform then lowers, and a new layer of powder is deposited on top of the previous layer. The process is repeated until the object is complete.

For Selective Laser Sintering, the laser selectively sinters thermoplastic powder based on a 3D model of the object.

This allows for more complex objects to be created, as the laser does not have to trace the entire outline of the object on each layer.

Stereolithography

Stereolithography is an Additive Manufacturing technology that creates three-dimensional objects by curing a photo-sensitive resin with an ultraviolet laser beam. The advantage of SLA over other Additive Manufacturing technologies is its ability to produce very smooth surfaces on the parts it creates.

SLA works by building up the object one layer at a time. The build material is a photopolymer (a type of plastic that changes properties when exposed to light) resin, which is deposited in a thin layer onto the build platform.

The UV laser beam traces the cross-sectional profile of the part for that layer and cures the plastic. The build platform then lowers by one layer of thickness, and the process repeats until the build is complete.

What Are the Benefits of Additive Manufacturing?

There are many benefits to using Additive Manufacturing over traditional manufacturing techniques, including:

1. Speed

Additive Manufacturing can be much faster than traditional manufacturing techniques. With conventional manufacturing, each component must be created separately and assembled.

With Additive Manufacturing, the entire object can be created in one piece. This reduces the amount of time and labour required to complete the object, as well as the number of potential errors.

2. Customisation

Additive Manufacturing allows for much greater customisation than traditional manufacturing. With conventional manufacturing, each component must be created separately and then assembled together.

This can limit the degree to which an object can be customised, as each component must be compatible with the others.

With additive technology, the entire object can be created in one piece to the customer’s precise specifications.

3. Reduced Waste

AM generates very little waste, as the build material is only used where needed.

In contrast, traditional manufacturing techniques often create a lot of waste, as the material is removed from the object to create the desired shape.

This waste can be costly to dispose of and can have a negative impact on the environment.

4. Reduced Costs

Additive technology can often be more cost-effective than traditional manufacturing, as it requires less material and labour.

It can also be used to create objects that would be too expensive to manufacture using traditional methods.

5. Increased Efficiency

The speed and customisation of additive technology can lead to increased efficiency in the manufacturing process.

This is because objects can be created quickly and to the customer’s precise specifications without the need for costly prototypes.

6. Increased Accuracy

The ability to create precise, customised objects means that additive technology can be used to create highly accurate objects.

This is often essential in industries such as aerospace and medicine, where there is a very small margin for error.

7. Increased Complexity

The ability to create objects in one piece means that additive technology can be used to create objects with a high degree of complexity.

This is not possible with traditional manufacturing, as the components would not be able to fit together.

In Summary

Additive Manufacturing is a type of 3D printing technology with many benefits over traditional manufacturing techniques. It’s faster, more customisable, and generates less waste. Additionally, it can be used to create objects that would be too expensive to manufacture using traditional methods.

This technology is an integral part of the future of manufacturing and will continue to impact how objects are created significantly.

FAQs

What Is the Meaning of Additive Manufacturing?

Additive Manufacturing is a 3D printing technology that creates objects by adding build material layer by layer. This contrasts with traditional manufacturing, which typically involves subtracting material from a block to create the desired shape.

What Is an Example of Additive Manufacturing?

An example of additive manufacturing would be the creation of medical implants. These implants are often created to precise specifications and must be made with high accuracy. Additive technology can be used to develop these implants quickly and efficiently.

Why Is It Called Additive Manufacturing Technology?

The term additive manufacturing technology refers to objects being created by adding build material layer by layer. This is in contrast to traditional manufacturing techniques, which involve subtractive processes (such as machining) or forming processes (such as injection moulding).

What Are the 7 Additive Manufacturing Processes?

There are seven main types of additive manufacturing processes:

1. Vat photopolymerisation
2. Material jetting
3. Powder bed fusion
4. Directed energy deposition
5. Sheet lamination
6. Material extrusion
7. Binder jetting

Which Are the 4 Basic Types of Manufacturing Processes?

The four main types of manufacturing processes are:

1. Casting
2. Machining
3. Forming
4. Joining