Types of Additive Manufacturing Processes

Additive manufacturing(AM) which gets more common day by day. Because the application and production steps are so different for additive manufacturing. We can produce various kinds of parts from various materials with any of these additive manufacturing categories. You can find some types of additive manufacturing. But here, we will give a different approach. Here, you can find information about these topics;

• Different types of additive manufacturing processes.
• Select a proper type for your application.
• Why the additive manufacturing processes are important?
• FAQs about additive manufacturing processes.

4 Different Types of Additive Manufacturing Processes

In this classification, we will classify the additive manufacturing processes under these titles;

• Liquid Polymer Systems,
• Discrete Particle Systems,
• Molten Material Systems,
• Solid Sheet Systems,

It is easier to comprehend the processes by classification of them according to the starting phase of the base material. You can also find the different techniques inside these titles and classes. So, this is a very important classification of additive manufacturing processes.

1 – Liquid Polymer Types of Additive Manufacturing

Maybe this is the most common application of additive manufacturing processes. In the general working principle of liquid polymer systems, there is a thermosetting polymer. The thermosetting gets hard with the exposal of UV lights. So, it converts from liquid to solid with the application of UV light. Because of this, the starting phase of the material in this class of methods is liquid.

Firstly, the material is provided in the liquid phase of the system. And then, a UV light source is applied to this liquid material to obtain a hard material. So, we obtain a solid part from these systems.

The general drawback of these systems is the availability of materials. We can only use specific resins which are thermosets.

Stereolitrography(SLA) Methods

Also, we call this additive manufacturing method as VAT polymerization. In these systems, the starting material is a thermosetting resin liquid. And there is a platform inside this liquid. Also, there are laser beam creators that send these UV beams to the intended places of the platform. These intended places are defined by the mirrors that direct the UV beams.

With the movements of these mirrors, the UV light is directed to the intended areas on the platform. So, in these areas, the thermosetting resin gets cured. Because of this, the general cross-section of the part takes place.

In each layer, the platform descends inside the thermosetting liquid. So, in each layer, the curing of the thermosetting resin takes place. At the end of the process, the complete part is obtained.

There are different kinds of industries started to use VAT polymerization techniques. The most important example is Nike. Nike produces some shoe sholes with this type of additive manufacturing technique.

Dual Beam SLA

There are also extensive technologies developed to use in the additive manufacturing industry. Dual-beam SLA is a new technology. These machines are using two UV beam systems to produce the parts more rapidly. Because the most important drawback of the SLA systems is the time. The general time that is consumed by the production of parts is somewhat high if we compare it with other technologies.

So, with the applications of extra beams on the systems, you can create the same part in shorter times. This type of additive manufacturing is a direct solution to the time problem of SLA systems.

Objet Technologies

Also, this is a very different approach that uses a very different technology. The thermosetting material is coming as a liquid. And very tiny floodlights complete the curing process on these droplets.

Furthermore, the most important advantage of this type of additive manufacturing, we can obtain shapes and objects that have different mechanical characteristics. For example, we can obtain objects that have different densities at different sections of the material.

Envisiontec

This company also produces low-cost additive manufacturing machines that use digital micro-mirror devices to produce the parts from photopolymer resins at a low cost. This is also a very different approach the liquid-based systems.

2 – Discrete Particle Types of Additive Manufacturing

As you understand from the name, we are dealing with discrete particles such as material powders with these types of additive manufacturing techniques. In general, we are using powders to melt them to combine. Or bind them with special glues or binders. So, these are the general approaches that we use in these systems.

This is a very advantageous system in that we can produce parts from different materials.

Selective Laser Sintering Systems(SLS)

In these systems, there is a powder in a container-like shape. These powders can be melted and come into the starting form without any changes. So, they are not behaving like thermosetting polymers. Because of this reason, we can use different kinds of materials such as ceramics, metals, and polymers.

We put the material powder inside a container. And then, the machine applies a laser beam to the intended areas. The sintering of these materials takes place with the application of a laser beam. So, they sintered together to obtain the part.

The production technique of the part is something like the VAT polymerization technique. After each layer of laser sintering, the platform descends. And then, the laser creates another cross-section.

The most important advantage of the SLS systems is, that there is no requirement for any support structures. You know that in layer-based systems, we need to use support structures to keep the material integrity. But, the around of the part is filled with powder. So, there is no requirement for any support structures.

Selective Laser Melting(SLM)

There are differences between SLS and SLM systems. The main difference is, that there is melting in this type of additive manufacturing process. So, to melt the material, we need to apply a more intense laser beam to the material. Also, we generally use these techniques to produce metal parts.

Because of this reason, the power source of the laser beam is very high if we compare it with other techniques. But the other kinds of parameters such as material powder containers and platforms are nearly the same with selective laser sintering.

In this method, we can also produce parts from ceramics and polymers. But in ceramics, the requirement for melting power is much more.

Electron Beam Melting(EBM)

In these types of additive manufacturing processes, they use electron beams, instead of laser beams. Also, these machines have powder material containers. And also they have platforms to obtain the part. But the melting source is different.

The difference between the electron beam from the laser melting is, that the beam is wider than the laser beam. So, accuracy can be a problematic issue in the application.

Another difference is, that the electron beam can be reflected in different portions of the part. So the total time required to produce the part is lower in electron beam melting processes.

Direct Metal Laser Sintering(DMLS)

This is a type of selective laser sintering. But this is special for the production of metal parts. The laser beam does not melt the metal powder in this technology. The temperatures are rising to the sintering temperatures of metals. So, the energy requirement of these methods is lesser than the melting technologies.

The general working principle of the DMLS technologies is the same as the other types of additive manufacturing techniques. So, there is a platform inside the metal powder container. And then a laser beam is applied with the help of the mirrors. The sintering of each layer takes place. And in each layer, the platform descends.

Binder Jetting Type of Additive Manufacturing

In binder jetting applications, again there is a container that contains the material powder inside it. And also, there is a binder jet that traverses along the surface of this platform. This platform descends and the binder jet applies a binder on the powder to produce the required cross-section of the part.

So, the main difference between this type of additive manufacturing technique, we apply binders from the nozzle that travels around the platform. And also, this is applied in each cycle. And in each cycle, a powder roller squeezes the powder on the platform.

In general, there are applications of binder jetting in medical and dental businesses.

3 – Molten Material Types of Additive Manufacturing

In these systems, the starting phases of the materials are in the molten state. But you can confuse these systems with liquid polymer systems. The general principle is very different. The main difference is that, in the molten material systems, the material is not a thermosetting resin. And there is no curing of the material. There is a conventional solidification of the molten material in these types of additive manufacturing systems.

Also, in general applications of the molten material systems, there is no application of containers that are full of molten material. In general, there is a tool or nozzle that molten material comes in a liquid phase.

The most important application of this type of additive manufacturing technique is the Fused Deposition Modeling method.

Energy consumption for these types of additive manufacturing systems is somewhat high. Because we need to melt the material completely. So, they consume more energy if we compare them with the sintering methods.

Fused Deposition Modeling(FDM)

In this type of additive manufacturing technique, the materials are in filament shape. And these material filaments are on the spools. And these spools are feeding the material to the nozzles of the end effector. In these nozzles, the material gets into a molten state.

According to the STL part geometry and layers in the CAD model, the nozzle travels the required paths on the platform. And in each layer, the nozzle travels around the cross-section of the part. Finally, we obtain the general geometry of the part.

In addition, the energy requirements for the FDM technique are lower than the other types. Because we use the polymer materials in the productioın of the parts. And melting points of the polymers are lower than the metals and ceramics.

You can see lots of freelancer FDM producers and machines. Also, you can find lots of kinds of tutorials about making FDM machines. Because the general requirement of the tooling and technology is low.

Also, the most important drawback of the FDM techniques, we need to create support structures to hold the part in balance. So, we need to use the extra material to apply these parts.

Material Extrusion Techniques

This is also another important type that uses the melting of the materials in the production of the parts. The melting of the material takes place right before the nozzle. And there is a screw mechanism at the nozzle that provides molten material to the nozzle.

This nozzle travels around the surface of the part according to the installed software in the machine. So, in each layer, we obtain the general structure of the part.

The main difference between the material extrusion technique is, that the melting of the material takes place with the action of a screw.

In general home-made and DIY additive manufacturing applications, these techniques are the most common ones.

Also, the general process application speed is very slow. Because of this reason, the application of material extrusion techniques is not common in serial production. 

4 – Solid Sheet Types of Additive Manufacturing

In these types of additive manufacturing systems, the starting phase of the materials is in the solid sheet. Also, they call these systems solid sheet deposition. The mechanisms of these additive manufacturing methods are somewhat different than the usual ones.

In solid sheet systems, there are sheet rolling mechanisms. In each layer, the mechanism lays a sheet layer. And then the bonding of these layers takes place with the application of the thermosetting resins. And also, there is another mechanism that lays sheets on the surface of the materials.

Sheet lamination techniques are very efficient systems that we can use.

Ultrasonic Additive Manufacturing Systems(UAM)

This is a very different type of additive manufacturing system. In the bonding of the layers, these machines are using vibrational sounds to melt the sheets. So, the melting and the bonding take place with this system.

In ultrasonic additive manufacturing systems, a roller travels around the laminated sheet. And this roller provides ultrasonic vibrations to melt the material. And this cycle goes on up to the production of the complete shape.

Laminated Object Manufacturing(LOM)

This is also a very common type of solid sheet additive manufacturing system. In the rolled sheet, the sheet material is coated with an adhesive that melts with the temperature. And each cycle, the roller lays the sheet on the surface of the material. And heat is applied to melt the adhesive material between the sheets.

Up to obtaining the general structure of the part, this cycle goes on.

Other Types of Additive Manufacturing Methods

There are also other types of additive manufacturing techniques that use different kinds of technologies. Because of these different techniques, the classification of these additive manufacturing methods is not possible in these 4 types of titles.

Directed Energy Deposition(DED) Techniques

Directed energy deposition is a very complex additive manufacturing technique that uses complex five-axis arms to deposit the material. We can deposit different kinds of materials with this method such as metals, plastics, and ceramics.

In the directed energy deposition technique, both the wires and powders are used as starting materials. Also, the most important advantage of this type of additive manufacturing technique is, that we can obtain very high accuracies and dimensional control of the parts.

Also in repairing applications, the use of the directed energy deposition techniques is very common.

With the use of the powders, we can increase the surface finish quality. So, in applications where surface finish is a very important parameter, we can use this technique with powders.

Selecting the Right AM Process for Your Applications

Selecting a proper type of additive manufacturing is a very important process for you. Because there are different types of additive manufacturing methods as you see above. So, you need to consider different kinds of parameters while you are choosing the proper one. Here, you can find several points to consider to select one of them.

Material

Material is a very important aspect of additive manufacturing methods. So, you need to know which kinds of materials you use in the production of parts with these methods. Because it directly affects the type of additive manufacturing method that you can use.

For example, if you are thinking about the production of metal parts with these methods, you can not use Fused Material Deposition or Material Extrusion techniques. You can use these types of additive manufacturing techniques in the production of plastic parts.

Size

Also, the product size is a very important parameter for the selection. Because these machines generally have a limited range of sizes. Also, the providers of these machines are producing different size ranges of machines. And with the increasing sizes, the machine costs are increasing.

You need to decide the general sizes of the parts that you want to produce the additive manufacturing.

Production Rate

Production rate affects the selection of the proper type of additive manufacturing technique for you. Because the production rates and the speeds are not the same for different applications.

For example, the material extrusion processes are very slow processes that we can not apply for the serial production of a part. But, they are good for the custom designs which are coming as an order.

Complexity

This is also a very important factor in the selection of a proper one. The complexity of the parts that you want to produce will affect your choices of the types of additive manufacturing techniques. For example, if you want to produce a complex shape from metals, you can consider discrete powder techniques.

Expectations from the Parts

Your expectations from parts are also very important. According to the application that you will use these parts, general expectations can change. For example, if you are expecting very good mechanical strength values from that part, you need to be aware of the possibility of it with the selected additive manufacturing methods.

Why the Additive Manufacturing is Important?

There are different reasons that additive manufacturing is important.

• Material Variety: If we take a look at the conventional manufacturing techniques, we will notice that their general applications of them are dependent on specific materials. For example, casting methods are mainly used for metals. There are different kinds of casting methods which are mainly for the metal parts. But, generally, we can apply each additive manufacturing technique to all classes of materials. This means these types of additive manufacturing techniques will be very common in the future.
• Efficient Systems: Also, we take a look at the conventional systems such as machining, where lots of chips are produced to manufacture the intended shape. So, material waste is very high in conventional techniques. But in additive manufacturing, the material waste is not high if we compare it with conventional techniques. Because the technique is different. We do not come from the raw shapes of materials to obtain the full shapes. So, we are not wasting materials in these systems.

Other Important Points

• Shape Variety: With additive manufacturing applications, we can produce a wide variety of shapes. We can produce nearly all kşnds of shapes and geometries with these methods. So, there are no shape and geometry restrictions in additive manufacturing techniques like the conventional ones. For example, there are lots of geometry restrictions in machining operations. Also, with the increasing complexity, the cost of tooling and operator experience increases. But in additive manufacturing, we can produce all kinds of shapes with the same approach.
• Easy Application: Nearly for all types of additive manufacturing methods, the general steps we should apply are the same. And nearly all types of them are automated systems. So, in general, we do not need a skilled workforce for additive manufacturing. For example, if we compare with the other kinds of conventional machining operations, we will see that, we do not need to have a complex application for complex shapes.

So, because of these reasons, additive manufacturing methods will be very common in the preceding years.

Conclusion on the Types of Additive Manufacturing Processes

So, as you see above there are different types of additive manufacturing processes available in the market. And they use different technologies such as sheet laying techniques or filament technologies.

And their applications of them to different materials available. We can use different techniques for different applications. There are also important parameters in selecting the proper process such as; material, size, and production quantity.

The importance of additive manufacturing processes is increasing day by day. With the advancing technologies and improvements, all the types of additive manufacturing techniques will be more common in the industry.

Also, there are lots of companies that are using additive manufacturing techniques in the serial production of their products. From the aerospace industry to the textile industry, you can find the biggest applications and users of these methods.

These are the general aspects of the types of additive manufacturing techniques.

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FAQs About the Types of Additive Manufacturing Processes