Three-dimensional (3D) printing has undoubtedly come a long way in the past few years. And, in today’s world, only a few forms are quite as interesting as laser powder bed fusion (LPBF).
With its ability to create some complex products and shapes, laser powder bed fusion is a revolution on its own. Here, we’ll look into how the operation works.
Understanding Laser Powder Bed Fusion (LPBF) Technology
So, what is laser powder bed fusion?
Laser powder bed fusion (LPBF) is a form of 3D printing that is used to create highly complex and detailed metal parts. Known to some as direct metal laser sintering (DMLS) and selective laser melting (SLM), this technology focuses on melting layers of metal powder with the use of a laser.
While many experts have debated its stand, this material jetting operation has been placed under the additive manufacturing category, thanks to the fact that it includes building objects by later from digital models.
The breakthrough developments in this selective laser melting technique were seen in the 1990s, when several companies began exploring powder bed fusion (PBF) and its use in manufacturing metal particles. For this process, metal powder particles were appropriately melted – using sources such as electron beams and lasers – to offer a more or less intricate part, layer by layer.
However, back in 1994, the EOS laser powder bed fusion technique was patented, while the Fraunhofer Institute also introduced selective laser melting as a term.
To be fair, both methods are quite similar. However, while melting involves moving a product from a solid to a liquid state, selective laser sintering materials aren’t given enough space to actually become a liquid since the heat source’s temperature doesn’t get so high.
How Does Laser Powder Bed Fusion Work?
So, we’ve looked into an overview of the laser powder bed fusion additive manufacturing process. Next, let’s examine how the process works and what manufacturers can achieve by conducting it.
How LPBF Works: Process and Principles
As you would expect, different manufacturers have what they hope to achieve here. However, the general workflow for additive manufacturing laser powder bed fusion can follow this structure:
Digital Design
In general, you want to start your process by creating a 3D computer-aided design (CAD) model. This shows the object you hope to print, as well as all of its intricacies and characteristics.
All in all, the model serves as a prototype for the 3D printer itself.
Powder Bed Preparation
Next, you spread a thin layer of the chosen metal across the build platform in the 3D printer. Different metals can be used with this process – we’ll go into detail later. But, the importance of this is for the powder layer to serve as the material to go through the selective heat sintering.
Laser Scanning
Moving on, you take a high-powered laser beam and direct it accurately onto the metal powder layer. The laser’s job is to scan the cross-section of the object based on the definitions of the CAD model that was used earlier.
As the laser emits energy, the powder particles are melted, joining them together to create the very first solid layer of the object you’re looking to achieve.
Layer-by-Layer Building
You now have your foundational layer, so it’s time to build on it. Lower the build platform on the recoating blade, thus adding a different layer of metal powder on the previously melted layer.
The new layeris scanned by the laser and joined to the underlying one, creating your first amalgamation. Then, the process is repeated time and again, layer by layer, until you create the entire object.
Cooling and Solidification
One important part of the process is the cooling and solidification. As each layer is melted and joined, you allow it to cool, ensuring that you’re able to achieve the right levels of structural integrity needed to get the desired object.
Post-Processing
Upon completion of the entire process, take the object through regular post-processing. Remove any excess powder, conduct the proper heat treatment to relieve stress, and round it all up with surface finishing to get the right surface quality levels.
Remember – you can always get counsel from us at KDM Fabrication if you need any help.
Critical Components Of LPBF Machines
Every laser powder bed fusion machine is a sophisticated device that is designed to perform at the highest level. From direct energy deposition to laser cutting and more, here are a few critical components of the machines that need to be in top shape every time.
- Build Platform: Here, you have the point where the 3D printed object is created layer by layer. You can move or lower it based on your requirements as well as the addition of each layer of the metal powder.
- Powder Delivery and Distribution System: To ensure optimal material jetting, you need this system. It helps to deliver and distribute the metal powder evenly across the build platform, setting the stage for the melting of each layer.
- Laser System: You want a high-powered laser whenever you’re incorporating your LPBF machine. As the fundamentals of laser powder bed fusion of metals have shown, the laser is what offers the energy needed to melt and fuse the metal together based on your CAD’s requirements.
- Scanning System: A scanning system navigates the laser beam across the build platform to melt the powder. It controls the laser’s movement across different directions and axes, thus creating the right 3D shape.
- Optical Systems: Every LPMF machine comes with optical systems that shape and focus the laser beam with optimal precision. Their role in ensuring accurate metal fusing and melting can’t possibly be overstated.
- Powder Bed and Recoating System: For laser beam powder bed fusion, the initial metal powder is held in the powder bed. With the melting of each layer, the powder bed is lowered, with a relocating blade adding a new powder layer for another pass. This entire system is what ensures that powder supply is consistent across the board.
- Inert Gas Atmosphere: Another critical part of the laser bed powder fusion machine is an inert gas atmosphere. Gases like argon and nitrogen are required to prevent the reaction between the powder and oxygen in the atmosphere.
- Heating and Cooling Systems: As expected, you need optimal heating and cooling to make sure that your material’s metallurgic properties can be optimized. Where necessary, these processes ensure temperature control across both processing and post-processing.
- Build Chamber: With the build chamber, you need a full, controlled space where the entire laser powder bed fusion process happens.
- Control and Monitoring System: Every laser-based powder bed fusion machine needs proper control systems to regulate every parameter and aspect of their operation. With this accurate monitoring, you can ensure that printed parts are of the highest quality across the board.
Metal Variants That Work Best With LPBF
One of the many benefits of powder bed laser fusion is the process’s compatibility with different metal variants. However, among the most prominent metal variants you can have with the process, here are the ream of the crop:
- Titanium Alloys: Arguably the most popular material for LPBF is titanium and its alloys. The laser powder bed fusion titanium process is great because of the material’s impressive strength-to-weight ratio and biocompatibility – which makes it great for different industrial applications.
- Nickel-Based Alloys: You can also find the process being applied to Nickel alloys. Known for their temperature resistance, these alloys – such as Inconel 718 and Inconel 625 – are also useful across different fields
- Stainless Steel Alloys: There are several grades of this material that are compatible with LPBF. Mostly, they offer impressive mechanical properties and can easily go through post-processing. So, they work quite well with this process overall.
- Aluminum Alloys: Strong and lightweight, aluminum and its alloys are popular options for lPBF as well.
- Cobalt-Chrome Alloys: Materials that combine chrome and cobalt are known for their wear resistance and biocompatibility. This is what makes them especially great for use in medical manufacturing.
- Maraging Steel: With maraging steel, you have a steel variant that has a low carbon content. It’s tough and strong, and its compatibility with LPBF makes it perfect in applications like defense and aerospace manufacturing.
- Tool Steel: Tool steels, such as H13 and D2, will need to go through proper steel fabrication. However, they work best for tooling applications as they are very hard.
At the end of the day, the material you choose will vary based on the capabilities of your LPBF machine as well as what you want to use your manufactured part to achieve. And, as innovations in the space continue to unfold, we expect to see even more materials get compatible with laser powder bed fusion.
LPBF’s Role In Manufacturing And High-Quality Production
Today’s manufacturing industry is rapid and decisive. With demand for products continuing to soar, a company’s ability to produce at high levels could easily be what saves them at the end of the day.
In many ways, this is why laser powder bed fusion is so important. In industries where high-performance, complex metal parts are needed, the process contributes some of the following to the overall success of any manufacturing workflow:
Complex Geometries
To begin with, LPBF enables the production of complex geometries that are almost impossible to achieve with the use of traditional manufacturing methods. This functionality is especially prominent in industries like medicine and aerospace, where you need components with optimized designs across the board.
Lightweight Structures
LPBF also makes it easy to create light structures that come with internal lattice designs, thus cutting weight without necessarily affecting a product’s mechanical properties.
In industries like automotive and aerospace manufacturing, weight reduction can easily help improve efficiency and cut costs. So, laser based powder bed fusion is critical here.
Customization and Personalization
Laser powder bed fusion 3D printing enables the production of customized, personalized product parts that can easily be used in different fields to ensure an excellent fit and functionality.
Rapid Prototyping
With LPBF, manufacturers are able to iterate their products faster and more effectively. This improves the speed of design and allows them to quickly test products before they move on to full-scale production.
All in all, the process accelerates the development of powder bed fusion parts and optimizes the product development cycle considerably.
Batch Production
In today’s production environment, being able to create products quickly and effectively is more than important. Fortunately, LPBF allows you to do that without any hassles.
Whether for small or medium part qualities, LPBF makes it easier for you to produce in bulk since the process is essentially repeatable. Just as well, the fact that the process is cost effective means that you can manufacture parts in limited volumes without having to go through expensive tooling.
As you would expect, this is one major advantage of LPBF over conventional manufacturing.
Material Performance
The materials created using LPBF exhibit impressive mechanical properties. And, they can be optimized for specific applications.
Thanks to the controlled melting and solidification, you can get parts that come with the highest mechanical properties, from tensile strength to fatigue resistance and more.
Reduced Assembly
One of the most underrated parts of lPBF is the fact that it allows you to protice integrated, complex designs in a single step. As a result, the process cuts down on the overall assembly requirements and can make supply chains easier to manage.
High-Quality Production
Finally, every LPBF machine comes with advanced control and monitoring systems that ensure optimal precision and repeatability of the entire manufacturing process. In fact, you can even find machine learning-based monitoring of laser powder bed fusion – essentially, the use of artificial intelligence and machine learning to control the entire process, resulting in reliable part production.
Applications of Laser Powder Bed Fusion
When it comes to laser powder bed fusion, efficiency is the name of the game. Fortunately, this also applies to the many industries where the process can be used.
So, what is laser powder bed fusion used for?
- Aerospace: For the aerospace industry, you can easily see LPBF being used for making light, strong components – from engine components to turbine blades and more.
- Medical and Dental: The process can also help develop prosthetics, implants, and other medical devices, taking advantage of precision in general manufacturing.
- Automotive: Vehicle manufacturers use LPBF to create light components that optimize fuel efficiency and general car performance. These include brackets, chassis components, and much more.
- Jewelry and Luxury Goods: Interestingly, the addition of material extrusion in the LPBF process means that it can help to create jewelry items with complex details that might be challenging to achieve in traditional manufacturing.
- Tooling and Manufacturing Aids: From molds to tool inserts and dies, LPBF helps to optimize different manufacturing processes. The process also helps in creating fixtures, jigs, and other manufacturing aids.
- Energy and Power Generation: LPBF helps to develop heat exchangers, gas turbines, and other equipment that help to optimize power generation – many of which require heat resistance and complex details.
- Defense and Aerospace: In the defense space, LPBF helps to create parts for satellites, drones, and even missile control systems. Once again, the process’s ability to create optimized complex designs comes in handy here.
- Research and Prototyping: For general material design, LPBF can be used in the initial research phase. Engineers and researchers can quickly iterate and examine the viability of their designs, thus improving testing across the board.
- Electronics and Electronics Enclosures: We can also see this system being used to create connectors, heat sinks, and other components used in electronics. Its general ability to create intricate designs and lightweight structures is beneficial in this field.
- Art and Design: Designers and artists can als employ laser powder bed fusion to create pieces like sculptures and decorative objects.
- Oil and Gas Industry: Finally, we’ve also seen improvements in the use of LPBF for the oil and gas industry, where the process is used to produce components that can easily withstand tough environments.
Advantages of Laser Powder Bed Fusion
Next up, let’s take a quick look at the advantages of laser powder bed fusion and why the process has become so popular. Generally, these benefits can be grouped into the following:
Developing Complex Geometries
Arguably the most prominent of these advantages is the fact that LPBF easily helps in developing products with highly intricate builds. This functionality has become especially handy in industries where lightweight, optimized designs are crucial.
Enhanced Customization
Manufacturers also get optimal customization from LPBF. Essentially, you will be able to create customized parts, allowing for greater product reliability and fit.
Material Efficiency
With its ability to only melt the necessary material for every layer, LPBF ensures high material use. This cuts down on waste and makes it a more sustainable manufacturing method compared to subtractive processes.
Reduced Lead Times
To be fair, the average powder bed fusion by laser time varies. However, the process generally enables quick prototyping and reduces product development cycles.
Lightweight Structures
Its ability to create light structures means that LPBF directly helps improve weight reduction and resource optimization across the board.
Reduced Assembly
With the application of LPBF, manufacturers can consolidate complex assemblies into a single part, thus cutting the need for complex assembly steps.
High-Quality Parts
The entire point of manufacturing is to create parts that are accurate and solid. With LPBF, you have a controlled melting and solidification workflow that leads to consistent parts in terms of mechanical properties.
Design Freedom
As a manufacturer, LPBF ensures that you have free reign over what to create. You can innovate and optimize your parts as much as you want, thus creating products that meet your taste.
Reduced Tooling Costs
Compared to traditional manufacturing methods, LPBF doesn’t necessarily need any tooling. This means that production costs can be cut even further.
Material Variety
As we explained earlier, you can easily incorporate LPBF with different materials. So, the process leads to the reaction of different parts with different mechanical properties.
Shorter Supply Chains
With LPBF, you suddenly don’t need complex supply chains anymore. You can create parts from digital designs directly, improving the overall efficiency of your manufacturing process and reducing your dependence on conventional part suppliers.
All of these advantages show that laser powder bed fusion is a strong, versatile process that can easily fit into any production workflow. And, it should come as no surprise that the process is being used in as many industries as we see.
What Are The Different Types Of Powder Bed Fusion?
In recent times, developments in additive manufacturing have made it possible to achieve different impressive processes. And, you might be wondering if laser powder bed fusion is the best of the bunch. Well, let’s see how it stacks up against a few others:
LPBF vs. Selective Laser Sintering (SLS)
It’s easy for many people to confuse laser powder bed fusion and selective laser sintering. Both are additive manufacturing processes, and they work by subjecting objects to laser energy.
However, both processes differ on several fronts – including the following:
Process Principle
Probably the biggest distinction line in the laser powder bed fusion vs selective laser sintering debate is in the working principles themselves.
In LPBF, a laser melts the metal powder in order to combine them by layers. The powder solidifies, forming the final 3D component. However, for SLS, a laser essentially fuses thermoplastics together. The powder isn’t melted entirely – instead, particles are fused at specific contact points.
Materials
In most cases, you see lPBF being used on materials like metal alloys. On the other hand, SLS is more flexible in terms of material selection as it works with nylons, plastics, etc.
Characteristics
Parts produced with LPBF come with higher strength and density since the powder is completely melted.
However, SLS parts tend to come with lower density as a result of the sintering itself. Still, their mechanical properties tend to be impressive nonetheless.
Surface Finish
The LPBF process generally results in smoother surface finishes as melting and solidification take place. For SLS, surfaces tend to be a bit rougher – although post-processing can help improve this.
Applications
While LPBF works best in industries like automotive and aerospace manufacturing, SLS is better suited for plastic production, prototyping, and more.
LPBF vs. Selective Laser Melting (SLM)
As explained earlier, people use laser powder bed fusion and selective laser melting interchangeably. Both processes work the same way, and they have essentially the same process details, materials, and workflows.
However, there are cases where you might see differences in the laser powder bed fusion vs selective laser melting debate. For instance, some manufacturers favor SLM in order to emphasize the total melting and fusion of the powder particles.
On the flip side, LPBF could be used to describe a wider spectrum of additive manufacturing processes that also involve material fusing.
All in all, both terms refer to the same thing – melting powder and fusing them to create intricate parts and products. At the end of the day, your terminology choice will only differ based on the industry and context.
LPBF vs. Direct Metal Laser Sintering (DMLS)
A similar trend to the above is visible when considering the laser powder bed fusion vs direct metal laser sintering debate. Both processes are incredibly similar, with their applications, materials, and work processes being pretty much the same.
The slight difference, of course, is that the use of these terminologies can differ based on their histories and the manufacturers’ differences. Some experts prefer to use direct metal laser sintering to describe the initial sintering process that happens when metal parts are being developed, while laser powder bed fusion can be used to refer to a broader workflow that also involves laser-based additive manufacturing.
At the end of the day, the objective is to create high-quality, complex parts that can be used in different industries.
Strengthening Final Products In LPBF Processing
In an ideal environment, the products you get from laser powder bed fusion will be optimal. However, in some cases, you might find that you need to do a bit to strengthen them – especially for applications in the defense and aerospace industries.
Of course, it always helps to get the right materials from the start. However, here are some strategies that could help ensure that what you end up with is strong enough to handle the intended function:
- Thermal Treatments: Solution heat treatment, annealing, and others can easily be added to optimize the product’s material properties and microstructure.
- Hot Isostatic Pressing (HIP): In the hIP process, the printed parts are subjected to elevated pressure and temperature levels in an inert gas environment. This process cuts down on internal porosity, thus optimizing material density and other properties.
- Stress Relief: These treatments make it easier to reduce any stress that might have built up in the initial printing process. It reduces the cracking risk and improves overall part stability.
- Surface Finishing: Machining, grinding, and other post-processing techniques can help to bolster the surface finish and dimensional accuracy for the printed parts.
- Shot Peening: With shot peening, you bombard the part surface with small metal particles. This process generally induces stresses in the surface layer, eventually improving fatigue life and crack resistance.
- Cold Work: Cold working can be applied to a few specific metal materials to make themes stronger and harder, giving them more functionality across the board.
- Design Optimization: When designing, you want to consider the part’s intended use. Feel free to incorporate radii, fillets, and other structures to help you get stronger and more versatile components.
Conclusion
Despite the fact that it’s been around for a while, there is still a lot that needs to be explored with laser powder bed fusion. Fortunately, we at KDM Fabrication are experts at this and will be able to help you get started with the process.
Contact us today and let’s begin!
