What Is Additive Manufacturing?

Additive manufacturing is the technique of creating three-dimensional products from CAD models by layering on the material using digital data. 

Additive Manufacturing, previously known as rapid prototyping, and currently popular as 3D printing. The term Rapid prototyping was coined to describe the time efficiency of the AM process and technology which created physical prototypes directly from digital model data. But Now, many parts are directly being manufactured by these machines, So it makes no sense to call them prototypes. While the name is still under debate, as per the recently formed Technical committee within ASTM, they adopted a consensus standard to now use the term Additive manufacturing. 

How does Additive Manufacturing Work?

Using a software-defined model which is computer-aided design (CAD) or 3D object scanners that contain full geometric description of parts which is to be printed, additive manufacturing allows for the creation of objects with precise geometric shapes. These are then built layer by layer, as with a 3D printing process, which is in contrast to traditional manufacturing that often requires machining or other techniques to remove surplus material. 

Advantages of Additive Manufacturing 

Additive manufacturing offers numerous advantages that revolutionize the production process. 

Below are nine significant benefits:










Fundamentals Of Additive Manufacturing

Knowing the fundamentals of manufacturing:

Any of the procedures that follow can be combined to produce any product:



When we talk about manufacturing systems, we first will try to understand the basics of manufacturing. Combining the processes below constant volume, subtractive, and additive can manufacture any product. So, it can be one process, it can be one and two, or it can be all three together.

What is constant volume process? 

In constant volume process, the starting and ending materials will be almost the same in quantity. Volume-wise, it will be nearly the same. The two major dominating processes are casting and forging.

 In casting, metal is heated until molten. It is poured into a mold or vessel to create the desired shape while in the molten or liquid state. 

 Forging is an application of either thermal and mechanical or only mechanical to produce steel billets or ingots that cause the material to change shape in the solid state.

What Is Subtractive Process?

The subtractive process is used today because the part geometries have become complex, and the production rate has decreased. There is a no-no mass production process here where we can have variation between one part and the other. So, subtractive tries to always give the freedom to produce complex jobs with the highest accuracy. A subtractive process can be done, and the production volume is lower than the constant volume process as we go for subtractive. We can generate profiles, whatever we want, depending upon the tool's geometry and the workpiece. So, we can have drilling, turning, milling, and grinding, which are part of a subtractive process. 

What is Additive Process?

Additive manufacturing and rapid prototyping are nearly identical processes. Additive manufacturing is the technique of creating three-dimensional products from CAD models by layering on material. Unlike subtractive manufacturing techniques, additive manufacturing is defined by the ASTM as combining materials to create items from 3D model data, often layer by layer. Thus, an item is created layer by layer to create a 3D model.

Subtractive vs Additive manufacturing product

This is a schematic representation of a comparison of subtractive and additive processes. In the subtractive process, we start with a huge chunk of material; then we do a lot of machining operations. 

And finally, we get an object done. When we get this object done, we also generate so much waste, scrap, or chips. So, now, to produce this output, we used so much material in the start, and then finally, after making the object, this is scrap, for which, initially, we spent so much energy to build up this part. Finally, we scoop away, remove whatever is unnecessary, and say it is scrap. This process is in no way energy efficient compared to additive manufacturing. In additive manufacturing, we use the starting material, do various processes, and convert the raw material into a finished part. We lay down our raw material in the required space alone. Doing so reduces the scrap or the waste from a larger amount to a smaller amount. The material can be a powder, a wire, or a sheet. From there, we build the object and add material at the required space to produce the output. The wastage is reduced, and it is energy efficient. This is the comparison between the subtractive process and the additive process.

Types Of Additive Manufacturing Process

Vat Polymerization 

Vat polymerization uses a vat of liquid photopolymer resin, which we will call it a special liquid, that hardens when exposed to Ultraviolet (UV) light. As our printing machine will print the object layer by layer by shining a light on the liquid and making it solid.

 Now, In this scenario, the substrate will move downward inside the liquid, unlike other 3D printers that use powder. Also, extra support will be provided inside the liquid as it does not provide enough support. UV light will be directed by tiny mirrors that move around to shape the object. After printing is done, Excess liquid will be removed and this new shape will be cleaned using alcohol and water. It is like giving the object a nice wash.

Powder bed fusion 

Powder bed fusion (PBF) involves selectively fusing powdered materials layer by layer using thermal energy, typically from a laser or electron beam, on a powder bed.

In our machines, each layer of powder is precisely laid out and to solidify this a powerful laser or electron beam will come in and act as a heat source after that it will be left to solidify. Here the path followed by the laser is also known as the scan pattern and will be given by users as per to desired shape.PBF parts exhibit high strength and stiffness, comparable to or better than bulk material. While offering fine resolution and quality, PBF faces challenges such as surface roughness, internal porosity, shrinkage, and powder handling. Despite drawbacks like slow production and high costs, PBF finds applications in diverse industries, including aerospace, and electronics, with the powder bed serving as built-in support. Check out AM PravaH software developed by Paanduv Applications to simulate these processes.

Extrusion Based System 

Material Extrusion-Based Additive Manufacturing (EB-AM) is a 3D printing process, known as Fused Deposition Modeling (FDM) or Fused Filament Fabrication, encompassing plastics, metals, and ceramics. Fused Deposition Modeling is a common material extrusion process, Here material is drawn through a nozzle, where it is heated and then deposited layer by layer. The nozzle can move horizontally and the platform moves up and down vertically after every layer is formed.

Material Jetting 

Material Jetting is an additive manufacturing technology that closely resembles traditional paper printing. Using printheads similar to inkjet printers, it deposits droplets of material layer by layer to create 3D objects. Originating in the mid-1990s, Solidscape pioneered "Drop-on-Demand" tech for wax printing. 3D Systems and Objet introduced their versions, advancing into MultiJet Printing (MJP) and PolyJet material jetting systems, respectively. Material jetting boasts speed and precision. Droplets of photosensitive material cure instantly under ultraviolet (UV) light, eliminating the need for additional curing. Despite high costs and the need for supports, that can be dissolved post-printing, material jetting offers exceptional dimensional accuracy, surface finish, and the ability to mix materials. It excels in creating prototypes, visual aids, and tooling due to its capacity for multi-material printing. 

Binder Jetting 

Binder Jetting (BJ), developed by MIT in the early 1990s, is a powder-bed additive manufacturing process for metals. Unlike laser-based methods, BJ uses a recoating blade to deposit metal powders layer by layer, binding them with polymer binders. The resulting green body has high porosity (40-50%), requiring post-processing like infiltration or sintering for increased strength. MBJ accommodates various metals and composites, offering advantages in productivity and surface roughness. No supporting structures are needed during printing, and a large build platform allows for multi-component production. However, accuracy and mechanical strength limitations arise due to post-processing challenges, resulting in geometry distortion and porosity. Micro-part application depends on the development of 3D printable micro-metal powders and recoating techniques. The choice of metal powder size influences surface roughness and complexity, with finer powders posing challenges in flowability and agglomeration. Advanced recoating techniques aim to address these issues, although real-time observation highlights potential agglomeration concerns with particles smaller than 10 µm in MBJ.

Sheet Lamination 

Sheet lamination processes, exemplified by Ultrasonic Additive Manufacturing (UAM) and Laminated Object Manufacturing (LOM), involve layering materials to create 3D objects. UAM utilizes metal sheets bonded through ultrasonic welding, requiring subsequent CNC machining and removal of unbound metal. In contrast, LOM employs paper and adhesive in a layer-by-layer approach with a cross-hatching method, facilitating easy post-build removal. While LOM is suitable for aesthetic models, UAM, accommodating metals like aluminum, copper, stainless steel, and titanium, excels in low-temperature applications, enabling the creation of internal geometries. UAM's non-melting process, allowing the bonding of different materials with minimal energy consumption, makes it versatile for various applications.

Directed Energy Deposition (DED) 

Directed Energy Deposition (DED) encompasses various terms like 'Laser Engineered Net Shaping' and 'Direct Metal Deposition' and is a sophisticated 3D printing process commonly employed for repairing or adding material to existing components. In a typical DED machine, a multi-axis arm-mounted nozzle deposits melted material onto a specified surface, solidifying upon contact. While similar to material extrusion, DED allows multi-directional nozzle movement and is not fixed to a specific axis. The process, often used with metals in powder or wire form, employs a laser, electron beam, or plasma arc for material melting in a controlled, low-oxygen atmosphere. DED offers advantages like precise control over grain structure, making it suitable for high-quality repair work, and a balance between surface quality and speed. However, finishes may vary, and further research is needed to enhance the process for broader applications.

Check out AM PravaH software developed by Paanduv Applications to simulate these processes.

Materials Used In Additive Manufacturing

Materials utilized in additive manufacturing Process (AM) span a diverse spectrum, tailored to meet the multifaceted demands of various applications. The selection of materials is influenced not only by their inherent properties but also by the specific AM processes employed. While the characteristics of the final product predominantly hinge on material properties, the Additive Manufacturing process itself can induce alterations in the material's microstructure due to the applied temperature and pressure. Below, we delineate several categories of materials integral to the additive manufacturing process:


Polymers:

Initially employed in stereolithography, polymers remain fundamental in Additive Manufacturing process. Evolving beyond early iterations, thermoplastics like PLA and ABS dominate filament-driven systems, with high-performance variants such as PEEK and PEKK gaining traction. Nylons and TPU find utility in powder bed fusion processes. While traditionally solid filaments or pellets, polymers are now available in liquid resin or powder forms.


Metals:

Aluminum, titanium, stainless steel, Inconel, and cobalt chrome constitute the primary metals employed in the Additive Manufacturing Process. Innovations, such as blue-light lasers, facilitate the printing of historically challenging materials like copper. Variations in metal composition and format, whether wire, powder, or mixed with other materials, cater to the intricacies of different printing methods.


Composites:

Composite materials, amalgamating disparate elements, emerge as a burgeoning frontier in AM. Reinforced polymers incorporating carbon and glass fibers offer versatility across various applications, ranging from tooling to end-use parts. Metal matrix composites (MMCs), blending metals with ceramics, expand the horizons of material possibilities in AM.


Ceramics:

Despite challenges in laser-based systems, ceramics find application in AM through innovative solutions like extrusion, material jetting, and photopolymerization. Utilizing ceramic slurries or blends, the printing process lays the groundwork for subsequent sintering, akin to bound metal deposition.


Sand:

Even sand undergoes the transformative process of AM through binder jetting, wherein selective binding of grains facilitates the creation of molds and tooling for diverse industrial applications, including foundry molds and vacuum-form tooling.

Applications of Additive Manufacturing

Additive manufacturing allows parts to be built without the need for traditional tooling and with few limitations in geometry. Equally, it is complementary to traditional subtractive methods and can be readily integrated into the existing production workspace.


Organizations that use metal parts can make a thorough analysis of current product and production lifecycles to reveal gaps where additive manufacturing could prove advantageous - in reducing development time, production steps, costs, and use of material.


The early adopters of additive manufacturing were high-end technology industries, for example, aerospace and motorsport. With the increasing application of the technology, there is potential for additive manufacturing to become mainstream and an integral part of every engineer and designer's toolkit.











AM PravaH the Ultimate Solution For Additive Manufacturing Industries 

AM PravaH is a parallelized computational modeling software with a Graphical User Interface (GUI) dedicated to AM processes and developed by Paanduv R&D. AM PravaH is powered by an ensemble of advanced numerical programs that are developed by researchers around the globe and by us; tailored and improvised by Paanduv R&D for AM specific tasks.

Computational modeling capabilities of AM PravaH


The current version of AM PravaH has the capability of modeling AM processes across scales including macroscale, and microscale. Additionally, particle modeling is included in the software for AM processes that use metal powders. At the macroscale, laser dynamics, melt pool dynamics, phase change, solidification, Marangoni effects, heat, and mass transfer, and surface tension effects are captured. At the microscale, grain structure, grain size, and grain morphology are captured. Also, a robust and advanced deep learning module is added for predicting AM process parameters and building quality using experimental or simulation data.

To connect or enquire for projects, Reach out at support@paanduv.com