Classification of Industrial Additive Manufacturing (AM)

Classification based on the overall Landscape of Additive Manufacturing

The AM is broadly classified into 2 categories:

• Technology
• Materials

Figure (1): Classification based on the overall Landscape of Additive Manufacturing (Image Courtesy oftoof EOS GmbH)

Technology

Technological Classification of Additive Manufacturing:

Today, Additive Manufacturing (AM) is not only available for industry grade applications but also for hobby printing thanks to learning- grade tabletop printing machines. Broadly there are 7 categories of AM processes worldwide while new techniques and processes are being introduced due to continuous emergence and expansion of this industry.

• VAT Photo – Polymerisation
• Material Jetting
• Binder Jetting
• Material Extrusion
• Powder Bed Fusion
• Sheet Lamination
• Direct Energy Deposition

VAT Photo – Polymerisation:-

VAT Photo – Polymerisation is an additive manufacturing process where a liquid photopolymer resin is selectively cured by a light source to build up a part layer by layer. The term “VAT” refers to the vat or container that holds the liquid resin during the printing process.

The VAT photo – polymerisation is further categorised into the following:

• Stereolithography (SLA)
• Digital Light Processing (DLP)
• Hybrid Photosynthesis Technology (HPS) [SLA + DLP]
• Liquid Crystal Display (LCD)
• Lubricant Sublayer Photo – Curing (LSPc)
• Programmable Photo Polymerisation (P3)
• Continuous Digital Light Manufacturing (CDLM)
• Continuous Liquid Interface Production (CLIP)

Material Jetting (MJ):

Material Jetting is an additive manufacturing process that works similarly to inkjet printing but instead of jetting ink, it deposits droplets of build material layer by layer to create a 3D object. Each layer is immediately cured or solidified using ultraviolet (UV) light, allowing for the creation of highly detailed and accurate parts.

The material jetting (MJ) is further categorized as follows:

• Material Jet Printing (MJP)
• Liquid Metal Jetting (LMJ)
• Polyjet (PJ)

Binder Jetting (BJ):

Binder Jetting is an additive manufacturing process that uses a liquid binding agent to selectively bind powder particles together to form a solid part. The process builds parts layer by layer, like other AM technologies, but it stands out for its ability to handle a wide range of materials and its relatively low cost.

The Binder Jetting (BJ) process is further categorized as:

1. Single Pass Jetting (SPJ)

Material Extrusion (ME):

Material Extrusion is an additive manufacturing process where a thermoplastic material is heated until it becomes semi-liquid and is then extruded through a nozzle to build up an object layer by layer. The extruded material solidifies and bonds with the previous layer, gradually forming the desired 3D shape.

Figure (2): Material Extrusion Process

The Material extrusion is further categorized into following:

• Fused Deposition Modelling (FDM)
• Fused Filament Fabrication (FFF)
• High Speed Extrusion (HSE)
• Independent Dual Extruder (IDEX)
• Cast in Motion (CIM)
• Atomic Diffusion Additive Manufacturing (ADAM)

Powder Bed Fusion (PBF):

Powder Bed Fusion is an additive manufacturing process where a heat source, typically a laser or electron beam, selectively fuses powdered material layer by layer to build a part. The process occurs in a controlled environment to ensure high precision and material properties.

The Powder Bed Fusion is further categorized into following:

• Laser Powder Bed Fusion (LPBF) further also known as:
  • Selective Laser Sintering (SLS)
  • Cold Metal Fusion (CMF)
  • Quantum Laser Sintering (QLS)
  • High Speed Sintering (HSS)
  • Direct Metal Laser Solidification (DMLS)
  • Selective Laser Melting (SLM)
  • Direct Metal Laser Melting (DMLM)
  • Hybrid Laser Powder Bed Fusion with CNC (HLPBF)

• Multi Jet Fusion (MJF)
• Selective Absorption Fusion (SAF)
• Electron Beam Melting (EBM)
• Mold Jet Technology (MJT)

Sheet Lamination:

Sheet Lamination, also known as Laminated Object Manufacturing (LOM), involves layering sheets of material and bonding them together to form a solid part. Each sheet is precisely cut to match the cross-sectional shape of the part at a particular layer. The layers are bonded using adhesives, heat, or pressure, creating a cohesive structure.

Direct Energy Deposition (DED):

Direct Energy Deposition is an additive manufacturing process that uses focused thermal energy, such as a laser, electron beam, or plasma arc, to fuse materials by melting them as they are being deposited. This technology can work with various materials, including metals, ceramics, and composites, making it highly versatile for different industrial applications.

The Direct Energy Deposition (DED) is further categorized as follows:

• Laser Direct Energy Deposition (LDED)
• Hybrid Laser Direct Energy Deposition with CNC (HLDED)
• Rapid Plasma Deposition (RPD)
• Wire Arc Additive Manufacturing (WAAM)

Materials

AM classifications based on Raw Material Form/Shape and Feed:

Extrusion Based Additive Manufacturing

Extrusion-based additive manufacturing is a process where a thermoplastic material is heated until it becomes semi-liquid and is then extruded through a nozzle to build up an object layer by layer. The extruded material solidifies and bonds with the previous layer, gradually forming the desired 3D shape.

Resin Based Additive Manufacturing

Resin-based additive manufacturing involves the use of liquid photopolymer resins that are selectively cured by a light source to form solid layers. These layers are built up sequentially to create a complete 3D object. The process is known for its high resolution and ability to produce intricate details and smooth surface finishes.

Powder Based Additive Manufacturing

Powder-based additive manufacturing involves spreading a layer of powdered material, which is selectively fused by an energy source to form a solid layer. The process repeats layer by layer until the entire part is built. The unfused powder supports the part during the build, eliminating the need for additional support structures.

Sheet Based Additive Manufacturing

Sheet-based additive manufacturing builds objects by stacking, bonding, and cutting sheets of material. Each sheet is cut to the desired shape using a laser or mechanical cutter and bonded to the previous layer to form the final 3D part. This method can utilize a variety of materials, including paper, plastic, and metal.

Stay tuned to our Blog series to get further information on the above technologies in detail.