Additive Manufacturing Processes & 3D Printing - What is the Difference?

VAT polymerisation involves building the model layer by layer from a vat of liquid photopolymer resin.

This works similar to a two-dimensional ink jet printer in that it generates things. A continuous or Drop on Demand (DOD) method is used to jet material onto a construction platform.

A powder-based substance and a binder are used in the binder jetting technique. The binder is generally liquid, whereas the construction material is usually powder. A print head travels horizontally along the machine's x and y axes, depositing alternating layers of construction and binding materials.

Stratasys' branded fuse deposition modelling (FDM) is a popular material extrusion method. Material is pulled via a nozzle, heated, and then deposited one layer at a time. After each fresh layer is deposited, the nozzle may move horizontally and a platform can move up and down vertically.

SLS machines include three parts (Gibson et al., 2010): a heat source to fuse the material, a means to regulate this heat source, and a mechanism to add new layers of material over the old. Because the powder material provides enough model support during the build process, the SLS method does not require any extra support structure. The build platform is housed in a temperature-controlled room with a temperature a few degrees below the melting point of the material, eliminating the need for the laser to fuse layers together. To maximise oxidation and model quality, the chamber is often flooded with nitrogen. To guarantee a high level of tolerance and fusion quality, models must be allowed to cool down. To increase quality, certain machines monitor the temperature layer by layer and adjust the laser's power and wattage accordingly.

Selective Laser Melting (SLM) uses Laser Melting with a Focus (SLM) A roller or a blade is used to distribute new layers of powder over prior ones in this procedure. When a blade is coated, it is frequently vibrated to promote a more uniform powder dispersal (Gibson et al., 2010). A new material supply is provided by a hopper or reservoir beneath or to the side of the bed.

Selective Heat Sintering (SHS) employs a heated thermal printhead, to fuse powder material together. Layers are applied with a roller in between fusion of layers, as previously. The method is most commonly used to create idea prototypes and structural components. The use of a thermal print head rather than a laser reduces the amount of heat and electricity required for the operation. Thermoplastic powders are utilised as support material, as previously. 

Direct Metal Laser Sintering (DMLS) is similar to SLS, except it utilises metals rather than plastic particles. Layer by layer, the powder is sinterised, and a variety of technical metals are accessible.

Electron Beam Melting (EBM) - A beam of electrons is used for melting metal particles. The process's excellent quality and finish make it ideal for producing high-grade parts for aircraft and medical applications. 

Ultrasonic additive manufacturing (UAM)along with laminated object manufacturing are two types of sheet lamination techniques (LOM). Metal sheets or ribbons are used in the Ultrasonic Additive Manufacturing process, and they are joined together using ultrasonic welding. More information may be found here.

‘Laser designed net shaping, directed light manufacturing, direct metal deposition, 3D laser cladding' are some of the terms used to describe Directed Energy Deposition (DED). It's a more advanced printing technique that's often used to repair or add material to existing components.