What is Additive Manufacturing?

Additive manufacturing refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. The term "3D Printing" is increasingly used as a synonym for Additive Manufacturing. However, the later is more accurate in that it describes a professional production technique which is clearly distinguished from conventional methods of material removal.

Additive vs Subtractive Manufacturing

• In subtractive manufacturing we start with stock and remove material to get the net shape (traditional machining).
• In additive manufacturing we start with nothing and add material to get the net shape.

In additive manufacturing, 3D objects are built by adding material in layer upon layer fashion. Materials ranging from plastics, thermoplastics, ceramics, biochemicals, metals, and concrete can be used for production in this sector. Even work is under process to develop human tissues using additive manufacturing techniques.

Following processes are involved in any AM technology:

1. A CAD sketch is produced using a computer 3D modeling software
2. The AM equipment is used to read this data from CAD file
3. The AM equipment layd down successive layers of material which is to be used for fabrication of the product (this may include liquid, powder, sheet material or others).

3D printing, rapid prototyping, layered manufacturing, direct digital manufacturing and additive fabrication are all subsets of additive manufacturing.

Additive manufacturing technology is being actively used in the industry ranging from aerospace, automotive, healthcare and product development.

Categories of Additive Manufacturing

Binder Jetting: Liquid bonding agent selectively deposited to join powder

Material Jetting: Droplets of build material selectively deposited

Powder Bed Fusion: Thermal energy selectively fuses regions of powder bed

Directed Energy Deposition: Focused thermal energy melts materials as deposited

Sheet Lamination: Sheets of material bonded together

Vat Photo-polymerization: Liquid photo-polymer selectively cured by light activation

Material Extrusion: Material selectively dispensed through nozzle or orifice

The eight steps in Additive Manufacturing (process chain):

1. Conceptualization and CAD
2. Conversion to STL
3. Transfer and manipulation of STL file on AM machine
4. Machine setup
5. Build
6. Part removal and cleanup
7. Post processing of part
8. Application