Additive manufacturing, commonly called 3D printing, is a group of manufacturing techniques that create a three-dimensional object by depositing, curing, or fusing material layer by layer from a digital model. Unlike subtractive manufacturing, it adds material only where required.
How additive manufacturing works
The process normally follows these stages:
- A three-dimensional model is produced using computer-aided design (CAD) software or captured through 3D scanning.
- The model is exported in a suitable file format and digitally divided into thin horizontal layers through slicing.
- The machine forms each layer using material such as a polymer filament, liquid photopolymer, resin, or metal powder.
- Successive layers are bonded until the complete object has been produced.
- Post-processing may then be required, such as removing supports, curing, sanding, machining, or applying a surface finish.
Common additive processes include material extrusion, where heated polymer is deposited through a nozzle; vat photopolymerization, where light cures liquid resin; and powder bed fusion, where thermal energy fuses selected regions of powder.
| Additive manufacturing | Subtractive manufacturing |
|---|---|
| Builds material layer by layer | Removes material from a larger workpiece |
| Can produce complex internal geometry | Geometry is limited by tool access |
| Usually creates less material waste | May produce significant waste material |
| Often slower for mass production | Can be efficient for repeated production |
| Supports customization without dedicated tooling | Changes may require new tools or setups |
Important advantages include rapid prototyping, mass customization, reduced material waste, and the production of complex or consolidated components. Limitations include slow production rates, restricted build size, visible layer lines, anisotropic properties, material limitations, and the possible need for support structures.
IB exam technique
For A4.1 Manufacturing techniques (HL), define the process through its layer-by-layer mechanism and connect it to CAD data. A common misconception is that all 3D printing uses melted plastic; additive manufacturing includes several processes and can use polymers, metals, ceramics, and composite materials. When evaluating its suitability, compare production volume, geometry, material properties, cost, waste, surface quality, and required post-processing.