3D printing is neither a mysterious nor a new technology; in fact, it has been contributing silently to industrial applications for nearly three decades. Generally, the methods of object formation can be classified into four types: subtractive manufacturing, compression molding, additive manufacturing, and growth modeling.

Subtractive Manufacturing: This method involves the removal of excess material from a base using separation techniques such as traditional turning, milling, grinding, drilling, planing, electrical discharge machining (EDM), and laser cutting.

Compression Molding: Utilizing the plasticity of materials under specific external forces, traditional techniques like forging, casting, and powder metallurgy fall under compression molding. This process is often used in the rough stage of model production but can also be directly applied to workpiece formation in processes like precision casting and forging.

Additive Manufacturing: Also known as layered manufacturing, this method involves adding materials in a structured manner using mechanical, physical, and chemical processes.

Growth Modeling: Refers to the formation method that utilizes the reactivity of materials, similar to how biological entities develop in nature. With advancements in reactive materials, biomimetics, biochemistry, and life sciences, growth modeling is expected to evolve significantly.

Narrowly defined, 3D printing primarily refers to additive manufacturing technology. This technology breaks away from traditional formation methods by combining rapid automated formation systems with computer data models, enabling the creation of complex prototypes without the need for traditional molds or machining. This significantly reduces product design and production cycles and lowers manufacturing costs.

To deepen understanding of 3D printing, here is an introduction to several mainstream 3D printing technologies:

LOM (Layered Object Manufacturing): One of the oldest and most mature 3D printing technologies, LOM has been rapidly evolving since its inception in 1991. Typically using materials like paper or PVC film, LOM is cost-effective and offers high precision, making it widely used in product concept visualization, model design evaluation, assembly inspection, and lost-wax casting.

SLA (Stereolithography Apparatus): Developed by Charles W. Hull in 1984, who later founded 3D Systems and launched the first commercial 3D printer, SLA-250, in 1988. SLA uses photopolymer resins cured layer by layer by ultraviolet lasers, producing high-precision three-dimensional models.

SLS (Selective Laser Sintering): Proposed by C.R. Deckard during his master's thesis at the University of Texas at Austin in 1989, SLS uses a laser to sinter powdered material, bonding it together to form a solid structure.

FDM (Fused Deposition Modeling): Developed by Scott Crump in 1988, who later established Stratasys and introduced the first FDM-based 3D printer in 1992. FDM involves heating and extruding thermoplastic filament to create layers that bond together to form an object.

3DP (Three-Dimension Printing): Invented by Professor Emanual Sachs at MIT in 1993, 3DP resembles inkjet printing, where a binder is sprayed onto a powder bed to form objects layer by layer.

PolyJet Technology: Developed by the Israeli company Objet in the early 2000s, PolyJet involves jetting photopolymer material and curing it with UV light to create precise layers, suitable for complex model production.

This detailed explanation aims to clarify the principles behind 3D printing technologies, paving the way for greater accessibility and innovation in the industry.