How does 3D printing work?

Each 3D printer constructs the parts according to the same principle: a digital model (called a 3D file or 3D model) is transformed into a three-dimensional physical object by adding one layer of material at a time. This is where the alternative additive manufacturing term comes from, in particular

3D printing is a fundamentally different way to produce parts than traditional materialized (CNC machining) or formative (injection molding) technologies.

In 3D printing, no special tools (for example, a cutting tool with a particular geometry or mold) are required. Instead, the part is manufactured directly on the built platform layer by layer, resulting in a unique set of advantages and limitations.

The process always starts with a 3D digital model (mainly in STL or OBJ format) – this is the plane of the physical object. This model is cut by the 3D printer software (called slicer) into thin two-dimensional layers, and then transformed into a set of machine language instructions (G code) that the printer can execute.

From now on, the operation of a 3D printer varies by process. For example, desktop FDM printers melt plastic filaments and apply them to the printing platform using a nozzle (such as a computer-controlled, high-precision glue gun). Large SLS industrial machines use a laser to melt (or sinter) thin layers of metal powders or plastics.

Available materials also vary depending on the process. Plastics are by far the most common, but metals can also be 3D printed. Produced parts can also have a wide range of specific physical properties, from optically transparent objects to gummy objects.

Depending on the part size and 3D printer type, the printing process usually takes between 4 and 18 hours. However, 3D printed parts are rarely ready for use outside the machine. They often require further treatment to reach the desired level of surface finish. These steps require more time and effort (usually manual).

A Brief History of 3D Printing

    • Sci-fi author Arthur C. Clarke first described the basic functions of a 3D printer in 1964.
    • The first 3D printer was released in 1987 by Chuck Hull of 3D Systems using the “stereolithography” (SLA) process.
    • In the 1990s and 1990s, other 3D printing technologies were developed, including Stratasys FDM and 3D Systems’ SLS. These printers were expensive and were mainly used for industrial prototyping.
    • In 2009, the ASTM F42 Committee published a document with standard terminology on additive manufacturing. 3D printing has thus become an industrial manufacturing technology.
    • In the same year, FDM patents expired and the first low-cost 3D desktop printers were developed through the RepRap project. What used to cost $200,000 suddenly went on sale for less than $2,000.
    • According to Wohlers, adoption of 3D printing is increasing: between 2015 and 2017 more than one million 3D desktop printers were sold worldwide and sales of industrial metal printers nearly doubled in 2017 compared to the previous year.


    • Possibility to reproduce any geometry (release the design process from the constraints of traditional manufacturing, impossible geometries…)
    • Provide an immediate response to changing market needs (reduce time to market).
    • Enable the differentiation and customization of products by consumers (mass customization, unit lot, tailored…).
    • Reduce assembly errors (and therefore costs).

Application sectors

    • Molds and dies: manufacture of parts with internal cooling channels, inserts or hybrid molds.
    • Medicine: manufacture of medical implants, orthopedic products and custom surgical tools and surgical programming and planning.
    • Aeronautics and automotive: manufacture of parts with lightweight structures or internal channels and subject to frequent design changes.
    • Architecture and topography:manufacture of models.
    • Design / Engineering: product development, models, first series, equipment housings…