Introduction to 3D Printing
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Fused Deposition Modeling (FDM) is the most widely used form of 3D printing in households around the world. This process involves extruding melted thermoplastic material layer by layer, allowing each layer to cool and solidify before the next one is added.
FDM is an additive manufacturing method, opposite to subtractive processes like CNC milling. Instead of cutting away from a solid block, FDM uses only the material needed for the part itself, with the exception of support structures used for overhangs. These supports are removed and discarded after printing.
The uniqueness of FDM printing primarily lies in three key areas: the material used, the slicing software that converts 3D models into G-code instructions, and the extrusion system. Other components like motors and control boards are not exclusive to FDM and are common across many digital fabrication methods.
FDM printing is considered one of the most affordable and accessible methods of 3D printing. Compared to other technologies, such as SLA or resin printing, both the machines and materials are more cost-effective. While resin printer prices have dropped in recent years, they generally offer smaller build volumes and involve more expensive consumables, and are generally less user friendly.
The material variety available for FDM is extensive. Options include flexible filaments, carbon fiber blends, nylon, polycarbonate, UV-resistant, and weather-resistant materials. Many high-temperature materials are also available, though they often require enclosed and actively heated environments. With hundreds of filament types on the market—each offering unique characteristics like strength, flexibility, and thermal resistance—it is possible to find a material suited to nearly any application, provided the printer is equipped with a compatible extruder and hotend.
Compared to resin-based printing processes, FDM is also much cleaner and easier to use. It avoids handling of toxic chemicals and typically involves less post-processing. This makes FDM a more beginner-friendly option and better suited for casual or home use.
In FDM 3D printing, axis orientation may be unfamiliar to those with a background in geometry or general mechanics. The X-axis moves the tool left to right, the Y-axis moves it forward and backward, and the Z-axis controls vertical movement. Though it may seem counterintuitive, this naming convention is standard within the 3D printing community.
The most common axis configurations are based on Cartesian and CoreXY designs. Cartesian printers operate with each axis independently controlled by its own stepper motor. Typically, the build plate moves in the Y direction, while the hotend moves in the X direction. The entire carriage moves in the Z direction. These printers are often referred to as “bed slingers.”
Some machines, such as the Ender 5 series, use Cartesian-style motor movement but have a vertically moving build plate. These are often grouped with “gantry-style” printers for simplicity. In general, printers where the bed moves vertically in the Z-axis are considered gantry-style, while those where the bed moves forward and backward in the Y-axis are considered Cartesian-style or more colloquially as "bed slingers".
CoreXY machines differ in that the X and Y axes are synchronized through a belt system driven by two stepper motors. This allows for smoother motion, reduced Z-wobble, and improved stability—especially during faster printing. CoreXY printers are gaining popularity due to these benefits and are now found in models like the Bambu Lab X1 and P1 series.
Printers such as the A1 and A1 Mini continue to use Cartesian-style configurations and are known as "bed slingers".
Delta printers operate on an entirely different principle, using three arms arranged in a triangle to position the extruder above the print bed. While they can offer high-speed printing and excellent quality, they require taller frames and are less compact than Cartesian or CoreXY alternatives. These machines are far less commonly used due to space and setup requirements, but they are capable of excellent results.
FDM printers use one of two extruder types: direct drive or Bowden. A direct drive extruder feeds filament directly into the hotend from a motor mounted on the print head. In contrast, a Bowden extruder uses a remote motor to push filament through a PTFE tube to the hotend.
Bowden systems reduce the weight of the print head, allowing for faster movement. However, they can struggle with materials like TPU (flexible filament) and often require precise tuning of retraction settings to avoid stringing. Direct extruders offer better precision, easier use with flexible materials, and generally improved extrusion control.
Recent industry advances, such as vibration compensation, have made the weight disadvantage of direct drive systems less significant. As a result, more manufacturers are now offering affordable models with direct drive setups, and Bowden configurations are becoming less common.
Read more about Extruders.
