Seattle Glossary and Reference Guide to 3D Printing Terminology and Concepts

Glossary of 3D Printing Terms [27]

S Screw-Based Extrusion Screw-based extrusion is a material deposition method used in 3D printing, particularly in direct pellet-fed extruders or paste extrusion systems. Instead of a filament-based approach, a screw mechanism pushes material through the nozzle. This technique allows for the use of recycled plastics, custom polymer blends, or thick pastes such as ceramics and food materials. It is common in large-format 3D printers and experimental research applications.
Seam Hiding Techniques Seam hiding techniques are used to minimize the visibility of Z-seams (layer start and end points) in FDM printing. Strategies include randomizing the seam position, aligning it with a model's corner, or using linear advance settings to reduce extruder pressure inconsistencies. Proper seam control improves the final aesthetic of the print.
Selective Laser Sintering (SLS) Selective Laser Sintering (SLS) is an industrial-grade 3D printing technology that uses a high-powered laser to sinter powdered material into solid layers. Materials commonly used in SLS include nylon, polyamides, and metals. The powder acts as both the material and support, enabling the creation of complex geometries without the need for additional support structures. SLS is widely adopted for functional prototyping and production of durable, end-use parts. The process delivers excellent mechanical properties and design freedom but requires specialized equipment and post-processing, such as powder removal. It's ideal for engineering, automotive, and aerospace industries.
Self-Leveling Bed A self-leveling bed is an advanced 3D printer feature that uses sensors and automated adjustments to ensure the build surface is perfectly leveled. This technology compensates for uneven surfaces, reducing the risk of poor first-layer adhesion and warping. Some printers use inductive, capacitive, or strain-gauge sensors to map the bed and adjust the Z-axis accordingly. Self-leveling beds significantly improve print consistency, particularly in large-format printers, where minor deviations can cause print failures.
Semi-Flexible Filament Semi-flexible filament, such as semi-rigid TPU or soft PETG, provides a balance between stiffness and elasticity. These materials are commonly used for shock-absorbing parts, protective casings, and ergonomic components. They are easier to print than fully flexible materials while still offering enhanced durability.
Sensorless Homing Sensorless homing is a method used in 3D printers to determine the home position of the print head or build plate without physical end-stop switches. Instead, it relies on motor current sensing to detect resistance when movement is blocked. This reduces mechanical complexity and potential failure points while allowing for more compact printer designs.
Sensorless Homing Sensorless homing is a method used in 3D printers to determine the home position of the print head or build plate without physical end-stop switches. Instead, it relies on motor current sensing to detect resistance when movement is blocked. This reduces mechanical complexity and potential failure points while allowing for more compact printer designs.
Shell Thickness Shell thickness refers to the outer walls of a 3D-printed object and is a key parameter in defining strength and durability. A thicker shell can enhance structural integrity, making the object more resistant to stress and impact. In FDM printing, shell thickness is typically defined in multiples of the nozzle diameter; for example, a 0.8 mm shell thickness with a 0.4 mm nozzle means two perimeter passes. In SLA and SLS printing, shell thickness influences resin curing or sintering stability. Optimizing shell thickness is essential to balancing material usage, print time, and the final product’s mechanical properties. Thin shells can lead to fragile prints, while overly thick shells waste material and increase print time.
Shrinkage Compensation Shrinkage compensation refers to the adjustments made in a 3D printing process to counteract material contraction during cooling. Thermoplastics like ABS tend to shrink more than PLA, leading to warping or dimensional inaccuracies. In SLS and metal 3D printing, shrinkage compensation is crucial due to sintering-related size reductions. Design modifications or software corrections (such as scaling up a model slightly) help ensure that the final dimensions match the intended specifications. Shrinkage varies depending on factors such as material composition, print speed, and cooling rates, requiring fine-tuned settings for accuracy.
Shrinkage Rate Shrinkage rate refers to the percentage reduction in size that a material undergoes after cooling or post-processing. This factor is critical when printing with materials like ABS, which can shrink by up to 8%, leading to warping or dimensional inaccuracy. Adjusting for shrinkage involves scaling the model slightly larger in slicing software or using a heated chamber to slow down cooling and reduce internal stresses.
Silica Gel for Filament Storage Silica gel packets are commonly used in filament storage to absorb moisture and prevent material degradation. Hygroscopic materials like nylon, PETG, and TPU can absorb moisture from the air, leading to print defects such as bubbling, stringing, or weak layer adhesion. Storing filament in airtight containers with silica gel extends material shelf life and ensures consistent print quality.
Sintering Temperature Sintering temperature is the specific temperature range at which powdered materials fuse together in processes such as metal 3D printing or SLS. It is below the material's melting point but high enough to create bonding through diffusion. Proper control of sintering temperature ensures strong, dense prints while preventing defects such as warping or incomplete fusion. Different materials require distinct sintering conditions; for example, nylon sinters at around 160–190°C, while metals can require temperatures above 1000°C.
Skeletal Structure Printing Skeletal structure printing refers to a 3D printing technique where an object is designed with a framework-like structure, reducing weight while maintaining strength. This is commonly used in aerospace, automotive, and medical applications where material efficiency is crucial. Lattice or honeycomb patterns are frequently incorporated into skeletal designs to enhance durability while minimizing material usage.
Skirt A skirt is a preliminary extrusion line printed around the object but not touching it. It helps prime the printer nozzle by ensuring smooth and consistent material flow before the actual model begins printing. Skirts can be adjusted in terms of line count and distance from the object, depending on the desired effect. They also help verify bed adhesion, ensuring there are no gaps or inconsistencies in the initial layers. Unlike a brim or raft, skirts do not provide structural support but are useful for catching potential extrusion issues early in the process.
Slicing Algorithm A slicing algorithm is the mathematical process used by slicing software to convert a 3D model into printable layers and tool paths. Different algorithms optimize aspects like infill generation, support placement, and travel paths to improve print quality and efficiency. Advanced slicing algorithms incorporate AI-driven enhancements to reduce print time and material waste while maintaining structural integrity.
Slicing Software Slicing software translates 3D models into instructions (G-code) for a 3D printer by dividing the model into horizontal layers. It determines parameters such as layer height, print speed, support generation, and infill density. Popular slicing software includes Cura, PrusaSlicer, and Simplify3D, each offering different levels of customization and optimization. Some slicers incorporate AI-driven enhancements to reduce print time or improve structural integrity. Proper configuration in slicing software significantly impacts the final print’s quality and success rate. Many slicers allow for previewing tool paths, estimating print time, and simulating potential errors before printing begins.
Smart Supports Smart supports are optimized support structures designed to minimize material use while maintaining stability for overhangs and bridges in 3D printing. Unlike traditional supports, which are often excessive, smart supports use algorithms to generate the least amount of necessary material. Some slicers, like Cura and PrusaSlicer, offer adaptive or tree-like supports, which branch out efficiently to provide stability while reducing post-processing work. Smart supports also reduce scarring on the final print by strategically placing minimal contact points.
Snap-Fit Joints Snap-fit joints are interlocking connections designed for assembly without adhesives or fasteners. Common in functional 3D-printed components, these joints rely on precise tolerances and material flexibility. PLA is generally too brittle for snap-fits, whereas PETG, ABS, and TPU offer better durability. Design considerations such as fillets at stress points prevent breakage during repeated use. Snap-fits can be categorized into cantilever, annular, or torsional designs, each serving different assembly purposes. Proper layer orientation during printing strengthens these joints by minimizing weak interlayer adhesion.
Spiral Layering Spiral layering is a method of printing where each layer gradually transitions into the next, avoiding abrupt layer lines. This is different from standard layering, where discrete layer changes create visible steps. It is mainly used in artistic and decorative prints for achieving a smooth, continuous appearance.
Spiral Vase Mode Spiral Vase Mode, or Spiralized Outer Contour Mode, is a special 3D printing technique that prints objects in a continuous, single-extrusion motion without distinct layer changes. This method eliminates seam lines, resulting in smoother, aesthetically pleasing prints. It is commonly used for decorative objects like vases, lampshades, and sculptures. Since the print consists of a single perimeter with no internal layers, it is generally weaker but more efficient in material usage. Vase Mode is particularly effective with transparent or semi-transparent materials to create visually striking effects.
Spiralizing Infill Spiralizing infill is a technique that generates continuous, curved infill patterns instead of traditional grid or rectilinear structures. This method enhances flexibility and impact resistance while reducing material usage. It is particularly useful for applications requiring shock absorption or lightweight structural components.
Stepper Motors Stepper motors are precise, digitally controlled motors that move a 3D printer’s axes, including the X, Y, and Z directions, as well as extruder feed systems. These motors operate in fixed angular steps, ensuring accurate positioning of the print head or build platform. Unlike conventional motors, steppers do not require feedback loops, as their movements are inherently precise. However, skipping steps due to mechanical resistance or misconfiguration can lead to layer misalignment. Proper calibration and cooling of stepper motors prevent overheating and improve print consistency. Stepper drivers control the voltage supplied to these motors, influencing noise levels and precision.
Stereolithography (SLA) Stereolithography (SLA) is a 3D printing technique that uses a laser to cure liquid resin into solid layers, one at a time. This process is known for its precision and ability to create intricate details, making it ideal for applications requiring high accuracy, such as dental models, jewelry, and prototypes. SLA printers use photopolymer resins, which harden when exposed to specific light wavelengths. Post-processing is essential in SLA to remove excess resin and strengthen the parts. Despite its higher cost compared to FDM, SLA is popular for industries demanding smooth surface finishes and complex geometries.
STL File Format STL (Standard Tessellation Language or Stereolithography) is the most commonly used file format for 3D printing. It represents 3D models as a mesh of interconnected triangles, defining the surface geometry without color, texture, or other attributes. While STL files are widely supported, they lack advanced features such as metadata or units of measurement. Errors like non-manifold geometry or gaps in an STL file can cause slicing issues, requiring repair before printing.
Strain Gauge Leveling Strain gauge leveling is an advanced bed leveling technology that uses force sensors integrated into the print head or bed to detect surface variations. Unlike inductive or capacitive sensors, strain gauges provide direct contact-based measurement, improving accuracy and consistency in print bed leveling.
Support Structures Support structures are additional printed material used in 3D printing to hold up overhanging sections of a model. These structures prevent parts of the print from collapsing during the fabrication process. In FDM (Fused Deposition Modeling), supports are often made from the same material as the print but can be removed post-printing. In SLA (Stereolithography) or DLP (Digital Light Processing), supports are typically thin resin columns designed for easy removal. Soluble supports, such as those made from PVA (Polyvinyl Alcohol) or HIPS (High-Impact Polystyrene), can be dissolved in water or a specific solvent, reducing manual post-processing work. Choosing the right support strategy affects surface quality, print success, and overall material efficiency.
Surface Finish Optimization Surface finish optimization involves techniques used to improve the final texture and appearance of 3D-printed objects. Post-processing methods such as sanding, vapor smoothing (for ABS with acetone), or resin coating can enhance surface smoothness. In SLA or SLS printing, surface finish can also be affected by print resolution, laser power, and layer exposure times. The choice of material, infill, and print settings all contribute to achieving a desired surface finish.