Design specifications for 3D models (Fuse 1 generation)

A successful 3D print starts with a well-designed model. Follow our best practices to optimize designs and reduce failures.

Recommended: 0.8 mm/800 micron diamater

A pin or wire is a feature whose length is at least two times greater than its width. Pins or wires with a diameter less than 0.8 mm may deform or break during the print.

Features less than 20 mm²: 0.2 mm/200 microns
Features greater than 20 mm²: 0.4 mm/400 microns

Clearance is the distance between two parts of a model (e.g., the distance between a pair of gears). Leave a slight clearance between printed parts intended to mesh or interface after printing, like assembly joints or gears.

Recommended: 1.0 mm/1,000 microns

Holes with a diameter of less than 1.0 mm in the X-, Y-, and Z-axes may close during printing. The accuracy of a hole not only depends on the diameter of the hole, but also on the thickness of the wall through which the hole is printed. The thicker the wall section, the less accurate the hole becomes. Through holes must also allow for line-of-sight clearance to ensure all material is cleared during post-processing.

Recommended: 3.5 mm/3,500 microns

Enclosed cavities remain filled with unsintered powder without proper drain holes. For best results, include at least two drain holes when designing a cavity, each greater than or equal to 3.5 mm in diameter.

Embossed details are shallow raised features on the surface of a model like text. Small embossed features may not be visible on the finished part. Use a bold font where possible for best results with embossed text.

Engraved details are imprinted or recessed features on the surface of a model. Small engraved features may not be visible on the finished part. Use a bold font where possible for best results with engraved text.

For the best results when printing with the Fuse Series printers, it is important to consider the unique properties of the specific material being used. The following guidelines will assist users in optimizing their designs for additive manufacturing with various powders on the Fuse Series printers.

Due to varying thermal expansion rates for different materials, the largest parts size printable in the Fuse Series printers varies. The largest part sizes achievable are given in the table below:

Nylon 12 Powder serves as an excellent general-purpose material due to its balanced material properties, ease of printing, and ease of post-processing as well as biocompatibility. The guidelines provided in the previous sections were compiled with Nylon 12 Powder in mind, so no additional design considerations are required.

Nylon 12 GF Powder excels at printing stiff, thermally resistant parts that are stable under load. It also has the benefit of biocompatibility for skin-contacting applications.

Design considerations specific to this material include:

• Surface roughness: The surface finish with this material is rougher than parts printed in Nylon 12 Powder. Designs that require a smooth finish should account for secondary post-processing steps needed to achieve a smooth finish whether that be machining, sanding, or another finishing process.
• Brittleness: The glass bead filler in Nylon 12 GF Powder provides enhanced stiffness, but also causes parts printed to be more brittle. Fine positive features may need to be thickened to prevent them from breaking in post-processing steps and in end-use. Brittleness is particularly notable across layers, so features requiring strength should generally be oriented to align with the XY plane whenever possible.
• Escape holes: The Surface Armor on parts printed with Nylon 12 GF Powder is tougher than when printed with Nylon 12 Powder. Escape holes should be larger, and ideally, all surfaces (internal and external) should have line of sight access so that the surface can be fully cleaned in the final cleaning steps using a media blaster.

Nylon 12 Tough Powder offers high ductility and high dimensional accuracy across the build chamber, allowing you to print more durable parts with less warpage, without sacrificing strength.

Design considerations specific to this material include:

• Model position: Orient parts towards the center of the build chamber and away from build chamber walls and floor, the back wall in particular, to reduce surface defects.
• Part spacing: Space all parts at least 5 mm from each other for best surface quality and easiest depowdering.

Nylon 12 White Powder combines the great qualities of Nylon 12 Powder with the customizability of white parts. Create functional prototypes and end-use customer-facing parts that can be dyed to match branding as well as medical devices and models with high contrast and detail.

Design considerations specific to this material include:

• Model position: Orient parts towards the center of the build chamber and away from build chamber walls and floor, the back wall in particular, to reduce surface defects.
• Model orientation: Large flat surfaces print with the best quality perpendicular to the print plane. Avoid facing flat faces towards the front of the build chamber.
• Layer lines: Slightly curved surfaces oriented along the Z-axis will result in layer lines on parts.
• Part spacing: Space all parts at least 3 mm from each other for best surface quality and easiest depowdering.

Parts printed with Nylon 11 Powder offer enhanced ductility compared to the ones printed with Nylon 12 Powder. They offer greater resistance to impact and vibration and are certified for biocompatible applications.

Design considerations specific to Nylon 11 Powder include:

• Warping: Nylon 11 Powder has an increased tendency to warp when large cross sections are printed in the XY plane. Follow the guidance for high aspect ratio parts to minimize the effects of warping.
• Clearances: Integrated assemblies require greater clearances. Leave at least 1 mm of clearance between the component pieces of integrated assemblies and iterate to optimize for the precise clearances that work best for the assembly’s requirements.
• Fine features: The minimum feature sizes for Nylon 11 Powder are slightly greater than those noted for Nylon 12 Powder and can vary depending upon the orientation of the feature on the part. This can have an effect on fine features such as small negative features, small positive features, thin walls, embossed text, and engraved text. To help ensure that fine features resolve correctly, try a small test print containing the desired features before printing the full part or a series of parts.

Nylon 11 CF Powder is a high-performance material offering excellent stiffness, temperature resistance, impact strength, and tensile strength. It also has a lower tendency to warp than Nylon 11 Powder and therefore is more suitable to print parts with large cross sections.

• Surface roughness: Similar to Nylon 12 GF, the surface finish is rougher than the surface finish of parts printed in Nylon 12 Powder. Designs that require a smooth finish should account for secondary post-processing steps needed to achieve a smooth finish whether that be machining, sanding, or another finishing process
• Anisotropic properties in X, Y, and Z: Due to a tendency for the carbon fibers to align in the X-axis, or parallel to the front door of the printer, the mechanical properties of parts differ in the X direction compared to the Y direction. Similar to other 3D printed parts, the mechanical properties in the Z direction also differ and are generally lower than XY properties. For maximum stiffness and strength, orient features so that they are aligned with the X-axis.

TPU 90A Powder is an elastomer that offers high tear strength and high elongation at break. With a Shore Hardness of 90A, it is a material with firm, rubber-like characteristics. Softer parts can be achieved by substituting solid features with lattice structures to achieve targeted levels of stiffness. TPU 90A Powder is biocompatible and suitable for skin-contacting applications.

• Thick cross sections: Fine features (including small pins, holes, and engraved or embossed text on the upper surfaces of geometries greater than 3–4 cm thick) may not resolve. This is caused by thermal buildup in the part and can be improved by re-orienting parts or hollowing out geometries.
• Fine features: The minimum feature sizes for TPU 90A Powder are slightly greater than those noted for Nylon 12 Powder and can vary depending upon the orientation of the feature on the part. This can have an effect on fine features such as small negative features, small positive features, thin walls, embossed text, and engraved text. To help ensure that fine features resolve correctly, try a small test print containing the desired features before printing the full part or a series of parts.
• Warping: TPU 90A Powder has a tendency to warp. Warping is typically most prevalent on the bottom faces of parts. Follow the guidance for high aspect ratio parts to minimize the effects of warping.
• Dimensional accuracy: The layout of a build may affect the dimensional accuracy of parts. Pack parts tightly and towards the bottom of the build chamber to achieve the best dimensional accuracy.
• When printing with V1.1 print settings, move parts roughly halfway up the build chamber for better Z-dimensional accuracy.
• Clearances: Integrated assemblies require greater clearances. Ensure a clearance of at least 1 mm to ensure that integrated assemblies function as intended. Clearances in close proximity to thick printed cross sections may require a greater gap, while clearances in close proximity to thin printed cross sections may achieve a smaller clearance.
• Circular feature elongation: Circular geometries with an axis in the XY plane tend to elongate and become slightly egg shaped or elliptical rather than circular. Choose a part orientation that orients circular geometry axes in the Z direction to mitigate this effect.

Polypropylene Powder is a genuine polypropylene material for 3D printing, used to produce parts with good durability and toughness. Parts produced are rigid but offer excellent ductility.

• Fine features: The minimum feature sizes for Polypropylene Powder are slightly greater than those noted for Nylon 12 Powder and can vary depending upon the orientation of the feature on the part. This can have an effect on fine features such as small negative features, small positive features, thin walls, embossed text, and engraved text. To help ensure that fine features resolve correctly, try a small test print containing the desired features before printing the full part or a series of parts.
• Minimum packing spacing: A minimum packing spacing of 2 mm should be used when performing job layout in Preform. Lower spacing (1 mm minimum) is possible but will impact the surface finish of parts.
• Warping: Polypropylene Powder has a tendency to warp. Warping is typically most prevalent on the bottom faces of parts with large cross sections. Warping may also occur for parts with long cross sections in the vertical direction. Follow the guidance for high aspect ratio parts to minimize the effects of warping.
• Surface roughness: The surface of parts printed with Polypropylene Powder is expected to be slightly rougher than parts printed with Nylon 12 Powder.
• Watertightness: Watertight parts may be produced with Polypropylene Powder. For optimal results, design walls with a thickness of 1 mm or greater. For thinner walls, consider conducting test prints to verify watertightness. Note: performance may vary depending on the specific geometry of the part.

• Fuse Series SLS Design Guide [EN] [DE] [ES] [FR] [IT] [JA] [RU] [ZH]
• Measuring SLS Dimensional Accuracy and Print Repeatability