Why Part Orientation Matters in 3D Printing

By Atif SuhailReviewed by Lexie CornerApr 10 2025

In 3D printing, part orientation refers to how a model is positioned on the print bed during fabrication. This decision directly affects the final part’s strength, accuracy, surface quality, and the amount of time and material required to produce it.¹

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Poor orientation can lead to weak spots, rough surfaces, warping, or excessive support structures. A well-chosen orientation, on the other hand, improves structural performance, visual finish, and printing efficiency.

Understanding these effects is key to reducing waste, minimizing post-processing, and ensuring reliable mechanical performance. Whether you're printing a prototype or a finished part, optimizing orientation is one of the most effective ways to improve results.¹

How Part Orientation Affects 3D Printing

Part orientation has a direct impact on the quality, performance, and efficiency of 3D-printed components. In layer-based processes such as Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and Selective Laser Melting (SLM), orientation influences not just how the part is printed but also how it behaves afterward.¹

Below are the key ways orientation affects print outcomes:

Print Strength and Layer Adhesion

3D printed parts, especially those made using FDM, are inherently anisotropic. Strength within the X and Y axes (within layers) is typically much higher than along the Z-axis, where layers are bonded together.

Because of this, part orientation must be aligned with expected loads.² FDM prints, for example, are significantly weaker under tensile stress along the Z-axis, often exhibiting 4 to 5 times less strength than those in the XY plane.²

Surface Finish and Aesthetics

Upward-facing surfaces generally produce the best finish in 3D printing, though results vary depending on the printing process.

In FDM, the top surface is smoothed by the extrusion nozzle, the bottom surface (in contact with the build plate) often appears glossy, and areas above support structures tend to show marks.

In SLA, the top surfaces are typically smooth, while the lower surfaces—where supports are attached—require post-processing to remove marks.

For powder bed processes like SLS and multi-jet fusion (MJF), the lower surfaces usually exhibit a rougher, grainier texture.^3,4

Print Time and Material Efficiency

Print time and material consumption are not just a function of part size—they're also deeply influenced by orientation. Taller parts take longer to print because more layers are needed, and certain orientations require significantly more support material.

For example, consider a cylinder: printing it horizontally requires far fewer layers than printing it vertically. At a 100 μm layer height, a horizontal orientation may need around 100 layers, while a vertical orientation could require 300. This becomes especially beneficial when printing multiple parts or large builds.⁵

Support Structures and Overhangs

Orientation directly affects how much support material a part needs. Poor orientation can lead to an excessive number of supports underneath overhangs, bridges, or features with minimal contact points. These support waste material, extend print time, and damage surface quality during removal.⁵

Support optimization methods (including heuristic approaches) evaluate each face’s angle to the build plate. If a face exceeds the 45 ° threshold, it's flagged for support. Smart orientation limits these flagged surfaces, especially in high-detail or internal areas, reducing post-processing and improving final part quality.^4,5

Dimensional Accuracy

Orientation also affects geometric accuracy and surface quality. Using the same cylinder example:

In FDM printing, if the cylinder (10 mm outer diameter, 6 mm inner diameter, 30 mm length) is printed vertically along its center axis, the printer forms it with concentric circular layers, resulting in a relatively smooth outer surface.⁵

But if it’s printed horizontally, the shape is built from stacked rectangles of varying widths, and the side in contact with the build plate will appear flattened. This shift in orientation leads to noticeable differences in both surface quality and dimensional accuracy.⁵

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Best Practices for Optimizing Part Orientation

Maximize Strength

In FDM and similar processes, parts are weakest along the Z-axis due to weaker interlayer bonding. To improve strength, align load-bearing features so that stress runs parallel to the layers, not across them. Flat orientations—such as laying brackets horizontally—help reduce delamination and improve tensile and flexural performance.

Orientation influences over 70 % of design rules in additive manufacturing (AM), making it one of the most critical factors in ensuring mechanical reliability.⁶

Reduce Support Dependence

Orient parts to avoid overhangs greater than 45 °, which reduces the need for support structures. Fewer supports mean lower material use, faster print times, and cleaner surfaces.

In SLA printing, poor orientation can cause shear stress, distortion, or even print failure. Choosing the right orientation not only improves efficiency but also prevents mechanical issues caused by excessive or poorly placed supports.^6,7

Enhance Surface Finish

Sloped or curved surfaces often show a staircase effect due to layer stacking. To reduce this, orient smooth or high-curvature areas upward or perpendicular to the build plane.

This improves surface quality and reduces the need for post-processing. Surface-focused orientation is especially valuable for medical devices or consumer products, where finish quality matters and extra polishing adds cost.^6,7

Optimize Print Speed

Print time increases with part height—taller prints require more layers and take longer to complete. Orienting parts to reduce their Z-height speeds up builds and lowers the risk of issues like warping.

This is especially useful in batch production or prototyping, where faster turnaround is key. Flatter orientations also reduce support needs and improve consistency across multiple prints.^6,7

Real-World Applications and Case Studies

Load-Bearing Parts in Engineering and Prototyping

In engineering and functional prototyping, part orientation is key to ensuring the mechanical strength of 3D-printed components, especially in load-bearing applications.

A study by B. Kogo et al. compared stainless-steel bars printed via SLM in horizontal and vertical orientations. The results showed that orientation directly influenced structural performance: horizontally printed parts displayed different delamination and crack patterns compared to vertical prints, due to anisotropic behavior.

These findings highlight how poor orientation can weaken a part and lead to premature failure, while aligning orientation with load paths can significantly improve strength. This is especially important when designing brackets, frames, or mechanical fixtures that must withstand real-world stresses.⁸

Integrating Orientation into the Design Process

In AM, part orientation must be considered early in the design process. Unlike conventional methods, AM benefits from function-oriented design, where geometry is developed with printing constraints in mind.

By analyzing part features during the embodiment stage, designers can reduce support structures, limit distortion, and improve build reliability. This early focus on orientation helps streamline production and improve overall print quality.⁹

Redesigning a Laser Cutting Head for Additive Manufacturing

In one design example, a laser cutting head used in CO₂ systems to cut MDF and acrylic was reworked for AM. The redesign aimed to improve airflow for lens cleaning, using CFD simulations integrated directly into the CAD model.

A 1 mm wall thickness was added to improve shape definition. The lens holder, printed in AlSi12 using SLM, was split into functional sections and oriented early in the design process to reduce distortion and ensure high print quality.⁹

Reducing Material and Time in Industrial Additive Manufacturing

In industrial AM, optimizing part orientation is essential for reducing support volume, build time, and computational load while maintaining accuracy and overall quality. Integrating orientation strategies into production workflows helps manufacturers increase efficiency without compromising performance.¹⁰

One study by Bacciaglia et al. (2024) highlights the impact of poor orientation on print economics. The team reoriented a highly elongated part, reducing support volume from 102.28 cm³ to just 5.57 cm³—a 94.5 % reduction. Manufacturing time was halved, and raw material use fell by 74 %.

The case underscores how rethinking orientation can dramatically cut cost and production time in AM.¹⁰

Explore More

Part orientation isn’t just a technical afterthought; it’s a core decision that defines the quality, strength, and cost of a 3D-printed part.

Whether you're printing a functional prototype or a commercial product, aligning orientation with the design’s needs is essential.

For more insights into additive manufacturing technologies and best practices, explore the following articles:

• The Global 3D Printing Market: Emerging Trends and Key Applications
• Optimizing Additive Manufacturing Processes with Machine Learning
• The Importance of Powder Testing for Additive Manufacturing
• Enabling Miniaturization with Micro Precision 3D Printing

Reference and Further Readings

(1)      Abdelrhman, A. M.; Gan, W. W.; Kurniawan, D. Effect of Part Orientation on Dimensional Accuracy, Part Strength, and Surface Quality of Three Dimensional Printed Part. In IOP Conference Series: Materials Science and Engineering; IOP Publishing, 2019; Vol. 694, p 12048. https://iopscience.iop.org/article/10.1088/1757-899X/694/1/012048/meta

(2)      Kovan, V.; Altan, G.; Topal, E. S. Effect of Layer Thickness and Print Orientation on Strength of 3D Printed and Adhesively Bonded Single Lap Joints. J. Mech. Sci. Technol. 2017, 31, 2197–2201. https://link.springer.com/article/10.1007/s12206-017-0415-7

(3)      Mathew, A.; Kishore, S. R.; Tomy, A. T.; Sugavaneswaran, M.; Scholz, S. G.; Elkaseer, A.; Wilson, V. H.; John Rajan, A. Vapour Polishing of Fused Deposition Modelling (FDM) Parts: A Critical Review of Different Techniques, and Subsequent Surface Finish and Mechanical Properties of the Post-Processed 3D-Printed Parts. Prog. Addit. Manuf. 2023, 8 (6), 1161–1178. https://link.springer.com/article/10.1007/s40964-022-00391-7

(4)      Chand, R.; Sharma, V. S.; Trehan, R.; Gupta, M. K.; Sarikaya, M. Investigating the Dimensional Accuracy and Surface Roughness for 3D Printed Parts Using a Multi-Jet Printer. J. Mater. Eng. Perform. 2023, 32 (3), 1145–1159. https://link.springer.com/article/10.1007/s11665-022-07153-0

(5)      Song, S.; Zhang, J.; Liu, M.; Li, F.; Bai, S. Effect of Build Orientation and Layer Thickness on Manufacturing Accuracy, Printing Time, and Material Consumption of 3D Printed Complete Denture Bases. J. Dent. 2023, 130, 104435. https://doi.org/10.1016/j.jdent.2023.104435

(6)      Birosz, M. T.; Safranyik, F.; Andó, M. Build Orientation Optimization of Additive Manufactured Parts for Better Mechanical Performance by Utilizing the Principal Stress Directions. J. Manuf. Process. 2022, 84, 1094–1102. https://doi.org/10.1016/j.jmapro.2022.10.038

(7)      Alomari, Y.; Birosz, M. T.; Andó, M. Part Orientation Optimization for Wire and Arc Additive Manufacturing Process for Convex and Non-Convex Shapes. Sci. Rep. 2023, 13 (1), 2203. https://doi.org/10.1038/s41598-023-29272-x.

(8)      Kogo, B.; Xu, C.; Wang, B.; Chizari, M.; Reza Kashyzadeh, K.; Ghorbani, S. An Experimental Analysis to Determine the Load-Bearing Capacity of 3D Printed Metals. Materials. 2022. https://doi.org/10.3390/ma15124333.

(9)      Leutenecker-Twelsiek, B.; Klahn, C.; Meboldt, M. Considering Part Orientation in Design for Additive Manufacturing. Procedia Cirp 2016, 50, 408–413. https://doi.org/10.1016/j.procir.2016.05.016

(10)    Bacciaglia, A.; Liverani, A.; Ceruti, A. Efficient Part Orientation Algorithm for Additive Manufacturing in Industrial Applications. Int. J. Adv. Manuf. Technol. 2024, 133 (11), 5443–5462. https://link.springer.com/article/10.1007/s00170-024-14039-z

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