Will your parts survive the elements? 3D printing for outdoor use

Parts that are 3D printed and meant for outdoor use must possess the necessary durability and reliability to withstand potentially harsh environmental conditions. This means they must maintain their functionality and structural integrity over an extended period of time, reducing the need for frequent replacements or repairs. In this article, we will take a look at essential factors, such as material choice and design considerations, for creating 3D printed parts that are suitable for outdoor use.

What environmental conditions do 3D printed parts need to withstand for outdoor use?

The conditions that an outdoor part must withstand will vary depending on your geographical location and the part’s application. However, there are several common environmental conditions that 3D printed parts might be subjected to. 

• UV exposure. Used outdoors, parts are exposed to sunlight, which contains UV radiation. This means your 3D printed parts should be made from materials with good UV resistance to prevent degradation, discoloration, or brittleness caused by prolonged exposure to UV rays.

• Temperature extremes. Parts should be able to maintain their mechanical properties and dimensional stability across a wide temperature range – both hot and cold – without warping, cracking, or becoming too brittle.

• Moisture and water exposure. Parts may encounter rain, snow, humidity, or even submersion in water, meaning they must be resistant to moisture absorption and have low water permeability to prevent swelling, weakening, or dimensional changes that could affect their functionality.

• Mechanical stress and impact. Outdoor parts may be subjected to mechanical stresses, vibrations, or impact forces due to wind, physical contact, or other factors. They should be designed and printed with sufficient strength, toughness, and impact resistance to withstand such forces without deformation, breakage, or failure.

• Chemical resistance. Depending on the outdoor environment, your part may be exposed to chemicals, pollutants, or corrosive substances. In these cases, parts should exhibit good chemical resistance to avoid degradation or loss of structural integrity.

• Weathering and aging. Outdoor parts should be able to withstand the effects of weathering and aging. This includes resistance to fading, cracking, or degradation caused by repeated exposure to outdoor elements, such as sunlight, temperature fluctuations, moisture, and pollutants.
  

What 3D printing materials are suitable for outdoor use?

There are a few options of 3D printing materials that offer good durability and weather resistance. Depending on your part’s application, you might want to consider one of the following.

• ASA. A filament known for its excellent weather resistance and UV stability. It can withstand prolonged exposure to sunlight without significant degradation, making it suitable for outdoor parts that require long-term durability.

• PETG. A versatile filament that combines the strength and toughness of materials like ABS with the ease of printing of PLA. It has low water absorption, good chemical resistance, and offers decent UV resistance, making it suitable for outdoor applications exposed to moisture and sunlight.

• TPU. A flexible filament known for its high elasticity, durability and UV resistance. It can withstand repeated bending and stretching, making it suitable for outdoor applications requiring flexibility and impact resistance, such as gaskets, seals, or protective covers.

• Nylon. Various types of nylon filaments, such as Nylon 6 and Nylon 12, are known for their strength, toughness, and resistance to wear and abrasion. They offer good mechanical properties and are suitable for outdoor applications that require high strength, such as functional prototypes, gears, or mechanical parts.

• Polycarbonate (PC). A high-temperature filament known for its excellent impact resistance, transparency, and dimensional and UV stability. It can also withstand a wide temperature range, making it suitable for outdoor parts exposed to extreme temperatures or requiring high impact resistance, such as enclosures or protective covers.

• Composite filaments. Special filaments that incorporate reinforcing fibers such as carbon fiber, fiberglass, or Kevlar. These filaments offer increased strength, stiffness, and impact resistance compared to standard filaments. They are suitable for outdoor applications that require exceptional mechanical properties, such as structural components or tooling.
  

What factors should you consider when designing 3D printed parts for outdoor use?

Designing 3D printed parts for outdoor use requires careful consideration of various factors to ensure their longevity and performance in harsh environmental conditions. Here are a few to consider.

• Part geometry. Adequate strength and stability is essential for outdoor applications. For example, if you're creating a bracket to hold a sign, ensuring sufficient load-bearing capacity and structural integrity is critical to withstand wind forces or vibrations. Optimizing the design to distribute stresses evenly can help prevent weak points or failure under external pressure.

• Orientation and support structures. Proper orientation during printing can significantly impact part strength. For instance, orienting a support column vertically rather than horizontally helps maintain its strength, preventing sagging or deflection over time. Additionally, using well-designed support structures can ensure accurate printing and minimize the risk of warping or distortion.

• Wall thickness. Determining an appropriate wall thickness is crucial for outdoor parts, such as housing for outdoor electronics. Here, using a thicker wall provides better protection against impact, moisture, and other environmental hazards. Thicker walls also enhance structural integrity, preventing deformation or vulnerability to physical stress.

• Venting and drainage. Incorporating venting or drainage features is essential when designing parts exposed to moisture, such as drainage channels that allow excess water to escape. Additionally, adequate venting in an outdoor electrical enclosure can prevent the accumulation of heat, ensuring optimal performance and preventing damage to sensitive components.

• Longevity and repairability Considering the expected lifespan and maintenance requirements of outdoor parts is crucial. Designing a durable and easily replaceable filter housing for an outdoor HVAC unit, for example, helps ensure efficient performance and simplifies regular maintenance. Anticipating wear and tear allows for designing parts that can withstand extended exposure to environmental factors, minimizing the need for frequent replacement.

What post-processing techniques can benefit 3D printed parts for outdoor use?

Even if you choose the right material for your part, long-term exposure to harsh outdoor conditions, such as direct sunlight and extreme temperatures, can still cause degradation over time. It is therefore recommended to consider additional protective measures, depending on the specific requirements of your outdoor application. Let’s take a look at several post-processing techniques that can help improve your outdoor part’s durability and longevity.

• Sanding and smoothing. Sanding the surface of 3D printed parts helps to remove layer lines and create a smoother finish. This not only improves the aesthetics of the part, but also reduces potential areas for dirt accumulation or water retention, which can lead to degradation over time.

• Sealing and priming. Applying a sealant or primer to the surface of your 3D printed part can provide added protection against moisture absorption and UV degradation. Sealants can create a barrier that prevents water penetration, while primers enhance adhesion and improve the surface finish for subsequent painting or coating.

• Painting and coating. Applying paint or protective coatings can significantly enhance the resistance of 3D printed parts to outdoor elements. Acrylic paints or UV-resistant coatings can provide an extra layer of defense against UV radiation, moisture, and chemicals. These coatings help prevent color fading, enhance weather resistance, and improve overall durability.

• Chemical treatments. Certain chemical treatments, such as vapor smoothing for ABS parts, can be used to achieve a polished surface finish. This technique involves exposing the printed part to acetone vapor, which melts the surface slightly, resulting in a smoother appearance.

• UV-resistant coatings. Applying specialized UV-resistant coatings specifically designed for outdoor use can help protect 3D printed parts from UV degradation. These coatings contain additives that provide increased UV resistance, preventing color fading, brittleness, and structural degradation caused by prolonged exposure to sunlight.

• Waterproofing. For parts exposed to moisture or water, applying waterproofing treatments or moisture-resistant coatings can help prevent water absorption and potential damage. These treatments create a barrier that reduces the risk of swelling, warping, or degradation due to prolonged exposure to moisture.

• Clear coatings. Transparent or clear protective coatings, such as polyurethane or epoxy resin, can be applied to maintain the appearance and integrity of transparent or translucent 3D printed parts. These coatings provide UV resistance, improve scratch resistance, and protect against environmental factors while preserving the optical properties of the part.

Get started with 3D printing for outdoor use

To get started with creating a 3D printed part for outdoor use, upload a CAD file to receive a free quote and lead times. 

You can also learn more about surface finishes that can increase your outdoor part’s lifespan, as well as how to select the best 3D printing process for your project.