3D-Printed Objects in a Vacuum: Outgassing Concerns and Solutions

When it comes to 3D printing objects intended for use in a vacuum environment, one critical issue to consider is the potential for outgassing. Outgassing refers to the release of volatile components from a material when it undergoes a change in pressure or temperature. In this article, we will explore the extent of outgassing in 3D-printed objects and how to mitigate the risks associated with this phenomenon.

Understanding Outgassing in 3D-Printed Parts

Outgassing can be a significant concern in vacuum environments due to the potential release of gases that can affect the performance of sensitive equipment. The specifics of outgassing depend on the material design and infill settings used during the 3D printing process. Generally, the extent of outgassing is influenced by several factors:

Material Design and Properties

Much of the outgassing likely comes from the filament or resin used in the printing process. Common 3D printing materials, such as PLA, PETG, and ABS, are less likely to outgas in a vacuum environment, as they are not highly porous. Polymers with lower molecular weights or those that contain more volatile components are more prone to outgassing.

Infill Settings

The infill pattern and density significantly impact how much gas can be trapped within the printed object. A solid infill or a dense infill pattern (like a 100% infill) is less likely to have macroscopic gas pockets, thereby reducing the outgassing potential. In contrast, open infill patterns and low infill densities can result in more permeable structures, leading to higher outgassing rates.

Evaluating the Extent of Outgassing

While many commonly used 3D printing materials do not pose a significant outgassing threat, it is still essential to understand the potential risks. Here are some key points to consider:

Material Stability

For a majority of 3D-printed objects, materials tend to be quite stable and less likely to release significant amounts of offgassing. However, this does not mean that all materials are identical in their behavior. Some materials may decompose or change under vacuum conditions, leading to outgassing.

Outgassing Testing

Before finalizing the design and production of a 3D-printed object intended for a vacuum environment, it is advisable to conduct outgassing tests. These tests can be conducted using specialized equipment that measures the amount of volatile organic compounds (VOCs) released by the material under vacuum conditions. This information can be crucial for ensuring the long-term stability and performance of the 3D-printed object in the desired environment.

Mitigating Outgassing Risks

To minimize the risk of outgassing, several strategies can be employed:

Material Selection

Choosing materials with low outgassing properties is a critical first step. Carbon-fiber-infused PLA, núcleo 3D nylon, and tungsten-filled PETG are examples of materials that are less prone to outgassing. It is also advisable to review the material datasheets provided by manufacturers to understand their outgassing characteristics.

Design Considerations

Designing the object to minimize porosity and ensuring a solid infill pattern can also help reduce outgassing. Additionally, optimizing the printing process parameters, such as temperature and bed adhesion, can further minimize the potential for gas traps within the printed object.

Post-Printing Coating

In cases where outgassing remains a concern, applying a protective coating to the surface of the 3D-printed object can provide an additional layer of protection. Clear Parylene or Parylene C coatings are often used for this purpose, as they provide an excellent barrier against gases and other contaminants. A well-applied coating can significantly reduce the risk of outgassing and protect the object's integrity in a vacuum environment.

Conclusion

In summary, while 3D-printed objects can pose outgassing risks in vacuum environments, the extent of this risk varies based on the specific material and infill settings used. Understanding the materials' stability, conducting outgassing tests, and employing appropriate design and post-processing techniques can help mitigate these risks, ensuring the long-term reliability and performance of your 3D-printed objects.