Moving beyond the hype: A practical look at plastic additive manufacturing materials
Key Highlights
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Additive manufacturing’s production shift hinges on materials, not machines, with reliability over time the decisive requirement.
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Early 3D-printing polymers targeted prototypes, but often lost mechanical properties within months, failing production expectations.
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Long-term environmental stability demands multiyear aging tests; elongation at break can flag early brittleness sooner.
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Plastics engineers should prioritize standardized, transparent material datasheets citing ASTM, ISO and UL test results.
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Additive manufacturing fits low-volume, high-mix, complex geometries and bridge builds; injection molding remains best for high volumes.
By Marty Johnson
3D Systems
Additive manufacturing (AM) has made enormous strides over the past decade, but its transition from prototyping to true production has not been driven by machines alone. The real enabler, and most often the limiting factor, has been materials.
From an engineering standpoint, the conversation around additive manufacturing must shift away from what is possible in the short term and toward what is reliable over time. Early materials in 3D printing were designed primarily for prototyping: They offered excellent accuracy and surface finish but lacked the long-term stability required for production use.
There was a time when many AM materials would begin to lose key mechanical properties within a matter of months. For engineers accustomed to traditional manufacturing processes like injection molding, that simply isn’t acceptable. Production materials must maintain performance over years, not weeks or months. That requirement fundamentally changed how additive materials needed to be developed and evaluated.
The shift to long-term performance
One of the most significant challenges in additive manufacturing materials has been long-term environmental stability. Many early photopolymers, particularly epoxy-based systems, continued to cure even after printing. This ongoing chemical activity can lead to discoloration, embrittlement and degradation of mechanical properties.
This is why long-term testing for 3D printed materials became essential. Evaluating materials over simulated multiyear periods, both indoors and outdoors, provides a much clearer picture of how parts will perform in real-world applications.
A key indicator of material durability is elongation at break. While properties like tensile strength or modulus might remain relatively stable over time, elongation often reveals early signs of brittleness. Once elongation drops significantly, the material is no longer suitable for many functional applications.
For engineers, this means that not all data is equally valuable. Understanding which properties truly indicate long-term performance is critical when selecting AM materials for production.
Engineering data over marketing claims
The AM industry has, at times, been driven by ambitious claims that outpace real-world performance. To move forward, the focus of the industry must be on standardized, transparent and honest data.
Comprehensive material data sheets are essential and should be supplied by all 3D printing vendors. These should include results based on recognized industry standards such as ASTM, ISO and UL testing. Properties like water absorption, chemical compatibility and environmental aging should be clearly documented.
The purpose of a data sheet is not simply to confirm that a material works; it is to quickly determine whether it does not. Eliminating unsuitable materials early in the process saves time, cost and engineering effort.
This approach also aligns AM more closely with traditional materials selection, where engineers routinely compare detailed specifications before committing to a design.
Understanding trade-offs in material performance
No material offers perfect performance across all properties. AM materials, particularly filled or composite systems, require careful evaluation of trade-offs.
For example, adding fillers can significantly increase stiffness and heat resistance, but often reduces elongation. A material with low elongation might still perform well if it has sufficiently high stiffness, but that depends entirely on the application.
Similarly, anisotropy — differences in properties based on print orientation — must be considered. Engineers need access to full X, Y and Z data to properly design parts that take advantage of directional strengths rather than being compromised by them.
Chemical compatibility is another frequently overlooked factor. Fluids such as oils, cleaners or other chemicals can degrade materials or interact negatively with fillers. These effects are often not immediately visible but can lead to long-term failures in production environments.
The importance of system integration
AM material performance cannot be separated from the broader system in which it operates: In additive manufacturing, the interaction between software, hardware, materials and process control determines the final outcome.
Variables such as laser power, scan strategy, curing conditions and post-processing all influence part quality. Without tight integration between these elements, consistency becomes difficult to achieve.
A fully integrated approach enables repeatable results, which is essential for applications requiring high reliability, such as medical devices, aerospace components or electrical systems with strict safety standards. If your 3D printing vendor cannot deliver this level of integration and control, then you won’t be successful at consistently 3D printing production parts.
Where additive manufacturing delivers value
AM is not a universal replacement for traditional manufacturing methods. Its strengths lie in specific use cases where its advantages outweigh its limitations.
These include:
- Low-volume, high-mix production
- Complex geometries that are difficult or impossible to mold
- Rapid iteration and design changes
- Bridge manufacturing before tooling is available
In these scenarios, additive manufacturing can provide significant economic and operational benefits. For example, in applications with many low-volume SKUs, the cost of creating and maintaining injection mold tools can be prohibitive. AM eliminates tooling entirely, enabling more flexible production.
However, for high-volume production, such as parts produced in the hundreds of thousands, traditional methods like injection molding remain more cost-effective.
Expanding applications across industries
As materials improve, AM is gaining traction in a range of industries.
In aerospace and defense, lightweighting remains a major driver. Reducing weight directly impacts fuel efficiency and operational costs. AM enables optimized designs that would be difficult to achieve with conventional methods.
In medical and dental applications, the ability to produce customized, biocompatible parts is transforming patient care. Advances in material science are enabling solutions such as monolithic denture production and other patient-specific devices.
Electronics is another area of growth, particularly with the development of flame-retardant materials that meet stringent safety standards. These materials open opportunities in applications like electrical connectors, where traditional manufacturing methods might be less efficient for low-volume production.
In composites, AM is being used to create tooling for carbon fiber parts, including complex molds that can be removed after curing. This expands design possibilities and reduces tooling constraints.
Scaling additive manufacturing
Scaling additive manufacturing for production involves more than increasing machine throughput, and the availability of suitable materials is often the primary constraint.
Without materials that meet the required mechanical, thermal and regulatory standards, applications cannot move forward, regardless of machine capability.
Regulatory requirements also play a significant role, particularly in industries like aerospace and medical. Certification processes can take years, requiring both patience and long-term investment. Choose a 3D printing vendor that has made the effort to document and comply with appropriate regulations and certifications.
In addition, adoption depends on a willingness to move away from established processes. Even when AM offers clear advantages, organizations must be prepared to rethink traditional workflows and evaluate new economic models.
A more mature industry
The AM industry is evolving beyond its early stages of rapid innovation and bold claims. Today, the focus is increasingly on practical applications, validated performance and measurable value.
Engineers are asking more rigorous questions:
- Will the material maintain its properties over time?
- Does it meet the required standards and certifications?
- Is it economically viable for the intended application?
Answering these questions requires a disciplined, data-driven approach and one that mature AM providers have been rising to in recent years.
Conclusion
AM has reached a point where its success depends on engineering rigor rather than technological novelty. Materials are at the center of this shift.
By focusing on long-term performance, standardized data and realistic application fit, engineers can unlock the true potential of additive manufacturing. The key is not to replace traditional methods entirely, but to apply AM where it delivers clear and measurable advantages.
Ultimately, success comes down to using the right tool for the job and ensuring that the material behind that tool is capable of delivering consistent, reliable performance over time. Expect to be able to get this data from your AM vendor and if you haven’t, then ask.
About the Author
Marty Johnson
Marty Johnson is VP, product and technical fellow for 3D Systems. He has been with the company since 2007 and specializes in polymer materials, systems and mechanical engineering, print process, additive manufacturing and product development.