Polymer powders for 3D printing: How can we measure ageing effects?
When polymeric materials are used in 3D printing, it is important to understand how the manufacturing process affects the physical and chemical properties of the polymer and its impact on the performance of the printed part.
This is especially important for polymer powder-based processes such as High-Speed Sintering (HSS) and Selective Laser Sintering (SLS) where the material may remain in the build chamber at elevated temperatures for long-periods of time. This can lead to degradation in the polymer which can impact the printing process and final part properties. This issue is augmented by the fact only 1/5th of the powder goes to make the part with the rest re-used in subsequent builds – so potential for further degradation.
It’s not easy to spot polymer degradation so manufacturers may use a powder multiple times before they notice an issue, or they may retire a powder after a certain number of builds just in case.
Why material characterization matters in 3D printing
Compared with other fabrication processes there is a lot more emphasis on the materials used in 3D printing, especially powders. That’s because powders can be quite unpredictable in how they behave. And, as already mentioned, they tend to be used multiple times so are more likely to undergo physical and chemical changes.
Powders can be predictable though if you measure the right properties, and that’s where material characterization comes in. With the right characterization tools, you can predict process performance and even part quality.
That’s exactly what we have tried to in a recent project with University of Sheffield and Netzsch Analysing and Testing. In this project we artificially aged samples of nylon-12 powder (glass filled and unfilled) and 3D printed tensile specimens with those powders using a High-Speed Sintering system. The interesting bit was that we characterized the virgin and aged powders using a range of analytical techniques, as below.
- Molecular weight and structure (branching) were determined using an OMNISEC multi-detector size exclusion chromatography (SEC) system from Malvern Panalytical.
- Melting and crystallization behaviour was measured with a DSC 214 Polyma Differential Scanning Calorimeter from Netzsch Analyzing and Testing.
- Oscillatory rheology measurements were made using a Kinexus Ultra Rotational Rheometer from Netzsch Analyzing and Testing.
So, what happened next?
If you are interested in finding out what this study revealed then tune into our live webinar on November 13, titled Using Material Characterization to Study the Ageing Effects of Polymer Powders for 3D Printing. We will show how polymer aging affects the macromolecular structure of nylon-12 and the impact this has on thermal, rheological, and mechanical behaviour.
We’ll be hearing from Malvern Panalytical’s Senior Applications Scientist Dr. Serena Agostini, as well as Dr. Natalie Rudolph from NETZSCH Analyzing & Testing and Dr. Candice Majewski from the University of Sheffield.
So, whether you’re a scientist interested in the insights that can be unlocked by these analytical techniques, or a polymer manufacturer looking at investigative tools to aid product development and improve quality control, or an additive manufacturer seeking methods to check degradation of polymer powders you’re working with, you will leave the session with new insights and learnings.
Register here to secure your spot on November 13!