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Engineering Materials

Controlling temperature is key for additive manufacturing

DSM, a global leader in engineering plastics and 3D printing with Somos SLA (stereolithography) materials, shares more than 25 years of knowledge in the automotive industry. Today, the groups are shifting gears by joining forces in application and material knowledge for additive manufacturing to address the market needs for more materials that are suitable for this industry.

With a deep understanding for the needs of the automotive market, DSM has developed high performance polymers for Filament Fused Fabrication (FFF) and Selective Laser Sintering (SLS) and materials for SLA. This blog focuses on the development and challenges of bringing semi crystalline polymers for FFF to the market. By using DSM’s extensive knowledge of application, process and material properties, developments can be sped up by predicting processing and material compositions by modeling technologies, including FFF, SLA, SLS and Multi Jet Fusion (MJF). 

Figure 4 shows the thermal history of the part during the print job. The ambient temperature is 25°C and the temperature of the heated glass substrate is 125°C. The first layers are close to 110°C, however, at a higher build geometry the temperature is close to 80°C. The effect of the heated bed fades away when the build is evolving.

Figure 4. Thermal history and temperature behavior at Tamb 25°C and Tbed 120°C.

When the temperature history is known, we can link the model to crystallization and volumetric shrinkage behavior. In this way, we can control the crystallization behavior during the build of the part. In Figures 5, 6 and 7, the chart on the left shows the temperature history that is plotted at a certain condition and the plot on the right is the crystallization conversion. When the material is fully crystallized, the value is 1. When we apply different settings, you can observe that the layers in crystallization behavior can be controlled. The dotted line in the right chart shows the difference between standard PA6 and optimized PA6 (Novamid ID 1070) for additive manufacturing. The difference in crystallization speed is clearly demonstrated. Slower crystallization helps to fuse the layers together, hence a stronger layer-to-layer adhesion.

Figure 5. This figure demonstrates that the first layers crystallizes first.

Figure 6. When all temperatures are low, crystallization is hindered.

Figure 7. When the ambient temperature is high, the last layers crystallize first.

As shown in the figures 5,6 and 7, we can control the crystallization of a printed FFF part by controlling the environment and bed temperatures. In figure 7, we clearly see that when we apply both temperatures around 100 degrees, we can print Novamid ID1070 (PA6) with limited warpage effects. 

We can “steer” the warpage and create parts that can be used for functional prototyping, as well as end use parts. Next to the crystallinity, we can also model the effect on layer thickness and printing speed on the fusion strength between layers. 

Currently, DSM is conducting trials on newly developed machines with heated chambers to obtain the right settings for the printer material combination. By fully understanding the process and material parameters, we can build a strong part with low warpage to meet the demands from the automotive industry.

To learn more about DSM in Additive Manufacturing click here. Also, to learm more about Novamid ID polyamide 6 and 6/66, Arnite ID PETP and Arnitel ID or to request test samples, contact us or visit plasticsfinder.com for additional information, including technical data sheets. 

Patrick Duis

Innovation manager

Published on

10 November 2017

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ABOUT THE AUTHOR

Patrick Duis

Innovation manager

Patrick Duis is Innovation manager at DSM Engineering Materials.

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