CEAD studies mechanical properties affected by temperature and nozzle diameter for LFAM process

When new materials are released to the market, they jump on the opportunity to test and research them extensively. Hereby they aim at the best printing settings using their extruder and various applications. In order to help companies kickstart their additive manufacturing process, they provide Flexbot and robot extruder users with the datasheets produced by material tests.

Measuring mechanical properties
This study focused on the best print temperature and extruder settings. Thermoplastic pellets enter the top of the extruder and exit through the nozzle at the bottom as beads with high viscosity. Inside the extruder’s barrel, a screw is responsible for the downwards movement of the pellets.

However, the extruder configurations affect the mechanical properties of the printed object differently. Examples of these settings are: the temperature of the extruder, the diameter of the nozzle, layer time, number of rotations of the screw per minute (RPM) and torque (the force delivered unto the pellets in the barrel by the screw).

Central in this research was a large scale application, thus two larger nozzles (9 and 12mm) were used in the material test. These nozzle sizes provided beads from 18 to 22mm wide. Furthermore, printing temperature varied as well. RPM, torque and layer time however were kept stable.

The focus thus lay on settings concerning temperature of the E25 extruder, nozzle diameters and their influence on the mechanical properties of prints.

High-end thermoplastic material
The high quality materials tested were ABS, PEI, PC. All materials were reinforced with 20% carbon fiber. These materials are applicable in various applications and are thus of great interest for research.

CEAD is always looking for high quality materials. In this case, the material was sponsored by Airtech Advanced Materials Group. Andrew was in close contact with Airtech during the research period. Sharing knowledge in both supplier and client directions creates a sustainable cooperation between all the stakeholders. These materials provided very promising research results, which allows the CEAD to inform future customers well about these Airtech materials.

Results of the material research
Frequent printing with all three materials allowed them to identify the behavior of the materials specifically for CEAD’s E25 extruder. Tests, conform to ASTM standards (D-638, D-790), were conducted in order to validate the tensile and flexural strength. Two of these tests can be seen in the video on this page.

What then became clear is that each material showed a different behavior. This demonstrates the importance of having their own process guideline for each material. The results ensure that CEAD and Airtech are able to advise customers on the best use of these high quality materials, focused on their application.