Design and Development of 3D Printed PEEK

Biomedical devices have potential to benefit from increased customization and enhanced material quality, which can be implemented using additive manufacturing. Customization of these biomedical devices is necessary to fit the individual constraints of each patient, while material quality dictates longevity. This research aims to examine the additive manufacturing parameters of Poly-Ether-Ether-Ketone (PEEK), which is a thermoplastic with mechanical properties similar to osseous tissue (bone tissue). PEEK is a unique and promising material due to its biocompatibility and proficiency for use in additive manufacturing. The objective of this research is to determine the ideal set of fused deposition modeling (FDM) parameters, using PEEK, which exhibits the optimal mechanical and surface qualities for use in biomedical applications aimed at tribo-corrosive environments.
A literature review was conducted to find the primary parameters to experiment within a set of value ranges for the fused deposition modeling of PEEK, which are: nozzle temperature, platform temperature, printing speed, layer height, and infill percentage. To efficiently test the interactions of these parameters, an L-27 Taguchi experimental design was produced: five parameters, each with three parameter levels for a total of 27 samples. Profilometry and indentation tests will repeatedly be performed to determine surface roughness, elastic modulus, hardness, and creep of each of the 27 samples. The results of the tests will be analyzed in order to sort out the parameters to use for an optimal quality 3D printed part using PEEK. Overall, advances in the additive manufacturing of composite Poly-Ether-Ether-Ketone maintain an encouraging outlook for the production of custom biomedical implants that possess properties similar to bone tissue.

Hi my name is Aditya Pulipaka and my mentors for URSP are Dr. Bagheri and Dr. Beheshti. My research project is on the Design, Development, and Characterization of 3D Printed PEEK. PEEK stands for Poly Ether Ether Ketone and is a thermoplastic, which means that the material is melted by the printer and then extruded to the place that it is wanted, where It will cool and harden. This material was chosen because it is biocompatible, where we hope to apply our research to biomedical applications, where these can be utilized in place of defective bone tissue. This material was specifically chosen, as initial tests show that it has mechanical properties similar to bone tissue. Since it has the ability to be 3D printed, it can be customizable to any patient to fit individual constraints in respect to height, width, length, and density. We use a Taguchi table, which is shown in the far-right picture, that details the different variables that a 3D printer has, which includes nozzle temperature, platform temperature, printing speed, and infill percentage. The importance of this table is that it is an experimental design that gives us 27 different combinations for samples each with different levels of all these printing properties. One of which of these samples can be seen in the picture on the lower left. When we print these samples, they are created within AutoCad, such as the picture in the upper left. This design is then placed within a slicer program, which the 3D printer will be able to read the code and print the desired sample.
The testing process includes indentation and roughness testing to test for tribological and surface properties, such as roughness, Elastic Modulus, hardness, and creep. Roughness will tell us exactly how the process parameters affect how wavy or roughly textured the surface is. Elastic modulus will give us a measure of PEEK’s resistance to non-permanent deformation. Hardness tests for PEEK’s resistance as well, however resistance to permanent deformation. Finally, creep is the slow movement of the material while undergoing permanent deformation. An example of this can be seen in the Depth vs. Time graph below, where the difference between final depth and initial depth is the desired creep value. In our results, the data that was of most noticeable significance was that nozzle temperature was found to have impacted elastic modulus and roughness. It was also found that the best nozzle temperature to print at was 420 C. For hardness and creep, we did not find any significant effect of the process parameters through statistical data analysis, however through observation, it could be seen that layer height and nozzle temperature also affected these properties. This was because under layer heights of 0.3 mm, the layers started to delaminate and come apart. Also during the printing phase, the samples would warp off of the printing surface. Future studies would dive deeper into nozzle temperature and have a more in-depth understanding of how surface properties are affected by different nozzle temperatures. Also composite polymers in mixing Hydroxyapatite with PEEK or another polymer is the next step in the research. Through literature review, multiple studies that shown that when mixed with other material, PEEK’s properties are improved for practical applications. Overall, I am thankful to Dr. Bagheri and Dr. Beheshti for giving me this opportunity and learning about the future of manufacturing in 3D printing.