Controllable interlayer shear strength and crystallinity of PEEK components by laser-assisted material extrusion
- PDF / 1,953,348 Bytes
- 10 Pages / 584.957 x 782.986 pts Page_size
- 20 Downloads / 167 Views
ser-assisted material extrusion was used in this study to realize high-performance 3D printing of semicrystalline polymers. A CO2 laser device was simply integrated into a traditional fused deposition modeling printer to supply the laser. The sample’s surface temperature was changed by controlling the laser power during printing, and thus the interlayer shear strength and crystallinity could both be effectively controlled. By implementing the laser-assisted process, the optimal interlayer shear strength of poly(ether ether ketone) (PEEK) could be improved by more than 45%, and the degree of crystallinity of PEEK was simultaneously improved by up to 34.5%, which has approached to the typical crystallinity of 35%. Therefore, the process provides a very effective solution for additive manufacturing of semicrystalline materials and helps clearly to establish a controllable mapping relationship between the laser parameters and material properties.
I. INTRODUCTION
Because of their advantages of thermal resistance, desirable mechanical properties, and biocompatibility,1–3 semicrystalline thermoplastic polymers, such as poly (ether ether ketone) (PEEK), poly(ether ketone), and polyphenylene sulfide, have been used as replacements for metals in cars, aircraft, industrial pumps, and medical applications.4–7 In particular, in their medical implant applications, PEEK-like materials can successfully support radiographic assessment, which gives them an advantage over metals.7 These excellent performance characteristics of semicrystalline plastics are closely related to their semicrystalline forms, which are significantly influenced by the thermal cycles in the forming process.8–12 Many industrial techniques have been used to manufacture products made of semicrystalline materials, such as injection molding, pressing, and sintering as well as emerging additive manufacturing processes.4,13,14 Compared to traditional manufacturing, additive manufacturing techniques such as selective laser sintering15,16 and fused deposition modeling (FDM)17 provide an innovative and effective way to simplify processing and realize the manufacturing of complex structural parts of high-performance polymers. Material extrusion, also known as FDM, can be used for rapid, inexpensive fabrication of thermoplastics. In the material extrusion process, the materials must be successively liquefied, rearranged, and then solidified; thus, they undergo a typical heating and cooling procedure,18–20 a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2018.131
which influences the product’s crystallinity and final properties, especially for semicrystalline materials.21 In the conventional semicrystalline material extrusion process, two problematic phenomena exist simultaneously. The internal crystallization is insufficient owing to too-rapid cooling without post-heat treatment or ambient heat treatment,14,22,23 whereas the external bonding strength of two adjacent layers is too low because of the low bonding temperature.24–26 Inc
Data Loading...
