![]() ![]() ![]() Spools of filament act as a feed for the extrusion head. 3D Printing PEEK for Fused filament fabrication (FFF) technologyįused filament fabrication ( FFF) is an Additive Manufacturing technology that extrudes continuous filaments of thermoplastic polymers to 3D print parts. When reinforced, both amorphous and semi-crystalline materials show considerable improvements in strength and stiffness way beyond their glass transition temperature (Tg), due to the higher thermal deflection temperature (HDT). In the direction parallel to the flow, this shrinkage will be more than in the transverse direction.ĭue to their shrinkage that leads to lower dimensional stability, semi-crystalline materials introduce greater difficulties in production processes.Among the semi-crystalline polymers there are: This anisotropy can be observed by analyzing the shrinkage of the material. The extrusion process through a nozzle generates a preferential orientation of the macromolecules in a direction parallel to the extrusion flow, thus making the material tend to be anisotropic. When exposed to a rise in temperature, the crystalline domains give the material greater stiffness - even at temperatures above the glass transition - thus allowing the polymer to maintain its mechanical properties over a wider temperature range than its amorphous counterpart. On the contrary, the semicrystalline have an ordered molecular structure with a precise melting temperature. Some examples of polymers with an amorphous morphology are: In general, amorphous materials look translucent and they have lower fatigue and stress resistance but better impact resistance. The disordered arrangement of the polymer chains does not induce preferential behaviors in particular directions, thus leading to a more isotropic behavior. This property leads to having a range of temperatures at which they will melt, therefore not precisely defined temperatures. Amorphous polymers have disorganized molecular chains intertwisted and randomly oriented.The main differences between semi-crystalline and amorphous polymers are firstly the arrangement of the molecular chains and, consequently, how that affects the behaviour of the polymer under heat: ![]() Differences between semi-crystalline and amorphous polymersĪccording to the arrangement of macromolecules in space, two main categories of polymers can be distinguished: Should you print PEEK or PEKK? To understand it, it is better to take a step back and explain the differences between semi-crystalline and amorphous materials first. The most popular are PEEK and PEKK ( Polyetherketoneketone), because they both show extraordinary properties in terms of mechanical, thermal, and chemical resistance. Some of the polymers that belong to the PAEK family ( polyaryletherketones), have shown to be 3D printable with FFF (Fused Filament Fabrication) technology. What is the difference between PEEK and PEKK? Both are semi-crystalline thermoplastics, but their degree of crystallinity highly depends on the way they are processed. ![]()
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