Therefore, the lower the percentage of crystallization nuclei in the polymer, the faster the cooling process will be, and therefore the layers will have a better adhesion to each other. Based on the crystallization nuclei, the molecular chains fold up and form ordered regions. In technical terms, as the extruded filament solidifies, a partial alignment of the polymer molecular chains occurs. Additionally, it also requires both a heated build plate and a heated chamber.ģD printed cooling system with PEEK (photo credits: Apium) The extrusion temperature will typically be between 644 and 680☏ (340 and 360☌). In the case of amorphous PEKK, the requirements will be very similar, but not as stringent. When using PEEK for 3D printing, you need a machine with an extruder that can reach 752☏ (400☌), as well as a chamber heated to 248☏ (120☌) and a building plate that can go up to 446☏ (230☌), so that the layers can adhere to it and to remove it without problems (thus preventing issues with warping). You also need a 3D printer that meets certain temperature requirements. When dealing with high performance polymers, one needs advanced knowledge to avoid making mistakes during printing, mainly to avoid wasting these expensive materials. In this section, we will mainly focus on Fused Deposition Molding (FDM). The crystallinity affects the properties of the final piece while the speed of crystalization and the rheological properties have an impact on the ease of printing. In general, when we talk about the 3D printing process, PEEK can achieve a high level of crystallization, while PEKK has a much weaker crystal structure. In this case, we are comparing two semi-crystalline elements, but their degree of crystallinity depends and varies depending on how they are processed. This concept refers to the total number of crystalline regions present in a polymer, and is represented as a percentage. The main distinction between these two materials is their degree of crystallinity and the speed of crystallisation. However, some of their characteristics differ due to their composition. PEEK and PEKK therefore have common properties, understandable as they belong to the same family of polymers. Parts printed using PEKK (photo credits: miniFactory) But what are the differences between these two high-performance thermoplastics? Which one should you choose? We explain everything you need to know! Often compared to metals, they have been compatible with certain additive manufacturing processes for a few years now, including material extrusion (FDM) and selective laser sintering. Generally used in the so-called traditional manufacturing industry (plastic injection, machining, etc.), PEEK and PEKK both have interesting thermal characteristics and are known for their strength. Two materials within the group are increasingly used by industry: PEEK and PEKK. Today we will focus on the category of high performance polymers and more specifically on the family of polyaryletherketones (PAEK). Whether it is a filament, resin or powder, each one has its specificities. If we look at plastics, they are very numerous and can be more or less technical to print with. Today, the market has a wide choice of materials, from polymers to metals, ceramics and organic inks. R.Materials in additive manufacturing are a key component of the process, giving the final part its own chemical properties and mechanical characteristics.
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