Printed layers will cool down and contract relative to warmer layers printed above. Part distortion due to the temperature differences between layers.If polymer solidification and cooling is too rapid, three issues will arise: In addition, printing PEEK at lower temperatures induces larger temperature gradients between the newly deposited layers and previously deposited layers. As a result, almost every PEEK property is affected by decreased crystallinity, reducing tensile strength, flexural, heat resistance, chemical resistance, density, and even coefficient of friction. 3D Printing PEEK at Colder TemperaturesģD printers that are not able to achieve a build chamber temperature of 133☌ or greater produce amorphous PEEK. The extrusion temperature for PEEK 3D printing should fall in the range of 365-440☌. To achieve in-situ crystallization of PEEK and maximize part properties a build chamber temperature and bed temperature of 133☌ or higher is needed. Our materials scientists recommend a minimum chamber temperature within 10☌ of PEEK’s glass transition temperature. In PEEK, the crystallization process is rapid which results in a large specific volume change during solidification at T m. In-situ crystallization is the organization of these polymer chains, creating a crystalline phase during the 3D printing process. In-situ Crystallization: Ideal 3D Printing Conditions for PEEKĬrystallization in polymers occur between the glass transition and melting temperature, where the polymer chains begin to fold and arrange. Semi-crystalline PEEK appears opaque beige, demonstrating a high level of crystallinity. For example, semi-crystalline PEEK can be used under conditions up to 240☌ but amorphous PEEK will begin to crystallize and deform at temperatures above 150☌.Īmorphous PEEK can be visually characterized by the translucent brown appearance, illustrating a low degree of crystallinity as light passes through the structure. This structural difference allows semi-crystalline PEEK to withstand higher tensile stress, creep, temperature, radiation, and chemical resistance compared to amorphous PEEK. On the other hand, the polymer chains in the amorphous phase can be stretched and broken with minimal loading because of weak bonding and entanglement. In semi-crystalline form, PEEK exhibits its best mechanical, chemical and thermal properties.įrom the theory of polymer physics, polymer chains in the crystalline phase are aligned and form stronger intermolecular bonds, resulting in greater strength and rigidity. Semi-crystalline PEEK: Maximizing Part Properties During crystallization the crystal growth is radial, forming spherulites. The crystalline phase consists of closely packed and ordered polymer chains (black) which are connected to each other by the randomly orientated, entangled amorphous state (blue). PEEK can be produced in an amorphous or semi-crystalline state. PEEK can also be amorphous, where it has little to no crystallinity in its structure. PEEK can have both crystalline and amorphous phases in its structure, known as a semi-crystalline solid. Ordered polymer chains are linked together by chains that are randomly orientated, labelled as the amorphous phase of the polymer. Crystals are folded polymer chains that organize into packed, ordered structures as shown in the image below. The degree of crystallinity in PEEK directly influences its mechanical and chemical properties. Already familiar semi-crystalline and amorphous PEEK phases? Jump to ideal printing conditions. To better understand how we can maximize the properties of 3D printed PEEK we must first understand crystallinity. In this article we analyze 3D printer requirements and optimal temperatures to print high quality, mechanically robust PEEK parts. A printer’s ability to achieve specific chamber, bed, and nozzle temperatures will determine a part’s level of crystallinity and desirable properties. That said, final part properties of PEEK are not guaranteed by simply 3D printing the material. Polyetheretherketone ( PEEK) is regarded as one of the highest performance thermoplastics due to its incredible mechanical, chemical, thermal, and weight-saving properties.

Peek plastic block