PEEK 3D printing is an exciting opportunity, as 3D printing of the material found at the top of the polymer pyramid allows parts to be manufactured faster, more cheaply and more flexibly compared to traditional manufacturing methods. However, the 3D printing of semi-crystalline polymers such as PEEK and PEKK and the issues to be considered differ significantly compared to the 3D printing of amorphous polymers (e.g., ULTEM). For amorphous polymers, acknowledging glass transition temperatures is key to optimal chamber temperature selection.
For semi-crystalline polymers, the choice of chamber temperature is mainly based on the crystallisation properties of the material. Thus, PEEK 3D printing requires a complete understanding of the material and a high-performance 3D printer such as miniFactory Ultra. The Ultra 3D printer can also print fibre reinforced PEEK and PEKK composites, allowing the performance of printed parts to be stretched to the limit.
Polyaryletherketone (PAEK) is a family of semi-crystalline thermoplastics with high-temperature stability and high mechanical strength. The two best-known materials in this group that can be 3D printed using FFF technology are PEEK (Polyetheretherketone) and PEKK (Polyetherketoneketone).
The main use of PEEK and PEKK materials is in various metal replacement applications, often combining high temperatures, high mechanical demands, and strong chemicals. The materials have inherent flame retardancy. Both materials have also been certified for use in demanding applications, for example, in the aerospace, oil and gas, and medical industries. PEEK 3D printing provides a cost-effective and flexible way to produce a variety of prototypes and production batches.
Until now, PEEK parts have been produced through injection moulding or machining. PEEK 3D printing is known to excel in areas where traditional manufacturing methods face challenges in terms of cost and production volumes. With 3D printing, part manufacturing need no longer depend on stock shapes but can produce larger parts, without wasting material, and at a significantly lower cost than before. 3D printing as a manufacturing method enables a completely new level of design freedom and integrated features for the parts to be manufactured, which are challenging or even impossible to achieve with traditional manufacturing methods.
PEEK and PEKK materials are also available for 3D printing in carbon fibre reinforced form. The carbon fibre improves the compressive strength, stiffness and load carrying capacity of materials. Carbon fibres also stabilise the printed piece and ensure significantly better dimensional accuracy of the parts to be printed. The temperature resistance of PEEK-CF material is up to +260°C. For 3D printing of carbon fibre reinforced PEEK material, miniFactory Ultra offers the perfect platform and the 250°C chamber of the device makes printed parts stronger than before. The carbon fibre reinforced PEEK material has been validated for our equipment.
PEEK 3D printing requires more knowledge and expertise from the user than 3D printing of amorphous materials. When printing PEEK material, attention should be paid to the crystallinity of the piece, as it is only when the material is fully crystalline that it achieves its excellent properties. If PEEK is printed in a printing chamber with a temperature below 130°C, there are often signs of incomplete crystallisation in the printed piece. If the piece shows signs of incomplete crystallisation or is even completely amorphous, post-treatment annealing will shrink and distort the piece uncontrollably by up to 3-5%. As a result, the dimensional accuracy of the part suffers and, in most cases, the part becomes unusable at worst.
If the printing chamber can be heated to 160-220°C, the pieces will crystallise efficiently, i.e., get rid of annealing and the challenges it brings. However, the pieces printed at this chamber temperature often have room for improvement in mechanical strength, especially in the Z-direction of the piece.
When the chamber can be heated to 250°C, like in a miniFactory Ultra 3D printer, the mechanical strength can also be increased. What makes PEEK 3D printing interesting, however, is that what works for one geometry often doesn't work for the next, and the process has to be re-optimised. miniFactory Ultra allows for part-specific optimisation, as all parameters are freely adjustable. Our years of experience in printing PEEK material can also be harnessed for your benefit with our service.
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The optimum nozzle temperature for PAEK family polymers is 410-440°C depending on the 3D printing equipment and how the nozzle temperature of each device is measured. As print speed increases, the nozzle temperature must also increase to ensure sufficient melting power. miniFactory Ultra nozzles can be heated up to 480°C, so the 3D printing of PEEK material is effortless.
Even PAEK family polymers absorb moisture, which weakens printing quality. It is extremely important that materials are pre-dried as per the instructions. More importantly, however, the material is also to be kept dry during the printing process. The miniFactory Ultra 3D printer features a heated filament chamber which pre-dries the material for optimal use and keeps moisture away from the material during printing. This feature allows you to always print at the same high quality avoiding any moisture-related problems.
PEEK 3D printed parts are suitable for many applications. The material is particularly sensitive to the uniformity of the process, and it is important that the printing process can be verified. The best way to make sure of this is to request a quality control report for the printed part that includes all the information about the part’s manufacturing process. miniFactory AARNI is an innovative process monitoring tool that works with the miniFactory Ultra 3D printer. With AARNI, you receive all the information visually for every print while consistently ensuring the quality of printed PEEK parts.
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