3D-printed Polyetheretherketone Research Articles

Influence of nozzle temperature and volumetric filling on the mechanical properties of 3D-printed PEEK

Abstract Fused deposition modeling is a layer-by-layer 3D printing technology used to additively manufacture polymers. A major benefit of 3D-printed polymers is the option of tailoring their mechanical properties by varying the process parameters. In addition, the present study investigates the influence of the filling degree (50 % or 100 %) and the nozzle temperature during manufacturing on the mechanical properties of 3D-printed poly-ether-ether-ketone (PEEK) material. PEEK samples were built either compact (filling degree 100 %) or closed-cell porous (filling degree 50 %), using three different nozzle temperatures (390 °C, 430 °C and 470 °C). In static bending tests, the bending properties were evaluated and compared with injection molded PEEK samples. Bending strength and modulus increased up to 21.1 %, when the nozzle temperature was increased and up to 40.8 % when the volumetric filling was altered. The results indicate that nozzle temperature and volumetric filling can be altered to tailor the bending properties of 3D-printed PEEK for particular applications. However, the mechanical properties of the 3D-printed samples determined in the current study could not achieve those of the properties of the injection molded PEEK.

3D-Printed PEEK Extravascular Stent in the Treatment of Nutcracker Syndrome: Imaging Evaluation and Short-Term Clinical Outcome

Minimally invasive options are safe and reliable alternatives for the treatment of nutcracker syndrome (NCS). After continued efforts, our team successfully devised a new and effective therapeutic method: 3D-printed extravascular stenting of the left renal vein. From December 2017 to May 2019, 28 patients (25 men and 3 women) from different parts of China between 18 and 37 years old (mean, 23.6 years) diagnosed with NCS were admitted for laparoscopic 3D-printed extravascular stenting treatment. The post-operative follow-up duration was 6–24 months (median, 16.3 months). Technical success of the operation was achieved in all patients. After treatment, the NCS symptoms all patients resolved or improved during the follow-up period, without relapse. Most symptoms, including macro-/microhematuria, proteinuria, and flank/abdominal pain, tended to resolve within 3–6 months after the surgery; other symptoms, such as left-sided varicocele, also showed varying degrees of improvement at different times post-operatively. Perioperative complications were noted in two patients, including transient and mild lymphatic leakage, without any adverse effects. All extravascular stents were visualized on computed tomography and Doppler ultrasound scans, and no migration or any side effects occurred during the entire follow-up period. Compared to endovascular stenting or polytetrafluoroethylene artificial vessel procedures, 3D-printed polyetheretherketone extravascular stenting has more advantages in terms of stent design and rigidity and approach rationality while successfully preventing stent migration and thrombosis. Therefore, this method may serve as an accurate and effective treatment for NCS patients.

Bacteria-Triggered pH-Responsive Osteopotentiating Coating on 3D-Printed Polyetheretherketone Scaffolds for Infective Bone Defect Repair

Biomaterial-enabled regeneration of the infected or contaminated bone defects remains one of the critical challenges in the development of new clinical treatments. Three-dimensional (3D) porous scaffolds, which can synchronously emulate the hierarchy of bone structures and additionally provide bactericidal and osteogenic features, offer a potential solution to tackle this issue. In this work, we construct hierarchical porous polyetheretherketone (PEEK) scaffolds via 3D printing, equipped with a pH-triggered osteopotentiating coating. In the design of the coating, silver nanoparticles (AgNPs) are trapped onto the first polydopamine (pDA) layer, and apatite is further anchored onto the second pDA layer. The unique pDA-Ag-pDA sandwich structure imparts bacteria-triggered pH-responsive ion-releasing behavior to the inert PEEK scaffolds, i.e., the liberation of Ag+ ions from the coating is augmented with decreasing pH value, which is associated with the metabolism of bacteria. These bioscaffolds exhibit excellent capability for eradicating bacteria, as well as harness acceptable cytocompatibility and protuberant osteogenetic potential of osteoblastic MC3T3-E1 cells. Importantly, in vivo evaluation indicates that the Ag/apatite codecorated multifunctional bioscaffolds present appealing in vivo antibacterial efficacy and excellent bone ingrowth and osseointegration in an infected critical-sized bone defect. Accordingly, such smart pH-triggered osteopromotive PEEK implants demonstrate strong potential in the treatment of the complicated infective bone disorders.

Influence of nozzle temperature and volumetric filling on the mechanical properties of 3D-printed PEEK

Abstract Fused deposition modeling is a layer-by-layer 3D printing technology used to additively manufacture polymers. A major benefit of 3D-printed polymers is the option of tailoring their mechanical properties by varying the process parameters. In addition, the present study investigates the influence of the filling degree (50 % or 100 %) and the nozzle temperature during manufacturing on the mechanical properties of 3D-printed poly-ether-ether-ketone (PEEK) material. PEEK samples were built either compact (filling degree 100 %) or closed-cell porous (filling degree 50 %), using three different nozzle temperatures (390 °C, 430 °C and 470 °C). In static bending tests, the bending properties were evaluated and compared with injection molded PEEK samples. Bending strength and modulus increased up to 21.1 %, when the nozzle temperature was increased and up to 40.8 % when the volumetric filling was altered. The results indicate that nozzle temperature and volumetric filling can be altered to tailor the bending properties of 3D-printed PEEK for particular applications. However, the mechanical properties of the 3D-printed samples determined in the current study could not achieve those of the properties of the injection molded PEEK.

Influence of sanding and plasma treatment on shear bond strength of 3D-printed PEI, PEEK and PEEK/CF

Increasing interest in 3D-printed high-performance polymers is observed due to their excellent mechanical properties and high resistance to chemical and thermal degradation. One of the ongoing challenges is to achieve sufficient joint strength because of the inertness of thermoplastics. In the current work, effects of surface treatment on shear bond strength of 3D-printed samples were focused and assessed. First, polyetherimide (PEI), polyether ether ketone (PEEK) and PEEK/CF(carbon fiber) as adherend were produced via FDM 3D printing. Then, sanding or atmospheric plasma treatments were carried out to improve the surface wettability of the 3D-printed specimens. Significantly, reduction in surface roughness was observed in sanding treated specimens, while nearly no change occurred in plasma-treated counterparts. However, surface free energy and wettability were greatly improved after plasma treatment. Single lap-shear tests and failure mode for PEI, PEEK and PEEK/CF using two different adhesives (film and liquid) were investigated, and the effect of surface treatment on bond strength was further compared. Results suggested that liquid adhesive contributed higher joint strength for surface-treated specimens in comparison to film adhesive. Besides, atmospheric plasma treatment is more efficient and safer method for 3D-printed PEEK and PEEK/CF, achieving a higher joining strength.

Thermal localization improves the interlayer adhesion and structural integrity of 3D printed PEEK lumbar spinal cages

Additive manufacturing (AM) is a potential application for polyetheretherketone (PEEK) spinal interbody fusion cages, which were introduced as an alternative to titanium cages because of their biocompatibility, radiolucency and strength. However, AM of PEEK is challenging due to its high melting temperature and thermal gradients. Although fused filament fabrication (FFF) techniques have been shown to 3D print PEEK, layer delamination was identified in first generation FFF PEEK cages [1]. A standard cage design [2] was 3D printed with a second generation FFF PEEK printer. The effect of changing layer cooling time on the FFF cages’ mechanical strength was investigated by varying nozzle sizes (0.2 mm and 0.4 mm), print speeds (1500 and 2500 mm/min), and the number of cages printed in a single build (1, 4 and 8). To calculate the porosity percentage, FFF cages were micro-CT scanned prior to destructive testing. Mechanical tests were then conducted on the FFF cages according to ASTM F2077 [2]. Although altering the cooling time of a layer was not able to change the failure mechanism of FFF cages, it was able to improve cages’ mechanical strength. Printing a single cage per build was associated with a higher ultimate load than printing multiple cages per build. Regardless of the cage number printed per build, cages printed with bigger nozzle diameter achieved higher ultimate load compared to cages printed with smaller nozzle diameter. Printing with a bigger nozzle diameter resulted in less porosity, which might have an additional benefit on the interlayer delamination failure mechanism.

3D-printed PEEK reactors and development of a complete continuous flow system for chemical synthesis

This paper presents the development of milli- and microfluidic reactors made of polyether ether ketone (PEEK) and 3D-printed equipment for a complete continuous flow system.

On the thermal processing and mechanical properties of 3D-printed polyether ether ketone

Abstract

Application of 3D-printed PEEK scapula prosthesis in the treatment of scapular benign fibrous histiocytoma: A case report

BackgroundBone benign fibrous histiocytoma (BFH) is an invasive primary bone tumor. When the local excision is not complete, the risk of recurrence is high, and hence, one-piece resection is necessary. The major challenge for clinicians is to reconstruct the bone after resection of the tumor. The present study investigated the efficacy of 3-dimensional (3D) printing technique in the treatment of benign fibrous histiocytoma of the scapula. MethodsThe patient with benign fibrous histiocytoma of scapular bone was treated with PEEK (polyetheretherketone) prosthesis replacement using the 3D printing technique. X-ray and computed tomography (CT) scans evaluated the relationship between the position of the prosthesis and that of the shoulder joint. Also, the constant score of the shoulder joint was calculated. ResultsThe anteroposterior radiograph showed that the position of the left scapula prosthesis is satisfactory and that of the shoulder joint is normal. Three months after the operation, the X-ray examination indicated the lack of flexibility and shift, as well as, dislocation and disjunction of PEEK prosthesis. The constant score of the left shoulder function was 68 points. Active shoulder joint activity: 120° on the lift, 90° on abduction, 50° on the external rotation, and 70° on internal rotation. ConclusionsThe application of 3D-printed PEEK scapula prosthesis with total shoulder replacement offers the possibility of accurate reconstruction, improves the operability of surgery, shortens the operation time, and allows early functional recovery of the patients.

Structure-Property Relationships for 3D printed PEEK Intervertebral Lumbar Cages Produced using Fused Filament Fabrication.

Recent advances in additive manufacturing technology now enable fused filament fabrication (FFF) of Polyetheretherketone (PEEK). A standardized lumbar fusion cage design was 3D printed with different speeds of the print head nozzle to investigate whether 3D printed PEEK cages exhibit sufficient material properties for lumbar fusion applications. It was observed that the compressive and shear strength of the 3D printed cages were 63-71% of the machined cages, whereas the torsion strength was 92%. Printing speed is an important printing parameter for 3D printed PEEK, which resulted in up to 20% porosity at the highest speed of 3000 mm/min, leading to reduced cage strength. Printing speeds below 1500 mm/min can be chosen as the optimal printing speed for this printer to reduce the printing time while maintaining strength. The crystallinity of printed PEEK did not differ significantly from as-machined PEEK cages from extruded rods, indicating that the processing provides similar microstructure.

Custom design and biomechanical analysis of 3D-printed PEEK rib prostheses

A tumour resection normally involves a large tissue resection and bone replacement. Polyether ether ketone (PEEK) has become a suitable candidate for use in various prostheses owing to its lightness in weight, modulus close to that of natural bone, and good biocompatibility, among other factors. This study proposes a new design method for a rib prosthesis using the centroid trajectory of the natural replaced rib, where the strength can be adjusted by monitoring the cross-sectional area, shape, and properties. A custom-designed rib prosthesis was manufactured using fused deposition modelling (FDM) manufacturing technology, and the mechanical behaviour was found to be close to that of a natural rib. A finite element analysis of the designed rib was carried out under similar loading conditions to those used in mechanical testing. The results indicate that the centroid trajectory derived from a natural rib diaphysis can provide reliable guidance for the design of a rib prosthesis. Such methodology not only offers considerable design freedom in terms of shape and required strength, but also benefits the quality of the surface finishing for samples manufactured using the FDM technique. FDM-printed PEEK rib prostheses have been successfully implanted, and good clinical performances have been achieved.Graphical abstract

Influence of Layer Thickness and Raster Angle on the Mechanical Properties of 3D-Printed PEEK and a Comparative Mechanical Study between PEEK and ABS.

Fused deposition modeling (FDM) is a rapidly growing 3D printing technology. However, printing materials are restricted to acrylonitrile butadiene styrene (ABS) or poly (lactic acid) (PLA) in most Fused deposition modeling (FDM) equipment. Here, we report on a new high-performance printing material, polyether-ether-ketone (PEEK), which could surmount these shortcomings. This paper is devoted to studying the influence of layer thickness and raster angle on the mechanical properties of 3D-printed PEEK. Samples with three different layer thicknesses (200, 300 and 400 μm) and raster angles (0°, 30° and 45°) were built using a polyether-ether-ketone (PEEK) 3D printing system and their tensile, compressive and bending strengths were tested. The optimal mechanical properties of polyether-ether-ketone (PEEK) samples were found at a layer thickness of 300 μm and a raster angle of 0°. To evaluate the printing performance of polyether-ether-ketone (PEEK) samples, a comparison was made between the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) and acrylonitrile butadiene styrene (ABS) parts. The results suggest that the average tensile strengths of polyether-ether-ketone (PEEK) parts were 108% higher than those for acrylonitrile butadiene styrene (ABS), and compressive strengths were 114% and bending strengths were 115%. However, the modulus of elasticity for both materials was similar. These results indicate that the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) are superior to 3D-printed ABS.