Papers by Keyword: PEEK

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Authors: M. Federica de Riccardis, Virginia Martina, Daniela Carbone, Paolo Rotolo, Annapaola Caricato, Gilberto Leggieri, Luciano Pilloni, Leander Tapfer, Rossella Giorgi, Elena Salernitano
Abstract: Poly(etherether-ketone)-alumina coating were deposited by EPD. In order to densify the coatings, conventional thermal treatments were performed at a temperature equal or higher than the melting point of the polymer. The samples treated at the lower temperature showed an increase in the quality of crystallinity of the polymer. As an alternative method, an excimer laser was used to treat the surface of the composite coatings. The laser beam irradiation did not induce any modification in the crystalline structure of the polymer and at the same time did not produce strong degradation of the polymer molecule, also when the laser beam fluence was higher than the ablation limit. The most relevant modification induced by both the treatments was a change in the morphology and the porosity.
Authors: Hua Fu, Bo Liao, Bao Chen Sun, Ai Ping Liu, Fang Juan Qi, Zhan Lai Ding
Abstract: A semi-metallic stainless steel/carbon fiber reinforced PEEK-based friction material was developed in this paper. The composite was PEEK 19.63wt%, stainless steel fiber 7.57 wt%, carbon fiber 10.97 wt%, cashew 6.51 wt% and fillers 55.33%. The molding process was blending for about 30 seconds at higher speed, pre-heating at the temperature of 80 for 30min, molding at 320 and pressure 35Mpa for 3min/mm, then post-curing at the temperature of 80 for 30min , 150 for 30min270 for 30min320 for 180min. The results of abrasion test showed that the developed material N3 had higher and steady friction coefficient and low abrasion value. The SEM morphology study showed that the wear mechanism was particle abrasion at low temperature but adherence abrasion as well as particle abrasion occurred at higher temperature. The cohesive strength of the composite and the heat-resistant property of resin matrix were the key factors affected wear loss. The abrasion depended on the strength of transformed films and matrix.
Authors: Katsuyuki Kida, Kota Kawai, Koshiro Mizobe, Hitonobu Koike, Kenji Kanemasu
Abstract: In our previous work, we designed a new joint system for humanoid sized robot. This system consists of a servomotor, a harmonic drive and a link unit. This link unit includes three components; polymer bushes, a metal cam plate and a metal camshaft. However elastic deformation of all-polymer bushes can cause a large backlash in the system. In the present work, a new bush was developed and its fatigue behavior was investigated.
Authors: Said Kebdani, S. Kebdani, M. Dahmane, Z. Azari
Abstract: There are a few years, it has become the use of artificial discs and effectively to compensate for damaged discs in humans due to the eccentric load applied on the spine. As we know very well that the success of a disc implantation depends strongly on the initial stability of the implant and the integration of the bone tissue of the vertebrae with these discs in the long term. Due to the optimal distribution of mechanical stresses in the surrounding bone. It is for this reason that the search for reasonable solutions to compensate the damaged disk and reduce the stresses in the cortical bone and spongy has become a very important research axis. Several alternatives have been studied, including implant design, prosthesis geometry, prosthetic components and biomaterials used. In this regard, we have proposed two new models for some innovative artificial disks by some of the biomechanics researchers and we have installed these discs between the two vertebrae L5 and S1 of the spine, to ensure spinal stability and avoid slipping, we installed a posterior attachment system (6 screws plus 2 rods) at the pedicular levels of the lumbar vertebra (S1-L5, L5-L4).It is for this technique that we have used finite elements in three dimensions and using the software ANSYS to know the extent of the realization of these discs under the influence of the load applied to them. The numerical results show that these disks played a very important role in the absorption of the stresses and to minimize, On the other hand, the lumbar inter-somatic cage (Model II) filled with cancellous bone is too great a role in reducing the stress compared to another synthetic (Model I) disc. In general, the new model of the inter-somatic cage filled with cancellous bone and reinforced by a posterior fixation system has given a lower level of stress in the cortical bone and the spongy bone of the lumbar vertebra (L5) compared to the healthy disk (D1).
Authors: D.T. Chavara, Cyndi X. Wang, Andrew Ruys
Abstract: Functionally graded materials (FGMs) can be found naturally in many biological structures, for example bamboo and the mollusc shell. They are defined as having a compositional or microstructural gradient, for example the gradation in fibre content in bamboo stems. A continuous bulk functionally graded material has the potential to be an ideal orthopaedic implant for load bearing applications. Due to the fabrication complexities involved in the production of these continuous bulk functionally graded materials, commercialisation and fabrication are still proving to be a challenge to researchers worldwide. This paper presents an overview of the redesigned novel commercially viable process known as the Impeller-Dry-Blending (IDB) process. Results presented in this paper of fabricated functionally graded materials illustrate the potential of IDB to produce continuous bulk functionally graded materials consisting of either compositional or porosity concentration changes. The successful fabrication of these continuous bulk functionally graded materials at such a low cost clearly demonstrates the commercial viability of the IDB process.
Authors: Hitonobu Koike, Kenji Kanemasu, Kiyoto Itakura, Shota Okazaki, Masahiro Takamiya, Katsuyuki Kida
Abstract: In this work, wear of reinforced poly-ether-ether-ketone (PEEK) polymer bushes in friction against 7075 aluminium alloy cam plates or titanium crankshafts is investigated in order to establish the application possibilities in transmission parts in humanoid robot joints under high load torque. The PEEK bush wear requires close examination as well as the input axis-output axis transmission error (backlash). Sliding wear tests were performed on bushes under 4000 kgfcm (392 Nm) load torque, while the cam plate oscillated in the humanoid robot leg joint evaluation system. The robot joint using PEEK bush achieved quite small backlash after the fatigue wear test.
Authors: Ignacio González, Alfredo Sanz, Antonio Fernandez
Abstract: This article describes the analysis of the three types of heating metallic meshes used for the resistance welding process of thermoplastic matrix composites. The analysis of the heating that takes place in the mesh will carry to optimize the process parameters and to assure a correct joint and properties in the whole area.
Authors: Hitonobu Koike, Koshiro Mizobe, Shunsuke Oyama, Yuji Kashima, Kenji Kanemasu, Katsuyuki Kida
Abstract: In this paper, the wear performance of polymer radial ball bearings (PEEK-PTFE and PPS-PTFE) were investigated. For effective operation of equipment in clean energy facilities environment, the polymer bearings were developed. These polymer bearings were produced by machining and their rolling contact fatigue (RCF) behavior under non-lubricated condition was carried out. PEEK accumulation layer with PTFE and graphite was formed on the bearing's inner ring under 3000 rpm high rotation speed. Due to the self-lubrication of PEEK layer, the wear loss of PEEK-PTFE bearing was lower than PPS-PTFE radial bearing. Moreover, it was found that the thin PEEK layer protected the raceway from the friction heat and wear. The wear durability of PEEK-PTFE bearing was superior to PPS-PTFE one.
Authors: Horia Octavian Manolea, Florian Obădan, Sanda Mihaela Popescu, Radu Rîcă, Petre Mărășescu, Alexandru Andrei Iliescu, Constantin Dăguci, Sebastian Gradinaru
Abstract: The lack of a periodontium for a dental implant may lead to high stress concentration at the bone level when the implants are prosthetically loaded. The present paper discusses the current possibilities of implant supported prosthesis making in order to mitigate the impact of occlusal forces. The cement layer may serve as an absorber for the strain, but its role is reduced and poses the risk of excess cement retained in the peri-implant tissue. The use of resin materials for the implant supported prosthetic restorations veneering it has been suggested for many years, but their role it is important in the case of full-arch fixed implant-supported prosthesis with cantilever distal extensions and less in single implant restorations. Nowadays, new materials like fiber-reinforced composites and high-performance polymers as PEEK may be used for the framework of the implant supported prosthetic restorations, but also for the implant or the prosthetic abutment realization.
Authors: T. Nakamura, Hiroki Nakamura, O. Fujita, T. Noguchi, K. Imagawa, T. Inoue
Abstract: Atomic Oxygen (AO) is a main constituent of the atmosphere on low earth orbit where the International Space Station (ISS) goes around, and is also known as the matter which deteriorate many kinds of polymers. However, the strength properties of polymers suffered from AO have not been fully clarified. To investigate this problem, we irradiated AO to Poly-Ether-Ether-Keton (PEEK) films under three kinds of tensile stresses. Based on the analysis of irradiated samples, the effects of AO fluence (total amount of AO per unit area) and tensile stresses on damage properties were discussed with regard to reaction efficiency Re, surface morph, and tensile strength properties. As a result, the following were obtained: (1) Test piece surfaces exhibited considerable damage covered by conical pits of 1μm sizes with a few μm depths. (2) Test piece thickness of irradiated area decreased almost proportionally to AO fluence. (3) Re and thickness reduction was accelerated by tensile stress. (4) Strength properties after AO irradiation were almost same as those of a pristine sample considering the decrease of specimen thickness.
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