Multi Objective Performances Optimization Of Poly-Ether-Ether-Ketone (PEEK) Material By Using Rotary Ultrasonic Assisted Drilling

• المؤلف الرئيسي: Manaf, Norshahidah
• التنسيق: أطروحة
• اللغة: الإنجليزية; الإنجليزية
• منشور في: 2019
• الموضوعات: T Technology (General); TJ Mechanical engineering and machinery
• الوصول للمادة أونلاين: http://eprints.utem.edu.my/id/eprint/24954/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=117955

Polyaryletheretherketone (PEEK) materials is a semi-crystalline, high purity polymers containing of replicating monomers of two ether groups and a keytone group. PEEK is a rigid opaque material considered as a good mechanical properties retained in high temperatures with a unique mixture of properties, which include wear, exceptional chemical and electrical resistance. The accumulative use of PEEK plastics can be seen in the growth of a wide range of orthopedic applications, including spinal fusion cages, artificial discs, femoral stems and cranial implant. Compared to other implant material, polymeric material like PEEK promote better cell bone growth compared to metallic materials like Titanium because PEEK’s surface topography enhance implant - bone contact. In the case of medical implants, fine surface roughness is one of the most importance requirement since the cells of surrounding tissue interact with the underlying substrate on the micro and nanometer scales. The tight tolerances in medical application for a fine surface roughness poses a major concern in conventional drilling process of PEEK implant materials. PEEK’s does not dissolve heat easily and has low service temperature compared to metal and it can melt if the drilling temperature increases above of the melting point. On the others hand, PEEK also deform when the cutting force and shear stress increases during the drilling process which can lead to rough machined surface and tolerance violation. In addition, conventional drilling process towards this material tends to generate high tensile thrust that results in poor hole quality and crack propagation. Considering these facts, in this thesis a new drilling technique which assisted by the ultrasonic vibration frequency known as Rotary Ultrasonic Assisted Drilling (RUAD) is propose aim to increase the hole qualities i.e. surface roughness, hole accuracy at entry and exit surface. A set of experimental work was conducted to evaluate the effects of the RUAD parameter namely cutting speed, feed rate, ultrasonic frequency and vibration amplitude towards the hole quality. A statistical analysis of variance (ANOVA) was employed to assess the relationship between parameters and output response. Subsequently, further analysis was performed to obtain the optimum RUAD parameter that can produce the best hole quality. From the analytical results, its demonstrated that the presence of the ultrasonic vibration was able to improve the hole quality and minimize the chipping area with acceptable tolerance value. Furthermore, based on the statistical optimisation result, combination of spindle speed of 3294 rpm and feed rate of 191 mm/min will produced the best hole qualities i.e. minimum surface roughness and minimum holes error. The findings from this deliberately experimental work can be used by implant manufacturer for effectively drilling PEEK material.