Polimer matrisli kompozitlerin lazer ile işlenmesi

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Thesis Type: Postgraduate

Institution Of The Thesis: Kocaeli University, Fen Bilimleri Enstitüsü, Makina Mühendisliği Bölümü, Turkey

Approval Date: 2021

Thesis Language: Turkish

Student: ORKAN BARAN KORKUSUZ

Supervisor: Tamer Sınmazçelik

Open Archive Collection: AVESIS Open Access Collection

Abstract:

There are various drawbacks and limitations in machining of polymer matrix composites with conventional methods, particularly in the aviation and space industries. Especially during machining, defects such as delaminations, breakage of fibers, fiber matrix interface deformations may occur. These defects adversely affect the static and dynamic properties of materials. On the other hand, known methods are not preferred in micro-scale machining of materials and creating functional surfaces due to their inadequacy. Laser machining is one of the popular methods that stand out in this context. Being a focused beam, laser is commonly used in advanced applications. The high energy density created by the laser enables the solid state material to rapidly transition to the vapor phase, allowing the materials to be machined without mechanical damages. However, the heat affected zone generated as result of thermal interaction should be limited to the minimum possible level. It is possible to create reproducible and high quality functional surfaces on the order of microns if working with appropriate laser parameters. Within the scope of the thesis study, the surface texture was created by laser ablation on the surface of polymer matrix composites materials reinforced with two different fiber types. Experimental studies were carried out using a Nd:YAG pulsed laser with a wavelength of 1064 nm, at 5 different energy densities, 5 different pulse durations and 3 different focal area distances. The surface structure of the formed cavity was observed with a stereo microscope and optical profilometer. Finally, inferences were made about principle of the laser mechanism and parameter optimization was aimed in order to obtain quality surfaces. Since the heat affected zone is related to the laser material interaction time, working with shorter pulse times limited the HAZ.