| Summary: | 碩士 === 國立雲林科技大學 === 機械工程系 === 104 === Various auxiliary mechanisms are employed in laser machining, for example jet, flame, electric/magnetic and water, in an attempt to remove slag out of holes or minimize the changes of thermal effect on the machining spot and thereby upgrade laser machining efficiency and quality. In this study, discharged plasma was employed to remove machining slag together with the discharged plasma by means of group effect so as to upgrade laser machining energy density and, at the same time, minimize the plasma energy loss induced by laser.
The author drilled holes in two types of metal, 5052 aluminum alloy and stainless steel (SUS304), and then drilled holes in a hard an brittle glass material using 532nm Nd:YAG laser. Two types of auxiliary discharged plasma mechanisms were employed, namely, normal discharged plasma and self-made discharged plasma. A hollow electrode was fitted inside the self-made discharged plasma, allowing laser light to pass through it so as to acquire the coaxial machining effect created by laser and discharged plasma.
In the earlier stage, the author measured energy and images. According to the results obtained by Power meter, laser energy increased 15% when discharged plasma was added. Based on the images created by the discharged plasma coupled to laser, the discharged plasma revealed a 20% increase of its energy when laser plasma was produced. According to the experiment on the ablated light spot, the size of laser’s ablated light spot increased by 18% when discharged plasma was added.
In this study, two types of machining mechanisms were employed, namely, No. 1: tilting the discharged plasma and laser light to a given angle for machining and No. 2: machining the discharged plasma and laser light coaxially. No. 1 mechanism resulted in a 40% increase of drilling efficiency; No. 2 mechanism resulted in a larger ingress and intact egress of metal material. Moreover, glass machining capability was superior to laser machining without auxiliary mechanism and outperformed laser machining aided by jet.
In the course of glass machining, the author noted splashed slag being obviously affected by the discharged plasma, which is an indication of the influence on the work-piece’s slag resulted from laser machining imposed by the discharged plasma. After analyzing the profile of the machining hole, the author found the machining hole growing larger, indicating slag removal rate higher than other machining mechanisms.
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