Experimental Investigation On 266nm Nanosecond Solid Laser Processing Of Polystyrene And CH Film

Polystyrene and CH film materials are used as ablative coating materials for laser inertial confinement fusion(ICF)due to their relatively low density and atomic number,and easy processing.During laser ICF tests,it is necessary to process micro-holes on the ablative coating material.Laser processing technology,because of its high precision,high efficiency and no debris production,is often used to process such micro-holes in the ablative coating materials.The 266 nm laser features a shorter wavelength and higher photon energy,and can therefore break the chemical bonds in materials directly and achieve the “photochemical” processing.As a result,it has become an important light source type in laser processing.To study the processing effect of 266 nm nanosecond solid-state laser on the micro-holes of polystyrene and CH film,and also to process high-quality micro-holes on polystyrene and CH film.The mechanism and process of 266 nm nanosecond solid-state laser processing of polystyrene and CH film were studied.The mechanism and theoretical model of UV laser ablation of polymer materials are discussed.According to the ablation mechanism of UV laser on polymer materials,the material removal mechanism of polystyrene and CH film by 266 nm nanosecond solid-state laser was explored.The results show that when the CH film is processed by266 nm nanosecond solid-state laser,the material removal mechanism is mainly photochemical ablation.Photochemical ablation and photothermal ablation coexist when polystyrene is processed by 266 nm nanosecond solid laser.The ratio of the two is affected by factors such as laser energy.The finite element simulation model was established to simulate the temperature field and stress field of laser processing polystyrene.The distribution of temperature field and stress field during laser processing of polystyrene was studied.When the material is irradiated by laser,the laser energy will rapidly increase the temperature in the irradiated area.The heat-affected zone occurs when the temperature of a material exceeds the melting point of the material.Due to the drastic change of material temperature,tensile stress and compressive stress have occurred around the irradiated zone.The value and range of stress increase continuously with the laser irradiation time.After laser irradiation,the stress value gradually decreases.Finally,the simulation results are verified by experiments.The effect of 266 nm nanosecond solid-state laser on polystyrene and CH film was tested.Single-factor experiments revealed the law of the effect of processing parameters such as laser pulse energy,number of laser pulses,and defocus on micro-hole dimensions such as the diameter and depth of micro-holes and the width of the recast layer.Through orthogonal experiments,the level of significance of the effect of each laser processing parameter on micro-hole dimensions was obtained.Moreover,the optimized process parameters were determined by comprehensive balancing for a 266 nm nanosecond solid-state laser to punch holes in polystyrene.