| As one of the most common mould materials, die steel plays an important rolein manufacturing of blanking dies and forming dies due to the properties of highhardness, high compressive strength and low wear. Act as the main processingmethod for high hardness material, precision grinding becomes very Inefficient forthe reasons of the low material removal rate and lack of flexibility. Compared withthe traditional machining methods, laser machining has advantages on applicationsof micro-fabrication for its properties of non-contact processing, high precision,high efficiency. Laser-assisted grinding machining is an advantage combination oflaser machining and grinding, laser and grinding are in charge of rough and finishworking respectively, so the efficiency can increase greatly meanwhile theprecision is guaranteed. Furthermore, the heavy wear of grinding wheel can besolved.First of all, this paper analyzed the advantage and disadvantage offemtosecond, picosecond, and nanosecond laser machining, then choose the mostsuitable laser device. Make a study of ablation threshold for metal based oncalculation method of area, obtain the single-pulse ablation threshold of Cr12under the action of10ns pulse width laser0.20J/cm2, the radius of focusing spotwaist54.5μm. Ablation threshold dependence for number of pulses is researchedthrough a serious of experiments with different number of pulses.Second part, the principle of laser drilling process is analyzed based onobserving surface morphology and EDS(Energy Dispersive X-ray Spectrometer)analysis of ablated spots on workpiece with scanning electron microscopy. Thenthrough this principle, make an in-depth study of the interaction law of nanosecondlaser and metal.In the end, the process and strategy of microstructure machining on metal bynanosecond laser is developed based on theoretical study, experimental verificationand design of the scheme. According to the parameters, two kinds of V-groove withdifferent size and some other structure are machined. |
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