Abstract: LS-WEDM (low speed wire electrical discharge machining) TC4 was regarded as the research object， the influence of peak current， open circuit voltage， pulse width， wire speed and wire tension’s effects on process time， kerf width and surface roughness was studied by SNR (signal to noise ratio) method. The gray correlation analysis was applied to realize the transformation from multi-objective parameter optimization to signal objective optimization of grey correlation degree and the optimum machining parameter combination of LS-WEDM were obtained under the multiple technical index requirements. Multi-objective parameter optimization results show that when the peak current is 30A， the open circuit voltage is 100V， the pulse width is 20μs， the wire speed is 105mm/s and wire tension is 12N， the surface roughness， kerf width and process time were reduced by 8.35%， 2.59% and 26.06%， respectively.

Key words: LS-WEDM, TC4, SNR, gray correlation analysis, parameter optimization