摇篮式电火花线切割机床运动学建模

Kinematics Modeling of Cradle-type WEDM Machine Tool

传统“X-Y-U-V”式电火花线切割机床受限于几何结构,加上电极丝倾斜时不易保证良好的冲液条件,难以加工锥度大于30°的工件。为提高电火花线切割机床加工上下异型、大锥度等工件时的表面质量和尺寸精度,并拓展其应用范围,提出了工件摆动而电极丝不发生倾斜的摇篮式电火花线切割机床构型。首先,基于刚体运动学的基本理论,建立了用于求解机床各轴数控指令的运动学模型;接着,引入机床几何误差进行精度建模,推导该误差至加工表面的映射关系,并依据此模型对数控指令进行误差补偿;最后,通过实验验证所提出的摇篮式电火花线切割机床加工上下异型、大锥度等工件的可行性。

Due to the structural limitation and the deterioration of the flushing condition caused by wire tilt,it is difficult for the traditional “X-Y-U-V”type wire electrical discharge machining(WEDM)to cut workpieces with a taper larger than 30°. In order to improve the surface quality and dimensional accuracy of the up and down abnormities workpieces or large-taper workpieces,a cradle-type WEDM configuration in which the workpiece swings without tilting the wire is proposed. Firstly,a kinematics model for solving the CNC commands of the machine tool is established based on this configuration.Then the geometric error of the machine tool is introduced for precision modeling,and the mapping relationship between this error and the machined surface is deduced. Moreover,error compensation is performed on the CNC commands based on this model. Finally,cutting experiments are conducted to verify the feasibility of the proposed cradle-type WEDM for machining up and down abnormities workpieces and large-taper workpieces.