Mouldmakers公司制造了一种取名为Metap的电火花加工附件,它能与一般的电火花机床配合使用,进行螺纹加工。这个附件的壳体用轻合金制成,内装一根被支承在绝缘的滚动轴承中的水平钢质芯轴,芯轴一端安装单头螺纹状电极。尼龙导向板与装在芯轴上的一个样板螺纹啮合,当轴旋转时就给电极传递轴向运动,这样,电极就按与样板螺纹相符的螺旋形轨迹加工出螺纹。 Moldmakers manufactures a spark-machining accessory, named Metap, that can be used with conventional EDM machines for threading. The housing of this appendix is ​​made of light alloy and houses a horizontal steel mandrel supported in an insulated roller bearing with a single threaded electrode on one end of the mandrel. The nylon guide plate is threadably engaged with a template mounted on the mandrel to impart axial movement to the electrode as the shaft rotates so that the electrode is threaded in a helical trajectory corresponding to the template thread.