The problem of eliminating edge-chipping at the entrance and exit of the hole while drilling brittle materials is still a challenging task in different industries.Grindingaided electrochemical discharge machining (G-ECDM) is a promising technology for drilling advanced hard-to-machine ceramics,glass,composites,and other brittle materials.Edge-chipping at the entrance of the hole can be fully eliminated by optimizing the machining parameters of G-ECDM.However,edge-chipping at the exit of the hole is difficult to eliminate during the drilling of ceramics and glass.This investigation suggests some practical ways to reduce edge-chipping at the exit of the hole.For this purpose,a three-dimensional finite element model was developed,and a coupled field analysis was conducted to study the effect of four parameters,i.e.,cutting depth,support length,applied voltage,and pulse-on time,on the maximum normal stress in the region where the edgechipping initiates.The model is capable of predicting the edge-chipping thickness,and the results predicted by the model are in close agreement with the experiment results.This investigation recommends the use of a low voltage and low pulse-on time at the hole entrance and exit when applying G-ECDM to reduce the edge-chipping thickness.Moreover,the use of a full rigid support in the form of a base plate or sacrificial plate beneath the workpiece can postpone the initiation of chipping by providing support when the tool reaches the bottom layer of the workpiece,thereby reducing the edge-chipping thickness.