An EDM machine requires a control loop for controlling the feed rate.
The CNC motion controller should adjust the feed rate continuously such that the setpoint error remains as small as possible. In order to keep the error small, the CNC controller needs to command the motors to speed up if the error is negative and slow down if the error is positive. The motion controller needs to be able to continuously change the speeds of the motors, and also the direction in which the motors are turning. Any CNC controller that is able to do this, and has the flexibility to program the behavior of the control algorithm is a very good solution. The CNC controller of Dynomotion meets these requirements. There might be other solutions that meet these too, however these are unknown to BaxEDM.
Most simple commercial CNC controllers do not allow the user to program their own control loop, nor are they able to dynamically reverse the feed rate. For such controllers, the only option is to use a control strategy in which the motors are stopped if the error goes positive. Although it is possible to machine with such a control strategy. This is not desired as the arc stability will be quite poor, which has a negative impact on the part finish. Next to that, the machine won’t automatically find the correct feed rate. In such a stop/go control scenario, the operator has to estimate the feed rate, which is difficult for each material type and thickness, which is clearly not desired.