The C-arc is the business end of the machine. It guides and positions the EDM wire. The wire guides should be as close to the workpiece as possible, this increases accuracy and provides better flushing so higher cutting speeds are possible.
This design has a nice feature that the opening in the C-arc is adjustable to minimize the distance to the workpiece. After adjustment, re-calibration is not required since the upper and lower wire guides are exactly positioned above each other with the help of an adjustable XY play-less precision leafspring mechanism.
Another feature of this design are quick release PVC wheels that clamp the wire to the actuated brass transport wheels. These come quite in handy when mounting the wire. The brass wire has the tendency to unspool quickly when no tension is applied. Without the quick release wheels, you need more than two hands to get the wire in place. With the wheels it’s an easy job to do by yourself.