Electrical Discharge Machining
Power PMAC motion control for EDM Machines. Sinker, Wire and Fast-Hole Adaptive gap control, path retrace and taper motion for EDM machine builders
Real-time, closed-loop gap control · Programmed-path retrace · written in C by the builder
Electrical discharge machining requires the feed rate to respond to gap conditions rather than follow a programmed velocity. That makes it as much a control challenge as a motion challenge, requiring a controller that lets machine builders define their own feed algorithms and execute them directly within the servo loop.
Our Power PMAC motion control solutions are designed to support this. Gap voltage and generator status are captured through analogue and digital inputs, while a machine-specific control algorithm, written in C, runs within the real-time servo task at the full servo update rate.
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Sinker and die-sink EDM.
Z-axis feed driven by gap condition, advancing during stable discharge, slowing as the gap closes and retracting on a short circuit. Jump and flushing cycles are programmed
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Wire EDM.
Four-axis motion with independent U and V axes for taper, coordinated through a kinematic transform so the programmed contour is maintained at the workpiece across taper angles. Wire feed, tension and guide axes run on the same controller as the contour axes. Corner strategies, including feed reduction and power schedule changes through direction changes, are implemented in the machine's control code.
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Fast-hole and small-hole drilling.
High cycle-rate advance, retract and re-entry sequences executed on the controller rather than under host supervision.
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Micro-EDM.
Fine feed resolution with a servo update rate fast enough to respond to gap conditions. Linear motors with scale feedback and Direct PWM current control are typically used for the feed axis.
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Retrofits.
Machines with sound mechanics and obsolete control electronics can be re-controlled while retaining the frame, tank and generator.
The feed algorithm is written by the machine builder in C and executed in the servo interrupt, with access to the controller's internal variables and I/O. It is not constrained to a parameter set defined for milling or turning.
The trajectory engine supports reversing along the programmed path under program control, which is the retract behaviour required when conditions deteriorate and machining must resume from the same point.
Supporting machine functions run on the same controller: G-code interpretation with user-definable G and M codes, PLC logic for dielectric, filtration, generator and interlock control, and EtherCAT for distributed I/O. The operator interface can be the Power PMAC NA HMI or a custom application.
Sinker and fast-hole machines typically use CK3M with analogue input modules for gap sensing. Wire machines with higher axis and I/O counts often suit Power UMAC. Where axes are low-voltage servo or linear motors, Power Brick LV combines control and drives in a single unit.
Discuss a project
Send us the machine specification or the control requirement and we will advise on whether Power PMAC is a suitable platform, and what hardware configuration it would need.
