Guide to Electrical Discharge Machining: Part 1
Di-Spark Ltd work closely with +GF+ AgieCharmilles: Supplying EDM to F1.
3, Introduction to Electrical Discharge Machining
Since the introduction of EDM over fifty years ago, improvements in technology have led to increases in cutting speeds and precision. Therefore the process capabilities and manufacturing applications have also expanded.
Developing from its initial niche within the toolmaking industry (mould tools and press tools) the capabilities of the Electrical Discharge Machining process are now allowing it to serve the production engineering, aerospace, motorsport, medical and scientific industries.
The Electrical Discharge Machining (EDM) process is changing rapidly but misconceptions formed some twenty years ago still exist.
Now augmented by automatic electrode changers, automatic wire feed, slug removers, robotic work-piece changers and palletisation, this fascinating manufacturing process should no longer be considered as a process of last resort or as a second class citizen to conventional machining processes but as a mainstream machining technique in its own right.
Many manufacturing applications for electrical discharge machining already exist, they are merely waiting to be discovered and implemented. As this occurs, the increased use of Electrical discharge machining in manufacturing will continue to grow and diversify through a combination of awareness and knowledge.
In manufacturing there will always be a need to find a better way to make something, awareness in EDM will help in this quest.
Knowledge of EDM will provide the ability to design parts that are not possible or cost effective to produce by any other method. The prospect of machining complex shapes in hardened or exotic materials will continue to attract engineers and designers.
Before Electrical discharge machining can gain wider acceptance in British manufacturing more designers and engineers will have to take their blinkers off. Peripheral vision will be required to identify the wider benefits that electrical discharge machining can offer, the most successful manufacturers of tomorrow will also be the most creative.
4. Clarification of EDM Terms
The EDM industry suffers from a non-standardisation of terminology, which often creates confusion. Electrical Discharge Machining is a generic term for a method of machining that encompasses wire EDM, spark EDM and EDM hole drilling.
4.1 SPARK EDM
Spark erosion machines also known as vertical, ram, solid or die sinking machines typically have an electrode mounted and used in the Z-axis only. The early models were adapted to drills or small milling machines. Their primary duties were removing broken taps and drills from work-pieces. In time, as power supplies grew in sophistication they warranted being attached to their own stand-alone machine tool.
At first, spark erosion electrical discharge machining was only used in an emergency, and then mostly in toolmaking applications. Today’s modern equipment is a far cry from these primitive beginnings. Very precise servo systems and powerful generators have been developed, machines have adaptive control, fuzzy logic, electrode and work-piece changers, and can drive up to six axes simultaneously. These are not machines for removing broken taps
