Spark & Wire Electrical Discharge Machining
Continuing our series of electrical discharge machining articles (extracts from our EDM manufacturing guide, ‘The EDM Handbook’), this extract takes a look at Machine and Technology Trends.
Di-Spark: The Spark & Wire Electrical Discharge Machining Company
13. SPARK & WIRE ELECTRICAL DISCHARGE MACHINING: MACHINE AND TECHNOLOGY TRENDS
Future trends for EDM machine tools will focus on the control and generator side.
All types of CNC EDM machine tools will probably continue to see the integration of the machine, control, power supply, and dielectric system into a single unit yielding a smaller footprint and more efficient utilisation of valuable factory floor space. The traditional free-standing controls and power supplies are on the wane, as we will continue to see more modular construction with pendant-type controls suspended above the floor or built into panels on the machine itself.
There is considerable activity in the subject of filtration by both the machine tool manufacturers and the suppliers of EDM ancillaries. Waste disposal is gaining importance as environmental concerns continue to increase. The days when an operator can routinely discard used filters will soon be over.
Power supplies will continue to improve as circuitry gets smaller, yet more powerful. Striving for efficiency by using less power and high frequencies seems a logical direction considering the sensitivity to recast and surface integrity shown by the aircraft and aerospace industries. Special wire circuitry has already been introduced to eliminate electrolysis and matrix depletion of carbides and other sensitive work-piece materials.
The general consensus is that cutting speeds of wire machines will continue to increase. However, at some point it may be that any limitations in speed will be found in the wire itself.
Accuracy and finish will continue to improve, with finer finishes being obtained with fewer skim cuts. Special circuitry already has finishes down into the sub-micron range.
Considering the large number of cutting parameters and the constantly changing machining conditions for every different application machine control systems will continue to develop greater monitoring capabilities, perhaps ultimately evolving into artificial intelligence (AI) units. Fuzzy logic enhanced controls are already in use, simply put, these units monitor and store all previous data on conditions and parameters of what worked and what did not. Based upon the data of past performance, it can select the most efficient parameters and continue to improve its future performance.
13.1 SPARK & WIRE ELECTRICAL DISCHARGE MACHINING: MARKET TRENDS
Trends in EDM are difficult, if not impossible, to predict but the EDM market as a whole will, continue to grow as machine tool technology and user knowledge and awareness improves.
While EDM has totally revolutionised the tool making industry, other manufacturing disciplines are only just beginning to fully examine or implement this exciting process. Generally speaking, production engineers are not fully aware of the benefits that EDM can offer. They are learning, but still have a long way.
At present, EDM use in Britain is undergoing a huge and rapid diversification, transforming existing manufacturing methods and creating new ones. No longer is EDM use limited to the tool room. Wire and spark erosion machines can now seen throughout a wide range of industries, producing everything from motorsport and aerospace parts to bone implants and fine surgical components. Part making ranges from R & D and prototyping to high-volume production.
Only when the perceptions are changed of EDM being a process of last resort or as a technique for purely removing broken taps will it gain wider acceptance. In order to do this the EDM industry must;
1) Educate the potential users such as designers, production engineers, managers and other decision-makers in British manufacturing of the total system benefits this process can offer.
2) Change the concept that EDM is a “black art”
3) Raise the level awareness to the increased production, reduced secondary operations, reduced tooling costs, unattended operations, reduced number of machining operations that EDM can offer.
13.2 SPARK & WIRE ELECTRICAL DISCHARGE MACHINING: THE FUTURE
In the world of EDM the reactions that take place occur in time units of nanoseconds and for efficient machining decisions need to be made at very high speeds. Machines have developed from mechanical servo systems to adaptive controls and fuzzy logic. As technology improves EDM machines will continue to become more and more intelligent offering the following benefits:
1) Reduced operator training time and learning curves.
2) Immediately infuse years of experience and machine technology thus helping to remove the reliance on operator knowledge.
3) Produce EDM parts with good surface finishes and minimal recast.
4) Increase productivity as machine intelligence supports unattended operations and machine tool autonomy.
5) Reduce lead times.
6) Increase process control and predictability thus removing the “black art” syndrome.
7) Help to produce consistent results from machine to machine.
