Spark erosion technique

Electro discharge (spark erosion) techniques rely heavily on the ability of EDM oil to act as an electrical insu-lant, to dissipate heat from the electrode, and to flush away erosion debris from the workpiece. EDM oils also are suitable for all die-sinking spark erosion operations. They should have low aromatic levels, good filterability, low fuming, high dielectric strength, excellent oxidation resistance and low color level. 

Fig. 8. Spark erosion technique and drag reduction equipment.

At this point we want to thank Dr. Drews from the PTB, Braunschweig for his generous support in applying the spark erosion technique. 

The range of surface quality reached with the different techniques is widespread depending on the material as well as on the machining parameters. Spark erosion techniques lead to a considerably rough surface. The surface quality obtained with laser ablation heavily depends on the material to be structured and on the correct parameter settings. Values between some 10 pm and about 1 pm are common. In... 

Hummel and Chang have shown that porous films can also been formed by a spark erosion technique [110]. The morphologies of these porous films exhibit less anisotropy than electrochemically formed porous structures although the pores propagate perpendicular to the surface. The growth rates of about 0.3 nm s are much slower than those of electrochemically formed porous layers. Porous layers formed in air and under nitrogen exhibited visible photoluminescence similar to the emission spectra obtained from electrochemically grown porous layers. 

The Ni(lll) specimen used in this research was a circular disk with a cross sectional area of about 0.785 cm (purchased from Cornell Laboratory ). Prior to its introduction into the main UHV chamber, it was oriented to +/- 1 by Laue backdiffrac-tion , cut by spark erosion and polished to 0.05 ft employing conventional polishing techniques. 

Several nanoscale multilayered materials have been prepared. Techniques of Rutherford backscatteiing, electron microscopy and microanalysis and other metallurgical tools have been used to investigate wear resistant, scratch resistant, microhardness, and spark erosion properties of these nanoscale multilayered materials. Preliminary results indicate that nanoscale multilayered materials with improved thermomechanical, properties can be synthesized for application in the EM gun system. Application of ion beam technology for the synthesis of gradient materials appears to have great potential for design of new materials with improved properties to be used in fabrication of many armament materials. 

The sintered magnets are hard and brittle. They can only he machined by the techniques developed for Alnicos, ceramic magnets or semiconductors. They can he sliced with diamond impregnated blades, surface ground with carborundum or diamond grinding wheels, or cut on electric spark-erosion machines (EDM). This must he done in a demagnetized state. 

Micro-heat exchangers Chemical etching, spark erosion, UV LIGA techniques Lab-on-a-chip , microelectronics thermal control 4... 

Numerous methods, which include inert gas condensation, high energy ball-milling, flame pyrolysis, electron beam vapour deposition, rapid solidification, reactive sputtering, chemical vapor deposition, sol-gel technique, microemulsion, co-precipitation, hydrothermal method, spark erosion and electrodeposition, are available for the synthesis of nanocrystalline materials (Koch, 2003b ... 

Further techniques to investigate compositional depth profiles of thicker films or film systems are stepwise-erosion by spark [96] or by laser pulses [97]. One shot erodes less than 0.1 pm film material, however, a proper uniformity in erosion is hard to obtain. 

In special cases GDOES can operate at much lower erosion rates and then becomes a surface depth profiling technique with the same depth sensitivity as. for instance, AES (108j. However, the effectiveness of GDOES lies in its high-sputter-rate mode. Other emission spectroscopies from surfaces are available, such as spark or la.ser ablation spectro.scopies, but they are less well adapted to quantitative depth protlling than GDOES. 

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