Research topics

    Electrochemical Micromachining (ECMM)  

So called silicon process, which is widely used in manufacturing semiconductor devices, is an established process. However, it is difficult to apply the process to other materials. For the progress of micro machine technology, metals are also required to be micromachined. For this, electrodischarge machining (EDM) seems a superior machining method. It, however, has weaknesses of leaving heat affected layer on the machined surface and of tool wear. The latter becomes especially troublesome when three dimensional shape is to be micromachined. Electrochemical machining (ECM) has advantages of leaving no heat affected layer and of no tool wear. Electrochemical machining, however, is hardly applicable in micromachining because of the expected difficulty in controlling machined shape. The electrode gap in ECM is considerably larger than that in EDM and the resulted resolution of the machined shape is inferior to EDM. However, if its electrode gap is kept at very small value, the resolution of machined shape will become better and the possibility of applying ECM to micromachining will increase. Our preliminary experiment showed that the machining voltage and electrolyte concentration can be lowered with the use of specially designed electrode gap control system and as a result the electrode gap can be decreased down to severalμm. The electrochemical dissolution at microscopic electrode gap is hardly known but seems to be a prospective phenomenon. We are going to study the feasibility of developing a new process for high quality three dimensional micromachining of metals.
   

Block diagram of the experimental setup  

Work 0.2 t Ni plate Tool electrode Pt90% / Ir10%φ170μm wire Electrolyte 14 g/dm3 NaClO3 Pulse on-time 160 ms Period 200 ms Machining voltage 3.8 V Tool electrode up and down movement 50μm

Example of machined hole  

  Then, we made an experimental machine to investigate possibilities of electrochemical micromachining. The photo shows an example of machined sample. The square part (□200μm) was machined fromφ500μm nickel wire. After one side of the square was machined in about 10 min, the work was rotated 90 degrees and the second side was machined. By repeating this operation 4 times, the square part was formed.

An example of machined sample
    References  

    etc. 　  Link to "The Japan Society of Electrical-Machineing Engineers"  
 

Contact 　 Technical consultation concerning electrochemical micromachining is acceptable.