Development of recycling method for CD-ROM using pulsed power

This paper describes a new recycling method for metal-coated plastics. Pulsed power technology was used to remove a metal layer (aluminum) from CD-ROM. The progress of removal and the state of discharge were investigated in detail. In addition, the shadow picture method including a digital image processing was used to estimate removal amount. A pulsed power generator using magnetic pulse compression (MPC-PPG) with maximum storage energy of 40 J/pulse was used. Pulsed power was applied to concentric ring electrodes placed on the CD-ROM. Separation between electrodes was about 35 mm. Results show that almost all of the metal layer was removed under application of about 30 shots of pulse power. A strong correlation between the removed area measured by the shadow picture method and the removed mass was obtained, allowing the removed area and mass to be measured instantly by the shadow picture method. Furthermore, it was revealed that the discharge onset voltage increases with gap length between the electrodes and the aluminum layer left on the surface. Due to the surface flashover voltage between ring electrodes of about 80 kV, a pulsed power source output voltage larger than 80 kV is required.