http://www.surfacetreatments.it/thinfilms Automatic Electropolishing (Vanessa Rampazzo - 15') Speaker: Vanessa Rampazzo - Legnaro National Laboratories of INFN | Duration: 15 min. Abstract Electropolishing is an electrochemical process adopted in order to reduce the internal surface roughness. The process involves a special equilibrium between the reagents and the products, that creates a differential electrical resistance through the micrometric peaks and valleys of surface. This regime is detected collecting the current in function of voltage. Observing dinamically the changes of the characteristic curve during the process it’s possible to ensure the best electropolishing setting. The Dynamic Control of the best electropolishing point int I-V Plane is done by an automatic program, that collects continuoulsy the voltage and current and calculates in real time the best setting. Roughness smoothing is accompanied by the removal of anomalies on the surface, as pitting and stratches. The automatic program is written in Labview language and works on a industrial computer, a PLC.

1. Automated EP V. Rampazzo Development of the software based on the tuning of the differential electrolytic conductance for controlling the Electropolishing process ISTITUTO NAZIONALE DI FISICA NUCLEARE LABORATORI NAZIONALI DI LEGNARO

2. I-V polarization curve for EP The method consists in computer monitoring the I-V characteristic. Tuning of the EP process in the minimum of the differential conductivity dI/dV

3. Schema of the automated EP Digital Input-output Analogical signals VOLTAGE CONTROL REGIME The best working point of the I-V characteristic is searched and followed by during the whole EP process Electrolytic cell Voltage Supply PLC PC Automation Software

6. Movie

7. Characteristic Curve Derivarive calculation

9. Graphic Graphic plot of characteristic curve I-V Short range scan EP Derivative dI/dV

11. Manual set of EP working point

15. Thanks for attention!