Issue link: https://iconnect007.uberflip.com/i/408601
November 2014 • SMT Magazine 49 problem," recalled the engineer, "but then I stumbled across a solution at an automation trade fair. This is where I discovered atmospher- ic pressure plasma." the solution The pretreatment process developed and patented under this brand name by Plasmatreat GmbH in the mid-90s is now used throughout the world in almost every branch of industry. The environmentally friendly in-line technolo- gy works under normal ambient air conditions, thereby dispensing with the need for a vacuum chamber. The plasma process performs two operations in a single step: It simultaneously brings about the microfine cleaning and strong activation of the plastic surface. The rise in temperature of the plastic surface during plasma treatment is typically less than 30°C and substrates can be transported through the plasma jet at speeds of several hundred meters per minute. For elec- tronic components, patented rotational nozzles with a special gentle action are used. Schneider was soon convinced of plasma's powers of activation, but now the manufactur- ing specialist had to face a complete different question: Would the sensitive electronics sur- vive the plasma treatment unscathed? It was clear from the very first tests per- formed on a plasma system supplied on loan that this plasma technique had not damaged the electronics. The surface energy of the plas- tic transistors which had caused the whole problem increased from below 30 dyne in the inactivated state to over 70 dyne following plas- ma treatment. The final visual UV inspection, which every SMD component undergoes before avionics: atmosPHeric PressUre PLasma case stUDy continues arTiCle figure 3: The smoothly working rotary plasma jet cleans and simultaneously activates the surface of the plastic components just before conformal coating. The pretreatment is done in a matter of seconds without damaging the sensitive electronics. (Photo: Plasmatreat)