Practical Etch Improvements

June 2006

Practical Etch Improvements

As photo chemical machined (PCM) parts become smaller and more complex, the need to properly maintain the etching machines become more critical. Along with solution chemical controls, the physical considerations of etch directionality and solution puddling on the top side of the work piece become more critical. On a horizontal conveyorized system etch directionality is when etched lines perpendicular to the conveyor direction etch at a different rate than etched lines that are parallel to the conveyor direction due to the dynamics of the forward conveyor direction. Puddling is the effect of etch solution accumulating on the surface of the work piece. In order to etch the top surface of the panel the solution puddle must be moved by the pressure of the spray nozzle thus replenishing fresh etchant to the metal surface. As this puddle increases in volume or becomes difficult to push over the sides of the panel due to the panel area, etched lines at the edge of the panel are etched more than etched lines under the middle of the puddle.

Ken Bridges, CTO, Kenchi International Ltd