What is Drag-out
Drag-out refers to the phenomenon where a liquid film or plating solution adheres to workpieces and their fixtures as they are withdrawn from a process solution or rinses. It is a measure of the cleaning solution lost during the emergence of the board after immersion. The volume of drag-out is influenced by various factors, including the viscosity of the solution, surface tension, withdrawal time, draining time, and the characteristics of the workpieces themselves, such as their shape and texture.
Managing drag-out is crucial in the PCB industry to prevent wastage and potential environmental contamination. The liquid film that remains on the workpieces and fixtures after removal can potentially drip onto the floor, leading to wastestream treatment challenges. If the drag-out liquid contains regulated substances, they must be properly removed or neutralized before being discharged into POTW sewers, in compliance with regulatory requirements.