Dataplate Training Chemical Processing for Nadcap Water Break Test Awareness By Konrad Burgoyne DTP-WBTA Issue 1 – 27 January 2012 Copyright © Dataplate 2001 - 2012 Dataplate Training Hydrophobic & Hydrophilic Conditions Surface conditions in relation to acceptance of aqueous (water) based liquid can be in two states Hydrophobic Hydrophilic Dataplate Training Hydrophobic Surface Condition Water or other water based liquid is repelled by the surface of the parts causing the water to bead on the surface indicating the part surface is not in a condition to interface with aqueous based chemistry. The most common cause is grease and oil. Dataplate Training Hydrophilic Surface Condition Water or other water based liquid is able to “stick” to the surface of the part indicating a water break free surface Dataplate Training Hydrophobic & Hydrophilic Conditions Hydrophilic (Water break free surface) Hydrophobic (Water broken surface) Dataplate Training Surface Cleaning Parts cleaning is essential to many industrial processes as a prelude to surface finishing or to protect sensitive components. Electroplating, anodising and conversion coatings are particularly sensitive to part cleanliness. Molecular layers of oil can prevent adhesion of the coating, or in the case of anodising and chemical conversion coatings prevent coatings from forming altogether Dataplate Training Cleaning Processes Cleaning processes include: Solvent cleaning Hot alkaline detergent cleaning Acid or alkaline etching In Treatments we use a solvent degreaser, Hot alkaline soak cleaner and an acid deoxidiser (mild etch) process Dataplate Training Surface Conditioning The cleaning processes within the treatments is formulated to enable the correct conditions to prepare the surface of parts Parameters important to the process stages include: Time of immersion or exposure Temperature to obtain optimum cleaning Concentration and formulation of the chemistry for optimum cleaning capability Dataplate Training Water Break Test The water break test is an effective way to visually confirm that the surface of the parts have been cleaned successfully and are in a condition to process further. If the surface of a part maintains a water break free surface for 30 seconds after immersion in clean water below 38°C it is considered clean. The water break test requires observation of the surface of the parts following a clean rinse stage to confirm a water break free surface is maintained for 30 seconds or more. Parts may be visually inspected at the end of the 30 second period. This may allow the operator to move to the next stage during the 30 second period and inspect the parts just before the next stage. E.g. Turco clean > Rinse > Check time for start of WBT > move to deoxidiser > Check time until 30 seconds elapsed > Inspect water break free surface > Immerse into deoxidiser on successful WBT Dataplate Training Process Control Flow Chart PCFC / Process Control Document PCD The Process Control Flow Chart (PCFC) lists each stage of the process and indicates where and when a water break test is required. The water break test is required after the cleaning process Dataplate Training Chemical Processing for Nadcap Questions?