Surface World Handbook 2017 - Page 178

ENVIRO TECH SURFACE TECHNOLOGIES Exploring a new solution to the problems caused by conventional cleaning and metal pretreatment systems in product fi nishing Enviro Tech Surface Technologies looks at some of the traditional problems associated with solvent and aqueous degreasing prior to painting and powder coating and explains how the DriPHOS® option can offer a viable alternative to conventional processes. The DriPHOS® surface treatment process has evolved to produce a revolution in metal fi nishing. DriPHOS ® the start of a great fi nish Traditionally jobbing painters and / or manufacturers of parts who have to subsequently degrease and then paint or powder coat have had the same problems that they have learnt to live with. These include: reject rates of between 3 - 8% after painting; residues of particulate that require further manual wiping after degreasing MAIN CAUSES AQUEOUS METHOD SOLVENT METHOD INADEQUATE DEGREASING - Solution out of spec or contaminated - Only vapour used - Temperature to low - Poor loading - Rinses contaminated - Wrong solvent used - Filters blocked - Solvent turned acidic - Wrong product used - Particulate left by vapour - Contaminated rinse water - Solvent turned acidic - Poor loading - Poor loading - Insuffi cient time to dry - Solvent trapped in parts - Poor loading - Parts not designed to drain properly RESIDUAL CONTAMINATION RETAINED MOISTURE - Parts not designed to drain properly NO INTERIM PROTECTION - No corrosion inhibitor - Residual contamination - High temperature draws moisture from atmosphere - Solution out of specifi cation 176 2017 - 2018 read online: