The Importance of Stencil Cleaning in SMT: Reducing Defects and Cutting Costs
Dr. Adam Klett, Director of Science at KYZEN Corporation, emphasizes the crucial role of high-quality stencil printing in SMT processes. He highlights that stencil cleanliness significantly impacts print quality, with dirty stencils leading to various defects. While periodic cleaning is common, the frequency varies based on process efficiency. Dr. Adam criticizes the use of isopropyl alcohol (IPA) for cleaning, citing its ineffectiveness with modern solder pastes and safety concerns. A picture of the bottom of a stencil cleaned with IPA clearly shows solder paste residue under UV light. (The paste contained a fluorescent dye.)
Although engineered solvents have a higher upfront cost, he argues they’re more economical in the long run due to reduced usage, less evaporation, fewer required cleanings and decreased defects. Dr. Adam estimates potential savings of over $20,000 annually per printer by increasing prints between cleanings. He stresses the importance of considering the total cost per board rather than focusing solely on individual consumable costs, aligning with KYZEN’s mission of providing innovative, environmentally responsible cleaning solutions.