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JUNE 2026 I SMT007 MAGAZINE 21 The QFN11 test board, for example, incorporates multiple pad-spacing configurations that allow assemblers to examine how cleaning performance varies across different geometries and process conditions. These transparent structures enable direct obser- vation of the effects of cleaning machine design, chemistry selection, and process optimization Cleaning Machine Categories Cleaning systems for electronic assemblies gener- ally fall into two primary categories: batch and inline systems. Both require integrated wash, rinse, and drying capability, but each offers distinct operational advantages. Batch Cleaning Systems Single-chamber batch systems perform washing and rinsing in a single process chamber. Two common configurations are used. The first uses rotating nozzles or nozzles with a tangential spray system. Boards are placed in baskets. Drying is accomplished with high-flow fan nozzle banks. There is no air knife system. The second batch cleaning approach uses a linear moving nozzle system, utilizing direct spray impingement. Boards are secured in dedicated fixtures; air knives are situated between wash and rinse stages. These systems often include advanced rinse water reclamation systems and mechanical and chemical filtration systems. Modern systems may also incorporate: • Ion exchange filtration for rinse water purification • Activated carbon filtration to remove non-ionic contaminants • Enhanced drying systems using air knives to reduce evaporation load Figure 6: Test boards QFN11 with glass test chine QFN48_11. Figure 7: Glass test chip QFN 11 can be easily inspected. Figure 8: Diverse batch cleaning machines with a rotation nozzle system and tangential spray. Quadrant Component Pitch (mm) Pad-to-Pad Spacing (mils) Pad Width (mils) 1 QFN 48 0.5 mm 12 8 2 QFN 48 0.5 mm 10 10 3 QFN 48 0.5 mm 8 12 4 QFN 48 0.5 mm 4 14