Water-based chemistries are used in batch and in-line cleaning of PCB assemblies, in fluxes and solder pastes, and in other electronic materials such as masks and coatings and dispensed products such as adhesives. Water-based chemistries have their own range of issues in terms of processing and handling, corroded, ionic contamination and cleanliness considerations. Aggressive Organic Acid (OA) soldering fluxes are one example. Electrovert® systems are compatible with and deliver excellent results with water-based chemistries, including the Electrovert Aquastorm® cleaner that combines advanced cleaning technologies in both batch and in-line type cleaners, and the Electrovert MicroCel™ centrifugal cleaning machine.
Water Based Chemistries
Adhesive materials (e.g., SMT adhesives for holding passive SMD components in place during wave soldering) are printed and dispensed accurately and precisely with MPM® stencil printing and CAMALOT® dispensing equipment using the range of dispensing pumps (such as auger pumps) available, depending on the application requirements.
ITW EAE product lines apply a wide range of materials into the assembly of electronics and industrial processes and applications.
Liquid Fluxes of different types may be applied by various techniques to solderable surfaces, such as paste fluxes (stencil printed onto bare PCBs with MPM® stencil printers or dispensed onto selective areas via CAMALOT® dispensing systems). All ITW EAE equipment is compatible with the various types of fluxes available, including No Clean (NC), Water Soluble (WS), Rosin Mildly Activated (RMA), and Rosin Activated (RA) that are used in the full range of semiconductor and board assembly processes.
ITW EAE’s assembly technology solutions are designed to excel in handling lead-free soldering technology. Lead-free alloys in solder paste typically have a tighter process window than traditional lead-bearing (e.g., SnPb) solders.
‘No-clean’ solder pastes and fluxes have their own unique characteristics and process requirements. Although they are intended to be left on the PCB assembly after processing, their ‘low-solids’ content requires precise, careful temperature profiling so that the active cleaning, wetting, and protective agents in the flux will have the opportunity to perform their function and form a good solder joint before they boil off.
Solder is still the primary means of attaching electronic components to a PCB to create a working electronic assembly. Whether solder is applied in a paste form or as a molten liquid, ITW EAE provides proven solutions for stencil printing, dispensing, reflow soldering, wave soldering, and cleaning soldered assemblies.
Solder pastes in every alloy type, flux chemistry, and particle size are precisely and accurately stencil printed with MPM® stencil printers and dispensed in semi-liquid form with CAMALOT® dispense systems. Accurate application, in terms of location and volume, is critical to forming good solder joints, since solder paste is by volume only 50-55% metals.
A wide range of solvent types are used in electronics manufacturing, from simple DI water to alcohols such as IPA to more aggressive and complex formulations. Solvents are used for cleaning and are also found in printed and dispensed electronic materials.