Aqueous cleaning technologies: Present and future

Pre and post cleaning are important in the heat treating process. The cleanliness of parts is often the difference between an acceptable part or a reject. In the past, heat treating operations had the latitude to choose between vapor degreasing, solvent immersion and aqueous cleaning alternatives. In today's regulated world, environmental/worker safety takes precedence over convenience or tradition. Vapor degreasers are regulated because of ozone depletion potential (e.g. 1,1,1 trichloroethane) or worker safety (e.g. perchloroethylene). Even commonly used solvents like mineral spirits fall under regulations due to VOC emissions and fire hazard potential. This modern world of ''regulated solvents'' has caused a serious reexamination of aqueous cleaning options. Water based cleaners do not threaten the protective ozone layer, emit high levels of VOCs, pose serious fire hazards or severe health risks to employees. Additionally, aqueous cleaning often produces cleaner parts at reduced costs. Conversion to aqueous cleaning processes requires the consideration of one or more of the following: (1) equipment requirements (capital costs), (2) production requirements (through-put), (3) space (4) drying of parts, (5) corrosion and (6) disposal of contaminated solutions. Each of these elements can be effectively addressed which makes aqueous cleaning an attractive alternative for the modern heat treating facility.