precision cleaning 1996 . surfaces, this method enables ‘visual- ization and classification of different materials. We have found a correlation between phase and friction imaging, an older technique for compositional imaging based on contact mode operation. Because it is based on TappingMode, phase imaging is gentler than friction imaging and provides bet- ter spatial resolution. q References 1. Images of these are included in Digital Insbwnents’ Application Note “Phase Imaging: Beyond Topography,” available upon request. Gmtozt Digital Instruments at (800) 873-9750 and ask for Felicta Kashevuroff in corporate cortununications. About the Author L% Don Cherno~ts the founder and president of Advance Surjixe Microscopy, an independent analytical service laboratory. Since 1986, Chernoff has been using scanning probe microscopy to tnvestigate and solve materials and processing problems for mmuf~twing, engineering and research 6b 2Ri.s article was reprinted with permtsston Figure 8: Contaminant deposit on glass. 5~ scans. a) TappingMode dual image showing the liq- from Digttd Instruments and Dr Cherno~ and uid-air interface of oil droplets (bright bumps in the height data, dark regions in phase). Needle- was orighdly adapted from his talk to the like crystals are bright and crisply-defined in the phase image. b) Contact mode dual image (height and friction) showing the substrate under the oil droplets and a cluster of crystals on NcumScope Users’ Meeting at S7M ‘95. the substrate. The oil droplets had high friction due to surface tension at the oil-probe inter- face. The crystal had low friction. Note: To make this comparison, we had to change probes and scanning modes and return to the same spot on the specimen. $ofessionals uf S&K Products lntemationd The 16-400 is desi&ed toaccommodate the latest developments in so/vent cleaning by utilizing CJ chemical targeted specifkaiiy at the soil and a second chemical that provides rinsing and drying capabilities. The system Js structured to implement the efficent und innovative co-solvent process. Our products offer the most efficient, low J em&ton operation avcziiabie in the market today. Goii us now to s#e how we can be of service. For Information Circle No. 45 December, 1996 . 13 1 VAPOR ZONE SOLVENT cleaning systems Stand-alone tanks equipped with reservoirs of boil- ing solvents which fill the tank with hot solcent t+Wkws but 90 percent &f met&l vapors, Parts to be cleaned are cooled and immersed in the waporized soluent, which condenses on the parts cleaning ap~~~a~ns, far exampfe. can use aque- to create a washing action. Existing wa~or degreaser ous or semi-aqueous alternatives. However, for crit- equipment can sometimes be retrofitted to comply ical, high-end precision cleaning applications. with evolving environmental standards and/or to solvent-based systems may still be required - modify and improve the cleaning process. particularly when exposure to water would damage the parts. Vapor degreasers generally use heat exchangers to boil solvents in a reservoir at the bottom of the tank. The boiled-off solvents migrate upward as hot vapor. A cooling jacket at the neck of the tank condenses Selection Criteria: the rising vapor, creating a “vapor barrier.” This prevents solvent escape The major consideration in selecting a new vapor degreaser or retro- by trapping most of It in the top of the tank. fitting an existing system is whether the cleaning parameters actually require the strength of a solvent-based system. Environmental compli- ance is the first consideration in selecting or retaining a vapor degreaser system. Rust and corrosion sensitivity may necessitate solvent-based cleaning of some ferrous-metal parts which cannot be exposed to water terns have about a five-year tife span. A solvent in aqueous or semi-aqueous systems. Soil types which solubilize best in solvents may necessitate vapor-degreaser cleaning. High volatility can compound environmental problems. Well-ventilated spaces are required Vapor degreasers are particularly effective in solubilizing and removing for operation of solvent-based systems. carbon, oil, grease and other organic deposits; for rust, chip and fine removal and surface preparation. These systems maintain their effective- ness partly because the cleaning solvent is constantly redistilling. So, the cleaning action is always accomplished with fresh solvent. Mast solvent system users choose this type of Cleaning action can also he enhanced with mechanical agitation from cieanlng method because of its industry standard, ultrasonic or spray-under-Immersion systems to increase effectiveness performance. material compatibility, cleaning and reduce cycle time. The choice of solvents also Impacts system effec- effectiveness. elimination of ODCs. worker safety tiveness. Cost for vapor degreasers range from $20,000 to $40,000 for smaller and cost. machines to $200,000 for larger systems. Compatibility Concerns: Varying amounts of solvent always escape, increasing worker exposure. The retrofit addition of spray units or other agitation tooling to maintam the effectiveness of retrofitted systems may require additional work space. I I Satisfaction Levels of Vapor Zone Industry Applications: Solvent System Users Some industrial processes still require the cleaning power of vaporized solvents. In these cases, environmentally safe application of solvent- Very satisfied based cleaning systems is sometimes possible. These applications provide Somewhat satisfied cleaning solutions in: l General industry: for metal precision parts, tools, machinery and components l Medical: for surgical parts l Semiconductor: for printed circuit boards l Electronic and electrical: for parts and components adverse to water exposure l Aviation: for airframe cleaning, GSE, turbine engines, thrust reversers, weapons systems l Printing: for blankets, ink rollers I Not at all satisfied 2.8% December, 1996 Now you can get the cleaning results you need while meeting virtually every environ- mental reauirement. Just use ARMAKi.EEN@ Metal Cleaners -the environmentally superior, biode- I gradable aqueous cleaners designed to remove grease and oils from virtually any metal surface without so/vents. Reliably replaces solvents . Exceptional cleaning performance l Non-toxic*, non-irritating to skin l Zero ozone-depleting potential l No glycol ethers, caustic sodas, hydrocarbons or cyclic amines l No residue after cleaning and rinse l No flash point (even when misted) l Wide material compatibility l Dilutable to specific needs ,,-j’*,!. ” l Economical 8,. l Mild odor l HMIS Rating: Toxicity 0, Flammability 0, Reactivity 0 Compatible with existing equipment l Ideal for use in ultrasonic, agitated batch washing at 120”-140°F and spray washer applications l Can be used as a spray Meet the product that meets your needs. Call today for a product sampie...1=800=824=0866. Available in three formulations f&Aero~“for aircraft/aerospace cleaning applications W&tom” for cleaning automotive parts M.GP~*‘for general purpose metal cleaning ‘Per OSHA and EPA Regulations **Patents Pending : .:. ‘,H- ,>r” Church & Dwight Co., Inc. l Specialty Cleaning Group 2 469 North Harrison Street l P.O. Box CN5297 Princeton, NJ 08543-5297 0 1996 Church 8. Dwtghl CO.. Inc. .' For Information Circle No. 6 DEIONIZED W ATER systems Sysrems that remove dissolved solids from tap water ting, streaking and ionic contamination. or nqueotls solutions, supplying high-purity deionized DI water heaters can raise temperatures to further increase cleaning water for use in precision cleaning and rinsing. DI and rinsing performance. water systems reduce water use, wastebuildup and problems resulting from spotting, streaking andionic Industry Applications: contaminarion on cleaned parts. DI water is recommended for use in precision cleaning whenever a final rinse is applied and parts must have a high quality finish. For example: Deionized (DI) water minimizes waste in preci- . Electronics, printed circuit and semiconductor: to reduce high-volume sion cleaning processes by extending the life of water use and sludge disposal problems by recycling process water, and cleaning chemistries and reducing water use. It to achieve high-quality final rinse results improves rinse efficiency and final product quality by eliminating spot- l Metal finishing: to produce ultra-clean surfaces prior to electroplating ting and streaking. l Optics: for precision lens and mirror washing Deionization removes dissolved ions, such as heavy metals, from water . Automotive: for cleaning critical components, carwashing or aqueous streams. The water to be purified passes through beds of syn- l Other general manufacturing thetic resins, where an “ion exchange” process occurs. Hydroxide ions in the resins exchange with negative ions in the stream. Selection Criteria: The resins are then “regenerated” by using acid or caustic chemicals to Level of purity, volume ofDl water required, tank size and pump size displace the captured ions, which are concentrated ain low-volume are among the important considerations in selecting DI systems. stream for disposal or processing. The regenerated resins are then ready Purity is measured in megohms, using an in-waterresistivity monitor for another cycle. to gauge the level of contamination.Dl water at 1 megohm would aver- DI water can be used to make up aqueous cleaning solutions, in theage less than 0.5 parts per million(ppm) total dissolved solids. emulsion cycle of semi-aqueous systems, in ultrasonic systems and other Ultra-high purity