Products Finishing magazine is the No. 1 industrial finishing publication in the world. We keep our readers informed about the latest news and trends in plating, painting, powder coating, anodizing, electrocoating, parts cleaning, and pretreatment.
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cleaning process is coolant management. Always ensure the coolant concentration is in check, and continuously remove chips from the process. Tramp oils (typically hydraulic fluids and way lubes) must be continuously removed by skimming, coalescing or with a centrifuge. Good housekeeping in the front-end will assure more consistent and efficient cleaning downstream. Aged coolant or stamping fluids left on machined parts for an extended time are more difficult to remove, and the potential for corrosion is high. Parts should transfer as quickly as possible from the machining centers to the washers. When parts are machined or formed off site, a cleaning process prior to shipment (along with the application of rust preventive) is appropriate. In selecting a parts cleaning program, one has many options, including the use of solvent. Ideally, most machined or stamped parts use aqueous cleaning. Washer Types Recirculating spray washers are the most common washers in high-production environments. Belt or conveyor washers, in single or multiple stages, enable a maximum number of parts to be processed. Spray nozzles should be aligned for the optimum patterns to ensure that the cleaning compound reaches critical areas. Higher pressures will provide improve soil removal (more "action" by the chemistry), and cabinet washers are also effective, especially if the part is rotated to enable effective contact of the chemistry. Immersion washers using racks, baskets or barrels are also effective for improved cleaning with added mechanical action, which can be achieved with circu- lation pumps or eductors in the tanks. The part-to-part contact of a barrel or tumbling program is also beneficial, as long as parts are not damaged in the cleaning process. Ultrasonic energy will substantially improve the cleaning process. Ultrasonic washers dislodge surface contaminants using high-frequency sound waves to agitate the cleaning solution, creating bubbles that rapidly implode on the part's surface. Ultrasonic cleaning is especially effective on challenging inert soils such as graphite, and enables better cleaning in deeply recessed areas such as blind holes and lap seams. Manufacturers have several choices when selecting an aqueous cleaning chemistry for parts washers. Alkaline cleaners are often chosen for their effectiveness on most soils, especially organic, and are compatible with ferrous substrates, and most washers. Suppliers are able to formulate alkaline cleaners that can be used on aluminum, zinc (and zinc-coated substrates) and yellow metals (copper and brass). Acid cleaners can be effective when inorganic soils like oxides, scale or Immersion washers using racks, baskets or barrels are also effective. The four key parameters of any aqueous cleaning program are captured in the term TACT: time, action, concentration and temperature. PRODUCTS FINISHING — pfonline.com 33 PARTS CLEANING