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46 PRODUCTION MACHINING :: DECEMBER 2016 PARTS CLEANING Cleaning Steel Medical Tubing VCN is currently being used to aqueously clean manufac- turing fluids and debris from the internal surface of small lumen stainless steel medical tubing (hypodermic needles, for example). is high volume unit has two cleaning chambers supported by one cleaning supply tank, one rinse tank and one vacuum pump. e process cleans, rinses and vacuum dries nested bunches of medical tubing. Another field unit is using VCN to clean sensitive electronic components contained within medical implants. e electronic network has tight areas; ultrasonics would damage the small electrical connections. VCN grows vapor bubbles within the network that are much gentler relative to ultra- sonic bubble implosion. Damage to the sensitive electronics has been eliminated with faster and better cleaning. VCN has been in use for years to clean chromatography components of manufacturing polishing compound from areas as small as 6 mils using an aqueous solution. e VCN process has eliminated a high rejection rate of parts cleaned with ultrasonics. Large areas can also be problematic when cavities or channels are deep or have large aspect ratios. Areas shielded with solid walls can dampen forced convection methods or ultrasonics and prevent any penetration of processing fluid chemistries. VCN can expand fluids to five times their volume, thus ejecting the bulk of fluid within these internal areas. e expansion of vapor produces the agitation needed to flush the parts' internals, and the cycling process assures a rapid turnover of fresh bulk fluid to guarantee a complete and uniform process. A unit that has been in operation for more than a year in the field is being used to remove filler from 3D printed parts. In a 3-percent aqueous solution, parts normally requiring days to remove filler were cleaned in 10 minutes to four hours, depending upon the complexity of the part. Range of Applications e VCN process works just as well in solvent systems as in aqueous systems. One solvent system in the field is presently cleaning machining oil from tightly wound copper and aluminum rolls of screen. e screen has a small mesh size of 3 to 4 mil wire wound into rolls three feet long and 8 to 10 inches in diameter. e solvent soaks into the mesh, and when the vacuum is pulled, the solvent vapor expands, forcing fluid through the mesh and out into the bulk fluid. Applying pressure fills the mesh with fresh solvent. A two-second cycle applied for four minutes cleans the mesh. e rolls are cleaned, then vacuum dried. Solvent is recycled using on-board vacuum distillation. VCN is being used in a range of applications and is continu- ously expanding to more applications. Applications include small and large tubes, delicate electronics, 3D printed parts, critical clean instrumentation, porous materials, medical devices and more. Processing can include cleaning, surface preparation, etching, coating, anodizing, sterilizing, passiv- ation and more. Combining VCN with ultrasonics covers most present day cleaning and surface preparation requirements. When used in aqueous applications, the VCN process typically requires a lower concentration of cleaning solution. In solvent applications, VCN can be combined with a vacuum solvent management process to achieve the highest environ- mental and safety standards. For more information from Vacuum Processing Systems, call 401-397-8578 or visit vacuumprocessingsystems.com. CONTRIBUTOR Dr. Donald Gray is president of Vacuum Processing Systems and inventor of the vacuum cycle nucleation process. For similar articles about parts cleaning equipment and processes, visit PM's Parts Cleaning Zone. LINK :: short.productionmachining.com/cleaning n Precise, Flexible Parts Cleaning: Patented Indexing Rotary Table Design. n Robot-Ready. n Easy to Operate: Powerful Siemens Controls. n Maintenance-Friendly: Easy Access, and QR Codes to Simplify Parts Replacement. ctgclean.com | 8 00.24 8.9274 Now THAT'S... The New LEAN JET ® RT-18 Parts Washer SMA RT !