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| Introduction to criteria of mold cleaning |
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If asked to describe the perfect cleaning system for molds and tooling that would allow a significant reduction in labor hours and tooling damage while providing consistent cleaning results, it would meet the 10 criteria listed below.
Repair technicians would like using it. The cleaning method would be totally non-abrasive to all types and hardness of steel, platings, coatings and polishes. It would not require a repair technician to manually control or stand watch over. Operation would not pose a safety hazard to man, machine or the surrounding area. The cleaning solution would be user- and environmentally-friendly. The cleaning unit would be easy to clean and maintain. It would not be loud or irritating. t would have the capability to clean subassemblies and tooling contained in plates. Must remove 90 percent of mold fouling. Must not leave behind any type of residue or film on tooling or plates. One cleaning method that comes close to meeting all of the above requirements is ultrasonic immersion cleaning. Nothing has more impact on reducing cleaning time, improving mold cleaning consistency and reducing tooling damage than this non-abrasive, user-friendly method. What Is It? How It Works The energy released from these microscopic scrubbing bubbles produces forces at 10,000oF at 7,500 psi, which is powerful enough to loosen contaminates without damaging critical edges or surface finishes. Cleaning Solution Highly alkaline solutionsÑsuch as sodium hydroxideÑdo the best job of removing stubborn contaminates, light rust and heavy grease on most tooling and plates with no harm to most applied platings and coatings. On the downside it can be caustic, posing a potential health risk and may require neutralization before disposal, depending upon local codes. Mild alkaline solutions also are available that perform well on many residues without the caustic issues. But in general, the friendlier the detergent, the less effective it will be on stubborn contaminates. Slightly acidic solutionsÑsuch as those containing low concentrations of citric acidÑexcel at rust and oxide removal, but need to be used with caution on some tool steels because they can react with the iron in the steel turning it gray. This normally does not cause a problem, but doesn't sit well with toolmakers. There also are several environmentally safe detergents being used that do a fair job removing most contaminates left from resins in use today. Combined with a minimal amount of hand scrubbing on heavily contaminated areas, these user-friendly solutions are gaining popularity with companies simply because of the ease of disposal, less mess and safer working conditions. Ultrasonic Power and Frequency The higher the kHz rating, the less aggressive the cleaning power. Common systems use either 40 or 30 and a few use 25 and 20. 30 kHz is a good compromise between cleaning ability and noise level. Lower ratings can be extremely loud and irritating. The heart of the system, transducers come in two types: (1) magnetostrictive and (2) piezoelectric. Magnetostrictive transducers are typically more rugged and create the most aggressive cavitation action. The best transducers also are zero-spaced and silver-brazed to the tank versus a bolted or epoxied transducer, which has more of a tendency to slowly fail over time. Tank Design and Construction Also make sure the tank is constructed of at least 12-gauge stainless steel and be sure to have the manufacturer weld a few support bars across the bottom to keep plates and tooling baskets from directing resting on the bottom of the tank. Also fabricate a tall (about four feet) stainless back-splash that runs the length of your system and will keep your walls clean and direct any run-off back into the tanks. When you fabricate or purchase tooling baskets be sure the handles are tall enough to extend above the surface of the hot cleaning solution and incorporate an eyehook to lift with an overhead chain hoist. Design the baskets to fit side by side across the bottom and make sure the basket material perforations are 1/4" or better so cavitation is not impeded. Buying Considerations Heavy-duty, bullet-proof, robust and solid all apply when shopping for an ultrasonic system that will perform reliably in a busy mold repair shop. And unless absolutely necessary, stay away from all the bells and whistles in the form of automatic loaders, conveyors, dryers and fancy cabinetry. The transducers are warranted for the life of the system. The tank is warranted for 20 years or more against cavitation wear through (which can drastically cut transducer life). The wash tank has a pump filtering system and is easily accessible. The pump intake is screened to keep small dowels, o-rings etc. from damaging the pump impeller. The tank drain valves are easily accessible. There are no protruding knobs, handles, switches or buttons. Tank heaters are easily accessible. Ultrasonic Pros Ease of use Simply place the plates or tooling in the tank, set the timer, turn it on and walk away; doesn't need to be baby-sat Cleans the mold while repair technicians work on other issues; like doubling your workforce Cleans some tooling without requiring removal from plates Predictable and consistent results Cleans hard-to-access areas like counter bores, threaded holes, pockets, water lines and bubbler tubes Does not harm sharp edges, applied platings, coatings textured or polished surfaces Extremely fast ROI Cons Ultrasonic Benefits Once the system is installed, you will see an immediate reduction of labor hours simply because of the speed in which tooling will be cleaned compared to the laborious task of hand cleaning one piece at a time. And as a bonus, there will be no more rounded over edges, or platings and coating scrubbed off.
About First-rate Mold Solution Co., Ltd. About www.firstratemold.com
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