Metal Finishing Guide Book


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Page 76 of 903

Mechanical Interaction The above end-user defined parameters are important to determine the type of mechanical interaction that the aqueous system is to develop. Mechanical interaction is the most important part of system design and can determine the success or failure of the system. Various forms of mechanical interaction can be employed simultaneously. The standard types of mechanical interaction can be defined as follows: 1. 2. 3. 2. 3. 4. 5. 6. 7. Soak Spray Soak and spray Soak with turbulation Soak with ultrasonics Vertical agitation Vertical agitation with ultrasonics Vertical agitation and rotation Vertical agitation and rotation with ultrasonics The lowest level of mechanical interaction is soaking alone, the highest degree of mechanical interaction is vertical agitation and rotation with ultrasonics. By determining the type of mechanical interaction to be employed, the end user can determine the degree of cleanliness or the cleaning specifications that the machine will be capable of achieving. Other factors to be defined by the end user and the system supplier include the following: Chemistry Establish what chemistry is to be employed, its pH and concentration level or ratio, and the ability of the chemistry to interact and remove the soils and oils on the parts. Most chemistries are alkaline and the percentage of chemistry to maintain a uniform process must be controlled. Temperature The temperature of the chemistry should be selected so as to ensure that the chemistry is working at its maximum capability. The heat source to maintain temperature and components for spray or pumping loss is to be specified (i.e., electric, steam, or gas). Enough heat is necessary to bring cold parts to temperature for chemical interaction, and for drying. Time The time should be selected so that the components are involved with mechanical interaction and chemistry to achieve an acceptable production level and an acceptable cleanliness specification. Drying The drying specification determines how dry components have to be or whether they have to be dried spot free. Summary of Cleaning Parameters In summary, part geometry, productivity, part delivery, and cleanliness specifications are normally defined by the end user. The type of mechanical interaction, the chemistry, its concentration and pH, temperature, time, and drying are nor73

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