Brookfield's Model AST-100 Viscometers are ideal for measuring and controlling viscosity of ceramic slurries. The industries that are best suited for this requirement are investment casting, "Lost Foam", and refractory coatings. Most precision cast product demand that the encapsulating stage, where the ceramic slurry is applied, is precisely controlled.
Within the industries noted, the companies require that the ceramic slurries remain consistent while they perform the essential encapsulation of their precision mold. This stage is crucial to the efficiency of their production of the end product. Not only does this slurry require the correct composition, percent solids, the viscosity should be maintained so that consistent product is produced. The mold may be first coated with higher viscosity, higher solids, coating to obtain crucial coverage of all exposed surfaces of the mold. Subsequent dipping of the mold into secondary and tertiary stages of the coating process still remains as crucial as the initial stage, however. If the predetermined amount of slurry is not applied, the firing of the ceramic may not hold up and the ceramic cast will fail when fired or filled with molten metal. Typically, this industry can waste a lot of material and produce low yields of fired castings due to improper viscosity control. The weaknesses of this coating may be realized as late in the process as molten metal insertion into the fired ceramic cast, after approximately 85% of the process was complete.
Manufacturers in this industry have already linked the % solids control with off-line viscosity measurements. However, the manual viscosity measurement method and the ever-changing process conditions within the dipping tanks hamper proper control of this critical stage. The condition of the off-line viscosity measurement is often a non-agitated sample that may not give a true representation of the coatings resistance to flow, viscosity. A more accurate method is to measure and eventually control the viscosity (% solids) of the ceramic slurry with the use of an advanced senor technology instrument like the Model AST-100.
The use of Brookfield's AST-100 typically provides a payback of instrument cost and installation within 6 months to one year.