Examination of Compound Distribution in Lubricating Greases

The quality of use of lubricating greases is strongly defined by the manufacturing process and the resulting grease structure, in addition to the chemical and physical properties determined by the formulation. The structure of the lubricating grease system of thickener and oil should be as "homogeneous" as possible. This means that the thickener should be evenly distributed in the total grease mass and should not contain any solid particles (thickener agglomerates). Up until now, the distribution of the thickener has been investigated randomly using mostly microscopic methods. An in-situ method for process monitoring is not known. By developing a measuring method, in the future the production process of the fat formulations could be monitored online and integrated into the regulation and control process.

In this research project the functionality of different measurement methods will be investigated. The testing and evaluation of the homogeneity of the lubricating greases is carried out experimentally by incident light reflection, transmitted light reflection, laser incident light or laser refractometry and an electromagnetic method, in which, for example, deflection in an electric field is used. The electromagnetic method offers the greatest potential for integration into online process control. In addition to "homogeneous" fat formulations, non-homogeneous, i.e. unfinished fat formulations are to be investigated. In this way, the applicability of the measuring methods for differentiating the lubricating grease quality with respect to homogeneity during the mixing process can be tested. The use of specifically produced thickener agglomerates of defined size as admixing components in a finished grease formulation can also reveal possible limits of determination of the measuring methods.

DGMK Research Report 809 has been published.