Evaluation of aged and recycled metalworking fluids by the tapping Torque©

A test method that evaluates aged and recycled metalworking fluids has been developed. This method was designed to help overcome some of the traditional barriers that hinder the implementation of new recycling technologies and improved chemical management practices. The test protocol described is based on the tapping torque method. Statistically significant increases in tapping torque resulted due to changes in metalworking fluid concentration, addition of particulate contamination, and loss of chemical components. The developmental work also involved an investigation of variations caused by the tapping tools selected for use in testing. Testing and data analysis for a comparison between two fluids can be completed in less than five hours.