Bursting bubbles in metalworking fluids

Oct 30, 2018

Have you ever wondered if tiny bubbles really cause trouble when it comes to metalworking fluids (MWF)? Or is it just a nuisance that can be avoided? In lubricants and MWF, uncontrolled foam, or ambient air dispersed in the lubricant, can have very adverse effects on the MWF process. Although it may seem somewhat impossible, there are ways to avoid this issue by identifying the cause and eliminating metalworking fluid foaming through formulation.

Not only can foam impede the performance of high-pressure, high-volume, high-velocity machine tools, but it also can likely lead to machine downtime and tool breakage. Other negative effects of foam include:

  • the breakdown of fluid film
  • heat removal impairment and increased rate of oxidation of the fluid
  • poor fluid flow caused by cavitation in pumps, pressure variation in hydraulic systems and even loss of fluid through vents

The good news is, it’s possible to formulate around foam! Incorporating antifoamers and defoamers to the process can be very beneficial. Antifoamers suppress foam during formulation; defoamers break up the foam during the use of fluids.

Before turning to a nonfoaming solution, it’s important to determine whether the issue is chemical or mechanical. Is the foam caused by a chemical problem that may be corrected by changing the low-foaming coolant or can a mechanical issue be addressed to eliminate the problem? Determining this will allow you to customize your formulation to better adjust to potential foam issues. Read more about ways to successfully formulate around foam in the latest TLT Lubrication Fundamentals column by Dr. Robert M. Gresham.

Why should you care?

There are plenty negative connotations surrounding foamy foams being complicated systems and bad for our lubricant systems. Fortunately, the formulator has many options to help control this problem.