Standard Guide for Evaluating Water-Miscible Metalworking Fluid Foaming Tendency

Importancia y uso:

4.1 The process of recirculating MWFs entrains air bubbles which can accumulate, forming foam.

4.2 Optimally, air bubbles burst open quickly after they are created. However, air bubble persistence is affected by MWF chemistry and the mechanisms by which energy is introduced into recirculating MWFs.

4.2.1 The primary mechanisms imparting energy into recirculating MWFs are:

4.2.1.1 Turbulent Flow—The high velocity (typically >0.75 m³ min^–1; >200 gal min^–1).

4.2.1.2 Impaction—Energy generated when MWF strikes the tool-workpiece zone.

4.2.1.3 Centrifugal Force—MWF moved by the force of rotating tools or work pieces.

4.3 When air bubbles persist, they tend to accumulate as foam. Persistent foam can:

4.3.1 Inhibit heat transfer;

4.3.2 Cause pump impeller cavitation;

4.3.3 Foul filters;

4.3.4 Overflow from MWF sumps;

4.3.5 Prevent proper lubrication;

4.3.6 Contribute to MWF mist formation, including bioaerosol dispersion; and

4.3.7 Contribute to safety and hygiene hazards in the plant.

4.4 To prevent the adverse effects of MWF foam accumulation, chemical agents are either formulated into MWF concentrate, added tankside, or both.

4.5 Laboratory tests are used to predict MWF foaming characteristics in end-use applications. However, no individual test is universally appropriate.

4.6 This guide reviews test protocols commonly in use to evaluate end-use diluted MWF foaming tendency and the impact of foam-control agents on MWF foaming tendency.

Subcomité:

E34.50

Referida por:

E2889-23, E2148-21

Volúmen:

11.03

Número ICS:

75.100 (Lubricants, industrial oils and related products)

Palabras clave:

coolant; foaming; metalworking fluid; MWF;