Metalworking lubricants, coolants, and fluids are used for metal forming, metal cutting, lapping, polishing, and grinding applications. They lubricate, decrease thermal deformation, and flush away removed material. The use of metal working fluids also improves surface finishes and increases tool life. The primary functions of cutting fluids in machining are :

• Lubricating the cutting process primarily at low cutting speeds

• Cooling the workpiece primarily at high cutting speeds

• Flushing chips away from the cutting zone

Secondary functions include:

• Corossion protection of the machined surface

• enabling part handling by cooling the hot surface

Process effects of using cutting fluids in machining include:

• Longer Tool Life

• Reduced Thermal Deformation of Workpiece

• Better Surface Finish (in some applications)

• Ease of Chip and Swarf handling

Metalworking

Metalworking is any process used to shape, form, cut, or machine a metal workpiece. Metalworking lubricants, coolants, and fluids are specialized coatings and carriers for metal forming, metal cutting, lapping, polishing, and grinding applications.

• Metal forming is a process used to plastically deform a workpiece. In order to achieve the desired shape or geometry, a force must be applied that exceeds the material's yield strength. Metal forming oils, greases, and fluids dissipate heat, lubricate the working surface, and prevent localized strain that would otherwise cause damaging effects both to the tool and finished product.

• Metal cutting is a machining operation used to remove material and dissect workpieces. The primary function of the cutting fluid differs dependent on the cutting speed. At low speed the fluid acts as a lubricant prevent galling, friction welds, or other friction-induced wear at the cutting surface. At high speeds the fluid primarily acts as a coolant, preventing thermal deformation. Cutting fluids also function to remove cuttings, inhibit corrosion, and improve the cutting surface finish.

• Lapping, polishing, and grinding are metalworking operations used to improve the surface of a workpiece. In lapping or polishing compounds, fluids or oils are used to carry abrasive powders. In grinding applications the main function of metal working lubricants, coolants, and fluids is to perform workpiece cooling.

Functional Uses

Metalworking fluids (MWFs) reduce or eliminate thermal deformation, localized strain, inhibit corrosion, and flush away removed material.

Thermal deformation is a phenomenon experienced in machining operations due to the combing effects of plastic strain and friction-induced heat at the tool and workpiece interface. The increased temperature gives rise to surface toughness, increased thermal error in precision machining operations, and decreased tool life. Cutting fluids counter these problems by lowering the coefficient of friction and transferring heat away via convection, thereby increasing the temperature gradient at the machining interface.

The following formula illustrates how heat is generated at the tool interface by friction:

Where:

Ic = Intensity of Friction Heat Source

F = Friction Force

Vx = Sliding Velocity

h = Plastic Contact Length

b = Cutting Width

Localized strain occurs when there is a break-down in the lubrication regime. Localized areas that experience undesired solid-to-solid contact experience a spike in friction. This may cause the material to undergo some amount of strain, damaging either the tool or workpiece. Metalworking fluids (MWFs) are carefully designed to effectively lubricate the workpiece by anticipating the temperature and pressure environment that they experience in a given metal forming operation.

Corrosion is a natural process where the surface of a substance, typically a metal, deteriorates due to a reaction that occurs within its environment. A corrosion inhibitor is added in small concentrations to the environment in order to control the rate or eliminate corrosion. In MWFs they are added to protect the untreated, exposed surface formed during the machining operation.

Types

Metalworking lubricants, coolants, and fluids include various types of fluids used in metalworking operations that are illustrated by the following table:

 

Electrical Discharge Machining (EDM) Fluids	EDM fluids are dielectric fluids that provide specific voltage and amperage characteristics in EDM operations. They serve two functions, to stabilize a fixed spark gap ionization potential and to remove eroded debris.
Flood or Mist Coolants	Flood or mist coolants are heat transfer fluids used to dissipate heat that is generated at the tool chip interface. They allow for heavier cuts, faster cutting speeds, and improved surface finishes in almost all machining operations.
Grinding Fluids	Grinding fluids are coolants that may also include extreme pressure or chemically-active additives. They are used to improve and protect surface finishes and may also be used to disperse abrasive powders.
Metal Cutting Fluids	Metal cutting fluids are used in metal machining to improve tool life (reduce wear), increase lubrication, reduce workpiece thermal deformation, improve surface finish, and flush away chips from the cutting zone.
Metal Forming Fluids	Metal forming oils, greases, and fluids are designed to enhance lubrication during extrusion, wire drawing, stamping, bending, swaging, rolling, embossing, and other deformation processes.
Mold Releases and Release Agents	Mold releases and release agents are film-forming lubricating oils, solid lubricants, waxes, fluids, or coatings that prevent other materials from sticking or adhering to an underlying surface.
Quenching Oils and Heat Treatment Fluids	Quenching oils and heat treatment fluids provide rapid or controlled cooling of metallic parts. They are used to temper, harden, or treat the material to achieve desired physical properties.

Metal-working using highly productive machinery with high cutting speeds requires large flows of coolant, and also produces a lot of swarf. Metal-working also generates oil mist which is a health risk to employees and a burden on the environment. Microscopic oil drops can affect sensitive electronics that govern machinery, which can result in sudden operational stoppages. Solving these problems by using effective coolant filtering, swarf management and air filtration systems opens up major opportunities for reduced costs and increased revenues.

Coolant recycling

• Improved productivity and product quality through rational coolant handling and constant filtration reduces stoppages for changes

• Reusing coolants = improved profitability, less environmental constraint swarf and coolant management

• Better price for refined swarf metals

• Less need for storage space, handling and storage of voluminous turnings

• Recycling of coolants that are filtered and returned to production Oil mist extraction/filtration

• Less sick leave due to less oil mist

• Less risk of affecting electronics

• Cleaner premises – less cleaning