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Minimal quantity lubrication (MQL)

Minimal quantity lubrication
For minimal costs and maximum environmental protection

Cooling lubricants and cooling lubrication systems fulfill numerous tasks in machining. Primarily, they dissipate heat and reduce friction. They provide for an even temperature in the workpiece and the tool and help to maintain tolerances. The cooling lubricant also transports the chips in many applications. The supply, processing and disposal of cooling lubricants often result in significant costs. They also have an impact on the environment. Therefore, it is worthwhile to consider alternatives.

One possible solution in the search for the optimum lubrication system is minimum quantity lubrication (MQL), which is gaining in importance. It provides a happy medium between wet and dry machining. In minimum quantity lubrication, the amount of lubricant used is reduced to a minimum. The maximum volume flow in MQL is less than 50 ml/hour. While up to 12,000 liters/hour of cooling lubricant are used and reprocessed in conventional wet machining, MQL only requires a quantity corresponding to one to two shot glasses. The air/oil mixture (aerosol) is supplied to the working position either directly via pressure or finely diffused via a compressed air stream. The optimum lubrication significantly reduces the frictional heat. Machining costs can be noticeably reduced with MQL. The environmental impact is also reduced, together with possible health hazards for the machine operator.

Workpiece and chips remain nearly dry

MQL is a loss or consumption type of lubrication. The medium used evaporates almost entirely at the working position. The workpiece is cooled additionally by the evaporation and by the compressed air stream. The residual heat is dissipated via the tool and the chips. The chips that are produced, as well as the workpieces and tools, remain nearly dry when the system is configured optimally.

Minimum quantity lubrication can be used wherever friction has to be minimized by application of a lubricant. It is ideal for drilling, gun-drilling, milling, for manufacturing threads and for turning. The amount of lubricant used and the setpoint value vary according to the cutting power, material, tool design and the amount of chips produced. Many practical applications in minimum quantity lubrication have shown that the amount of lubrication used during machining in most cases is between 5 and 30 ml/h.

MQL requires minimal to extensive modification of the machining center and tools, depending on the machining conditions. Important criteria are the reliable removal of chips from the machine and exhaust of the aerosol vapors. For high-performance cutting, machines, tools and toolholding systems specially designed for MQL are used.

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Minimal quantity lubrication (MQL)

Minimal quantity lubrication For minimal costs and maximum environmental protection

Workpiece and chips remain nearly dry

Minimal quantity lubrication
For minimal costs and maximum environmental protection