2nd generation lead analysis for the automotive industry

Lead (Twist) Analysis Module for MountainsMap+

Automatic generation of lead analysis reports

Mercedes-Benz Engineering Standard compliance

Controlling lead structure in the automotive industry

In the automotive industry the interface between theseal and the shaft is critical. Turning and grindingmanufacturing processes imprint a helix-likestructure known as lead (or twist) on the surface ofthe shaft. The lead structure must be controlled toensure leak-tightness between the shaft and itssealing ring, while respecting a range of design andperformance criteria. Absence of leak-tightness canlead, for example, to unacceptable oil consumption.

Lead analysis algorithms

Daimler Mercedes-Benz developed a 1st generationlead analysis algorithm in 1997, deriving functionalparameters to satisfy specific requirements. In 2009an improved 2nd generation lead analysis algorithmwas published in a new Mercedes-Benz engineeringstandard. This algorithm has been widely adoptedin the automotive industry. It is integrated into theLead Analysis module under license from Mercedes-Benz.

Measurement data

The lead measurement data set is obtained by astylus or optical profilometer combined with arotation unit. The profilometer executes ameasurement strategy defined in the new standard.Contact Digital Surf for information on data formatsthat are read by the Lead (Twist) Analysis optionalmodule.

Automatic 2nd generation lead analysis reports

The module applies the 2nd generation leadanalysis algorithm to the measurement data set andgenerates a lead analysis report automatically.

The report contains four blocks:• Lead parameters.• Dewobbled measured surface structure

(topography).• Lead surface (topography).• Comparison of profile extracted from measured

surface with profile extracted from lead surface.

Reference

Mercedes-Benz Engineering Standard MBN 31 007-7Edition 2009-04

2nd generation lead analysisin accordance with the 2009 Mercedes-Benz engineering standard

Lead surface

Measured surface (dewobbled)

Comparison of lead profile and surface profile

Diameter 40.0 mmEvaluation Length 2.00 mmMaximum wavelength 0.400 mmNumber of threads DG -1.0Depth Dt 1.91 µmPeriod length DP 0.100 mmSupply cross section DF 117 µm2

Supply cross section per turn DFu 117 µm2/UContact length DLu 18.1%Angle Dy -0.0456°

Lead parameters

Lead (Twist) Analysis Module for MountainsMap+

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Doc Revision: 20160627