Customer base INDEX

Lubricant base oils must meet minimum performance characteristics of viscosity, viscosity index, pour point and volatility, all of which must meet required standards. When dealing with re-refined base oils, additional characteristics such as colour and odour must also be considered. These properties, of dark colour and odour, are readily perceived by customers and consumers as representing deficiencies in quality. Many examples of re-refined base oils have a definite, characteristic, oxidised or cracked odour which may be totally unacceptable in some countries and markets. Table 15.2 gives quality guidelines for the acceptance of re-refined 150 and 500 base oils. 

Many methods have been developed to represent changes in base stock viscosity with temperature. A useful method has to be able to express these changes for base stocks of all viscosities of interest, the meaning of the scale has to be readily apparent, the measurement must be relatively simple and cheap, and it must be widely accepted by base stock manufacturers and formulators and customers. The method that has emerged and lasted (too long for some ) is the viscosity index (VI) procedure. By this method the viscosity-temperature relationship of any base stock can be expressed by a single number, originally on a 0 to 100... 

It is unclear how different component scores are aggregated and weighted in the final index - the Coalition reports that suggested weights were defined based on a survey of Coalition members - but future versions of the Index promise to be based on stakeholder desires and a multi-criteria analysis that should allow different audiences to weight their own, customized index. 

It is possible to produce a composite index based upon multiple service measures and this can be a useful management tool, particularly for communicating service performance internally. Such an index is shown in Table 2.4 where the weight attached to each service element reflects the importance that the customers attach to those elements. 

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