The essence of these materials is that they are solid friction modifiers.  Some are lubricants but others deliver a more sophisticated friction characteristic that allows for the traction and braking demands that often accompany rolling. These materials are not oil based and do not contain graphite; they do contain molybdenum disulphide  (MoS2) as one of the key, solid material ingredients.  The technology has developed to deliver the active friction modifiers in a stick form that can be moulded into a wide range of convenient shapes.  For some applications, the solid lubricant material can be suspended in a water based carrier to facilitate its delivery, more popular is the stick formulation which is applied to the rolling surface in a spring loaded applicator.



The virtue of the stick system is in its simplicity, requiring no power or control systems to function reliably, The diagram shows how this is applied to a double flanged crane wheel.  The applicators supply a constant force to the sticks bearing on the wheel surface.  Simple adjustment targets the sticks on the relevant part of the wheel and thereafter no further attention is needed until the sticks have been consumed and the applicators are ready for refilling; this is generally after 6 months or even longer.



This dependability is largely due to the self-regulation property of the product.  The stick only deposits to generate up to a maximum sub-micron film coating onto the surface, it then reduces the deposition until the demand for lubrication depletes the film thickness; the stick then resumes coating with lubricant.

 

​SL is a solid lubricant with a low coefficient of friction that reduces wear between rolling components.

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SFM is a solid friction modifier (not a lubricant) that has a controlled friction characteristic and reduces wear between rolling components but also allows traction and braking forces to be transmitted without slip.