I suppose that there could be variations in individual particle density, formation of hollow particles, formation of odd shaped particles or a wider range of particle sizes or numerous other similar issues which could affect bulk density and also segregation.

With a normally very consistant material such as polymer chip, I guess it may be theoretically possible to use apparent / bulk density measurement to give an indication that something was out of the ordinary and that segregation was likely to occur but I am not aware of it being used for that purpose. ■

I am not sure i understand what you are doing here.

Is this a master batch system where you have two types of identically sized pellets, one without colourant and one with a large proportion of colourant and you want the two to mix consistantly prior to extrusion?

Or are you adding a powdered colourant direct to a large mass of plastic pellets?

In your first post you appear to be asking about segregation of plastic pellets, in your reply you appear to be talking about segregation between plastic pellets and a colourant and imply a large difference in particle size between the two.

Could you clarify please? ■