Testing cotton fibers have always been important for spinning industry. This test is done using HVI (High Volume Instrument) machines. The most famous manufacturer of HVI machines is USTER. Testing in HVI machines is done on a bunch of fibers at the same time and the average of the result is considered as the final result.
Different parameters are checked in testing which every one of these parameters show a unique property of fibers. Following tables show these parameters. The data shown here are extracted from USTER HVI documentation.
Length and Strength
Color and Trash
“Tr Trash” also is known as “Tr ID” or “Leaf Grade”. This parameter shows Classer’s grade (Classer is an expert who grades the looks of the cotton fibers with eyes). This parameter is based on standards of different countries so it may be different in one country to another. Although this parameter is not the same as “Trash” but a relationship can be found between these two parameters. The following table shows an example of this relationship:
The following table shows color grade according to the US standards: