A cotton sample opening device was placed on an HVI line to evaluate the opening device's effectiveness for improving sample preparation and test results on samples of roller ginned American Pima cotton. Other cottons including samples of roller ginned Upland, saw ginned Upland and saw ginned American Pima were also included in the evaluation. The most positive results were found for the samples of roller ginned American Pima Cotton. This paper focuses on the results found for the roller ginned American Pima Cotton samples.

Opening was found to facilitate specimen preparation and improve repeatability of length, strength and uniformity measurements. Modification of fiber properties, as a result of opening, was found for the most part to be insignificant. Initial tests of a recently constructed cotton opener also look favorable.