Monitoring and control of the AFIS® instrument

The AFIS^® instrument has proven to be an indispensable tool for fiber research, testing and evaluation, and process control in textile manufacturing. To realize its potential, however, it must be carefully maintained and monitored to ensure that measurements are accurate and repeatable. For example, experience has shown that contamination caused by sticky cotton will cause drifting and level shifts in fiber property measurements. All instruments for measuring cotton fiber properties-whether it be the manual Stelometer or the more sophisticated, computerized ones like the HVI and the AFIS-require calibration to achieve reliable, repeatable results. Calibration, in turn, requires standard cottons, or other suitable standard materials, selected and maintained for that purpose. In a previous phase of this project, a set of seven standard cottons were selected and evaluated. A subset of three of these was then selected for use in controlling the short-term and long-term stability of the AFIS. This paper reports on results obtained in tracking the various sources of instrument variability and implications for controlling the quality of AFIS measurements.