DEVELOPMENT OF A CORRELATION FOR EVALUATING THE CIGARETTE FIRMNESS FOR PRODUCTION QUALITY CONTROL

Cigarette quality can be monitored in the market by evaluating its degree of rigidity, which is defined as the ratio of the final cigarette diameter, following a compression test, to its initial diameter, and is usually called cigarette firmness. Aiming the comparison between several products, the measured firmness is corrected to a previously specified reference moisture value by means of an exponential model, as validated and accepted by cigarette manufacturers. Following already qualified procedures, the firmness of eleven cigarette brands were measured in this work as a function of upright deformation, as produced by applying a standard load, mean circumference and specified tobacco moisture. The method of minimum squares was used for generating several correlations, together with the uncertainty evaluation, in order to achieve the one that could result in the lowest uncertainties, not estimated yet. The conclusion is that the tobacco characteristics are the largest contribution to the uncertainty of firmness measurement, resulting in a poor repeatability. On the basis of these results, it is suggested that a product acceptance criteria in the production line be established on the basis of the measurement uncertainties, using for reference the firmness value ranges usually accepted and tested by the market.