Proposal of a new Algorithm for the manufacturing quantity evaluation: integrated demand manufacturing quantity, IDMQ

The present paper aims at defining and testing a new model for the manufacturing quantity evaluation. The proposed model has been applied to a company that produces permeable contact lenses, Soleko S.p.A.. In particular, we have analysed the production of toric soft contact lenses, the most important product of the company, first of all for their great technological content. Moreover, the market of contact lenses, is rapidly growing, especially in Asiatic regions, such as China and India. The study started from a preliminary analysis of the production statistics of the last years, in order to put in evidence the most frequent defects and their main causes. Well known tools have been applied, like Pareto and Ishikawa diagrams. The most important result of the above statistical analysis is the discover of a relation between the dimension of the production lot and the defectiveness. In fact, by comparing the production of the company destined to two different markets, Italy and Japan, we can notice a great difference of defectiveness, higher for the Italian production, linked to a different lot dimension, bigger for the Japanese production. The correlation between defectiveness and lot dimension, suggested us to study a new algorithm to manage the orders of toric contact lenses, then called: “Integrated Demand Manufacturing Quantity” (IDMQ). The proposed method, like other Entity Manufacturing Quantity methods, integrates the productiveness with the market demand.