Optimal Mixture of Materials and Condition in Producing Flat Glasses for Automobile Windscreens in Nigeria

Abstract

The selection of materials is an essential element for engineering designers. This study investigated the optimal mixture of materials and condition in producing flat glasses for automobile windscreens in Nigeria. To achieve this, 10 pairs of compositions of material mixtures and cullet (broken glasses) were used. The standard material mixture (80/20 wt. % of material mix/cullet) from the local industry was modified to have batches of up to 60/40 wt. % material mix/cullet. These material mixtures were used to produce flat glasses by adopting procedures of industrial float glass process of Pilkington Brothers in variable conditions of annealing temperature and time. The average density of each pair of flat glass was measured using water displacement method, and each pair was later laminated to produce a total of 10 automobile windscreens. The windscreens were subjected to 2.25kg drop ball impact test from a height of 4m at 90⁰. The study revealed that the density of the flat glass produced was significantly (p< 0.01) related to squared composition (wt. %) of cullet (R²=97.65%). The highest and lowest densities of 2.23g/cm³ and 1.95g/cm³ were obtained at cullet inclusions of 40 wt. % and 20 wt. % respectively at constant annealing temperature (550⁰C) and time (60 min). The optimal batch obtained composed of 40 wt. % cullet inclusion, annealed at 500⁰C for 50 minutes. Increased cullet composition was found to reduce the melting temperature of the batch mixture and fractured characteristics of the windscreens produced. Employing this design in the windscreens manufacturing industry saves production cost, facilitates a competitive market, enhance the quality of windscreens, reduce emissions and curb environmental degradation.