Wall thickness distribution in plug‐assist vacuum formed strawberry containers

An experimental study on the influence of processing parameters namely film temperature, plug velocity, and temperature on wall thickness distribution in plug‐assist vacuum thermoformed fresh strawberry container using high‐impact polystyrene is presented. Film temperatures of 118, 125, 136, 150, and 165°C, plug velocities of 0.15, 0.20, and 0.27 m/s, and plug temperatures of 25, 60, 100, 123, and 135°C were used in the thermoforming. Increasing the plug velocity resulted in improved wall thickness distribution due to elastic deformation of the plastic sheet during thermoforming. Decreasing the stretching time and the temperature difference between the plastic film and plug was important for good wall thickness distribution. Better wall thickness was obtained at the plug velocity of 0.27 m/s and the plug temperature of 123°C.