Virtual Simulation of Top Load Performance of Plastic Bottles

摘要

A novel analytical computational model was developed to predict Top Load and Side Load performance of oval containers. The performance of oval and other non round containers is dependent on the thickness distribution achieved during blow molding. Simulating blow molding and performance of containers using Virtual Prototyping? Software and feeding the input for Finite Element Analysis provides an accurate mechanism to predict container performance. A 24oz. generic oval container with aspect ratio of 1.58 was simulated for empty and filled top load performance.A critical part of blow molding oval containers is the ability to achieve a more uniform thickness profile along the circumference of the container at any given height. This is achieved by using preferential heating where the infra-red heating ovens have special slotted reflector plates that allow the preform to be heated differently 90° apart. For the 24oz. oval container with a high aspect ratio it was observed that the use of preferential heating is necessary to achieve uniform thickness distribution in the range of 0.3mm-0.4mm. A non preferentially heated preform resulted in container thickness being 0.4-0.6mm in a concentrated region adjoining the minor axis. The preferentially heated performs resulted in containers having better empty and filled Top load. The side grip load was the only performance characteristic that was higher for the non preferentially heated containers but that works only in a small region and the non uniformity of thickness makes the container not aesthetically pleasing and would not be acceptable in a production process due to inconsistency in material distribution.