Industry-Academia Computational and Experimental Investigations into a Mould Tool for Aluminium Food Containers
As toolmakers, Rhondda-Cynon Tâf based FSG Tool & Die Ltd. (FSG) has designed and built production systems for market-leading manufacturers for the last 30 years, including the design of pressing tools for the aluminium forming industry.
Aluminium containers are formed by combining mechanical and air pressure to force a foil blank into a shaped die cavity.
FSG sought the support of the ASTUTE 2020 team to improve the performance of the press tooling components used in the manufacture of standard and smooth wall aluminium food containers such as take-away food, frozen food, desserts and airline meals.
The containers are formed in three distinct steps: an initial pressing of the blank to form the basic shape with a lip, "wipe down" to turn the edge of the lip back on itself and finally, curling to neaten the lip edge. This is done at a rate of approx. 65 trays a minute. at this high speed, it is difficult to identify which aspects of the process are affecting the quality of the containers. Using computational simulation and material testing techniques, the astute 2020 team were able to investigate each stage of the process in detail.
The main challenge focused on resolving a common defect known as “earring” in smooth-walled aluminium containers. The defects occur randomly at the corners of the containers, with the problem thought to be with the curling process. Although small, this irregularity at the edge may prevent an effective seal being achieved if a lid or film is added to the final container leading to contamination or spillage of the contents.
Computational Engineering Modelling and Advanced Materials Technology were the main areas of expertise that the ASTUTE 2020 team brought to this project. The research involved understanding the material characteristics of the foil to determine if the properties were uniform in all directions (isotropic) or whether they had been affected by the manufacturing of the foil or container. The material was sampled for tensile testing at angles of 0, 45 & 90O to the rolling direction in both the finished tray and the base material to determine any bias (anisotropy). Using this data, ASTUTE 2020 developed a computational model that could mimic the occurrence of the curl defect, and then explore the parameters to be changed to eliminate this defect. The computational model could successfully simulate all three manufacturing steps i.e. deep drawing, wipe down, and curling and the outputs gave directions for modifications to be made to the process to improve the quality of the containers.
This collaboration has allowed FSG to increase their technical understanding of the critical features of the tool production; improving the reliability of the container quality for the manufacturers and customers.
The research into the containers has allowed FSG to invest in the development of the new tool, creating new products, process and services to the firm. The improved knowledge and techniques developed from this research project will lead to increased production and orders, creating opportunities to grow the workforce at FSG at a later stage.
With increased market demand for deeper and multi-compartment containers, FSG is well-positioned to satisfy these customer requests and take a leading role amongst toolmakers in europe.
FSG has continued to operate throughout the COVID-19 pandemic, repurposing their production lines to manufacture tools for visor products for the medical, pharmaceutical and food supply chain industries; highlighting FSG’s R&D capabilities to adapt production within a short space of time to support the fight against COVID-19.