This application involves the manufacturing of 3 piece metal cans used for food and other consumer packaging solutions. As part of the process, the can body needs to be coated to provide both physical protection and cosmetic quality. The can body requires an internal lacquer coating to create a barrier between the metal and can contents to ensure food safety and prevent damage to the packaging. The external can surface needs a decorative coating to provide product identity/branding and a decorative finish. Both coating processes require controlled thermal curing of large tin plate sheets, performed in a specifically designed Wicket oven. As part of the can assembly process, curing of lacquer applied to the welded side seam is performed in a separate side seam / side stripe oven.
To control the thermal cure processes of 3 piece cans and ensure product safety and function, it is necessary to provide a temperature profile through the Wicket oven. This profile demonstrates that the whole sheet surface is achieving the correct 'time at temperature' to cure either lacquer, or decorative inks and varnishes, against very specific supplier guidelines. In the side seam cure process, temperature profile data is needed for the rapid side stripe oven to guarantee that the food contents are protected from contamination from the welded can seam. Process validation is essential to comply with strict FDA and other food legislation, to ensure food safety for the consumer.
- Prevent under or over cure of internal lacquer coating to eliminate risk of food contamination and ensure consumer safety
- Eliminate risk of overheating, which may compromise metal packaging strength and damage external print ink color
- Identify and correct temperature imbalance (hot and cold spots), which can lead to uneven heating of entire sheet surface
- Provide fully traceable certified process validation reports to comply with FDA requirements and protect against potential warranty claims