Adhesive joint use and aging in food machinery: A case-study on beverage filling systems

The objective of this work is to evaluate the introduction of bonding technology in the assembly of beverage filling machines. In this specific field, bonding has two potential great advantages with respect to welding, that are the speed of application and the absence of thermal distortions. Furthermore, since it presents fewer risks for safety at work, it allows the simultaneous execution of other assembly operations. On the other hand, the use of bonding requires a design process integrated by tests related to the specific application and operating conditions, that in the case of food machinery are: i) bonding of low surface roughness, austenitic stainless steel without surface preparation but degreasing; ii) contact of the joint with the chemically aggressive substances used for cleaning and sanitization. In the present study, first a technical-economical comparison with welding (business case) was done on a component of the structure of a filling machine. Then the adhesive appropriate for the application was identified experimentally with tests on single-lap joints (SLJ) with different surface finishes and subjected to chemical aging under the cleaning and sanitization agents. Finally, the scale-up to a larger and more complex structure was performed by joining two modules of the outer casing of a filling machine.