FOCUS ON JOINING TECHNOLOGIES
Sealant on mechanical part . Image : Shutterstock . com .
so oxidations / oil / greases must be carefully removed . First clean or degrease the metal , then grind or blast , otherwise impurities can be ground ( blasted ) into the metal during the grinding process and continue to have a separating effect on the adhesive . Metals that are stored at cold or lower temperatures should be sufficiently tempered before bonding to avoid condensation ,” advised 3M .
Mechanical roughening ( abrasion ) of the surfaces to be bonded is also a simple , highly effective pre-treatment , even for difficult-tobond metal surfaces such as titanium .
Manufacturing processes
For more than 20 years , Fraunhofer IFAM in Germany has been developing specific simulations to understand in detail the manufacturing steps of dosing ; applying ; joining ; fixing ; hybrid joining and curing to minimise sources of error . In adhesive bonding , the manufacturing process is key for improving the quality of the final product . Fraunhofer IFAM has been researching the flow behaviour of adhesives to understand industrial dispensing , application and squeezing with the aim of improving adhesive manufacturing .
“ Adhesive bonding is the pioneering joining process of the 21st century . It enables the reliable bonding of identical , as well as dissimilar , materials with an adhesive and is therefore essential for the advancing multi-material lightweight construction . Unlike welding or riveting , adhesive bonds do not weaken the mechanical properties of the parts to be joined . In addition to mechanics , bonded joints integrate specific requirements : They can conduct heat , electrically insulate , seal or bridge tolerances ,” explained the research specialist .
“ The integration of adhesive bonding into industrial manufacturing requires an approach tailored to the specific application . Adhesive selection must take into account requirements for the end product and for the manufacturing process . The design of bonded joints is based on analytical or numerical calculation . This is based on the experimental characteristic values of materials , joints and components . At the same time , the flow and curing properties are characterised to design the manufacturing process ,” it added .
Bonding processes must also be designed individually . In the transportation industry ’ s body-in-white bonding of automotive construction , windscreen bonding of rail vehicle construction and sandwich bonding of aviation differ greatly from each other . Micro-bonding in electronics requires special adhesives and boundary conditions , as the adhesive quantities are millions of times lower than those for bonding in civil engineering . Medical technology places new demands on the safety and biocompatibility of adhesives . In the aerospace sector , adhesives can be used at extremely high and extremely low temperatures . In the packaging industry , on the other hand , manufacturing costs and speeds play a decisive role . n
Fast-Flex-Mont2 project
The “ Fast-FlexMont2 ” (“ Research on Agile Production Technologies for CFRP Box Structures ”) joint project is a dynamic demonstrator that makes it possible to optimise the production processes of aircraft vertical tail planes . Aimed at non-interruption of rudder hinges to the vertical tail plane box by long waiting times , researchers at Fraunhofer IFAM — in cooperation with Airbus Operations GmbH and FFT Produktionssysteme GmbH — developed the application and outsourced curing of shim material ( gap-filling material ) as parallel processes .
Automated and digitally linked processes allow volume-accurate dispensing and application as well as precise shaping and edge finishing of the liquid shim . After curing of the gapfilling material , the finished shimmed rudder hinge is inserted into the vertical tail plane . The German Federal Ministry of Economics and Climate Protection funded the project .
Supported by digitisation , automated process technologies not only enable the application of shim material based on component variants and according to requirements , but also the outsourcing of the curing process in preparation for the assembly of components in the aircraft vertical stabilizer box , using the rudder hinges as an example . Lightweight robotics-based assembly assistance systems are used to facilitate manual manufacturing processes while ensuring consistent quality .
See the YouTube video on www . youtube . com / watch ? v = GqZb--jYeQE on automated rudder hinge assembly in aircraft vertical Tail Planes ( VTP ) by Fraunhofer IFAM .
Image : Shutterstock . com .
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