Gluing is a joining technology that is becoming increasingly popular. Both the application as a single technology and also when used in combination with other joining technologies, including clinching and spot welding. Glue joins are increasingly being used in the automotive industry in particular.
There are many different types of glue. At AWL we integrate mainly machines for applying vibration damping glue, sealing glues and construction glues. We are specifically involved in the latter category. Structural glue can be classified as 1k and 2k glues.
AWL often applies adhesives based on epoxy resins. These consist of two components, namely resin and a catalyser. Whenever these two components are mixed together a chemical reaction takes place.
How does it work?
In the gluing process, two glued parts are joined together by the glue. After hardening, the glue seam forms a joint between the glued parts. To be able to guarantee a good and strong gluing process, many conditions have to be met:
The seam must be constructed in such a way that it is possible to make a good glue joint. The load must preferably be a shearing load and not a peeling load. Care must be taken in the cleanliness of the parts to be glued together. Moreover, a solution must be found for ensuring that the materials being glued together are properly positioned. This can be achieved by combining spot welding or clinching into the gluing process. Then it becomes a hybrid join, which combines the advantages of both processes.
The glue itself
There are very many different types of glue that have their own specific advantages and disadvantages. The automobile industry uses a lot of glues based on epoxy. The glue is available in one and two-component versions (1K and 2K). 1K glue only hardens at a high temperature in an oven. For the automotive industry this is often not a problem as parts usually have to go through an oven during the painting process. Some types of glue must be warmed before use, which is necessary for lowering the level of viscosity.
Equipment specific to glue
These include glue dosage applicators and gluing heads. This equipment is selected for a specific gluing process and depends on the type of glue (1K or 2K, heated or not heated). The gluing head can be fitted to a robot or mounted in a fixed position. When it is mounted in a fixed position, the component is moved under the gluing head by the robot.
The actual machine
For example, the clamping method is very important: The thickness of the glue layer must lie between a minimum and a maximum level. In some cases the parts have to be heated before they can be glued together.
Equipment such as camera stations for checking whether the glue tracks have been applied according to the specifications.
In 2011 two AWL employees attended the European Adhesive Specialist (EAS) training course that is certified by the German Fraunhofer Institute BIAS in Bremen. This also provides AWL with the fundamental knowledge required for developing optimal gluing processes in collaboration with its customers.