The welding processes available are:
- TIG welding
- MIG/MAG welding
- Plasma welding
- Laser welding
- Friction stir welding
- Spot welding
A number of measuring instruments used specifically for scientific purposes are available in the welding lab. Examples of these are:
- A pyrometer, which measures thermal radiation
- Special camera equipment that filters laser light
- A laser scanner that measures geometries and profiles of weld joints
- Data logging of weld parameters like current and voltage
Welding is regarded as a mature technology, but still there are many challenging developments taking place, both with new techniques like friction stir welding and with established processes like MIG/MAG welding. Exploitation of these new developments is a core activity for the welding technology group. Some explanations are given below.
MIG/MAG tandem welding
Tandem welding means that two welding wires, controlled by separate power sources are fed into the weld pool simultaneously. This allows higher welding speed and higher productivity.
MIG/MAG low heat input methods
Low heat input welding allows welding of thin sheets in a better way than traditional MIG/MAG welding. The lower heat input can be achieved in different ways, for example by pulsing of the welding current.
Plasma welding is also a traditional welding process, which is gaining increasing interest, due to the high productivity and high quality achievable. It is also of interest as a hybrid process in combination with MIG welding.
The advantage of laser welding is the minimal heat input to the material being welded. With laser welding deep and narrow weld joints can be produced with high welding speed. Also this process is sometimes combined with MIG/MAG welding into "laser hybrid" welding.
Friction stir welding
Friction stir involves a rotating tool moving forwards in the joint between two sheets of metal lying next to each other. The metal does not melt as with fusion welding, but it softens due to the friction heat so the metal sheets can be joined together. The temperature is considerably lower than in conventional welding.
By additive manufacturing it is possible to build up new geometries on a component drop by drop. The technique can be seen as a cost and resource effective alternative to traditional manufacturing. This process involves a metal wire being fed forward and melted using a laser. The process is more or less the same as rapid prototyping, but in this case finished metal components are the result.