- Materials are joined without the addition of extra materials which requires the highest level of fixturing and joint preparation. Since no material is added, it is necessary for the materials to be welded to remain in intimate contact during the welding process. Any significant separation of the materials can result in an unacceptable weld profile or complete failure of the welded joint.
- Fixturing to ensure consistent fit-up of the weld joint is a key to successful fiber laser welding. An important benefit of fiber laser is welded joints with exceptional cosmetic appearance. In some cases, these welds are almost perfectly blended with the surrounding material. Depending on the fixturing and joint fit-up, some welds may have small amounts of concavity (which may not be acceptable for product designs that require fatigue properties similar to those of the base material) or convexity.
Material is added to the weld joint usually in the form of metallic wire or powder. Three reasons for adding material to the weld are:
- Joint fit-up: By adding extra material, the joint becomes more tolerant to joint mismatch. Acceptable welds may be produced from joints with less than perfect fit-up.
- Weld geometry: Addition of filler metal is used to control the shape and size of the weld. Maintaining a crown (convex surface of the weld) creates a reinforcement which is important for joints requiring mechanical strength and fatigue life in the overall product’s design performance.
- Dissimilar metals: Filler metal is added to facilitate welding of dissimilar metals and alloys which are otherwise metallurgically incompatible.