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D. Shah and V. J. Badheka
3.2 Type 2 Friction Stir Additive Manufacturing
Another novel technique of solid-state welding is friction stir additive manufacturing
using a non-consumable tool. The fundamentals of the process are analogous to
friction stir lap welding (FSLW) and only differ in their functions. The type 2 FSAM,
involves producing a lap joint of two sheets by FSW and then welding more sheets in
a similar fashion to the existing structure in lap configuration using successive FSW
operations [37]. A custom non-consumable rotating tool with the specific designed
pin and shoulder parameters is inserted into the top plate. The depth of the pin is
designed to enter 20–30% of the lower plate generally for efficient joining, and other
parameters are varied according to the requirement.
In the first step of the process, a non-consumable rotating tool produces a lap joint
of the two overlapping plates in the traversing direction. This process is repeated
again by placing another sheet of metal on top of the structure. The friction stir lap
welding is repeated by sequentially stacking the plates on top of the welded structure,
and a multi-layered build is prepared additively as shown in Fig. 6. The thickness of
the final structure to be produced by Type 2 FSAM is controlled by the number of
steps.
Fig. 6 Schematic of a type 2 FSAM process where a structure is built by welding four plates in
lap configuration; the distinct stirred zones (third body regions) formed are highlighted by zone 1,
zone 2 and zone 3 and have distinct microstructure [73]
D. Shah and V. J. Badheka
3.2 Type 2 Friction Stir Additive Manufacturing
Another novel technique of solid-state welding is friction stir additive manufacturing
using a non-consumable tool. The fundamentals of the process are analogous to
friction stir lap welding (FSLW) and only differ in their functions. The type 2 FSAM,
involves producing a lap joint of two sheets by FSW and then welding more sheets in
a similar fashion to the existing structure in lap configuration using successive FSW
operations [37]. A custom non-consumable rotating tool with the specific designed
pin and shoulder parameters is inserted into the top plate. The depth of the pin is
designed to enter 20–30% of the lower plate generally for efficient joining, and other
parameters are varied according to the requirement.
In the first step of the process, a non-consumable rotating tool produces a lap joint
of the two overlapping plates in the traversing direction. This process is repeated
again by placing another sheet of metal on top of the structure. The friction stir lap
welding is repeated by sequentially stacking the plates on top of the welded structure,
and a multi-layered build is prepared additively as shown in Fig. 6. The thickness of
the final structure to be produced by Type 2 FSAM is controlled by the number of
steps.
Fig. 6 Schematic of a type 2 FSAM process where a structure is built by welding four plates in
lap configuration; the distinct stirred zones (third body regions) formed are highlighted by zone 1,
zone 2 and zone 3 and have distinct microstructure [73]