Shoulderless Friction Stir Welding: a low-force solid state keyhole joining technique for deep welding of labile structures

Hoßfeld, Max

doi:10.1007/s11740-021-01083-x

Cited by 6 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of particular note are the following: Other increasingly important benefits in terms of environmental objectives include the direct recycling of material normally considered waste, such as machine chips [3], and the possibility of high-quality part repair [5,7]. The main disadvantages of friction-based solid-state additive processes are the comparatively high process forces stemming from their solely mechanical working principles [8]. These forces must be supported by the substrate and subsequently by the structure of the build.…”

Section: Introductionmentioning

confidence: 99%

Advances in Additive Friction Extrusion Deposition (AFED): Process and Tool Design

Hossfeld,

Wright

2024

JMMP

Self Cite

View full text Add to dashboard Cite

Additive friction extrusion deposition (AFED) is a recently developed additive manufacturing technique that promises high deposition rates at low forces. Due to the novelty of the process, the underlying phenomena and their interactions are not fully understood, and in particular, the processing strategy and tool design are still in their infancy. This work contributes to the state-of-the-art of AFED through a comprehensive analysis of its working principles and an experimental program, including a representative sample component. The working principle and process mechanics of AFED are broken down into their individual components. The forces and their origins and effects on the process are described, and measures of process efficiency and theoretical minimum energy consumption are derived. Three geometrical features of the extrusion die were identified as most relevant to the active material flow, process forces, and deposition quality: the topography of the inner and outer circular surfaces and the geometry of its extrusion channels. Based on this, the experimental program investigated seven different tool designs in terms of efficiency, force reduction, and throughput. The experiments using AA 6061-T6 as feedstock show that AFED is capable of both high material throughput (close to 550 mm3/s) and reduced substrate forces, for example, the forces for a run at 100 mm3/s remained continuously below 500 N and for a run at 400 mm3/s below 3500 N. The material flow and microstructure of AFED were assessed from macro-sections. Significant differences were found between the advancing and retracting sides for both process effects and material flow. Banded structures in the microstructure show strong similarities to other solid-state processes. The manufacturing of the sample components demonstrates that AFED is already capable of producing industrial-grade components. In mechanical tests, interlayer bonding defects resulted in more brittle failure behavior in the build direction of the structure, whereas in the horizontal direction, mechanical properties corresponding to a T4 temper were achieved.

show abstract

Section: Introductionmentioning

confidence: 99%

Advances in Additive Friction Extrusion Deposition (AFED): Process and Tool Design

Hossfeld,

Wright

2024

JMMP

Self Cite

View full text Add to dashboard Cite

show abstract

“…22 Another effective way to solve the tool durability problem is to use a simple tool shape that reduces stress concentration, such as a probeless tool 23 or a shoulderless tool. 24 In this study, FSW with a simple spherical tool that is neither probeless nor shoulderless but rather integrates the probe and shoulder was proposed. A spherical tool allows localised welding with a narrow weld width and can be expected to extend tool life due to its simple shape; however, this tool tends to generate flash and weld thinning and has a narrow range of welding conditions, limiting its application.…”

Section: Introductionmentioning

confidence: 99%

“…22 Another effective way to solve the tool durability problem is to use a simple tool shape that reduces stress concentration, such as a probeless tool 23 or a shoulderless tool. 24…”

Section: Introductionmentioning

confidence: 99%

Development of friction stir welding method using a tilted spherical tool

Mukuda,

Noguchi,

Morisada

et al. 2024

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

The feasibility of friction stir welding (FSW) with a simple spherical tool, which has neither a shoulder nor a probe, was studied. The spherical tool allows for localised welding with narrow weld widths and extended tool life but tends to generate flashes and weld thinning. The material flow around the spherical tool during FSW of the aluminium alloys was observed in detail, and the flash generation behaviour was discussed. As a result, a new FSW method in which a spherical tool tilted to the retreating side (RS) was developed, and by expanding the flow path of the leading surface on the RS, the flow of hot material was controlled to reduce flash and smooth the weld surface.

show abstract

“…To the best of the author's knowledge, this approach from Kumar et al is still the only one which targets friction during FSW more generally and not related to a specific application, i.e., a welding case with specific parameters, joint and tool design. Kumar et al studied the interaction of a simplified FSW tool, a cylindrical steel pin with 7 mm diameter, and an AA 7020-T6 aluminum sheet with 4.4 mm thickness at three different contact pressures (13,26, and 39 MPa), each combined with four different spindle speeds (200, 600, 1000, and 1400 rpm). With a duration of more than 30 min for each experiment and manual temperature recording every 30 s, the focus of their investigation was on the long-term behavior of the frictional system.…”

Section: Introductionmentioning

confidence: 99%

On Friction, Heat Input, and Material Flow Initiation during Friction Stir Welding: Tool and Process Optimization

Hoßfeld

2023

JMMP

Self Cite

View full text Add to dashboard Cite

The Friction Stir Welding (FSW) process depends entirely upon mechanical contact between the tool and the workpiece. As a result of this, all process phenomena and process outcomes such as weld geometry and mechanical properties are governed by FSW’s frictional system. The following work characterizes this system with a focus on process initialization, heat input and material flow. For this purpose, an experimental program for the isolated investigation of the frictional system was carried out. Short-term effects such as contact initiation, run-in behavior and frictional transitions are considered as well as the influences of process parameters and geometry. The system and its behavior are analyzed quantitatively and qualitatively by experiments altering the normal pressure, relative velocity, and tool geometry. The experiments demonstrate a self-similar behavior of the process, including an important wear transition which initiates the material flow, and a subsequent equilibrium of forces, heat balance, and temperatures. The interaction between the tool and the welded material is described, as is the link between the frictional interface and material flow initialization. Based on these findings, recommendations are provided for process optimization and tool design.

show abstract

Shoulderless Friction Stir Welding: a low-force solid state keyhole joining technique for deep welding of labile structures

Cited by 6 publications

References 17 publications

Advances in Additive Friction Extrusion Deposition (AFED): Process and Tool Design

Advances in Additive Friction Extrusion Deposition (AFED): Process and Tool Design

Development of friction stir welding method using a tilted spherical tool

On Friction, Heat Input, and Material Flow Initiation during Friction Stir Welding: Tool and Process Optimization

Contact Info

Product

Resources

About