J. J. S. Dilip

Use of Friction Surfacing for Additive Manufacturing

In this work, we explore the possibility of utilizing friction surfacing, an emerging solid-state surface coating process, for layer-by-layer manufacture of three-dimensional metallic parts. One possibility in this regard (single-track friction surfacing) is to utilize friction surfacing for depositing a track or layer of material (sufficiently wide to cover the entire layer area), which is subsequently shaped to its corresponding slice counter using CNC machining. Another possibility (multi-track friction surfacing) is to generate a layer from multiple overlapping tracks of friction surfaced material, which is subsequently shaped as required using CNC machining. In the current work, sound multi-layered deposits in various ferrous materials were realized using friction surfacing in both single- and multi-track approaches. Samples with fully enclosed internal cavities and those consisting of different materials in different layers were also successfully produced. The deposits showed fine-grain wrought microstructures with excellent bonding between individual layers and tracks. Basic mechanical properties of these deposits were found to be at par with their standard processed wrought counterparts. Overall, the current work shows that it is possible to develop a uniquely capable new additive manufacturing process based on friction surfacing.

Additive manufacturing with friction welding and friction deposition processes

Most of the commercially available additive manufacturing processes that are meant for fabrication of fully dense metallic parts involve melting and solidification. Consequently, these processes suffer from a variety of metallurgical problems. Processes that can facilitate material addition in solid-state are therefore ideally suited for additive manufacturing. In this work, we explore two new solid-state processes, viz. friction welding and friction deposition, for additive manufacturing. Stainless steel samples produced using these processes showed excellent layer bonding and Z-direction tensile properties. The authors believe that these processes are uniquely capable and can offer significant benefits over existing commercial additive manufacturing processes.

A new additive manufacturing process based on friction deposition

Additive manufacturing involves layer-by-layer fabrication of three-dimensional parts under computer control. The current study demonstrates a novel concept for additive manufacturing, in which material addition is achieved in solid-state through a process that can be termed as “friction deposition.” The present work reports preliminary results on the proposed new approach. Individual layers up to a thickness of 1 to 2 mm can be added up successively by friction deposition. A solid cylinder of 20 mm dia and 50 mm height was successfully produced with austenitic stainless steel AISI 304. Microstructural studies and tensile tests were conducted to ascertain the quality of bonding between the layers. The results show that the proposed approach is indeed quite amenable for additive manufacturing and can lead to a viable commercial process.