Benjamin Lossen

Friction spinning – Twist phenomena and the capability of influencing them

The friction spinning process can be allocated to the incremental forming techniques. The process consists of process elements from both metal spinning and friction welding. The selective combination of process elements from these two processes results in the integration of friction sub-processes in a spinning process. This implies self-induced heat generation with the possibility of manufacturing functionally graded parts from tube and sheets. Compared with conventional spinning processes, this in-process heat treatment permits the extension of existing forming limits and also the production of more complex geometries. Furthermore, the defined adjustment of part properties like strength, grain size/orientation and surface conditions can be achieved through the appropriate process parameter settings and consequently by setting a specific temperature profile in combination with the degree of deformation. The results presented from tube forming start with an investigation into the resulting twist phenomena ...

Friction-Spinning – Innovative Opportunity for Overcoming Process Limits in Spinning Processes

Normally, work-hardening effects limit the deformation that can be attained during cold working processes like spinning. By integrating self-induced heat generation (based on deliberately added friction processes) more complex forming operations become possible. This in-process heat treatment thus makes it feasible to dramatically extend the existing forming limits and produce more complex geometries, as well as favorable part properties (e.g. microstructure) from a wide variety of alloys. It is then possible to use semi-finished parts like sheet metal blanks, profiles, tubes and also solids for friction spinning.

Friction-Spinning - Influence of Tool and Machine Parameters on the Surface Texture

The incremental forming process of “friction-spinning” is suited to the manufacture of functionally graded workpieces made from tubes and sheets with the defined adjustment of material properties. The innovative feature of this new process is the use of process elements from both metal spinning and friction welding. As the workpieces are being processed, friction sub-processes are employed to achieve self-induced heat generation. Compared with conventional spinning processes, this in-process heat treatment permits the extension of existing forming limits and allows more complex geometries to be achieved, together with defined, favorable part properties. These properties, like strength, grain size or surface conditions, can be influenced by the set of specific temperature profiles that prevail during the manufacturing process in combination with the degree of deformation. The temperature profiles can be adjusted by selecting appropriate process and tool parameters in a defined manner. This paper presents the influence of the aforementioned parameters on the surface texture. The results presented start with the analysis of the surface texture development. Following this, the effects of the significant process parameters and tool geometries that give rise to the typical structure and hardness are explained.

Friction-Spinning – an Innovative Incremental Forming Process for the Manufacturing of Functional Graded Parts

Friction spinning is an innovative incremental forming process for the manufacture of tailor-made components with defined functionally graded properties. The process is characterized by the use of friction sub-processes for self-induced heat generation that can be employed for the defined thermo-mechanical treatment. Due to this in-process heat treatment, it is possible to extend the forming limits and achieve more complex geometries as well as favorable part properties. One very interesting application for friction spinning is the sealing of tube ends. There are a lot of conceivable application fields, including the substitution of soldering or welding operations in chemical engineering. Another interesting field is the use of this incremental forming process for industrial or automotive applications such as the manufacture of very slim cylindrical cups. An advantage of this method is the feasibility of defined control of the thickness distribution in the bottom and side wall area. This is supported by a new tool system with a pivoting forming tool. The pivot movement is controlled by a process control system. This system makes it possible to achieve different contact conditions between the tool and the workpiece during the process so as to attain a defined influence on the material flow and hence to enhance the attainable bottom wall thickness compared with previous fixed-angle tools. This tool concept thus offers an opportunity to improve the properties of the components as well as to manufacture new and complex geometries, such as hollow, fully closed roll type parts.