Investigation of Friction and Wear in temperature-assisted Aluminium Sheet Metal Forming

RAmP - Subproject

The research project described below is part of the SME collaborative project RAmP (Robust Forming of high-strength Aluminium Alloys by multi-dimensional Process Windows) within LOEWE‘s ALLEGRO focus and is being carried out as a dual PhD position with Filzek TRIBOtech.

Motivation

Aluminium has made important contributions to resource-efficient lightweight construction for decades. Strongly growing sectors such as the e-bike and automation industry as well as the automotive industry place high demands on lightweight construction measures. In addition to increases in operational efficiency, the focus is on the benefits of use: these result from higher achievable dynamics (automation), handling advantages (e-bike) and load capacity and lateral dynamics (automotive). Existing alloy and production concepts cannot satisfactorily solve the challenges of lightweight material construction.

This is where the “RAmP” project comes in: the core of the project is to further develop the limited know-how on temperature-assisted forming of high-strength aluminium and to increase process robustness. Temperature-assisted aluminium sheet metal forming promises increased formability and thus the possibility of producing highly complex aluminium components.

Figure 1 – Process Routes for Temperature-assisted Aluminium Sheet Metal Forming and Clustering of tribological Systems

Tribology is a central research topic in the further development of temperature-assisted forming processes (see Figure 1). For the successful industrial implementation and increase of the robustness of these processes, the investigation of friction and tool wear under different tribological conditions is essential. With the tribometers used so far, it is not possible to satisfactorily investigate friction and especially tool wear of these temperature-assisted processes.

Objective

The aim of the project is to carry out process-related strip drawing tests in order to obtain information on the friction and wear behaviour during hot forming of high-strength aluminium alloys. Based on the test results, the construction and validation of a wear model is planned, which can be used in FE simulations of forming processes.

The aim of the tribology subproject is to carry out process-related strip drawing tests in order to obtain information on the friction and wear behaviour during temperature-assisted forming. With the strip drawing test and the forming processes of project partners, a tribological clustering is to be achieved: Depending on different parameters, recommendations will be made for lubricants, their application, tool coating and process route. The overall aim is to increase the robustness of high-strength aluminium sheet metal forming.

Approach

A strip drawing test machine is already in use at PtU for process-related friction measurement for temperature-assisted aluminium sheet metal forming (see Fig. 2).

Figure 2 – Strip Drawing Test: Test Concept und Test Bench

The further development of this facility is planned until the end of 2019 in order to use it for the above-mentioned investigations. For this purpose, the system is extended by the elements and functions shown in principle in Figure 3. After completion of the system expansion, different lubricants are tested under different process conditions (temperature, normal contact stress, tool coating, etc.). A suitable wear model is derived from the gained knowledge. This wear model is validated in real forming tests in associated work packages of the Allegro overall project.

In the present project the further development of this facility is planned in order to use it for the above mentioned investigations. For this purpose the facility will be optimized and upgraded for wear tests. Basically, different lubricants and tool surfaces are investigated under different process conditions (temperature, contact normal stress, drawing path, etc.). The test results obtained are used for the tribological clustering.

Within the scope of the test bench extension and the execution of experiments, some student work is offered. Thematically, the focus of the work can be adapted to the students' strengths and interests.

Acknowledgment

This project (HA project no. 822/19-142) is funded in the framework of Hessen ModellProjekte, financed with funds of LOEWE – Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz, Förderlinie 3: KMU-Verbundvorhaben (State Offensive for the Development of Scientific and Economic Excellence). We would also like to thank the companies involved in the RAmP collaborative project, in particular Filzek TRIBOtech, and all ALLEGRO participants for their excellent cooperation.