Fabrication of a rectangular-shaped WAAM aluminium body using the CMT technique
What is Additive Manufacturing?
Additive Manufacturing (AM) is about building parts from 3D CAD data through layer by layer material deposition. Especially with respect to cost and resource efficiency, this technology offers plenty of new potentials compared to the conventional, subtractive manufacturing approach. Advantages are especially seen in the drastic shortening of product development cycles as well as in the reduction of raw material used for part fabrication.
Current challenges within WAAM are:
- improving the material quality of WAAM parts
- increasing process stability and reproducibility of WAAM process technologies (Internal stress, warpage and pore reduction)
- bringing part design and manufacturing more closely together (design for WAAM)
WAAM aluminium body and schematic illustration of possible positions for the extraction of tensile samples
Wire-Arc Additive Manufacturing (WAAM)
AM variant, layer by layer deposition welding is used to produce a near net shape geometry. Local melting of the wire feedstock and re-melting of the already deposited material thereby occurs through the electric arc of a welding torch. By contrast with other AM technologies, WAAM allows for comparatively high deposition rates and theoretically unlimited part size. LKR is experienced in processing both, commercially available welding wires on aluminium and magnesium basis as well as purpose-made in-house material. The available equipment ranges from alloy development and preparation, in house horizontally and vertical casting machines, direct and indirect extrusion presses, wire drag – rig, CMT and plasma torch modules to latest WIG welding systems. Twin welding torches allow for the investigation of various double wire supply concepts.
Numerical simulation of the temperature distribution while creating the layer structure of a WAAM wall
methods for online monitoring and controlling the WAAM process
Besides enhancing the suitability of the CMT and WIG welding systems for aluminium and magnesium materials, LKR has put the strategic focus of its research activities on the development of methods for online monitoring and controlling the WAAM process. The goal is to create autonomous WAAM deposition systems that can automatically adapt relevant process parameters in the case of quality deviations and thus take an optimizing and corrective action on part fabrication. Numerical methods to simulate the temperature distribution within WAAM parts help to ameliorate process understanding at an early stage. In turn, this eventually supports the achievement of process stability on experimental level.
- Feasibility studies and concept development
- Fabrication of WAAM prototypes and WAAM demonstrator parts
- Process and materials characterisation
- Optimisation of existing WAAM processes
- Development of purpose-made WAAM wires
- Analysis of WAAM processes with numerical methods