Wire-Guide Nozzle assisted Near-Net Shape Additive Manufacturing
Publication Date: 2015-Sep-17
The IP.com Prior Art Database
The Near-Net Shape Additive Manufacturing is a process in 3 phases: fabrication of a coarse pre-form, machining of the pre-form, finishing of the mechanized pre-form.
In the case of Aeronautic parts of Titanium parts and other expensive metals parts, the interest lies in the reduction Buy-To-Fly factor, namely the ratio between the amount of material to provide to manufacture a piece and the amount of material of the piece once finished.
The coarse pre-form can be obtained by forging, but also by Additive Manufacturing. For the latter, the Wire-Arc Additive-Manufacturing (WAAM) is preferred partly thanks to the good metallurgical integrity of the final product which results from the purity of the filler metal and to some extent for their capacity to be robotized and their deposition rates.
All the usual welding processes can be employed, to wit Tungsten Arc Welding, Metal Inert Gas and Plasma Arc Welding. The highest deposition rates would be achieved with Metal Inert Gas and Plasma Arc Welding, whilst the best metallurgical integrity would be obtained with Tungsten Arc Welding. At this regards, it is worth reminding that Tungsten Arc Welding is the only welding process which is in compliance with most of the Welding Procedure Specifications in use in the Aeronautic sector.
However, Tungsten Arc Welding deposition rate is low. Moreover, the filler metal wire is oriented at 90° relatively to the electrode and is thus aligned with the joint, which is an important drawback in terms of overall size and positioning reliability, all the more taking into account the robot trajectories required by the Additive Manufacturing.
A Wire-Guide Nozzle Assembly for Robotic TIG Welding Torch, as described for example in the patent n° US7329827B2 meets...