RHP Technology: Manufacturing of next generation welding electrodes

Today’s manufacturing concepts for the fabrication of complex-shaped welding electrodes are still based on the time-consuming and costly machining of tungsten alloy rods. Even in automated welding applications, these electrodes must be changed frequently but manually. In addition, the shapes that can be produced are limited. In this case, more complex geometries will allow for the automatic replacement of the spent electrodes.

Tungsten-based electrodes are used for various types of welding applications. In most welding processes, such as tungsten inert gas (TIG) or plasma arc welding (PAW), tungsten rods are used as welding electrodes. When using plasma welding processes, more complex geometries are used, especially when such welding systems are automated, as in additive manufacturing. These electrodes are complex in shape and are a consumable material.

Today, more than 100 electrical propulsion systems in satellites are equipped with products made by the Austrian company RHP Technology, a spin-off of the former Department of Advanced Materials and Aerospace Technology of the Austrian Institute of Technology GmbH (AIT). These space applications require complex shaped parts which are made by powder injection moulding using a refractory metal. 

The focus of this development activity is on the use of a successfully applied Metal Injection Moulding (MIM) of refractory metals used in electric propulsion systems and the aim is now to transfer this knowledge to non-space applications.

As part of the project, which is funded by the ESA Spark Funding Austria, RHP Technology will use its experience from the manufacturing space components and transfer this technology to the production of plasma welding electrodes with complex shapes. In addition to the geometries used today, a new electrode configuration will be investigated with the focus to be used in the Plasma Metal Deposition (PMD®) process. This additive manufacturing method allows the realisation of large metallic structures in various metals and alloys. In this case, the goal is to realise an electrode, which allows the increasing welding speed in additive manufacturing. Additionally, a standard geometry will be used for the initial development activities and verification of the MIM manufacturing process.

The main advantage of the manufacturing technology used for the space components is that this technology offers high productivity, and it is also a cost-efficient method. The higher the number of produced units, the more cost-efficient and sustainable production is possible.

About ESA Spark Funding Austria

ESA Spark Funding Austria is a funding program implemented by Science Park Graz / ESA Space Solutions Austria in collaboration with ESA Space Solutions and the Austrian Aeronautics and Space Agency (FFG/ALR). In the program, Austrian companies can receive zero-equity funding of € 50,000.00 to integrate space technology or space assets/services into existing product lines or create entirely new products/services. The first call was implemented in 2021, and a new one will be launched in 2023.

A big thanks to the author of this article: Aigerim Rabl