Over the last two decades, additive manufacturing (AM), also known as 3D printing, has transformed from a niche technology mostly used for prototypes into being widely deployed across multiple industry sectors including aerospace, automotive, electronics, machinery and medical. Traditionally, the technology has been limited to small-medium sized components and layerwise processes with horizontal linear layers. With the increase in available build volume and build rate of commercial 3D printers over the last 10 years there has been an increasing interest in AM of large scale components, particularly in automotive, architecture and aerospace. Unfortunately, large parts come with a trade off in geometrical tolerances and surface quality.
Robot based additive manufacturing has emerged as a potential affordable solution to both non-linear AM and AM of medium-large scale components. The concept is based on the use of 6-axis industrial robots and a hybrid AM approach, where a component can first be manufactured at near-net-shape by AM and then machined to meet the final demands on geometrical tolerances, resolution and surface quality in a single flexible manufacturing cell. This solution offers scalability and flexibility since it can be used with robots of any size (even on track motion rails) and with almost any material. Robots are used today for AM of concrete, metals, thermoplastics, thermosets, composites and even food.
One of the main benefits of using 6-axis robots is the possibility to change the orientation of the material deposition unit during printing. This enables flexible printing strategies with non-linear tool paths or angled layers. One of the concerns of a layerwise process is the mechanical performance at the layer boundaries. Using a robot, material can be deposited in the optimal orientation to increase part strength.
The inherent flexible nature of industrial robotics makes it possible to in-line AM as a sub-process in an existing production flow in a way which cannot be accomplished with traditional 3D printers. The use of tool changers allows us to use multiple deposition units or manufacturing processes (machining, laquering etc.) in a single manufacturing cell. It is also possible to integrate quality assurance such as vision inspection systems or 3D scanners.
Today, most industrial robot arms can be used for AM, including ABB, KUKA and Universal Robots. However, a key challenge is generation of advanced tool paths and streamlined process optimization and control. SoftDREAM is an innovation project where some of the leading actors in robotic AM in Europe has come together to develop software able do just this. The outcome will be a generic solution for tool path generation, process simulation and optimization and real-time monitoring.