MEPCA reports on an interesting use of a robot arm – as part of a 3D printing solution to create artwork.
Additive Manufacturing (3D printing) is finding many uses in manufacturing for prototyping, low volume manufacture and for making items with complex shapes which cannot easily be reproduced by other means.
The main challenge with the process is posed by complex geometry – when an object is to be fabricated, the shape must be broken down into a series of machine tool paths that will accumulate material by building up layers in a stable and reliable way. For this reason, 3D printing needs to be a precisely controlled process, both in terms of the type of movement and the deposition of materials.
A project at the Centre for Fine Print Research (CFPR), based at the University of the West of England, is looking at 3D printing a little differently, with the emphasis on meaningful expression rather than the accurate reproduction of digital data. A flexible Mitsubishi Electric MELFA RV-Series articulated arm industrial robot is at the centre of the project.
The CFPR has expertise in ceramics, photo-cure resins and thermoplastics, all of which are being investigated with the new robotic platform. Previous work evaluated the 3D printer as a tool to manipulate materials, or produce unusual surface textures.
Using a 3D printer in unusual ways means moving beyond the use of CAD models and slicing algorithms, as these are too automated. By writing proprietary software, it is possible to develop printing methods from the point of view of how the material can be expressively played with.
To achieve this the project is using a robot arm to research technologies and techniques to sense and manipulate materials in a dynamic way, rather than deposit them in fixed, rigid or ‘machine-like’ ways. The robot is running printer paths defined by proprietary software and requires a high degree of automation and real-time responsiveness.
Conventionally 3D printers are machines with three linear axis and fabrication occurs in fixed horizontal layers. The MELFA robot arm, however, can offer both freedom of movement and a set of expansion capabilities, including pneumatics and digital IO, which are integrated into the chassis of the arm itself; which makes for a useful combination of force control, movement range and reliability.
Proprietary software is being developed which must respond very quickly and dynamically to changes in the material’s properties and the construction of the printed object. This means that the control program cannot be rigid in its operation. Instead it must constantly and iteratively interpret its working task environment and autonomously correct its behaviour.
The MELFA robot has proven to be a good tool to create artistic objects using PLA (poly lactic acid). The development team used the full extent of the robot’s movement to push the material beyond its normal operating envelope and create new effects. The same set-up is planned to develop artistic creations with ceramics and photo-cure resins, the production process for which could then feed-back to commercial industrial applications.
