A Researcher at Fraunhofer IPA have found a way to eliminate some of the numerous process steps from the first sketch to the finished component. The CAD model, technical drawing and settings on the machine are no longer required and all that is required are nine simple characters.
Omission of incorrect production steps
There are numerous error-prone process steps and a lot of working time between the first sketch and the finished component: First, a designer creates a three-dimensional CAD model. From this she then derives a two-dimensional technical drawing and supplements it with additional information: tolerances, fits, parallelism, the roughness of the surface and the like. She hands over the CAD model and technical drawing to the manufacturer. For simple components, this makes the appropriate settings directly on the machine. For more complex geometries, however, it is recommended to load the data into CAM software, which then automatically generates machine commands. However, the manufacturer must decide for himself which milling cutters and drills are suitable for processing the raw material and how the raw part should best be clamped.
At the Fraunhofer Institute for Production Engineering and Automation IPA, Tobias Herrmann from the Lightweight Construction Technologies department has now found a way to save some of these many process steps in design and production. The CAD model and technical drawing are replaced by a nomenclature made up of nine basic symbols that can be used to specify everything that a milling machine is supposed to do. A worker writes these symbols directly onto the raw material with a pen: R5, for example, stands for a curve with a radius of five millimeters, F20 for a 20 millimeter wide chamfer or E10 for a milling of ten millimeters, the exact shape and Dimensions are specified using lines on the raw material.
Counteract the shortage of skilled workers
There are also nine conventions, such as that when drawing contours and features, only lines at an angle of 0°, 45° or 90° are permitted or that the workpiece zero point is always in the upper left corner from the machine operator's perspective. Once the raw material has been labeled and clamped, it is scanned by a laser scanner, the characters are interpreted and a vector graphic is derived from them. Software then translates the vector graphics into machine commands (NC code) within a few seconds and creates a target component as a CAD model. The machine commands not only contain precise information about where the machine should do what with which tool, but the software also provides for tool changes. It therefore prescribes where the machine should use other cutters or drills.
With these properties, “EasyCNC,” as Tobias Herrmann calls his development, would not only be a shortcut to the finished component, but also a remedy for the rampant shortage of skilled workers. Because EasyCNC transfers the specialist knowledge of experienced designers and manufacturers into software commands. “The know-how for processing is no longer stored in the heads of the designers and manufacturers, but in the machine and software,” says the researcher.
Access to existing machines through intermediate control
Until then, however, there are still a few open questions to be answered, including how to get access to old CNC machines. Existing machines are often not designed for digitalization. It is not intended for external systems to access it and give it commands. Herrmann is now trying to influence the machine commands via an intermediate control. CNC machines could then also access networks and databases. In addition, instructions and instructions can be passed on to the machine operator. However, in order to implement this, many tests on machine communication and system integration are still necessary.
Meanwhile, Herrmann's project partners at EVT Eye Vision Technology GmbH are continuing to refine their deep learning algorithms. The algorithms that recognize and classify the lines and characters on the raw part in conjunction with a laser scanning system developed by EVT are essential for the further processing steps. Reuss Maschinenbau GmbH & Co. KG, another project partner, is currently developing a prototype of a milling machine into which EVT's laser scanning system will be integrated, along with facilities for component cleaning and the additional control connection. The planned completion of the project is September 30, 2023.