Fraunhofer Institute for Production Technology IPTResearch project "AdaptCAD"
Nowadays, it is common for industrial workpieces to consist not of the once familiar straightforward geometries like cylindrical or conical areas but of three-dimensional surfaces, which require simultaneous five-axis processes if they are to be produced using conventional production methods such as milling. Parallel to this, there is a growing requirement on the market for customized products resulting in the need for very low-volume production of parts. Wherever highly complex part design is required, computer-based 3D CAD models are now generated. The production planner can then use model-assisted machine simulations to run preliminary tests on the planned production process.
However, in the majority of cases the 3D-CAD model and the actual workpiece are usually not identical, despite precision planning. The inaccuracies in the model impact the subsequent production processes and not all of the actual effects are taken into account in the simulation. Consequently, errors can occur during the production process and prevent the required part quality and dimensions from being achieved. In the majority of cases, several planning, simulation and production cycles are needed in order to achieve the desired production outcome. This gives rise not only to extended throughput times but also to high levels of waste.
Faster algorithm for CAD models improves component quality
The aim of the "AdaptCAD" project was to detect and minimize deviations between the 3-D CAD model and the real component. By adapting the CAD model to the actual manufacturing result, the planning effort for subsequent processes is significantly reduced.
To achieve the project goal, the team first designed a 3-D CAD model of the demonstrator component. During the manufacturing process, high-frequency machine and sensor data from the machine tool were recorded using suitable acquisition solutions. This data was automatically transferred to a database and stored in a structured manner.
The team used the data to compare the actual geometry of the workpiece with the CAD model constructed in advance and to adjust the model according to the deviations.
New algorithm adapts three-dimensional models and enables adapted path planning of subsequent processes
The central task in the project was the development of an algorithm that for the first time allows the adaptation of three-dimensional models. An existing algorithm for two-dimensional modeling served as a basis, which the Aachen research team extended and optimized for three-dimensional modeling. The aim was to construct a model not only on a numerical basis, since numerical models are either inaccurate or require too long computing times. In addition, numerical models are difficult to use for CAM path planning of subsequent processes.
The "AdaptCAD" approach is based on an analytical model. With this method, the project partners were able to perform path planning of the subsequent processes directly on the adapted CAD model.
The algorithm was integrated into a commercial CAD/CAM system. In the final stage of the project, the team successfully manufactured demonstrator components in several test series together with a partner from the automotive sector.
Project Partners
- CP autosport GmbH, Büren
- Exapt Systemtechnik GmbH, Aachen
- ModuleWorks GmbH, Aachen
Project Funding
European Fund for Regional Development (EFRE)
Project Manager
Project Management Jülich, Research Center Jülich GmbH