Exzellenzclusters PhoenixD - Task Group M4: Machines, Automation and Organization

Shorter product life cycles and small batch sizes pose major challenges for modern production technology. In optical manufacturing, stringent quality requirements and the use of complex, multi-stage processes add to these challenges. To address them, automated and self-optimizing systems are needed. In PhoenixD, such systems are implemented using virtual models on which the properties of optical components can already be simulated during manufacturing. On the basis of these simulations, both individual manufacturing processes and entire process chains can be adjusted.

Objectives

To create the virtual models, extensive knowledge about the component currently in production is required. For example, the forces acting during the process must be measured. Actuators are also needed to adjust the processes. For this purpose, Working Group M4 is developing a magnetically levitated linear actuator. Similar to a magnetic-levitation train (Transrapid), the workpiece holder levitates and can be precisely aligned in all spatial directions. The acting forces can be measured and adjusted with high precision. The actuator is therefore ideal for capturing and adapting individual manufacturing processes. To also enable the adaptation of entire process chains, all production processes used must be linked together flexibly and modularly. Working Group M4 is researching how such a manufacturing system should be designed.

Benefits

This research enables precise, dynamic alignment of components during manufacturing—similar to a magnetic levitation train. The precise measurement and control of forces and real-time position deviations are ensured by the linear actuator’s high dynamics, stiffness, and precision. The overarching goal of these studies is to create an end-to-end process chain by flexibly and modularly linking all production processes to support adaptive manufacturing.

Approach

Adaptive manufacturing in PhoenixD aims to increase the accuracy of established manufacturing methods through state feedback and in-process parameter adjustment (quality control loop). This allows components to be produced both precisely and productively—and thus cost-effectively. One highly productive method, for example, is the flexographic printing process investigated in Working Group M2 – Additive/Subtractive Manufacturing. The quality control loop approach requires that the process state be captured by sensors. In addition, adjusting the process parameters requires suitable actuators.

Adjustable parameters include the printing force between the impression roller and the substrate, as well as the alignment of the substrate relative to the roller. However, in the flexographic printing machines currently available on the market, there is no way to make these parameter adjustments during the printing process. In this context, Working Group M4 is researching a flexibly deployable linear actuator with a long travel stroke in the X-direction and electromagnetic guidance (see Figure 1). The guidance system consists of eight electromagnets mounted on the carriage that operate on the basis of reluctance force. The air gaps between the magnets are measured using eddy-current sensors. In addition, the magnetic flux density is measured with Hall sensors. With the magnetic guidance, the actuator can perform not only linear motion but also fine positioning in the remaining five degrees of freedom (two translational and three rotational). Moreover, the bearing forces can be estimated from the air gap and the coil current of the magnets, as well as from the magnetic flux density, from which the process forces can then be derived. The requirement for sensing and actuation capabilities is thus fulfilled.

Are you also interested in a cooperation project?

Contact Jingcai Zhang via email at zhang@ifw.uni.hannover.de or by phone at +49 511 762 19763.