Contour measurement for profile bending

The objectives of the project are the development of online and offline measuring devices suitable for the industrial use to measure the contour of bent profiles and, based on this, the implementation of a controlled three-roll profile bending process. By automating and digitizing the contour measurement, auxiliary process times are to be reduced on the one hand and continuous quality control is to be enabled on the other.


As a kinematic bending process, three-roll profile bending offers the advantage of high flexibility of the producible contours. However, this requires high personnel expenditure for setting up the process and measuring the bent profiles and has so far only allowed a very low degree of automation. The reason for this is the iterative process guidance and the lack of industrial-suited measurement technology to determine the profile contour. The industrial standard provides a manual measurement of the profiles using templates as well as substitutional values such as secant and segment height dimensions. This results in high auxiliary process times and an in part insufficient description of the profile contour.

[01] Mobile measurement device
[01] Function principle


The basis for the realization of a closed-loop process control is the further development of an existing optical measuring system, which enables online recording of all necessary process and product parameters. Also tactile measurement devices (mobile and stationary) are developed to support the machine operators in order to measure the contour of curved profiles. The aim of this approach is to virtually visualize the profile contour and to enable a digital target/actual comparison of the profile contour. Indirect measurement variables, such as the radius progression, as well as direct measurement variables such as secant and segment height dimensions can be determined for controlling the quality of a part and the bending process can be adapted on this basis.

A first prototype of a mobile tactile measuring device (Figure 01) provides promising results (Figure 02).

[02] Manual traversing of the profile (left) measurement results (right)


This project (HA project no. 632/18-55) is funded in the framework of Hessen ModellProjekte, financed with funds of LOEWE – Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz, Förderlinie 3: KMU-Verbundvorhaben (State Offensive for the Development of Scientific and Economic Excellence).