Energy harvesting has an essential role in the development of reliable devices for environmental wireless sensor networks (EWSN) in the Internet of Things (IoT), without considering the need to replace discharged batteries. Thermoelectric energy is a renewable energy source that can be exploited in order to efficiently charge a battery. The paper presents a simulation of an environment monitoring device powered by a thermoelectric generator (TEG) that harvests energy from the temperature difference between air and soil. The simulation represents a mathematical description of an EWSN, which consists of a sensor model powered by a DC/DC boost converter via a TEG and a load, which simulates data transmission, a control algorithm and data collection. The results section provides a detailed description of the harvested energy parameters and properties and their possibilities for use. The harvested energy allows supplying the load with an average power of 129.04 $\mathsf{\mu }$W and maximum power of 752.27 $\mathsf{\mu }$W. The first part of the results section examines the process of temperature differences and the daily amount of harvested energy. The second part of the results section provides a comprehensive analysis of various settings for the EWSN device’s operational period and sleep consumption. The study investigates the device’s number of operational cycles, quantity of energy used, discharge time, failures and overheads.

This article presents the latest research results on the enhancement of robot-based incremental sheet metal forming performance in detail and comprehensively. Since the low robot stiffness leads to deformations of the robot and thus deviations of the final part, the presented contributions aim for increasing the part accuracy. The article demonstrates how an advanced sensor network, analogous to a µGPS, can be established for tracking the tool pose utilizing innovative shadow imaging sensor technology. Static experiments show that a measurement uncertainty below of 50 µm is achievable after the correction of systematic errors. Additional experiments demonstrated the applicability of the sensor network for measuring the tool position on a moving robot. Based on the measurement, a robot position correction will be enabled to achieve a reduction of machine-dependent component tolerances. A further approach to reduce the geometric deviations due to robot deformation is reducing the forming forces in robot-based two-point incremental forming. This is achieved by a modular vibration unit that has been specially developed for this purpose. The introduction of ultrasonic vibrations into the forming process has been shown to reduce the forces in the sheet metal plane by 70%. As a result, the sensor network and the introduction of ultrasonic vibrations provide a robust foundation for the advancement of higher accuracy classes with cost-effective robot technology, which is becoming increasingly crucial in the industry.

This paper provides an overview of the development of a 3D formed and metal-based facade element that combines a custom design and solar thermal functionality. To achieve this, a novel simplified solar thermal collector structure was developed using formed sheet metal half-shells with an integrated channel structure on the inside and a special absorber coating on the outside. The sheet metal half-shells were manufactured by highly innovative incremental sheet forming (ISF), which allows seamless integration into existing facades. As a part of this paper, the initial test results on thermal efficiency and the energy accumulation of the new collector type are presented.

Incremental sheet forming (ISF) is a flexible manufacturing process for sheet metal parts in small to medium quantities. Successive movements of a stylus create the geometry of the sheet metal part. ISF can be performed with or without a counter tool. By using counter tools, the geometry deviation of the formed sheet metal part can be reduced. To achieve the broader application of ISF, counter tools must be cost-effective, fast, and individually producible, even for batch sizes of only one part. In addition to milling, which has been the main method used to date, additive manufacturing (AM) also makes it possible to meet these requirements for flexible counter tool production. To investigate the suitability of AM for the production of counter tools for the ISF and to learn more about the load on the counter tool, a cylindrical counter tool made of polylactic acid (PLA) was produced using the fused filament fabrication (FFF) process. This counter tool was used for the ISF of drawing steel. Based on the force measurement results, a first step towards suitability evaluation of 3D-printed counter tools for ISF was taken, and possibilities, as well as application limits for such counter tools were discussed.

Shearing high-strength steels often leads to a subpar cut quality and excessive stress on the tool components. To enhance the quality of the cut surface, intricate techniques like fine blanking are commonly employed. However, for applications with lower quality requirements, precision shear cutting offers an alternative solution. This research paper introduces a novel approach to directly superimpose radial stress on a workpiece during the precision shear cutting process and showcases for the first time how the application of direct stress superimposition can impact the cut surface by concurrently modifying the shear cutting edge and punch surface. A statistical experimental design is employed to investigate the interrelationships between the parameters and their effects. The results indicate that the overall cut quality, including cylindricity, clean-cut angle, rollover height, and tool stress, defined by punch force and retraction force, is influenced by the superimposed stress. Regarding the clean-cut zone, the statistical significance of direct radially superimposed stress was not observed, except when interacting with sheet thickness and clearance. Additionally, the sheet thickness and cutting gap emerged as significant parameters affecting the overall quality of the cut surface.