Predictive 3D roll grinding method for reducing paper quality variations in coating machines

The predominant trend in paper machines is towards an increased running speed. At the same time, the paper produced must have a higher and more even quality. In printing papers the main end-use properties and quality components are runnability, printability, and print quality. These coexistent requirements create new demands for the behaviour of rolls under production conditions. High quality printing paper grades are coated. In blade coating the thickness of the coating film on the paper surface is found to be heavily dependent on the run-out of the backing roll which supports the paper web against the metering blade. The run-out tolerance of backing rolls at running speed has lately been 50 µm and should be substantially reduced in the future. The new tolerances can no longer be met by tightening the traditional roll manufacturing tolerances. A new predictive 3D grinding method has been developed to improve roll behaviour in the paper production environment. It consists of a measuring system, which can verify the rotational and geometry errors of the roll at running speed, and a 3D grinding system, which controls the grinding process according to the information gained by these measurements. In this study, the new method was applied to the backing rolls of a coating station. The experiments were carried out in a paper mill, on a medium-weight coated (MWC) paper production line. The paper was analysed before and after the predictive 3D grinding. The predictive 3D grinding reduced the machine direction (MD) ash variation caused by the backing rolls by an average of 76 %. Ash variation correlates well with coating variation. As a result of a more even coating film, MD gloss variation was reduced by 82 %. Reduced gloss variation improves the print quality of LWC paper. The variation in thickness caused by the backing rolls was reduced by 74 %. More even paper thickness reduces excitations and therefore improves runnability in calendering, winding, and printing. A new paradigm for roll grinding was set. The applications of the technology are not limited to high-speed paper machine rolls; the method can also be applied to different kinds of nips of rolls. The method can compensate for a systematic error causing nip force variation, such as uneven thermal expansion or the uneven flexural stiffness of a roll. The technology can be applied in different industries, such as the steel, plastics, or aluminium industries. With this method, it is also possible to use rolls in applications which have requirements too high to be met by traditional technology.reviewe

Proceedings of the 5th Baltic Mechatronics Symposium - Espoo April 17, 2020

The Baltic Mechatronics Symposium is annual symposium with the objective to provide a forum for young scientists from Baltic countries to exchange knowledge, experience, results and information in large variety of fields in mechatronics. The symposium was organized in co-operation with Taltech and Aalto University. Due to Coronavirus COVID-19 the symposium was organized as a virtual conference. The content of the proceedings1. Monitoring Cleanliness of Public Transportation with Computer Vision2. Device for Bending and Cutting Coaxial Wires for Cryostat in Quantum Computing3. Inertial Measurement Method and Application for Bowling Performance Metrics4. Mechatronics Escape Room5. Hardware-In-the-Loop Test Setup for Tuning Semi-Active Hydraulic Suspension Systems6. Newtonian Telescope Design for Stand-off Laser Induced Breakdown Spectroscopy7. Simulation and Testing of Temperature Behavior in Flat Type Linear Motor Carrier8. Powder Removal Device for Metal Additive Manufacturing9. Self-Leveling Spreader Beam for Adjusting the Orientation of an Overhead Crane Loa

Predictive ability of financial variables in changing economic circumstances

We analyze three key financial variables, the term spread, real stock returns and the real short-term interest rate, and study which economic factors underlie changes in their predictive power for GDP growth in a large set of industrialized countries. Our results show that the enhanced predictive content of financial variables is connected to increased GDP and stock market volatility as well as turning points in business cycles. Periods with a zero lower bound of interest rates appear to reduce the predictive ability of stock markets. Moreover, we find qualified evidence that inflation persistence increases the predictive content of financial variables.fi=vertaisarvioitu|en=peerReviewed

Proceedings of the 4th Baltic Mechatronics Symposium - Tallinn April 25, 2019

The Baltic Mechatronics Symposium is annual symposium with the objective to provide a forum for young scientists from Baltic countries to exchange knowledge, experience, results and information in large variety of fields in mechatronics. The symposium was organized in co-operation with Taltech and Aalto University. The venue of the symposium was Nordic Hotel Forum Tallinn.The symposium was organized parallel to the 12th International DAAAM Baltic Conference and 27th International Baltic Conference BALTMATTRIB 2019. The selected papers are published in Proceedings of Estonian Academy of Sciences indexed in ISI Web of Science. The content of the proceedings: 1. Continuous wet spinning of cellulose nanofibrils 2. Development of motor efficiency test setup for direct driven hydraulic actuator 3. Development of pressure former for continuous nanopaper manufacturing 4. Device for tree volume measurements 5. Effect of external load on rotor vibration 6. Granular jamming based gripper for heavy objects 7. Integrated car camera system for monitoring inner cabin and outer traffic 8. Inverted pendulum controlled with CNC control system 9. Multi-material mixer and extruder for 3D printing 10. Object detection and trajectory planning using a LIDAR for an automated overhead cran