A methodology of roll pass design calculation for rails rolling using regression equations

In process of shaped profiles experimental rolling, it is often necessary to make adjustments to new roll pass design to ensure their physical filling, control between gaps in the values of real broadenings and reductions. In order to reduce number of possible adjustments in roll pass design process and mastering new profiles, the task of developing a model for calculating roll passes becomes actual. A model for calculating roll pass design for rolling railway rails presented. This model based on roll pass design for rolling R65 rails. The regression equations of deformation logarithmic degree were derived using example of two pre-finishing and finishing roll passes, which were used to calculate UIC60E1 rail roll pass design. A high degree of convergence of the geometry of the calculated and operating roll pass has been established. The maximum deviations from geometry of existing roll pass and calculated ones according to proposed method did not exceed 1-2 mm on each of them. It was shown that the developed model calculates exact roll pass geometry, which can be loaded into the program of a processing machine. The proposed calculation methodology can be used at roll pass design of shaped profiles of the same type of different profile sizes of the same mill, resulting in significant reduction of roll pass designed development time and number of adjustments.

Self-Supporting Microchannel Liquid-Cooled Plate for T/R Modules Based on Additive Manufacturing: Study on Its Pass Design, Formation Process and Boiling Heat Transfer Performance

The additive manufacturing technology of laser-based powder bed fusion (L-PBF), which is used to produce boiling heat transfer structures, offers a high processing flexibility and can provide lattice structures with a high surface-to-volume ratio. As an important part of the phased array radar, the plentiful transmit/receive (T/R) modules can generate considerable heat. Targeting this local overheating problem, this study discusses the pass design, the optimal formation process, and boiling heat transfer performance of microchannel liquid-cooled plates based on L-PBF additive manufacturing technology. The optimum design and process parameters were obtained by performing basic channel experiments. On this basis, the design and formation experiments of the microchannel structure were performed, and then the porosity and pore morphology of microchannel liquid-cooled plate samples were analysed. The boiling heat transfer experiments were conducted with deionised water, and the boiling heat transfer characteristics were compared with the saturated boiling curve of a traditional copper-tube liquid-cooled plate. The average wall temperature of the designed samples decreased by 4% compared with that of the traditional liquid-cooled plate under the same heat flow density the value reduced from 111.9 °C to 108.2 °C. Furthermore, within the same optimal boiling temperature range, the average heat flow densities of all the prepared samples increased by >60% compared with those of the traditional liquid-cooled plate the value increased from minimum 16 W∙cm−2 to maximum 34 W∙cm−2. The self-supporting microchannel structure can considerably improve the heat dissipation effect of T/R modules and solve the local overheating problem.

Efficient One-pass Synthesis for Digital Microfluidic Biochips

Digital microfluidics biochips are a promising emerging technology that provides fluidic experimental capabilities on a chip (i.e., following the lab-on-a-chip paradigm). However, the design of such biochips still constitutes a challenging task that is usually tackled by multiple individual design steps, such as binding, scheduling, placement, and routing. Performing these steps consecutively may lead to design gaps and infeasible results. To address these shortcomings, the concept of one-pass design for digital microfluidics biochips has recently been proposed—a holistic approach avoiding the design gaps by considering the whole synthesis process as large. But implementations of this concept available thus far suffer from either high computational effort or costly results. In this article, we present an efficient one-pass solution that is runtime efficient (i.e., rarely needing more than a second to successfully synthesize a design) while, at the same time, producing better results than previously published heuristic approaches. Experimental results confirm the benefits of the proposed solution and allow for realizing really large assays composed of thousands of operations in reasonable runtime.

A computational method for pass design of the four-roll rolling process for sizing of round sections

The four-roll rolling process (4RP) enables the further evolution of sizing processes in rolling mills for round sections. The well-known advantages of the three-roll process over the two-roll process can be further improved using the 4RP. The participation of four rolls in the deformation zone instead of three or two leads to a significant increase in deformation efficiency. The present work shows a pass design method for pass sequences in the four-roll rolling process. Here, three basic types of roll groove geometries are discussed: the flat groove, the non-opened single-radius groove, and a tangentially opened type of a single radius groove. Based on a predefined cross-sectional evolution, grooves are found numerically to satisfy two conditions, i.e., the cross section of the rolled section and the groove filling criterion. The equations of the equivalent pass method, together with a suitable model for lateral spread and the geometric equations of the groove are solved by nonlinear optimization to minimize the sectional and filling errors of a specific pass. Combined for several rolling passes, a complete pass design can be carried out for the reduction of a specified initial section to a final section. The presented results show, how a pass design method for the four-roll rolling process can be constructed. The newly developed model is implemented in a software solution for pass design and analysis of full section rolling mills. An exemplified pass design is discussed to show the possibilities and limitations of the new model.