Sheet Bulk Forming of Thin-Walled Components with External Gearing through Upsetting Using Controllable Deformation Zone Method

Sheet-bulk metal forming (SBMF) is a promising process for manufacturing complex sheet components with functional elements. In this study, the entire forming process for a typical thin-walled component with external gearing is investigated, including sheet forming and bulk forming processes. Deep drawn cups are prepared during sheet forming; subsequently, upsetting is performed on the sidewall to form external gearing. The upsetting method performed is known as upsetting with a controllable deformation zone (U-CDZ). Compared with the conventional upsetting method, a floating counter punch with a counter force is used in the U-CDZ method such that the forming mechanism is changed into the accumulation of the deformation zone instead of deformation throughout the entire sidewall. The effects of the counter force and material flow are investigated to understand the mechanism. The forming quality, i.e., the formfilling and effective strain distribution, improved, whereas a high forming load is avoided. In addition, a punch with a lock bead is used to prevent folding at the inner corner during the experiment.

Flow-induced Folding in Multi-scaled Bulk Forming of Flanged Parts and its Prediction and Avoidance

The quality of manufactured parts and the efficiency of forming processes are crucial in deformation-based manufacturing. In product miniaturization and micro-manufacturing, size effect induces many unknowns. Flow-induced folding related to size effect is one of them and has not yet been fully studied. In this research, the formation mechanism of folding defects in axisymmetric bulk forming was investigated, and a design-based method was employed to evaluate different tooling and process route designs for making a case-study multi-flanged part with three features and to explore the design-based avoidance of folding defects. In addition, a design evaluating framework of folding-free bulk forming was proposed, implemented and validated. Via analysis of the material flow, energy consumption, folding formation, and product precision of the four proposed forming processes for the case-study part, an upsetting-extrusion forming method via using a nested punch was found to be the most desirable. It was then implemented in the physical forming with three size scales. The results revealed that the flow-induced folding in the macropart was severe and regularly circuitous, but it is slight and irregular in meso and microscale. These findings are useful in the defect-free forming of multi-flanged structures and multi-scaled axisymmetric parts

MODERN PRINCIPLES OF TREATMENT OF VESICOURETERAL REFLUX IN CHILDREN

The article presents data on the tactics and methods of treatment of patients with vesicoureteral reflux (VUR). The article examines the most frequently used methods of treatment of VUR in children (surgical antireflux operations, neoimplantation of the ureter, endoscopic correction, methods of introducing bulk-forming substances) in detail, and analyzes the advantages and disadvantages of the described treatment methods.

DEVELOPMENT AND EVALUATION OF A NOVEL TIME AND PH-DEPENDENT COLON TARGETED DRUG DELIVERY OF ORNIDAZOLE

Objective: The anti-amoebic drug Ornidazole was developed in this study as a novel colon-specific drug delivery method for the treatment of colonic diseases such as diverticulitis, inflammatory bowel syndrome, and Crohn’s disease. Pectin forms a matrix with a pH-sensitive polymeric coating that prevents drug release in the upper gastrointestinal tract, thereby addressing solubility issues. Pectin is sometimes used as an adsorbent, bulk-forming agent. Methods: Ornidazole-containing core tablets were directly compressed. Ornidazole compression coated tablets were formulated with varying polymer proportions in the coat. All the tablets were studied for weight uniformity, hardness, friability, drug content, and in vitro dissolution tests Results: All formulations demonstrated good Fourier-transform infrared compliance and no interaction between drug, polymer, and other excipients. The study’s findings show that the formulation F6 coated with Eudragit RS 100 had a drug release of 99.230.8 for 24 h. Conclusion: As a result, (F6) is regarded as the optimal formulation. The pH in the colon causes the release of Ornidazole from tablets.

Strategies for residual stress adjustment in bulk metal forming

The family of bulk forming technologies comprises processes characterised by a complex three-dimensional stress and strain state. Besides shape and material properties, also residual stresses are modified during a bulk metal forming process. The state of residual stresses affects important properties, like fatigue behaviour and corrosion resistance. An adjustment of the residual stresses is possible through subsequent process steps such as heat treatments or mechanical surface modification technologies, like shot peening and deep rolling. However, these additional manufacturing steps involve supplementary costs, longer manufacturing times and harmful effects on the product quality. Therefore, an optimized strategy consists in a targeted introduction of residual stresses during the forming processes. To enable this approach, a fundamental understanding of the underlying mechanisms of residual stress generation in dependence of the forming parameters is necessary. The current state of the art is reviewed in this paper. Strategies for the manipulation of the residual stresses in different bulk forming processes are classified according to the underlying principles of process modification.

An alternative method of teaching the mechanics of bulk metal forming to undergraduates: Newtonian and Lagrangian approaches

An alternative method of teaching the mechanics of bulk metal forming to undergraduate students is presented. This method has been practiced by us at the University of Florida, Gainesville, FL, USA, and at Mahindra University, Hyderabad, India. Certain key factors differentiate it from the procedures employed in standard textbooks. The relevant fundamental background is laid, emphasizing the materials science and solid mechanics aspects that govern the analysis of all bulk metal forming operations. In this unique approach, we avoid usage of empirical expressions completely and analyse processes from first principles. At the same time, we refrain from rigorous mathematical descriptions which may distract the undergraduate engineering student. Using both the energy balance (Lagrangian) and the force balance (Newtonian) methods, we analyse representative bulk forming processes. An illustrative example enables students to appreciate the comparative orders of magnitude of specific forces encountered in different processes. We present tested methods that helped students to appreciate the ease with which a large number of seemingly unrelated processes can be understood and analyzed. We have used this presentation as the standalone lecture material while teaching the topic. It has helped students to avoid the burden of using multiple reference textbooks to gain an understanding of the mechanics of bulk forming processes.