Substitutive Press-Bolster and Press-Ram Models for the Virtual Estimation of Stamping-Tool Cambering

Today’s stamping simulations are realized by ignoring the elastic deformation of the press and tooling system through the assumption of a rigid behavior and a perfect press stroke. However, in reality, the press and tool components deform elastically and are one of the major error sources for the final adjustment and blue-spotting of the dies. In order to tackle this issue, a new approach is proposed in this study that substitutes the press stiffness by means of a substitutive model composed of cost-effective shell and beam elements. The substitute model was calibrated using full-scale measurements, in which a 20,000 kN trial press was experimentally characterized by measuring its deformation under static loads. To examine the robustness of the substitute model, a medium-size tool and a large-size tool were simulated together with the substitutive model. To this end, a B-pillar tool was re-machined based on the substitute-model results and a new cambering procedure was proposed and validated throughout the blue-painting procedure. The newly developed substitute model was able to replicate the global stiffness of the press with a high accuracy and affordable calculation time. The implementation of the findings can aid toolmakers in eliminating most of the reworking and home-line trials.

DESIGN OF A COMPUTER-AIDED GEAR MANUFACTURING TOOL – RACK-SHAPED CUTTER

In this work, the calculation of Maag gear shaper cutter parameters is performed for spur gears with helical teeth in three variants – straight-tooth tool with machine offset, helical-tooth tool without machine offset and helical-tooth tool with machine offset. It is therefore a prerequisite that the manufactured involute gearing has helical teeth for each variant. The created CAD program is universal and can be used for construction in other combinations as well. The tool clamping angles on the tool holder, the cutting geometry of the cutter and the characteristic of the gearing are introduced into the calculation. The output of the work will be then calculated individual parameters of the Maag shaping cutter in the tooling system, necessary for its construction. The calculation are performed in program T-Flex CAD and the summary output is graphical 2D/3D representation of the rack-shaped cutter in its base, normal and side planes, always in a different design based on the change of the tool input data and gearing characteristic. The analysis of the tool´s involute profile was solved by vector calculus and matrices and by rotating the tool in the chosen coordinate systems. The specific calculation of the tool parameters will be solved using goniometric functions.

Design of Tooling System and Identifying Crucial Processing Parameters for NFPC Manufacturing in Automotive Applications

The aim of this study was to design a tooling system for manufacturing automotive components using a natural fiber polymer composite (NFPC) material. As a case study, an automotive battery cover was selected and a compression molding tool was designed, keeping in mind the need for the simplicity of the tool and ensuring the low cost of this process. However, since the original part was injection-molded with virgin polypropene, some vital changes made in the part and tool design process were documented as a guideline to show new designers how to approach the design of parts and tools using a natural fiber polymer composite material. Additionally, the challenges faced during the manufacturing of composite parts with the new tool were also documented and solutions to these challenges were suggested for large-scale production. Finally, compressive testing was performed to evaluate the performance of the structure of the designed part and to compare the recycled polymer with NFPC material. Both wood and palm fiber composite material perform better in compression testing compared to the recycled polymer material.

INFLUENCE OF TOOLING SYSTEM ACCURACY ON DYNAMIC CHARACTERISTICS OF MULTI-PURPOSE MACHINE

Рассмотрена характерная для современного машиностроения тенденция по увеличению концентрации технологических операций на многоцелевых станках и интенсификации режимов резания. Приведен анализ станочных парков различных металлообрабатывающих предприятий, который показал преобладание станков фрезерно-расточной группы. Проанализированы причины широкой номенклатуры инструментальной системы станков фрезерно-расточной группы и рассмотрено влияние многообразия инструментальной системы на динамические характеристики многоцелевых станков. Рассмотрен пример характерной для станков фрезерно-расточной группы среднего типоразмера инструментальной системы, которая включает в себя цанговый патрон, цангу и фрезу. Приведены расчеты точности и жесткости для различных вариантов инструментальной системы. С целью подтверждения полученных теоретических расчетов были проведены экспериментальные исследования в условиях реального производства при обработке серийно изготавливаемой детали типа «Корпус» на фрезерном многоцелевом станке модели VMC-600. Результаты обработки экспериментальных данных показали, что точность инструментальной системы значительно влияет на геометрическую точность обработанной детали, виброустойчивость инструментальной системы и ее жесткость. Низкая точность инструментальной системы приводит к значительному отжиму режущего инструмента на рекомендуемых режимах резания, который может превысить величину допуска на обработку, что должно быть учтено на этапе проектирования технологического процесса путем занижения режимов резания The article discusses the characteristic tendency of modern mechanical engineering to increase the concentration of technological operations on multi-purpose machine tools and intensify cutting modes. We give the analysis of machine parks of various metalworking enterprises, which showed the prevalence of milling and boring machines. This article analyzes the reasons for a wide range of tool systems for milling-boring machines and considers the influence of the diversity of the tool system on the dynamic characteristics of multi-purpose machines. We considered an example of a medium-sized tool system typical for milling and boring machines, which includes a collet chuck, a collet and a milling cutter. We give calculations of accuracy and stiffness for various versions of the instrumental system. In order to confirm the obtained theoretical calculations, we carried out experimental studies in real production conditions when processing a serially manufactured part on a VMC-600 multi-purpose milling machine. The results of experimental data processing showed that the accuracy of the tool system significantly affects the geometric accuracy of the machined part, vibration resistance of the tool system and its rigidity. The low accuracy of the tool system leads to a significant squeezing out of the cutting tool at the recommended cutting conditions, which can exceed the machining tolerance, which should be taken into account at the design stage of the technological process by understating the cutting conditions

Additively Manufactured Parametric Universal Clip-System: An Open Source Approach for Aiding Personal Exposure Measurement in the Breathing Zone

Design for additive manufacturing is adopted to help solve problems inherent to attaching active personal sampler systems to workers for monitoring their breathing zone. A novel and parametric 3D printable clip system was designed with an open source Computer-aided design (CAD) system and was additively manufactured. The concept was first tested with a simple clip design, and when it was found to be functional, the ability of the innovative and open source design to be extended to other applications was demonstrated by designing another tooling system. The clip system was tested for mechanical stress test to establish a minimum lifetime of 5000 openings, a cleaning test, and a supply chain test. The designs were also tested three times in field conditions. The design cost and functionalities of the clip system were compared to commercial systems. This study presents an innovative custom-designed clip system that can aid in attaching different tools for personal exposure measurement to a worker’s harness without hindering the operation of the worker. The customizable clip system opens new possibilities for occupational health professionals since the basic design can be altered to hold different kinds of samplers and tools. The solution is shared using an open source methodology.

Flexible system for micro-clinching processes design and analysis

With the development of microprocessors, actuators and structural micro-components, new concepts of micro-electro-mechanical systems/machines are constantly being introduced. One of the consequences of this tendency is seeking for best techniques to connect metal micro-components. Because of tools simplicity, no additional fastening parts and the undisturbed structure of the material, clinching appears to be a promising method for joining in micro-scale. A procedure for the analysis of micro-clinching process is proposed in the paper, and unique, support flexible tooling system designed. This system allows to easily change key parameters of the process. With the use of flexible micro-tooling, a successful micro-clinching of silver sheets of thickness 0.18 mm has been conducted. An effective numerical method - Rapid Numerical Strength Test - for modelling the process of tearing the joints has been presented. Compliance of key phenomena recognized in modelling with experimental results was obtained.