Forming of Components with Microgearings from Coil Material—Numerical Modeling of the Process Chain and Experimental Validation

Compared to alternative production methods, cold forming offers technological, economic and ecological potential for the mass production of microgears. Within the current boundaries of the technology, the cold forming of modules m < 0.2 mm is not possible due to size effects, high tool stresses and handling problems. The investigations of this contribution present a novel process chain for the multi-step forming of microgears with a module of m = 0.1 mm. For this purpose, a numerical model of the first two steps of the process chain is set up and confirmed based on experimental forming tests. The results have proven the feasibility of the process chain by a complete forming of the gear teeth.

Development and Implementation of Crater and Flank Tool Wear Model for Hard Turning Simulations

This paper concerns the tool wear in hard turning of AISI 52100 hardened steel by means of PCBN tools. The purposes of this work are the development of a tool wear model and its implementation in a FEM-based procedure for predicting crater and flank wear progression during machining operations for studying the influence of tool wear on the process in terms of tool geometry modifications and stress variation on the tool. Deform 2D FEM software has been utilized to simulate the orthogonal cutting process and the tool wear model has been implemented into the software by means of a dedicated subroutine able to estimate the wear rate and to update the geometry of the worn tool. Previous performed research showed the employment of analytical models for the evaluation of crater wear of flank wear separately, and FEM models only for the crater depth evolution without pointing their attention on the behavior of flank width. A new analytical model, concerning both crater and flank wear, has been proposed and validated by the authors. The validation of the model has been achieved by the comparison between experimental and simulated wear parameters. For doing this, an extended experimental campaign has been accomplished. The comparison results have shown good agreement. Once validated, the FEM strategy has been utilized for examining the influence of tool wear on the effective rake angle and the related tool stresses, individuating the excessive positive rake angle value as the final tool breakage mechanism.

USING ANSYS WB FOR OPTIMIZING PARAMETERS OF A TOOL FOR ROTARY FRICTION BORING

The authors developed a special design of a rotary friction tool with a self-rotating cup cutter for rotary friction boring of large holes. This paper presents the results of parametric optimization of stressed components of the rotary friction tool by virtual experiments in ANSYS WB. The authors predicted the cutting force components at the worst position of the cup cutter, which was 20 degrees as contact forces in the process of boring a large diameter hole, and built a design model. Using the Johnson-Cook model as the failure criterion for the elements of the mesh, projections of the cutting forces resulting from the hole processing were obtained. The relation between input and output parameters (stresses) is established, optimization criteria are specified, and optimal parameters of the tool stresses components are chosen. It was also found that the averaged values of the force at the initial moment (cutting into the workpiece) change linearly, then becoming practically constant. The idea of parametric optimization consisted in carrying out several virtual experiments, in which the possible range of variation of the basic dimensions was indicated and the optimization criteria were set, the optimal parameters of the tool design were selected from the presented candidates. The optimization method bypasses the design cycle, which is costly and time-consuming due to prototype testing and subsequent refinement.

Finite Element Analysis of Tool Stresses, Temperature and Prediction of Cutting Forces in Turning Process

The paper presents the simulation model of turning the process of C45 non-alloy steel with a tool made of carbide insert. A 3D final element model used a lagrangian incremental type and re-meshing chip separation criterion was experimentally verified by measure cutting forces using piezoelectric dynamometer. In addition, stresses and temperature in the tooltip were predicted and examine. This work could investigate failure the tooltip, which would be great interest to predict wear and damage of cutting tool.

Strahlbearbeitung von Fließpresswerkzeugen*/Abrasive blasting and shot peening of cold forging tools - Integration of abrasive blasting and shot peening in the tool making process

Beim Kaltfließpressen besitzt die Oberflächenbeschaffenheit des Werkzeugs einen ausgeprägten Einfluss auf das Werkzeugeinsatzverhalten. Durch die hohen Werkzeugbeanspruchungen ist in vielen Fällen die Standmenge durch Ermüdungsversagen begrenzt. Vor diesem Hintergrund wurde in diesem Fachbeitrag das Potential der Integration einer abrasiven und verfestigenden Strahlbearbeitung in den Werkzeugherstellungsprozess zur Steigerung der Werkzeugstandmenge untersucht. &nbsp; In cold forging the surface integrity of the tool has a major influence on the tool behavior. Due to the high tool stresses, tool life is often limited by fatigue. In order to enhance tool life, the integration of abrasive blasting and shot peening in the tool making process was investigated in the current study.

Influence of Process Errors on the Tool Load in Microblanking of Thin Metal Foils With Silicon Punches

The trend toward miniaturization of metallic microparts results in the need of high-precision production methods. Major challenges are, for example, downsizing of tools and adequate positioning accuracy within blanking. Starting from a novel approach for tool miniaturization and its realization, the aim of this study is showing the assessment of tool sensitivity against process errors. Etched silicon punches were used for blanking copper foils, where outbreaks occurred at the cutting edge. Hence, tool stresses during blanking were analyzed by finite element (FE) method in dependency of defined positioning and process errors and evaluated concerning tool stresses and sheared edge quality.

Evaluating the Effect of PCD & TialN Coated Carbide End Mill’s Rake Angle on Machinability of Titanium Alloy Ti-6Al-4V

This study evaluates the machinability of titanium alloy, Ti6Al4V in terms of tool-chip interface temperature, cutting forces and tool stresses by varying rake angle of PCD insert and compares the results with TiAlN coated carbide inserted end mill using finite element numerical simulations. It has been found that tool rake angle has significant effect and behaves differently for different evaluation parameters and also shows different behavior for two different cutting material inserts. It reduces cutting forces with every positive angle geometry, about 50% reduction is observed for both cutting tool materials for a change in angle from-7° to 34°, but for tool-chip interface temperature, 15% reduction has been observed when angle is changed from-7° to 15° but it starts rising again when angle is increased to 34° for PCD insert, but for TiAlN coated carbide insert a continuous drop of about 20% has been observed. For tool stresses tool rake angle has different effect. The stresses remains almost unchanged when angle is changed from-7° to 15° but increased by almost 20% when angle is changed to 34° for both insert materials. Results also have shown that PCD insert due to its excellent thermal conductivity and strength at elevated temperatures dissipates most of the heat into the chip and has almost half temperature near the tool edge as compared to TiAlN coated carbide insert and thus can be used for machining of Ti6Al4V alloy at much higher cutting speeds than TiAlN coated carbide insert with positive rake angle geometries (around 15°).