Punching processes are widely used for producing automobile parts, mechanical components, and other parts. To produce highly accurate parts, it is important to estimate the ratio of the sheared surface to the cut surface. Many researchers have applied the finite-element method (FEM) to analyze the ratio of the sheared surface to the fracture surface on cut surfaces by using ductile fracture criteria. However, it is difficult to determine the fracture criteria on the cut surface by tensile tests or bending tests because the punching process involves many complicated steps. In this study, FEM was applied to the punching process to determine the values of critical fracture criteria (C) by using the ductile fracture criteria proposed by Cockcroft and Latham, Oyane, and Ayada. The ductile fracture criteria were compared with the boundary between the shear surface and the fracture surfaces using experiments performed with a simple punching system. The values of the ductile fracture criteria for the fracture initiation of the formed cut surface were predicted under various clearances between the punch and the die with various punch diameters. The influence of stress triaxiality and the effect of punch diameter on the sheared surface length are also discussed.

The correct choice of process parameters is important in predicting the cut surface and obtaining a fully-fine sheared surface in the fine blanking process. The researchers used the value of the critical fracture criterion obtained by long duration experiments to predict the conditions of cut surfaces in the fine blanking process. In this study, the clearance-dependent critical ductile fracture criteria obtained by the Cockcroft-Latham and Oyane criteria were used to reduce the time and cost of experiments to obtain the value of the critical fracture criterion. The Finite Element Method (FEM) was applied to fine blanking processes to study the influences of process parameters such as the initial compression, the punch and die corner radii and the shape and size of the V-ring indenter on the length of the sheared surface. The effects of stress triaxiality and punch diameters on the cut surface produced by the fine blanking process are also discussed. The verified process parameters and tool geometry for obtaining a fully-fine sheared SPCC surface are described. The results showed that the accurate and stable prediction of ductile fracture initiation can be achieved using the Oyane criterion.

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Deep drawing is a metal forming process that involves complex metal flow and widely used in various manufacturing. The process parameters such as punch corner radius and die corner radius affect the product quality. The punch velocity is also important to obtain the desired product shape. However, it is rare to observe the combination of process parameters effects such as punch and di corner radii and punch speed. In this study, the influences of punch corner radius, die corner radius, and punch speed on deep drawn formability and defect formation are analysed. Taguchi Method is applied to build the design of simulations, and the axisymmetric model is used to simulate with Finite Element Analysis-based ABAQUS software. The results showed that the punch corner radius and die corner radius mainly affect stress and strain distribution and the punch velocity affect the formability of the product and the production time.

The tail-shaft is one of the components of the apron feeder on the conveyor. Its role is quite significant, as it includes a take-up system to adjust the tension and slackness of the chain on the sprocket against the Lamella. Based on observations in a mining industry, it was found that tail-shaft damage frequently occurs, likely due to the excess load carried by the conveyor. Therefore, researchers were interested in investigating the maximum capacity of the tail-shaft. The research was conducted using the Finite Element Analysis method with Solidworks Research License. The material used for the tail-shaft is DIN 1.0038. Torque variations tested on the tail-shaft were from 42,000 N.m to 58,000 N.m. Based on the simulation results, the maximum torque that the tail-shaft can withstand is 54,000 N.m with a safety factor value greater than 1, whereas when given a torque of 58,000 N.m, the safety factor value is less than 1. The tail-shaft experiences a maximum stress that exceeds the yield strength of DIN 1.0038 material, which can cause damage to the material. The initial damage appears at the end of the shaft due to the use of chamfer. This is known based on the results of simulations that have been conducted.