Evaluation of Formability Criteria for Sheet Metal Materials


Civelek F., ÖZDEMİR A.

JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, 2024 (ESCI) identifier

Abstract

Predicting potential failures while manufacturing parts from sheet metal materials or knowing the forming limits of the sheet is extremely important in terms of economic design and manufacturing of molds, product quality, production rate and cost. On the other hand, the Forming Limit Diagram (FLD) is widely preferred to evaluate the deformation ability of sheet metals. One of the important method used to measure the stretch forming ability of sheet materials is the Erichsen cupping test. In this test, the sheet metal clamped between the die and the blank holder is formed with a spherical punch, and the distance taken by the punch until crack formation begins on the sheet surface is defined as the Erichsen Index (EI). In this study, researches related to the effects of the factors arising from material properties and experimental conditions on FLD and EI values were compiled and evaluated. In general, it has been detected that the formability of sheet materials enhances with the increase of the strain hardening exponent (n) and the temperature. In the literature, it was found out that the EI value got larger with the increase in sheet thickness and punch diameter, as well as with lubrication.