18.1 CUPPING TESTS

The Swift cup test is the determination of the limiting drawing ratio for flat-bottom cups. In the Erichsen and Olsen tests, cups are formed by stretching over a hemispherical tool. The flanges are very large so little drawing occurs. The results depend on stretchability rather than drawability. The Olsen test is used in America and the Erichsen in Europe. Figure 18.1 shows the setup.

Figure 18.1: Olsen and Erichsen tests.

The Fukui conical cup test involves both stretching and drawing over a ball. The opening is much larger than the ball so a conical cup is developed. The flanges are allowed to draw in. Figure 18.2 shows the setup. A failed Fukui cup is shown in Figure 18.3.

Figure 18.2: Fukui test.

Figure 18.3: Failed Fukui cup. Courtesy of Institut de Recherches de la Sid rurgie Fran aise.

Figure 18.4 shows comparison of the relative amounts of stretch and draw in these tests.

Figure 18.4: Relative amounts of stretching and drawing in these cupping tests.

18.2 LDH TEST

The cupping tests discussed above are losing favor because of irreproducibility. Hecker ^[*] attributed this to insufficient size of the penetrator, inability to prevent inadvertent drawing in of the flange, and inconsistent...