Simple evaluation of the limit to which a sheet may be
drawn was performed by drawing a cup from a circular
blank. The apparatus consisted of a pair of annular
platens and a punch, all concentric to each other, Fig. 4.
The platens were made of 20 mm thick aluminium
plates and internally heated by 500 W coiled elements—
they were thermally isolated from the loading frame. A
50 mm diameter die was used in all the drawing experiments
with a die shoulder radius of 10 mm. The details
of the test rig with a complete set of drawings may be
found in reference [16]. The entire rig was mounted on
an Instron testing machine (Model no. 1186) to carry
out the deep drawing tests.