Improvement of deep drawing conditions utilizing LDPE/Gr/MWCNT composite films

The main purpose of this work is reduction of friction coefficient in deep drawing die to improve the deep drawing conditions of St37 blank sheet. For this purpose, graphite (Gr) and multi wall carbon nanotube (MWCNT) were introduced into low density poly(ethylene) (LDPE), and blown composite films were prepared by co-rotating extruder. The composite films (LDPE/Gr, LDPE/MWCNT, and LDPE/Gr/MWCNT) were used as lubricants in deep drawing of St37 blanks. Gr was added in the content of 5, 10, 15, 20 and 25 wt%, and MWCNT was added in content of 0.1, 0.5, 1 and 2 wt%. The effect of filler content on drawing depth, forming force, and thinning of St37 blanks was investigated. The results of experiments indicated that MWCNT was more beneficial than Gr in improving the drawing depth, forming force, and thinning of St37 blanks when Gr and MWCNT were singly combined. Deep drawing tests using LDPE/Gr/MWCNT hybrid composite films revealed that hybrid composite films were more suitable in improvement of deep drawing conditions of St37 blanks. Minimum thinning (8.5%), forming force (49470 N), and maximum drawing depth (13.5 mm) were obtained using LDPE/15 wt% Gr/2 wt% MWCNT hybrid composite film.