RT Journal Article
SR Electronic
A1 Gondár, Ernest
A1 Schrek, Alexander
A1 Švec, Pavol
T1 Optimization of Overmolding Process of Metal-Plastic Part
JF Manufacturing Technology Journal
YR 2015
VO 15
IS 3
SP 334
OP 339
DO 10.21062/ujep/x.2015/a/1213-2489/MT/15/3/334
UL https://journalmt.com/artkey/mft-201503-0013.php
AB Metal-plastic parts with steel inserts prepared by overmolding technique showed several cracks. Cracks marked as no 1 and 2 were noticed immediately after overmoulding process. Cracks no 3 and 4 were propagated only several days after overmolding, during post crystallization of plastic. The superposition of both high residual stresses at the metal-plastic interface and creation of cold joints in overmolding plastic were the reasons of cracks initiations. Residual stresses at the metal-plastic interface exceeding the yield strength of plastic were confirmed by simulation in Moldflow software. The differences in the melt front temperature above 20 °C were simulated in the critical areas where the cold joints created in the real metal-plastic parts. Cracks no 1, 2 and 3 were eliminated by increasing of plastic thickness in the critical areas. Cracks no 4 were eliminated by decreasing of packing pressure, what also contributed to the elimination of cracks no 3.