Assesment of polymer flowability on laser microstructured metal inserts with profilometric studies
K.Bula 1*, B.Korzeniewski1, P.Brzęk1, W. Woźniak1,
1Institute of Materials Technology, Poznan University of Technology, Poznan, Poland
*Corresponding author karol.bula@put.poznan.pl
To increase micromechanical adhesion between polymer and metal for direct joining realised by overmolding, metal surface structuring is often most expected [1-3]. The purpose of this study was to evaluate the infiltration efficiency of the microstructure of laser-engraved steel by molten polymer material as a function of melt flow length on structured metallic surface. Polymer-metal joints were prepared from austenitic steel (316) and polyamide 6. The surfaces of the metal inserts were microstructured by the engraving with using a low power (60 W) pulsed laser fiber. Four different microstructures were produced on steel plates. The process of injection molding (overmolding) of 316 steel inserts was carried out with the use of preheating their surface with an external infrared radiator, which was moved in the gripper by the additional manipulator (Fig. 1a). A series of bi-material joints were made without heating and with preheating of the inserts surface before the overmolding. Evaluation of the degree of infiltration of grooves on metal inserts as a function of the polymer melt flow distance (150 mm) was carried out on the basis of selected roughness parameters and related to microstructural variants and as in the case of cold and hot insert. A gradually decrease in the value of Ra and Rz [mm] parameters from the gate to the edge was observed in case of cold insert, while in case of preheated inserts no signifficant changes of Ra parameter was seen (Fig. 1b,c). This research was financially supported by the PUT, internal subsidy 0613/SIGR/2403.
References
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