抄録
Injection molding of BMC (Bulk Molding Compound) has more advantages than other molding process. However, the molded parts have the poor mechanical strength, which is the serious defect. This is caused mainly by the fiber breakage in process of mixing and injection of BMC. Therefore, in order to clarify the phenomenon in mixing and to study the influence of mixing operation on the properties of parts, the properties of both injection molding parts and compression molding parts produced with the BMC of various mixing time are examined. Moreover, the situation of the breakage of the glass fiber in BMC is observed. The main results are as follows : 1) There is little difference between the strength of molded parts composed of 3 mm chopped strand and that composed of 13 mm chopped strand. 2) Both the tensile strength and the flexural strength of injection molding parts of BMC increase to the same degree as the compression molding parts with increase of mixing time. 3) This results from both the improvement of interfacial bonding between glass fiber and matrix and the homogenizing of BMC due to the good dispersion of glass fiber into matrix.
