The self-made low frequency vibration injection-molding device was adopted to explore relationship between mechanical property and morphology for HDPE injected moldings

and the mechanical properties are bettered and the morphology can be controlled in the low frequency vibration force field．In the research the morphology and mechanical properties produced by conventional injection molding(CIM) were used to compare with which obtained via vibration injection molding(VIM)．As for the vibration injection molding is concerned

the main vibration processing variables are vibration frequency and vibration pressure amplitude and the effect of tensile strength and morphology influenced by different vibration processing conditions．SE micrographs show the transformation of crystal from spherulite to lamellar is noticed

and the shish-kebab stucture and cylindrite structure were obtained in the shear layer via different vibration injection molding conditions．The changes of frequency (0＜f＜2.33 Hz) are beneficial to refine

orientate crystals and enhance the crystallinity in the shear layer from 59.77％ to 64.10％ produced by conventional injection molding and vibration injection molding

respectively

with shish-kebab structure in the shear layer．As a result the over-all mechanical properties are as a function of vibration frequency in vibration injection molding．The increase of vibration pressure amplitude(0＜PA＜59.4 MPa)is favor in promotion of tensile strength of vibration injection molded specimens because of the obviously preferred orientation of crystals with about 2％ increase of crystallinity in both core and shear layers

and the cylindrite crystal structure occurs in the shear layer of vibration injection moldings．On the other hand

the elongation at break becomes small because of growing of the lamella scale in the core of vibration injection-molded specimens．