Abstract: An elastic dynamic model for doubletoggle clamping unit on a highspeed precision plastics molding machine was derived, by modality analysis principium, which was used in detailed study of KED/KES. The vibration acceleration signal of the toggle was measured. Through LMS，the vibration displacement was obtained by eliminating the trend item, smoothing, and secondary frequent domain integral, and compared it with theoretical value. The model was proved to be reasonable, which provided a basis for the design of toggle mechanisms.

Key words: injection molding machine, doubletoggle clamping unit, real mode superposition method, vibration, frequency domain