Abstract: In view of the problems of materials and manufacturing cost for a steel harmonic gear, a harmonic reducer was fabricated by engineering thermoplastics instead of traditional steel in this work. The structure and relevant parameters of a plastic flexspline were designed to meet the requirement of the transmission, and the corresponding injection mold was also designed. In such a mold design, a computer aided engineering (CAE) method was adopted to confirm that no stagnation phenomenon appeared in the gating system designed. This design also ensured that the deformation of flexspline inner diameter is less than 0.3 mm in the cooling system so as to meet the requirement of the flexspline.

Key words: harmonic gear, engineering thermoplastics, flexspline structure, injection mold