- Zhoushan Hongfa Plastic Machinery Co., Ltd is a large professional manufacturer in precision screw, barrel, parallel twin screw, double-hole barrel, bimetal barrel screw, tie bar, twist and steel wire in China. Our company is located in No. 2 Shantan Industrial Zone of Jintang in Dinghai District, Zhoushan, Zhejiang Province, covering an area of 45000 square meters.