The purpose of pre-shrinking finishing: make the fabric obtain a stable shape. Using a pre-shrinking machine for pre-shrinking can reduce the warp shrinkage of the fabric. Improve the dimensional stability of the fabric during the wearing process and reduce the shrinkage rate. Pre-shrinking mechanism: After the wetted fabric is passed through the tentering device, it is firmly attached to the outer surface of the felt in a loose state. The felt is wrapped on a small-diameter cloth feeding roller, and the outer surface is stretched; Covering the large drying cylinder with reverse curvature, the stretched felt surface shrinks, and the fabric close to it is also forcibly shrinked to play a pre-shrinking effect.