Introduction With and people's increasing requirements to clothing, the blended spinning is becoming an important factor for enterprise to improve competitiveness and market share, and the main factor that decides the quality of blended fiber is the length of fiber. According to this market requirement and based on client's need, our company researched and developed ASFA311Afiber breaking sett frame with domestic advanced level. This machine adopts gas pressurizing and integrative interlocked control method, the main length of fiber is decided by the center distance of bearing seat through adjusting the pressure and draft ratio in accordance with the customer's requirement. The machine also adopts PLC control. This machine is widely used in stretch-breaking of wool, spun silk, stainless steel fiber and glass reinforced plastic, etc.