Paper Defects In Paper Making Process
Paper defects in paper making process always is a annoying problem, it will influence the paper quality and increase production cost, so how to find out the problem in paper making line by paper defects, and how to solve the problem?
How To Find The Paper Defects?
1. Confirm the paper defects characteristics: such as holes, cracks, spots, streaks and so on.
2. Confirm the paper defects frequency: Continuous occurs is system problems, rollers, pump impellers, etc; Appeared occasionally is the problem of the additives or preparation materials; Sporadic appears is the aggregates fall off; The new problems occuring should check the operating parameters, adding way and adding amount, operational problems, etc; There is a regular interval occuring may be the problem of wire or felt.
1. Air Bubbles: Cause: Too more water in the paper; The coating porosity, not let the moisture to escape; Low z-strength;
2. Calender cuts: Cause: Occurs at the calender or super calender machine. It caused by excess paper that accumulates as a blister at a nip entrance. The cut occurs when the blister passes through the nip.
3. Edge cuts: Cause: Edge tears fold over during the winding operation; A dull or nicked slitter that nicks the edge after which the stress of winding will cause the tear to open up or if the reel is bumped on the edge.
4. Bursts: Cause: Burst web inside the reel is caused by too high web tension between a hard and soft section of the reel during winding, and results in a machine direction shearing force that exceeds the web strength.