What are the effects of cooling stereotypes on the quality of rolled products?
1 cooling temperature: products in the coiling should be cooled to about 20-25 ℃. If the cooling is insufficient, the film will be sticky, wrinkled and uneven after the roll, the shrinkage is also large; if the cooling too much, the surface of the roller will be too low because of the temperature condensate water, the product will be sticky after the storage period Moldy or blooming, especially during the summer wet season.
2 cooling roller flow channel structure: In order to improve the cooling effect and to control the heat, are generally used to force the cooling method. But the cooling roller inlet side of the roller surface temperature is often lower than the outlet side, so the product at both ends of the cooling degree is different, the shrinkage rate is not the same, the film will be wrinkled and uneven after the film, the hard film will produce unilateral Warping. The solution is to improve the chute structure of the chill roll so that the surface temperature of the chill roll is uniform.
3 cooling roll speed: cooling roll speed is too small, will make the film wrinkle; or too fast, the product appears cold pull phenomenon. Resulting in increased shrinkage, so the operation must be strictly controlled cooling roller speed. Typically, the cooling roll has a linear speed of 20% to 30% faster than the previous ginning roll. For rigid polyvinyl chloride sheets, the traction speed can not be too large, usually about 15% faster than the calendering machine.