The requirements for twist-free roving for winding are as follows:
(1) good banding and flat banding;
(2) good untwisted roving without looping and forming "bird's nest" yarn when it is unwound from the yarn barrel;
(3) uniform tension and no drape;
(4) uniform linear density, generally less than (+) 7%; (3) good soakability of untwisted roving, when it passes through resin groove It is easy to wet and soak the resin.