1, the gas supply pressure is insufficient or excessive pressure and air pressure is not urgent given, can lead to inaccurate feeding, after feeder forbid we should first check the gas source is stable, we must ensure that urgency given air pressure. 2, the air feeder relaxation time adjustment is not good, appear relaxed too late, resulting in material backwards, and the emergence feeding inaccurate. 3, when the distance is longer feed or punch faster air speed adjustment screw feeder is not adjusted well, leading to the feed to keep up with the emergence of errors. 4, raw material thickness exceeding air feeder nominal thickness, resulting in the feeder cylinder does not work. 5, the above reason is not, it may be an air feeder "0" ring wear.