X axis stepper misbehaving

[Gerry]

Hello, got a problem with the X-axis stepper. When I start printing everything is fine - the first 8-15 layers are laid out as they should be. But then the stepper suddenly jumps to the right and gets a different x(0) point. The printing continues, but the new layers are laid out a bit off to the right from the print. This keeps happening to both small and big prints. Jumps tend to be both singular and multiple during the whole printing session. When this happens there usually is enough filament and the reel's inertia isn't affecting the motor. The belt tension isn't a problem either as it is sitting quite tight, although it is scraping the inner wall of the printed stepper chassis. Could this be the problem or is something else at play here?

[zhangxueyou]

I think somewhere of the filament is stuck, the x motor can not pull the filament, so x axis jumped.