Stack convyor

I am dealing with a stack convyor
I used this code

lifter.grab(arrivedComponent)
Servo.move(stackPosition,compSize_Z)
Pusher.move(compSize_Z)
Pusher move(0)
Servo.move(stackPosition,0)

The arrivee componenet that i av already attached it to the lifter doesn’t come back with the lifter
Any solution ?