Hi Im a total newbie at 3d printing, I got a z605 aurora printer I have printed a few things but after it prints the first layer it rapids across the second layer really fast and doesn't print exactly on the top of the other layer, also I cant get it to print in the middle of the bed, I just trick the limit to move it. any ideas see attached photo, im using 3mm PLA.2014-09-21 08.22.16.jpg2014-09-21 08.22.16.jpg2014-09-21 08.22.16.jpg