I have just bought one of those desktop Chinese laser cutter machines. I set it all up expecting to all go smooth (how wrong was I). When I turned the machine on the laser head moves to the left hits the stop switch then moves to the back of the machine, but there does not seem to be a stop switch and when it goes back as far as it will go it just starts making a slight banging noise. If anyone can help me on this then that would be great.