PCB positioning mechanism for exposure machine

The utility model discloses a PCB (Printed Circuit Board) positioning mechanism for an exposure machine, which comprises a support plate, a control arm and a support roller, a double-output-shaft motor is arranged on the surface of the support plate, two groups of worms are arranged on the double-output-shaft motor, two groups of worm gears meshed with the worms are arranged on the surface of the support plate, the control arm is connected to the surfaces of the worm gears, and the support roller is arranged on the control arm. The control arm is arranged in an L shape, the left end of the control arm is movably connected with pushing strips, the supporting roller is installed on the surface of the supporting plate, the surface of the supporting roller is provided with a conveying belt, a PCB is conveyed to the position under an exposure machine through the conveying belt, then the motor controls the two sets of pushing strips to move synchronously, and the pushing strips move from the position above the conv