Plastic heat sealing machine control circuit

It uses a monostable delay circuit composed of a 555 time base integrated
circuit to control the energization time of the electric heating piece EH and the curing time of the heat sealing plastic.
    When the bakelite pressure plate on the casing is pressed down, the permanent magnet embedded in the pressure plate
closes to the contact of the reed switch KR installed on the fixed platen, turns on the power of the time base integrated circuit Az, and enters the ready state. Press the micro switch S, Az will work.
    Heating delay time tl. 1(R1+RP)C3. Adjust the potentiometer RP to
change the heating delay time between 0.5 and 12 seconds.