Ignitor for electronic detonator
An ignitor for an electronic detonator, the ignitor including a microcontroller and a capacitor mounted on a printed circuit board (PCB) and electrically connected to one another, the microcontroller configured to discharge the capacitor in response to an actuation signal received by the microcontroller, a pair of conductive traces extending from the capacitor, a resistive element extending between the conductive traces and configured to radiate heat in response to current flowing therethrough, and a shroud disposed over the resistive element, the shroud containing a pyrotechnic composition that at least partially covers the resistive element.
1. A method of manufacturing an ignitor for an electronic detonator, the method comprising:
mounting a microcontroller and a capacitor on a printed circuit board (PCB) in electrical communication with one another, with a pair of conductive traces extending from the capacitor, the microcontroller configured to discharge the capacitor upon receiving an actuation signal;
connecting the conductive traces to one another with a resistive element adapted to radiate heat in response to current flowing therethrough;
placing a shroud over the resistive element, the shroud disposed within, and separate from, a tubular shell of the electronic detonator, the shroud disposed over the resistive element and having an open end directed away from the PCB; and
filling the shroud with a pyrotechnic composition that at least partially covers the resistive element by disposing a predetermined quantity of the pyrotechnic composition in a liquid or semi-liquid state in the shroud using an automated process.
2. The method of claim 1 , wherein the resistive element is mounted on a peninsular portion of the PCB that extends from a relatively wider main portion of the PCB upon which the microcontroller and the capacitor are mounted, and wherein placing the shroud over the resistive element comprises crimping a first end of the shroud into notches formed in sides of the peninsular portion with a second, open end of the shroud oriented to direct heat radiated by the pyrotechnic composition in a predetermined direction.
3. The method of claim 1 , wherein connecting the conductive traces to one another with the resistive element comprises installing a surface mount resistor on the PCB using a surface mount technology (SMT) process.
4. The method of claim 1 , wherein connecting the conductive traces to one another with the resistive element comprises soldering a bridge wire to the conductive traces.
5. The method of claim 1 , further comprising allowing the pyrotechnic composition to cure or dry into a solid mass that at least partially envelopes the resistive element.