Experimental Study on Ignition Time of Industrial Electronic Detonator Ignition Head under Different Ignition Voltages

In response to the practical engineering problem that the firing capacitor of electronic detonators may lose power after being impacted, which subsequently lead to insufficient firing energy and unreliable detonation, the firing time of metal bridge and bridge-wire ignition heads under different firing voltages were studied through the high-speed schlieren testing system. The influence of the initial energy input to the ignition head on the thermal decomposition stage, flame growth period, and flame duration was clarified, and the relationship between the total ignition time and the ignition voltage and ignition energy for two types ignition heads was obtained. The results show that within the range of 13−21 V, the rate of change of the total firing time of the ignition heads with voltage decreases first and then increases. As the firing voltage increases, the time reduction rates of the thermal decomposition, flame growth period, and flame duration of the metal bridge model ignition heads are 66.2%, 76.6%, and 15.0% respectively. The time reduction rates of the three stages of the bridge-wire ignition heads are 28.0%, 39.2%, and 30.0% respectively, and the firing time of each stage of the metal bridge model ignition head is shorter than that of the bridge-wire. When the ignition energy is between 1.9 and 4.9 mJ, the firing consistency and accuracy of the metal bridge model and bridge-wire ignition head will be affected. When the ignition energy is less than 1.9 mJ, the metal bridge mode ignition heads will fail to fire due to insufficient firing energy. This study provides a basis for the design of the firing margin of electronic detonators, which will reduce the misfire rate of electronic detonators in small-hole blasting.