In order to study the effect of explosion impact on the damage and ignition time of the ignition head of the electronic detonator, the lead thiocyanate ignition agent was prepared and its microstructure was observed, and the ignition voltage of the ignition head sample dipped in was measured to test its quality. The underwater explosion method was used to impact the sample detonator without basic charge, and the damage of the ignition head was observed by disassembling the impact detonator, and the high-speed schlieren system was used to carry out the ignition test on the ignition head without obvious damage. The results show that the ultimate pressures of the unguarded, heat-shrinkable and silica gel ignition heads were 98.22, 117.12 and 156.27 MPa, respectively. The three types of protection ignition heads were damaged to varying degrees above the ultimate pressure. Under the wall thickness of 0.38 and 0.50 mm, the explosion miss-fire rate of the three types of protective ignition head showed a trend of decreasing with the decrease of impact strength, and the protective effect of silicone type was better than heat shrinkable type, and the effect of non-protective type was the worst. Under 98.22 MPa, the high pressure gas causes the fragments of the ignition head to fly away, resulting in the reduction of the quality of the ignition head used for ignition, the reduction of the intensity of ignition, and finally the obvious shortening of the ignition time. The ignition time of the heat-shrinkable ignition head at 117.12 MPa was increased by 8.30% compared with no impact, which may affect the delay accuracy of the electronic detonator. The ignition time of the silicone ignition head at 156.27 MPa was almost unaffected.

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.