In the production process of heating (glow) plug for diesel engines is a process of compacting magnesium oxide (MgO) with vibrations. The purpose of the assignment is controlling the process for the insurance of quality. With optimised process, we can insure higher density of MgO, which has a positive influence on life expectancy of the plug. The need for control leads to analysis of kinematic of the process. For this reason, we gathered accelerations during the process of compacting. We than transformed the data to frequency domain. We then compared this data to theoretical harmonic oscillation that is supposed to be provided during the process. Results show that real data does not seem to be harmonic, which will make the process of control and optimisation harder.