Abstract
The variation of the principal force parameters associated with polymethylmethacrylate ablation by means of continuous CO₂ laser radiation was subjected to investigation. The complex parameter, defined as the sum of the target weight and the reactive recoil force of the ablation flux, was measured using a force-measuring device with computer registration and a time resolution of 126.5 ms. The experimental data for the initial interval of 0-2 s were approximated by a model function, which enabled the identification of changes in the target weight and recoil force of the ablation flux during irradiation. The energy efficiency of the process in a low thrust jet engine (Cm = 115 μN/W) has been determined for the moment when the ablation rate reaches the stationary regime. This decreases with the laser irradiation time due to the formation of a crater with a concave surface and an increase in the gas pressure in the ablation chamber. It should be noted that the type of the ablation curve and, consequently, the approximating function for the initial stage of ablation are specific to each polymer and laser beam parameter.