In this master's thesis, we examine the influence of cryogenic media flow rates on the thrust force (feed force) and the cutting torque of the drill during the drilling process in titanium alloy Ti6Al4V. A mixture of liquid carbon dioxide (LCO2) + oil and a mixture of LCO2 + molybdenum disulfide (MoS2) is used as a cryogenic medium. The results are compared to dry drilling (reference) and include chip analysis. It has been found that during drilling the supply of LCO2 itself or its increased amount results in increased thrust force (feed force), regardless of which lubricant was added (oil or MoS2). Higher flow rates of LCO2 cause a higher cutting torque when cryogenic drilling with LCO2 + oil, while with LCO2 + MoS2 they cause a lower cutting torque. Furthermore, it was found that higher flow rates of MoS2 cause a higher cutting torque when drilling with LCO2 + MoS2. Analysis of the chips showed that both cryogenic media (mixtures) allow better chip formation and an increment in brittleness of chips, compared to dry drilling.
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