This master’s thesis investigates the feasibility of drilling 35D deep holes in Ti6Al4V titanium alloy using cryogenic cooling based on a mixture of liquid CO₂ and minimal quantity lubrication (MQL). The study was carried out in three phases: feasibility testing, parameter optimization, and a tool durability test. Experiments were conducted using 3 mm gundrills, a vertical CNC machining center, a Kistler force measurement system, and the ArcLub One cryogenic delivery unit. Results demonstrate that liquid CO₂ combined with MQL ensures stable chip evacuation, reduces cutting forces, and significantly decreases tool wear. More than a 300–370 % increase in tool life was achieved compared to conventional machining. The produced holes met IT7–IT8 dimensional tolerances, while surface roughness values were within the N7 quality range. Economic evaluation showed that the investment into a CO₂-based cooling system pays off after approximately 9000 drilled holes. The findings confirm both the technical feasibility and economic viability of CO₂‑assisted cutting for deep drilling titanium alloys.
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