Precision Titanium CNC Machining — Technical Case Studies

Severe Thin-Wall Resonant Trap — Trochoidal Milling Breakthrough & CMM Verification

Background & Technical Pain Point

Project Overview: Manufacturing a high-stress titanium alloy dynamic housing assembly for a commercial aerospace subsystem. The engineering blueprint specifies the utilization of Grade 5 titanium (Ti-6Al-4V) to sustain violent operating vibrations. The Technical Pain Point: The structural architecture features a complex unbraced thin-wall geometry with a continuous depth of 45 mm and a targeted nominal wall thickness restricted to just 0.60 mm (±0.015 mm). During initial prototyping trials by the client's previous supplier, traditional linear slotting passes induced intense dynamic harmonic resonance (chatter). The severe micro-vibrations led to rapid tool choking, micro-cracking along the material grain boundaries, and an unacceptable wall deformation displacement yielding an out-of-tolerance variance of +0.18 mm, resulting in a 100% scrap rate.

Advanced Manufacturing Strategy & Kinetic Process Breakthroughs

BOZE Process Engineering: To eliminate harmonic displacement and circumvent severe work hardening, the BOZE engineering matrix re-engineered the entire manufacturing workflow. We deployed a high-rigidity 5-Axis Machining Center equipped with a specialized hydraulic anti-vibration fixture setup to stabilize the part base. Kinetic Toolpath Strategy: We transitioned from linear milling to an optimized dynamic high-feed trochoidal milling toolpath. We selected a custom 4-flute sub-micron grain tungsten carbide end mill coated with PVD multi-layer AlTiN, running a strict axial depth of cut (aₚ) of 20 mm combined with an extremely conservative radial engagement (aₑ) limited to exactly 6% of the tool diameter. The cutting velocity (Vc) was locked at 85 m/min with a constant feed per tooth (fz) maintained at 0.08 mm. Simultaneously, a water-soluble synthetic ester coolant was delivered directly into the primary shear zone at a continuous high pressure of 70 bar (1000 psi), instantly flushing the turnings and repressing thermal concentration.

Final Quality Metrology Report & CMM Deviation Analysis

Metrology & Validation: Final dimensional verification was executed inside our climate-controlled metrology lab utilizing a high-precision coordinate measuring machine (CMM) calibrated to an accuracy boundary of 0.0015 mm. Definitive Tolerance Report: The actual measured thin-wall profile demonstrated flawless consistency, holding a continuous nominal thickness of 0.605 mm, representing a maximum deviations variance of a mere +0.005 mm — safely inside the client's stringent ±0.015 mm gating threshold. True positioning alignment relative to the structural datum reference framework achieved a strict boundary of ∅0.02 mm. Microstructural grain examination via digital microscopy confirmed a complete absence of alpha-case contamination, and the final surface finish recorded an ultra-clean roughness rating of Ra ≤ 0.4 µm, fully verifying absolute structural component integrity.

5,000-Piece Grade 23 ELI Bone Screws — Ra ≤ 0.4 µm, Zero-Contamination

Challenge: M3.5 × 14 mm cortical bone screws in Grade 23 Ti-6Al-4V ELI (ASTM F136), thread Ra ≤ 0.4 µm, zero burrs, cleanroom packaging for direct surgical use.

Solution: Swiss-type turning with precision-ground form tools and thread whirling achieved Ra 0.38 µm. Multi-stage ultrasonic cleaning with deionized water and solvent extract verified residues < 10 µg.

Result: 100% dimensional compliance. Ra 0.38-0.42 µm (Cpk 1.67). Delivered ISO Class 5 with full EN 10204 3.1 MTR per heat lot.

UHV Gas Showerhead — 2,400 Micro-Drilled Ø0.3 mm Holes

Challenge: Grade 5 Ti gas showerhead with 2,400 holes at ±0.01 mm positional accuracy, Ra ≤ 0.1 µm ID finish, UHV 10⁻⁹ Torr compatibility.

Solution: Micro-drilling with peck cycles and high-pressure through-tool coolant achieved consistent hole geometry. Post-drilling electropolishing removed micro-burrs and achieved Ra 0.08 µm ID finish.

Result: 100% holes within spec. Position ±0.008 mm. Ra 0.08 µm after electropolishing. Outgassing < 1×10⁻¹¹ Torr·L/s for 3nm fab readiness.