5-Axis Vertical Deep Hole Drilling for Curved Airfoil Cooling Holes

Customer Background

The customer is an aerospace component manufacturer producing curved airfoil components — guide vanes, blade sections, and structural housings — that require cooling and oil-feed holes drilled at compound angles into curved surfaces. The parts are relatively small but geometrically complex, with hole patterns that change angle from one position to the next.

The Challenge

Drilling multi-angle deep holes into curved aerospace components is fundamentally different from drilling flat workpieces:

Curved, free-form surfaces. Each hole must enter the curved airfoil surface at a precise, often compound angle relative to the local surface normal. Because the surface curves, no single drill orientation works for every hole in the pattern.

Fixture-intensive legacy process. Previously, each hole angle required a custom-angle fixture or a time-consuming manual setup with sine plates. A single blade could require 5-7 different fixture configurations, and each fixture change re-introduced positioning error.

Single-clamping process integration. The components also need milling and spot-facing operations around the hole entries. Completing drilling and milling in separate setups accumulated tolerance and doubled handling.

Tool-change flexibility. The mix of small-diameter deep drills, end mills, and spot facers meant frequent manual tool changes between operations — a significant source of downtime.

Repeatability across a batch. With dozens of parts per batch and multiple angled holes per part, any variation in fixture positioning or manual setup multiplied across the production run.

The Solution

RuidCNC supplied a 5-Axis Vertical Type Deep Hole Drilling Machine — a cradle-type machining center integrating deep hole drilling with a 5-axis positioning system:

• 5-axis cradle configuration — A-axis tilting and C-axis rotation work alongside X, Y, Z linear axes, positioning the workpiece at any compound angle in a single clamping
• Single-setup machining — all angled holes plus milling and spot-facing are completed without re-clamping, eliminating fixture-change positioning errors
• 24-position tool magazine — automatic tool changer carries deep hole drills, end mills, and spot facers, switching tools automatically between processes
• Integrated deep hole drilling function — supports gun drilling feed and high-pressure coolant for deep, small-diameter holes in hardened blade materials
• Rigid cradle construction — designed for heavy-duty use, maintaining positional accuracy while the table tilts and rotates under load
• Advanced CNC control — 5-axis simultaneous positioning with precise, repeatable angle programming across the batch

Key Machine Specifications

Parameter	Specification
Axis configuration	5 (X, Y, Z, A, C)
Table type	Cradle-type swivel rotary
Tool magazine	24 positions
Processes supported	Deep hole drilling, milling, spot-facing
Workpiece positioning	Multi-angle, single clamping

Results

Metric	Fixture-Based Process	5-Axis Vertical	Improvement
Fixture setups per part	5–7	1	Eliminated
Total setup time per part	2.8 hours	25 minutes	85% reduction
Cycle time per part (12 holes)	3.5 hours	1.4 hours	60% reduction
Angular positioning error	±0.3° cumulative	±0.05°	83% better
Hole position accuracy	±0.05 mm	±0.015 mm	70% better
Scrap from re-setup errors	4.2%	0.3%	93% reduction

Process Validation

The process was validated through:

• CMM inspection of hole position and angle across a full batch
• Cut-section verification of hole depth and entry quality on sample parts
• Dimensional comparison against the CAD model for all 12 holes per part
• Repeatability study across 30 consecutively machined components

Conclusion

The cradle-type 5-axis vertical deep hole drilling machine removes the fixture bottleneck from curved airfoil production. By positioning the workpiece at any compound angle in a single clamping and integrating drilling, milling, and spot-facing through a 24-position tool magazine, the customer eliminated 5-7 fixture setups per part, cut setup time by 85%, and improved angular accuracy by an order of magnitude. The single-clamping approach also reduced scrap from re-setup errors from 4.2% to 0.3%.

Figures are representative of typical applications.