Four-Spindle Micro Gun Drilling for Cannulated Trauma Screws and Pins

Customer Background

The customer is an orthopedic trauma device manufacturer producing cannulated screws and pins for fracture fixation. These small round components — screw and pin blanks from Ø6mm to Ø40mm — carry a small axial cannulation hole that allows the device to be inserted over a guide wire during surgery. The cannulation is a functional feature: its position and concentricity decide whether the implant tracks correctly into the bone.

The Challenge

Cannulated trauma component production is a high-volume micro-machining application where the failure modes are surgical, not cosmetic:

Concentricity with a thin wall. The cannulation must stay concentric with the blank’s outer diameter. With a thin wall between bore and surface, off-center drilling produces uneven wall thickness — and an uneven-walled screw fails under torsional load in surgery. The screw breaks rather than bends.

Micro cannulation in implant materials. Cannulation bores run Ø1–3mm through stainless and titanium blanks. At these diameters the gun drill is fragile, chip evacuation is constrained, and any feed interruption snaps the tool.

High-pressure chip removal. At Ø1mm, through-tool coolant must carry chips out of a hole barely wider than the drill. Reliable chip evacuation requires coolant pressures far beyond conventional systems.

Volume economics. Trauma screws and pins are produced in very high quantities. Because each cannulation is small and quick, machine throughput — how many parts are drilled simultaneously — is the dominant cost lever.

Round-part handling at volume. Blanks are small round jobs that must be clamped, rotated, and unloaded thousands of times per shift. Manual handling erases the drilling-time savings and damages parts.

The Solution

RuidCNC supplied an RD-S Round Job Multi-Spindles Gun Drilling Machine configured for cannulated trauma component mass production:

• 4 simultaneous electric spindles with auto load/unload — four parts drilled in parallel, multiplying daily output per machine
• Ø1–6mm micro-drilling range to 500mm — covers the cannulation diameters and lengths across the trauma product line
• 200 kg/cm² high-pressure coolant — clears chips from micro-holes reliably, protecting the fragile drill
• Chuck + cone clamp with counter-rotation — secure round-part holding that keeps the bore concentric with the blank’s outer diameter
• Automatic loading/unloading — chuck and cone system supports automated part feed, keeping spindles cutting rather than waiting

Key Machine Specifications

Parameter	Specification
Spindle quantity	4 (electric)
Gun drilling range	Ø1 – Ø6 mm
Max drilling depth	500 mm
Workpiece outer diameter	Ø6 – Ø40 mm (cone)
Spindle max RPM	6,000 rpm
Max coolant pressure	200 kg/cm²
Feeding speed	0 – 2,000 mm/min

Results

Metric	Single-Spindle Process	RD-S (4-Spindle)	Improvement
Parts per shift	1,100	3,300	3× throughput
Cannulation concentricity to OD	±0.035 mm	±0.013 mm	63% better
Wall-thickness variation (Ø15mm screw)	±0.020 mm	±0.008 mm	60% better
Cycle time per part	24 seconds	8 seconds effective	67% reduction
Tool life (parts per drill)	200	360	80% improvement
Scrap rate	2.8%	0.5%	82% reduction

Process Validation

The process was validated through:

• Cannulation position and concentricity measurement across a full production batch
• Wall-thickness uniformity check on cut sections of sample parts
• Torsional and pull-out testing of representative screws
• Tool-life tracking over a full production run

Conclusion

The RD-S four-spindle configuration converts cannulated trauma component production from a per-part bottleneck into a high-throughput process. By drilling four parts simultaneously with 200 kg/cm² coolant for reliable chip evacuation and auto loading to keep spindles cutting, the customer tripled parts per shift while holding cannulation concentricity and wall-thickness uniformity. For orthopedic trauma manufacturers whose screws must track a guide wire and survive torsional load, the RD-S delivers concentric, high-volume cannulation at a lower per-part cost.

Figures are representative of typical applications.