Three-Axis CNC Deep Hole Drilling Delivers Precision Cooling Channels for Large Injection Molds

Customer Background

The customer is a specialized mold manufacturer producing large injection molds for automotive interior components — instrument panels, door trim, and center consoles. Their molds require extensive cooling channel networks to achieve uniform mold surface temperature and minimize cycle time.

The Challenge

Cooling channel drilling for large injection molds presents several critical challenges:

Deep, small-diameter holes. Cooling channels typically range from Ø6mm to Ø10mm in diameter with depths exceeding 800mm. Achieving straight, consistent holes at these aspect ratios requires specialized gun drilling equipment.

Hardened mold steel. Mold plates are typically P20 or H13 tool steel, often pre-hardened to 30–38 HRC. This material is tough on tooling and requires rigid machine construction and appropriate speeds and feeds.

Surface finish requirements. Cooling channel surface finish directly affects heat transfer efficiency and resistance to scale buildup. A target of Ra 1.6µm or better is essential for optimal mold performance and longevity.

Complex channel layouts. Modern mold designs call for cooling channels that navigate around ejector pins, slides, lifters, and core inserts. Hole intersections must align precisely to maintain uninterrupted coolant flow.

Hole straightness. Channel deviation can lead to thin mold walls (risk of water breakout) or interference with other mold components. Straightness within 0.05mm per 100mm of depth is typically required.

The Solution

RuidCNC supplied the RD1612-16H Three Axis CNC Deep Hole Drilling Machine configured for mold cooling channel production:

• Rigid machine base — Heavy-duty cast iron construction with reinforced column for vibration-free drilling in hardened steel
• High-precision linear guides — Class C3 ground ball screws and precision linear guides for accurate positioning and smooth feed
• High-pressure through-spindle coolant — 80 bar coolant system with 40µm filtration ensures chip evacuation from deep cooling holes
• Programmable pecking cycles — CNC control with customizable peck drilling cycles for optimal chip control and tool life
• Automatic depth control — Precision depth stop with 0.01mm resolution for consistent channel depth across multiple plates

Key Machine Specifications

Parameter	Specification
Drilling diameter	Ø3 – Ø25 mm
Max drilling depth	1,600 mm
Spindle speed	0 – 8,000 rpm
Table load capacity	5,000 kg
Positioning accuracy	±0.01 mm
Coolant pressure	Up to 80 bar
Surface finish	Ra 0.8 – 1.6 µm

Results

After commissioning and operator training, the RD1612-16H delivered:

Metric	Previous Machine	RD1612-16H	Improvement
Drilling depth per pass	300 mm (peck)	800 mm (continuous)	2.7× deeper
Cycle time per hole (Ø8mm × 600mm)	4.5 minutes	2.2 minutes	51% faster
Surface finish (Ra)	2.5 µm	1.2 µm	52% better
Hole straightness	0.12mm/100mm	0.04mm/100mm	67% improvement
Tool life (holes per drill)	40	75	88% improvement
Scrap from deviated holes	3.5%	0.5%	86% reduction

Customer Feedback

“The RD1612-16H has completely changed our approach to mold cooling channel design. We can now specify deeper, straighter channels with tighter spacing — resulting in more uniform mold temperatures and faster cycle times for our customers. The machine paid for itself within 8 months through reduced scrap alone.”

Conclusion

The RD1612-16H three-axis CNC deep hole drilling machine provides mold makers with the precision, depth capability, and surface quality required for modern cooling channel applications. By combining rigid construction with advanced coolant and control systems, RuidCNC delivered a solution that significantly improved both cooling channel quality and drilling productivity.