Deep Hole Drilling for Die-Cast Die Cooling Channels

Customer Background

The customer is a die-cast die manufacturer producing large H13 tool steel dies for automotive and industrial aluminum die-casting. Inside every die block runs a network of deep cooling channels whose geometry controls how fast the casting solidifies. Better cooling circuits mean shorter die-cast cycle times, fewer casting defects, and a longer die life — so the cooling holes are a direct lever on the foundry’s profitability.

The Challenge

Cooling channels in die-cast dies are deep, straight, and unforgiving:

Hardened H13 tool steel. Die blocks are heat-treated before final machining. Drilling deep holes in hardened H13 demands torque and rigidity — a flexible machine wanders and the hole drifts.

Deep, straight cooling circuits. Cooling channels run up to 1,600mm into the die and must stay straight so coolant flows without dead zones. A channel that bends or drifts creates a hot spot in the die, which shows up as shrinkage or soldering in every casting it serves.

Surface finish drives heat transfer. The cooling channel wall finish directly affects how fast the die pulls heat and how quickly scale builds up. A target of Ra 1.6µm or better keeps coolant flowing efficiently and resists mineral buildup over the die’s life.

Channels must navigate the die’s internals. Cooling circuits thread around core pins, slides, and inserts, and every intersection must align precisely to maintain uninterrupted coolant flow. A misplaced intersection surfaces as a hot spot in the castings, not a cosmetic defect.

Positional accuracy across a large, heavy die. Die blocks can weigh 8-12 tons. Every cooling hole must land at a precise depth relative to the die’s parting line and cavity surface, and that accuracy must hold across the whole 2200 × 1400mm block.

Cooling is a cost lever, not a detail. The foundry’s cycle time is set by how fast the die pulls heat. Deeper, straighter, better-placed cooling channels shorten solidification time — meaning the drilling machine pays for itself in cycle-time gains at the casting cell.

Mixed hole sizes on one die. A single die needs thin Ø6mm channels near the cavity and larger Ø25-40mm main coolant passages — the machine must cover the range without tooling overkill.

The Solution

RuidCNC supplied a Three Axis CNC Deep Hole Drilling Machine (RD2012-16H) configured for die-cast die cooling circuit production:

• Ø3-50mm drilling, 1,600mm depth — covers thin cavity channels and large main passages
• 157 N·m spindle torque with 15/18.5 kW — drills hardened H13 without wander
• 2200 × 1400mm worktable, 15-ton capacity — large die blocks held in a single setup
• 3-10 MPa through-spindle coolant at 110 L/min — reliable chip evacuation from deep holes in hard steel
• Cast iron base with FEA-optimized ribbing — rigid, vibration-damped structure for straight holes
• Syntec 21MA-E CNC — programmable cooling-circuit patterns across the die block

Key Machine Specifications

Parameter	Specification
Drilling diameter range	Ø3 – Ø50 mm (up to Ø60 special)
Max drilling depth	1,600 mm
X / Y axis travel	2,000 / 1,200 mm
Worktable	2200 × 1400 mm
Max load capacity	15 tons
Spindle max speed	6,000 rpm
Spindle max output torque	157 N·m
Coolant pressure	3 – 10 MPa

Results

Metric	Previous Process	3-Axis RD2012-16H	Improvement
Cooling channel straightness	0.3 mm/m	0.08 mm/m	73% better
Cooling channel surface finish (Ra)	2.5 µm	1.2 µm	52% better
Die-cast cycle time per casting	62 seconds	48 seconds	23% reduction
Setups per die block	2–3	1	Eliminated
Continuous channel depth drilled	800 mm	1,600 mm	2× deeper
Rework on cooling circuits	4%	0.7%	83% reduction
Tool life (holes per drill)	40	75	88% improvement
Die life	Baseline	+30%	30% longer

Process Validation

The process was validated through:

• Cooling circuit position and straightness measurement on a CMM
• Cooling channel surface finish measurement along the bore
• Flow-rate testing of completed cooling circuits
• Die-cast trial cycles to confirm thermal performance and cycle-time reduction
• First-article dimensional inspection of drilled dies against the drawing

Conclusion

The 3-Axis CNC Deep Hole Drilling Machine turns die-cast die cooling from a deep-hole challenge into a competitive lever. With the torque and rigidity to drill hardened H13, the reach to machine cooling circuits to 1,600mm, and the table capacity to hold large dies in one setup, the customer improved cooling channel straightness by 73%, cut die-cast cycle time by 23%, improved channel surface finish by 52%, and extended die life by 30%. For die shops whose customers buy casting cycle time, the RD2012-16H is a direct investment in foundry throughput.

Figures are representative of typical applications.