LPDC mold cooling water channel design, including water channel diameter, spacing, distance from the mold cavity, and strong and weak zoning
The cooling water circuit is the core of controlling sequential solidification, stabilizing mold temperature, and improving cycle time. The water circuit layout is uniform ≠ reasonable, and strengthening cooling in the hot section and weak cooling in the gate area are the underlying logic; If the waterway is too close to the mold cavity, it will leak water and crack, and if it is too far away, the temperature control will be ineffective.
1、 Quantitative standards for waterway dimensions, spacing, and wall thickness
The diameter of the conventional cooling hole is between 8 and 12mm; The hot zone of the large mold can be enlarged by 14 to 16mm; Small waterways are prone to scaling and blockage, resulting in insufficient flow.
Safe distance from waterway to cavity surface: 12-20mm; lower limit of 12-15mm for enhanced cooling in the hot zone; The upper limit of the gate area is set at 18-22mm, with weak cooling to ensure late solidification.
Distance between waterway centers: 25-40mm; reduce the dense area of hot nodes to 20-25mm to enhance heat transfer; Increase the spacing in the gate area to reduce cooling.
Priority should be given to R arc transition in waterway turning, and right angle drilling is prohibited. Eddy currents, air blockages, and uneven heat transfer are also prohibited at right angle positions; Mark the entrances and exits of waterways to distinguish between incoming and outgoing water.
The water circuit scheme of Xinfeng Machinery follows gradient cooling: moderate cooling of the thin wall at the far end, strong cooling of the hot section in the middle, and weak cooling of the sprue area, establishing a positive solidification gradient from the casting to the sprue.
2、 Waterway zoning, independent circuits, scale and leakage point inspection
It is necessary to partition independent circuits: gate circuit, main thermal section circuit, and remote thin-walled circuit, with each circuit separately regulated for pressure and water control; Connecting everything in series will result in an increase in remote water temperature and cooling failure.
The water pressure in the waterway is 0.2-0.4MPa, and soft water is recommended for cooling water. Long term use of hard water can lead to scaling and blockage of the waterway, causing the mold temperature to drift slowly.
Waterway pressure test: After the mold processing is completed, press 0.6MPa and hold for 30 minutes without leakage; The insert and slider water circuit are separately tested for pressure.
Water leakage warning: If there are water stains on the parting surface and joint of the mold, priority should be given to checking the water seal plug; Water leakage directly causes local rapid cooling of the mold cavity, with alternating occurrences of cold insulation and aluminum adhesion.
3、 Differences in Waterway Control for Overseas Customers
Southeast Asian mold waterways are simply connected in series, without zoning, with poor cooling gradients, relying on extended pressure maintenance to compensate for looseness.
The North American mold waterway zoning drawings are solidified, and the flow rate and water temperature of each circuit are included in the process control. The waterway pressure test report is accompanied by the tooling documents.
European customers extensively use irregular shaped cooling inserts that conform to the contour of the hot section, ensuring uniform heat transfer, stable beat, and minimal defect fluctuations.
In the high-temperature workshop in the Middle East, the cooling water is matched with a cooling tower to control the inlet water temperature and avoid the high temperature environment offsetting the cooling effect.
4、 Defective chain of poor waterway design
The waterway in the sprue area is too dense and too close to the mold cavity → the sprue is forced to cool and solidify prematurely → the shrinkage channel is cut off, and the hot spot is loose;
Waterway connection without zoning → remote water temperature rises, insufficient cooling → remote suffocation, cold isolation;
The waterway is too close to the mold cavity → the thickness of the mold wall is thin, thermal fatigue cracking occurs, and the waterway leaks water;
Right angle waterway → air blockage and scale buildup, heat transfer failure, mold temperature loss of control.
5、 Long tail traffic layout ideas
Low pressure casting cooling water circuit, conformal cooling, and mold water circuit zoning, aimed at mold designers.
keywords LPDC die cooling channel design、conformal cooling for low pressure casting mold；
Question category: Distance between cooling line and cavity surface LPDC;
Comparison category: Separate Cooling Loop vs Series Cooling Circuit Mold.
Suitable for mold cooling and sequential solidification DFM special pages.
6、 Common misconceptions in the industry
Misconception 1: The more waterways and denser the cooling, the better. The sprue area cannot be strongly cooled, otherwise it will be directly cut off and shrunk.
Misconception 2: Connecting waterways in series saves trouble, as the remote water temperature increases and the cooling gradient becomes completely out of control.
Misconception 3: The closer the waterway is to the mold cavity, the stronger the cooling. If the distance is too close, the mold is prone to thermal fatigue, cracking, and water leakage.
FAQ
Q: What is the diameter of a regular cooling water circuit?
A：φ8–φ12mm。
Q: What is the distance from the waterway to the cavity surface?
A：12–20mm； Gate area 18-22mm.
Q: What is the distance between the centers of waterways?
A：25–40mm， Hot zone 20-25mm.
Q: Water pressure test pressure?
A：0.6MPa， Maintain pressure for 30 minutes.
Q: Cooling strategy for gate area?
A: Weak cold, increase the distance of the waterway.
Q: Recommended cooling water?
A: Soft water to reduce scale blockage.
Q: Requirements for turning waterways?
A: R arc, right angles are prohibited.
Q: Why do we need an independent circuit?
A: Partition temperature control and establish a sequential solidification gradient.
