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Causes, Cleaning Solutions, and Preventive Measures of Water Scale Blockage in Die Casting Molds

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  • Release time: 2026-11-07

Causes, Cleaning Solutions, and Preventive Measures of Water Scale Blockage in Die Casting Molds
Waterway blockage is the hidden culprit of mold cooling failure, local hotspots, and premature cracking due to thermal fatigue. Many factories only discover waterway blockage after the mold is scrapped. Xinfeng Machinery has sorted out the entire solution.
1、 Classification of scale and impurity blockage
The water type mold temperature machine is most prone to producing calcium carbonate scale; The oil type mold temperature machine is composed of oil coke, carbon deposits, and oxidized resin; There are also suspended particles of rust, aluminum shavings, and mold release agent residues. Scale adheres to the inner wall of the waterway, causing a significant decrease in thermal conductivity. Even if the flow rate of the mold temperature machine is normal, the heat dissipation capacity of the mold cavity drops sharply. The waterway of the alloy wheel mold is complex and has many fine circuits, making it even more difficult to clear after blockage.
2、 Blocking early identification signals
The temperature difference between the inlet and outlet of the mold temperature machine continues to increase, the mold cavity experiences long-term high temperatures, there are repeated hot cracks and shrinkage defects at the same location, and the pressure of the mold temperature machine rises. Many technicians think it's a problem with the aluminum liquid or mold, ignoring the blockage of the water circuit.
3、 Online and offline cleaning solutions
Online acid washing: Food grade organic acid circulation cleaning, suitable for mild scale, no need to dismantle molds; Offline disassembly and cleaning: high-pressure water jet, pulse cleaning, suitable for thick scale and oil coke blockage. Strong hydrochloric acid should be used with caution as it can corrode the inner walls of waterways and accelerate rusting. Special sludge cleaning agent is circulated for oil based systems.
4、 Prevention system (more cost-effective in the long run)
The water-based system requires mandatory soft water and filters, with regular water quality testing; Regularly compare waterway flow records and establish a flow ledger. Regularly replace the heat transfer oil in the oil type mold temperature machine, control the upper limit of oil temperature, and reduce oil oxidation and coking. Before delivering the new mold, all waterways should be washed clean to remove any machining iron filings.
5、 Determination of blockage that cannot be unblocked
The waterway is severely scaled in multiple areas, with localized rust penetration and corroded pits on the inner wall. The dredging value is low, and only replacement of inserts or abandonment of renovation is possible. The water circuit load of low pressure casting molds is low, and the probability of scale blockage is lower than that of high-pressure die-casting molds. Google's "die casting mold water line descaling" is aimed at maintenance engineers.
FAQ
How often should the waterway be cleaned?
The soft water working condition of the water type machine is 6-12 months; Hard water needs to be checked every three months.
2. Will acid washing corrode the waterway of the mold?
Organic acids with appropriate concentration and time control have low risk; Strong acids are prone to corrosion.
How much does the decrease in traffic indicate the need for cleaning?
If the initial flow rate of the new mold decreases by more than 20%, it needs to be investigated.
4. Will oil mold temperature machine accumulate scale?
No, the blockage is oil coke and carbon deposits.
Can the waterway of the mold be blown clean with high-pressure air?
It can only blow loose debris and cannot dissolve scale and oil stains.
6. Does blockage only occur in old molds?
Residual iron filings from new mold processing can also cause early clogging of filters and waterways.
Is it easier for the waterway of wheel hub molds to get blocked?
Multiple circuits and narrow channels make it easier to block compared to simple shells.
8. Will waterway blockage directly cause mold cracking?
Localized sustained high temperature, thermal stress amplification, and significantly accelerated crack initiation rate.

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