How to quickly identify and prevent water blockage in aluminum alloy casting molds

How to quickly identify and prevent water blockage in aluminum alloy casting molds
The blockage of the water circuit in water-cooled LPDC molds is a hidden fault in mass production. The blockage is caused by the deposition of impurities in the cooling water, and the occurrence of defects is delayed.
The flow rate of a single waterway has decreased by more than 20%, resulting in insufficient cooling intensity in the corresponding cavity area, and a gradual increase in loose hot joints and porosity defects.
In the initial stage of blockage, there is no obvious leakage, only a slow decline in yield, which is easily overlooked by on-site process personnel.
The open circulation of cooling water in the factories in the Middle East and Southeast Asia increases the probability of blockage by three times as sediment, scale, and mold release agent residue enter the waterway.
The hardness of the cooling water is higher than 250mg/L. After long-term high-temperature cycling, the rate of scaling on the inner wall is significantly accelerated, and narrow waterways are more prone to blockage.
The sedimentation rate of scale in fine circuits with an inner diameter of less than 8mm is 2.2 times that of coarse circuits with an inner diameter of over 12mm, which needs to be avoided during the design phase.
Xinfeng Machinery reserves a filter joint at the entrance of the mold water circuit for customers to install filters and intercept solid impurities.
Regular flow monitoring is an effective means of predicting blockages, and it is recommended to record the inflow and outflow data of each circuit every 10 days.
Many customers only look at the total water pressure of the inlet, ignoring the flow rate of a single circuit, causing local blockages in the waterway, and the change in total water pressure is not significant.
Chemical acid washing can dissolve scale, but improper acid washing control can corrode the inner wall of the waterway and induce later leakage.
After pickling, a pressure test must be conducted to confirm that there is no pitting or microcracks on the inner wall before resuming production.
The severely blocked waterway cannot be unblocked, so the circuit can only be abandoned and an external cooling structure can be reprocessed, resulting in high mold modification costs.
Google LPDC mold cooling channel blockage is a pain point term for operations and maintenance, aimed at equipment maintenance supervisors in foundries.
This content undertakes the operation and maintenance flow of existing molds, and is linked with the cooling water circuit design article to improve the technical content system.
There is also a risk of blockage in the water cooling circuit of CPC molds, with complex sealing structures and higher difficulty in dismantling and unblocking compared to ordinary LPDC molds.
Suggest softening the cooling water to control the hardness within 100mg/L, significantly reducing the rate of scaling and deposition.
Before long-term storage of the mold, it is necessary to drain the accumulated water in the waterway to prevent static water from forming scale on the inner wall of the pipeline.
The wheel hub mold is divided into independent waterways, and a single circuit blockage will only affect the local cavity. Compared to a series waterway, the risk controllability is stronger.
Once the front section of the series waterway is blocked, the cooling of the entire circuit will fail, and large-scale casting defects will concentrate and erupt.
The water treatment facilities in overseas customer factories are uneven, and many factories in Southeast Asia lack cooling water softening systems.

## FAQ

Q: How much decrease in flow indicates the risk of waterway blockage?
A: The single loop flow rate has decreased by more than 20% and needs to be carefully investigated.
Q: What is the target for controlling the hardness of cooling water?
A: Suggest controlling within 100mg/L to reduce scaling.
Q: What is the inner diameter of a fine waterway that is prone to blockage?
A: Circuits with an inner diameter less than 8mm tend to experience faster scaling and blockage.
Q: How often is the water flow checked?
A: It is recommended to record flow data every 10 days for mass production conditions.
Q: What are the risks of acid washing and dredging?
A: Improper control can corrode the inner wall of the waterway, causing later leakage.
Q: Is there a higher risk of blockage in connected waterways?
A: Yes, a single blockage caused the entire circuit to fail.
Q: Which regions have a high incidence of mold waterway blockage?
A: Open cooling water circulation production lines in the Middle East and Southeast Asia.
Q: What needs to be done to store the water circuit during shutdown?
A: Drain accumulated water and reduce static scale deposition.