Aluminum alloy die-casting infiltration process, applicable scope and defect repair boundary
Infiltration is a remedial process for micro hole leakage in castings, but it is not a universal solution. Many overseas customers mistakenly believe that infiltration can replace mold optimization, and Xinfeng Machinery combs the applicable boundaries.
1、 Principles and media of infiltration repair
Infiltration relies on vacuum pressure to infiltrate organic resin into the connected micropores inside the casting, and after solidification, seal the leakage channel. The mainstream impregnating agents are divided into organic resins and inorganic impregnating agents. Organic resins are more widely used and suitable for ADC12 and A356 aluminum alloy die-casting parts. Only effective for * * connected micropores and capillary leakage * *; Large holes, through cracks, and cold insulation cracks cannot be repaired.
2、 Defect types suitable for infiltration
Fine and dispersed shrinkage, tiny pores, X-ray display of single pore diameter 0.1-0.3mm, interconnected leakage parts, high infiltration yield. Motor casings, valve pressure components, and water-cooled heat dissipation casings are high-frequency application categories that are impregnated. The wheels produced by alloy wheel mold are strictly controlled by the host factory for safety components, and many are directly prohibited from infiltration repair.
3、 Defects that cannot be repaired by infiltration
Cold insulation, hot cracking, large-sized shrinkage, slag inclusion, large-area continuous shrinkage, resin cannot penetrate or cracks under stress after solidification. Statistics show that about 34% of overseas customers have misconceptions: continuous shrinkage and looseness caused by mold design defects, hoping for infiltration to save them, but ultimately scrapped them in bulk. Infiltration is a backend remedy and cannot replace mold shrinkage and cooling optimization.
4、 Differences in Infiltration between Die Casting and Low Pressure Castings
ADC12 die-casting parts have many pores, and infiltration is widely used in shell factories; A356 low-pressure wheel hub safety components prioritize pre control solidification and limit infiltration according to the process specifications of the head engine factory. Low pressure casting relies on maintaining pressure and compensating for shrinkage, resulting in fewer defects in an ideal state and a lower infiltration utilization rate than high-pressure die casting. After infiltration, residual chemicals on the surface of the casting need to be cleaned and dried.
5、 Prioritize optimization of the mold end to reduce infiltration dependence
Overflow groove, sequential cooling, and optimized gate position reduce shrinkage from the source, resulting in production costs far lower than batch infiltration. Long term infiltration will increase individual labor hours, chemical costs, quality inspection costs, and there is also a risk of infiltration detachment and leakage recurrence under high temperature conditions. The pores of metal injection mold parts are sintered pores, and the infiltration scheme is completely different. Google's "aluminum die casting impact process" is suitable for quality engineers to search for.
FAQ
Will there be water or air leakage again after infiltration?
Under high temperature alternating working conditions, organic resin aging poses a risk of re leakage.
Can infiltration pass X-ray inspection?
Resin filled pores, the contour of the pores can still be seen on X-ray images, and defects cannot be concealed.
Can infiltration parts still undergo T6 heat treatment?
Organic resins are not resistant to high temperatures, and infiltration must be completed before heat treatment, or high-temperature resistant inorganic infiltration agents must be selected.
4. Is infiltration allowed for wheel hub components?
Most car wheel hub manufacturers do not accept infiltration repair parts.
Will infiltration affect the size of castings?
Micro porous filling, with almost no change in macroscopic dimensions.
6. Should it be polished and cleaned before infiltration?
Oil stains and cutting fluids can hinder resin infiltration and must be cleaned and dried.
What is the general infiltration yield rate?
The yield of fine micropores is 85-95%, and the yield of continuous shrinkage is less than 40%.
Which is cheaper, mold optimization or infiltration?
Stable mass production scenarios, one-time investment in mold optimization, and lower long-term single piece costs.
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